The optimal volume of resistance exercise to prescribe for trained individuals is unclear. The purpose of this study was to randomly assign resistance trained individuals to 6-weeks of squat exercise, prescribed at 80% of a 1 repetition-maximum (1-RM), using either one, four, or eight sets of repetitions to failure performed twice per week. Participants then performed the same peaking program for 4-weeks. Squat 1-RM, quadriceps muscle activation, and contractile rate of force development (RFD) were measured before, during, and after the training program. 32 resistance-trained male participants completed the 10-week program. Squat 1-RM was significantly increased for all groups after 6 and 10-weeks of training (P < 0.05). The 8-set group was significantly stronger than the 1-set group after 3-weeks of training (7.9% difference, P < 0.05), and remained stronger after 6 and 10-weeks of training (P < 0.05). Peak muscle activation did not change during the study. Early (30, 50 ms) and peak RFD was significantly decreased for all groups after 6 and 10-weeks of training (P < 0.05). Peak isometric force output did not change for any group. The results of this study support resistance exercise prescription in excess of 4-sets (i.e. 8-sets) for faster and greater strength gains as compared to 1-set training. Common neuromuscular changes are attributed to high intensity squats (80% 1-RM) combined with a repetition to failure prescription. This prescription may not be useful for sports application owing to decreased early and peak RFD. Individual responsiveness to 1-set of training should be evaluated in the first 3-weeks of training.

Background

There has been a literally decades old argument going on regarding the optimal volume of strength training (and here I’m primarily focusing on the argument about doing a single set vs. multiple sets) for various goals including strength, hypertrophy and the training of athletes. 

Claims that “One set is just as good as three” or what have you are often made based on a variety of arguments.  Most of those I’m not going to address here since I want to focus primarily on the research into the topic.  I’m also going to be focusing only on the issue of strength since muscular size gains are sort of a different issue.

In general the proponents of single set training are also advocates of training to failure, that is taking each set to the point of momentary muscular failure (where no more repetitions can be performed). I’d mention only in passing that there can actually be different definitions of failure here.  In contrast, those advocating multiple sets often (but not always) work at something less than the point of failure.  Again, not universal but common as it can be difficult to perform lots of sets to the point of actual failure.

I’d also note empirically that almost all successful athletes, strength/power or other have used multiple sets in training which at least lends some empirical weight to the idea that multiple sets are better.  One oft brought up exception is football where there are examples of winning teams that use a single set to failure approach winning championships (an equal if not larger number of teams use multiple set programs). The problem being that football is a very complex sport ruled as much by skill, tactics and strategy as what the athlete does in the weight room. 

A good team will usually beat a strong team although a good and strong team may beat either (or may lose because something tactically or strategically happened on the field).  Football players also have the additional factor of being so beaten up (especially in season) that they can’t do more than a single set of machine training; they are just too wrecked to do more.  In any case, using football success or failure to ‘prove’ the relative merits of one style of training versus another just sort of misses the point in a lot of ways: the strength training program is at most one part of a very complex sport and win/loss ratios don’t prove anything.

So what does the research on the topic say?  Part of the confusion is that it is actually fairly mixed which makes it possible to draw different conclusions depending on how you look at the issue.  Certainly some data does seem to show that a single set is ‘as effective’ as three although there is also research showing multiple sets to be superior.   A lot of this has to do with the difficulty in designing decent training programs, often far more than just the variable of number of sets is changing and this makes interpretation difficult.   

For example, several of the studies ostensibly comparing different numbers of sets were also looking at periodized training models (so not only did one group do multiple sets, they also use a variety of rep ranges) and as often as not it’s 1 repetition maximum (1 RM) that is being tested.  If the periodization group worked into low repetitions (as they usually do) but the single set group did not, that automatically biases the results towards the multiple set/periodized group.  Simply because a 1 RM requires practice and the group performing lower repetitions gets it.  But you can’t conclude much about the volume of training per se from such a study.

In a related vein, some of the studies, for example, will have the single set group train on machines (as many of the ‘one set to failure’ groups advocate machine training) while the multiple set group will train on compound free weight exercises.  Subjects are then often tested on the free weight movements that only the multiple set group performed; specificity alone would predict superior results but the study design is a bit biased towards the free weight group.

Perhaps the biggest issue is the training status of the subjects.  As a generality, most of the research showing that one set is as good as three is done in beginners but plenty of other research shows that beginners pretty much make the same gains almost no matter what they do (a topic I discuss in detail in the Beginning Weight Training series).   And extrapolating from studies done on beginners to trained athletes clearly misses the point due to changes in what is required to stimulate further gains in trained versus untrained individuals.

As a final issue, many trained athletes perform far more than three sets of a given exercise (or at least more than three sets for a given muscle group) and it’s possible that studies comparing one to three sets of training simply aren’t looking at volumes that are different enough to see a real difference in gains.    A study examining far greater differences in number of sets (while hopefully avoiding some of the issues I mentioned above) might help to determine if more sets are or are not better from the standpoint of strength gains.

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The Paper

To address the above issue, the study recruited 43 males who had been performing resistance training at least twice weekly for the past two years (experience was 6.6 +- 1 year) with a minimum back squat of at least 130% of body weight; subjects were excluded if they were listed as taking any performance enhancers.  So these were not total beginners.

The training program was divided into 12 total weeks.  The first two weeks were a break-in/washout period that simple served to standardize their training and eliminate any residual effects from their previous training; back squats were not performed during this two week period. A basic three way split (chest/biceps, back/triceps, legs) routine was performed during this period.

The next 6 weeks were the primary training period and subjects were assigned to either a one, four or eight set squat program and the back squat was the only lower body exercise performed.  During this period, a two way split was used with chest/shoulders and arms trained on one day and legs and back trained on the other.  The volume of all exercises except the squat was identical between groups.

For the squat training, the intensity was set at 80% of 1 their starting 1 RM and all sets were taken to the point of volitional muscular failure.  For the multiple set groups, three minutes were taken between sets and all groups performed the same warm-up (10 body weight squats, 10 reps at 50% 1RM, then singles at 60% and 70% of 1RM) prior to the work sets.  Basically the only variable between all three groups was the number of sets of squats performed and each group ended up having 11 total subjects.

Following the main training block, all participants performed an identical 4 week ‘peaking’ program consisting of low repetition, high-load exercises combined with ballistic exercises.  Squats were performed at 3X4RM for all groups during this period.

The subjects were tested on a variety of things including squat 1RM (which was tested in a fairly standard way with depth taken to a measured knee angle of 90 degrees).  As well, to examine neuromuscular factors in strength, knee extension rate of force development (RFD, effectively how quickly a muscle can generate force) along with maximal isometric quadriceps strength, a variety of EMG measured was also made.  Finally, body fat and body composition was measured via skinfold.  All tests were performed after the washout period, at 3 and 6 weeks and again after the 4 week peaking block.  One thing that is not described is how weights were or were not progressed throughout the study which is an odd ommission.

Finally, to examine individual response, the researchers grouped the results for each squat group into high responders (defined as making >20% strength gains), medium responders (10-19% gains) and low responders (less than 10% gains).  Ill come back to this but each squat volume group had it’s share of high responders (3 in the 1 set group, 5 in the 4 set group and 5 in the 8 set group) as well as low responders (6 in the 1 set group, 5 in the 4 set group and 2 in the 8 set group).

I’ve presented the reults below in terms of average changes in squat strength (in kilograms) among groups.

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* indicates a difference from the post-washout period.  the letter ‘a’ indicates a difference from the single set group.

Note that only the eight set group showed further strength gains after the peaking program.   I think it’s interesting that the eight set group made better gains despite starting out with higher absolute numbers.  Usually it’s the opposite with the group that is less well trained that shows the best results.

In terms of body composition, all three gropus showed minor changes, primarily a small loss of body fat but there was no difference beteween groups.  The 8 set group also saw a significant increase in total body weight possibly suggesting an increase in muscle mass.  In terms of the neuromuscular adaptations measured there were no changes in quadriceps force output or activation although all groups showed a drop in rate of force development.

As I mentioned, one observation was that there were high, medium and low responders in all three groups with average increases in squat strength of 29.4±2.2% for high responders, 14.3±0.9% for medium responders and 2.6±2.0% for low responders.  11 of the 13 total low responders were from the one and four set groups although the design of the study makes it impossible to know if these subjects would have responded differently with more sets.

As well, it’s impossible to know if the 10 high responders in the four and eight set group would have gotten the same results off of one set.  That is, it’s possible that these subjects would have been low and high responders regardless of training volume.  It’s also impossible to know if the three high responders in the one set group would have gotten different results on the higher volume training programs.  The researchers do state:

Nonetheless, that the numbers are so clearly skewed to associate high volumes with responsiveness lends some weight to the argument that regardless of categorical variables, high training volumes are preferred to develop strength.

Of some interest, the researchers point out that the 8 set group was the only group to achieve significant strength gains (compared to the 1-set group) by the three week mark; they conclude that for short-term strength improvement, clearly a higher volume approach is indicated. 

Looking at the neuromuscular adaptations, the researchers suggest that the lack of improvement in force output or activation suggests that trained individuals can already recruit maximal numbers of muscle fibers. They also note that this type of training did decrease explosiveness (as evidenced by decreased RFD), most likely due to the high-intensity nature of the training along with each set being taken to failure.  It’s also possible that testing neuromuscular variables with an isolated leg extension doesn’t show possible neuromuscular adaptations during the squat itself.

A final point made by the researchers is that previous studies of one versus three sets may have been limited in that the training volumes were just too similar, they suggest that subsequent research on training volume use at least four sets for the multi-set group in order to give a more realistic comparison (and potentially show differential results).

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My Comments

I don’t have a tremendous amount to add to the above.  The study, which was far more well controlled than most previously on this topic (in that only a single variable, the number of sets of back squats done), showed that, on average the higher volumes generated higher strength gains.

Certainly there was some individual response (and clearly a single set to failure does generate significant strength gains in at least *some* subjects) but, in the aggregate, more people made better gains with the higher  volumes.  And this was especially true over the shorter periods of time (i.e. only the 8 set group had made significant strength gains by week 3). 

That final point has some clear relevance for athletes in a situation where they may have a limited time per year to make strength gains (usually in the early part of the season) before other training becomes too important for them to be constantly wrecking themselves in the weight room.  An athlete with only 8 weeks to improve strength might be best served by a high volume program to get the maximal results in the shortest period of time before reducing weight room work to lower or maintenance levels.  Even short blocks of ‘top up’ training might be best served by higher volumes for the same reason.

Of course this brings up a potential negative of higher volumes: the time and energy commitment.  Athletes often have a lot on their plate in terms of training and spending endless hours in the weight room (if their sport isn’t already based in the weight room like powerlifting or Olympic lifting) may not be a good use of time depending on how their weight room work impacts on other work.  

An athlete for whom strength is a secondary characteristic (see The Sports, Training and Adaptation Continuums) and for whom lots of weight room work impairs their actual sports training wouldn’t be best served by spending tons of time in the weight room regardless of the potential gains.  Clearly for an athlete for whom maximal strength is absolutely required in their sport, putting in the extra volume would appear to be indicated.  Typically those athletes don’t have as many capacities to develop, mind you, giving them more time to invest in the weight room.

This also brings me to my final point and that is the reality of the time requirements of the high-volume training.  Consider that the eight set group was spending 30 minutes squatting twice per week compared to about 5 minutes for the single set group.    And that’s just for that one exercise.  By the time you add in other exercises at higher volumes, you’re see a large increase in overall training time.  For any given trainee depending on their goals, etc. it may or may not be worth spending that much extra time training for the difference in gains.

That is, a missed point in a lot of the single versus multiple set arguments tends to ignore the time commitment (along with the goals, etc.) of the trainee.  For someone with very limited time and modest training goals (i.e. general trainee looking for basic strength, health, etc.) a low volume of training may give them all the gains that they want or need.  Even if a higher volume would generate greater strength gains, there is always a huge point of diminishing returns in this: you end up spending 4-5 times as long in the gym for far less than 4-5 times the gains.  Whether that time investment is worthwhile simply depends on the situation.

Finally I’d note that the presence of high, medium and low responders in all three groups (again noting more high responders in the higher volume groups and more low responders in the single set groups) does lend at least some weight to the idea of individual response although it’s impossible to know if any of the subjects would have gotten different results on the different programs. But clearly some people get excellent results from low volumes (while others get nothing) and vice versa. 

Many coaches and trainers tend to engage in some projection, often assuming that what works for them will de facto work for anyone that they train.  It may be that some of the one set to failure proponents are the high responders from that type of training, but that doesn’t mean that everyone will be.  And, again, vice versa.  Just because one person gets the most results out of lots of volume doesn’t mean that everyone else will.  

Addressing this within the context of the current study, the researchers state “We recommend that responsiveness to single-set training be evaluated in the early stages (<3-weeks) of a training program, with progression to higher volumes of training in those who are not responsive to lower training volumes.”  Basically, if low volumes are working for someone, that’s great; if not, change it.

Background

A long-held belief that has floated around the world of strength and hypertrophy training is that training legs (for a variety of reasons including hormonal) has a positive effect on either strength or size.  Many, many systems of training are based around that (including Dan John’s Mass Made Simple which I recently reviewed and others).

Previously I examined a paper that looked at this in a confusingly titled Casein Hydrolysate and Anabolic Hormones and Growth – Research Review (this was  a brief period when I was looking at two papers at once, it’s the second paper I reviewed) which, in a somewhat confusing study design found no impact of raising ‘ostensibly anabolic hormones’ (translation: testosterone and growth hormone) on size gains.

They concluded that the small hormonal pulses caused by leg training did not in fact affect growth in the arms.  I talked in some detail about a bunch of other issues related to the topic and I’d refer readers to that review rather than write it all again here.

However, a single paper (I’d note that the same group had done a second paper with identical results) isn’t the case closed answer to things; that’s not how science works.  And when another paper comes along with opposite conclusions, you have to look at all the data to see what’s going on.

Which is a, for me anyhow, fairly short introduction to today’s paper which, as you might imagine, looked at the same topic with (at least somewhat) different results.

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The Paper

Eleven untrained male subjects were recruited, aged 20-34 years, none had performed any strength training in the previous 6 months.  Two subjects did not complete the study which means that only 9 did.  The study lasted a total of 11 weeks and weight training was carried out 4 days/week with the biceps being trained at every workout.

However, each arm was only trained twice/week.  For one of the arms, the biceps exercises were performed after the subjects had performed heavy leg training.  For the other arm, arms only was trained.  Subjects were informed to ‘keep the arms relaxed’ during the leg training although I doubt this happened; folks always hold on for dear life on heavy leg machine work.

This design confused some people (check the comments section) in the previous research review and I want to explain it.  Basically the study was allowing each subject to be his own control.  That is, for all 9 individuals who finished the study, each one trained one arm after heavy leg training and the other arm without heavy leg training. This way any differences in arm size or strength gains could be attributed to the performance (or not) of the leg training rather than just to being differences between individuals.

That is, say we took two people and had one of them train arms after legs and the only one train just arms.  Let’s say that the first guy made better gains. We wouldn’t be able to say if it was due to the leg training per se, or if it was just because he had better gains (maybe the first guy would have made better gains no matter what he did).  The study design used, having each subject be their own control avoids this confound.

The researchers measured both strength gains (for biceps and arms) with 1 repetition maximum (1RM) biceps curl, leg strength was measured as 1 repetition maximum leg press.  Peak power was also measured for the biceps at 30 and 60% of 1RM.  Muscle size changes were measured using magnetic resonance tomography to determine changes in muscle cross sectional area and 9 images were taken with the final 4 being used to determine changes in muscle size (this will make more sense in a second…maybe).

Hormone levels were measured to ensure that changes in testosterone and growth hormone had actually occurred during the leg training which consisted of leg press, leg extension and leg curl. The arm training consisted of warm-ups followed by 2 sets each of biceps curl, hammer curl and reverse curl. The training was marginally periodized and started with 3 sets of 10RM and 8RM with 60-90 seconds rest in weeks 1-5 and was adjusted to 8RM and 6RM for weeks 6-10.   This note will seem out of place but the subjects were told to ‘relax the arms while performing the leg exercises’.

In terms of strength, the leg press strength went up 23%.  For the arm trained alone, the strength gains was from 39.2 to 44.7kg over 11 weeks; for legs plus arms the gain was from 37.5 to 45.3 kg so the relative improvement was greater.  It’s worth mentioning that the legs plus arms ‘arm’ started out weaker meaning they had more room to improve.  But note that the end result was only 1kg difference in maximum strength; sure it’s 20% gain vs. 15% gain but the absolute amount and the end difference is still pretty irrelevant.  Peak power increased in both the arms only and legs+arms group with no difference between them.

But what about size?  Recall from above that the researchers took a bunch of sequential photos of the arm and then looked at the final 4 to look at size differences.  And here’s where it gets confusing.  The researchers found that the size gains for arms only vs. leg+arms were identical for the first 2 measured slices but that the legs+arms group had larger gains in the last two (furthest away) slices.  I know, this doesn’t make any sense, here’s the chart.

That's so weird....

What you can see is that for Section 6 and 7, both groups made identical gains.  For sections 8 and 9 the legs+arm arm made gains and the arms only group did not.  And the results of all of this is colored by the error bars which are almost as large as the difference between groups.  I have no clue about sections 1-5 which were not reported on.

The researchers state that “ANOVA analyses revealed that both groups increased the CSA of the two proximal sections, while only L+A increased the elbow flexors’ CSA at the two middle sections, where the CSA of th elbow flexors was largest.”  Essentially, the belly of the biceps is where the difference was seen.

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My Comments

Ok, so now we have two disagreeing papers, what’s going on?    In the study described in Casein Hydrolysate and Anabolic Hormones and Growth – Research Review, training legs with arms had no impact on size gains.  In this study, there was a difference although an odd one (only part of the arm showed a differential growth) with a very very slight difference gain in strength although this is confounded by the legs+arm group ‘arm’ starting weaker.  Sure they made better relative gains but they also had more room to improve.  And although the legs+arm ‘arm’ ended up a bit stronger, the difference was a stunning 1kg (2.2 lbs) stronger.  Yippee.

First, how do we explain the discrepancy between studies?  I mean other than just dismissing whichever study you don’t agree with.

The researchers suggest that the main difference in results is in the timing of the exercises.  In the first study on the topic, the leg training was done AFTER the arm training while in this paper the leg training was done BEFORE the arm training and perhaps anabolic hormones need to be increased prior to the arm training to have an impact.  This would require further study.  Basically they’d need to repeat the study and have one group do legs + arms with legs first and the other legs+arms with leg training second to see if timing was the difference.

Regarding the rather odd regional difference in growth, the researchers simply state “..the finding of no statistical significant increase in CSA at the part of the elbow flexors with the largest CSA in A was not expected and the reasons remain unknown.”  Science speak for “I dunno.”

Here’s my actual random-assed guess.  Recall from above how subjects were told to ‘keep the arms relaxed’ during the leg training.  Have you ever seen anybody actually do it on heavy leg machine training?  Me neither.  Invariably they hold on to the machine handles with a death grip and I am willing to semi-seriously argue that the legs+arms group got a better direct arm training stimulus from the isometric work.  Please note the phrase ‘semi-seriously’ and don’t get all freaked in the comments on this one.

So what’s the conclusion of all of this?  Honestly, I’m not sure.  The difference in strength gains was minimal and I can’t make any more sense of the size gains, especially the weird differential size gains seen in different ‘parts’ of the biceps, than the researchers did.  Small group size, measurement error, just variability in all of this.  I’m sure at least one person will argue that ‘If they’d squatted like real men, there would have been a difference’ in the comments section.

Maybe a longer study would show more pronounced results.   There’s just no way to tell.   Frankly, given the exceedingly small differences in anything measured I find it hard to use this study to support the long-held idea that training legs has a systemic anabolic effect.

It is interesting to note that the subjects reported generalized fatigue during the arm training following the heavy leg work and this is a practical consideration that people tend to miss I think.  If the goal is increased upper body strength or size, training heavy legs first often takes so much out of the person that the upper body training is compromised.  Sometimes severely.

Anybody who has done the classic 20-rep squat routine can attest this, you’re usually cooked after the squat set which means compromised upper body work.  And if you want to use this study as support for the impact of leg training, you can’t say “Just train legs last” because timing may matter.

As usually I think it comes down to priorities; if your goal is optimal upper body training, tiring yourself out first with heavy leg training would seem to have as many cons as pros.  Even if the hormonal effect is improving overall gains, the impact (at least based on this study’s results) would appear to be tiny at best.

And I realize that I’m finishing up this research review without much of a conclusion.  But this paper has been making the rounds to ‘prove’ the old idea of training legs to improve upper body growth.  Certainly it adds to the body of literature (we now have two studies showing no impact of leg training on arm growth and one study showing a small effect with the difference appearing to be when legs were trained).  But too many guys have gotten huge upper bodies (go to any weight room) without ever training legs for the argument that leg training is required to make much sense.

There is substantial evidence that static stretching may inhibit performance in strength and power activities. However, most of this research has involved stretching routines dissimilar to those practiced by athletes. The purpose of this study was to evaluate whether the decline in performance normally associated with static stretching pervades when the static stretching is conducted prior to a sport specific warm-up. Thirteen netball players completed two experimental warm-up conditions. Day 1 warm-up involved a submaximal run followed by 15 min of static stretching and a netball specific skill warm-up. Day 2 followed the same design; however, the static stretching was replaced with a 15 min dynamic warm-up routine to allow for a direct comparison between the static stretching and dynamic warm-up effects. Participants performed a countermovement vertical jump and 20m sprint after the first warm-up intervention (static or dynamic) and also after the netball specific skill warm-up. The static stretching condition resulted in significantly worse performance than the dynamic warm-up in vertical jump height (-4.2%, 0.40 ES) and 20m sprint time (1.4%, 0.34 ES) (p<0.05). However, no significant differences in either performance variable were evident when the skill-based warm-up was preceded by static stretching or a dynamic warm-up routine. This suggests that the practice of a subsequent high-intensity skill based warm-up restored the differences between the two warm-up interventions. Hence, if static stretching is to be included in the warm-up period, it is recommended that a period of high-intensity sport-specific skills based activity is included prior to the on-court/field performance.

My Comments: As I discussed recently in The Importance of Context, people these days seem to love them some absolutes and there tends to be no shortage of them to go around, especially when it comes to training.  Always do this, never do that, you get the idea.   The situational context is irrelevant, there are simply black and white absolutes that apply across the board.

And a recent never is that you should never ever static stretch before high-intensity training of any sort with endless coaches and gurus repeating that idea.  And certainly this seems to be based on quite a body of research.  A number of studies have shown that extensive static stretching done immediately prior to various types of exercise performance such as vertical jumping, sprinting and weightlifting impair strength and/or power output.

Now, as I mentioned in Warming Up for the Weight Room Part 1, even if static stretching does decrease strength and power outputs, there may still be times to do it before training.  Usually this is in the case of a severe muscular tightness that impairs either technique or safety.  In that context, proper technique and not hurting the person is far outweighed by any decrease in performance.

However, I made another point in that article which was this: many of the studies don’t really reflect how athletes typically go about their training.  That is, anyone who has trained as an athlete or actually coached athletes in the real world knows that it’s fairly rare (especially among strength/power type athletes, endurance guys are often years behind the curve) to go straight from static stretching immediately into high-performance work.  At the very least some type of drills are generally done between the two, usually more than that (e.g. multiple progressive intensity sports specific warm-ups) is done.

There is also an issue of the extent of stretching: many of the negative performance studies have used levels of static stretching that far exceed what most athletes would ever do in practice (again, something anyone who’s actually worked with athletes would know).  That is, it would be rare to hold a stretch for 2-4 minutes in the real world, static stretching of perhaps 30 seconds per muscle group would be far more realistic.  Yet it is generally that type of extremely prolonged static stretching that has been tested and found to impair performance (some studies have shown shorter stretching periods to have a similar negative impact).

Which brings us to today’s study which set to test the above in a more real-world type of situation.

The study examined 13 netball players from the Australian Institute of Sport.  Both groups first performed a sub-maximal run as a general warm-up.  Then one group performed static stretching (9 stretches held for 30 second each) and the other performed a dynamic warm-up consisting of 16 rather common dynamic movements.  Both the static and dynamic warm-ups lasted 15 minutes. After a short-rest, both groups were tested on 20m sprint and vertical jump.  Then both groups performed a netball specific skill warm-up consisting of various short sprints, shuffling, accelerations, direction changes and jumping.  Then the performance tests were performed a second time to see if anything had changed.

And the results?  Well, in keeping with previous work, the static stretching routine did in fact hurt performance on the 20 m sprint and vertical jumping compared to the dynamic warm-up.  However, after performing the specific skills warm-ups described above, results were no different on the second set of performance tests.  That is, any loss of performance due to static stretching was eliminated simply by performing a variety of sport specific skills prior to the maximal effort testing.

Basically, by testing the athletes in a situation that more accurately reflects how athletes actually train, they found that much of the concern over static stretching is unfounded.  As they state in the discussion:

The results suggest that if an inhibitory effect was present after static stretching, that the SKILL component of the warm-up routine was able to dissipate the negative effect.  This supports the suggestion by Young and Behm that practice attempts of the required tests may offset potential negative effects of static stretching.

The also note that their results are in contrast to another study examining both a dynamic performance warm-up and a static-stretching warm-up but in that study, the static stretching was done after the performance warm-up and immediately prior to the testing.  Basically, order of warm-up matters which I also discussed in Warming Up for the Weight Room Part 1.  And so long as it’s followed by some sort of dynamic, skill specific, progressive warm-up (e.g. progressively heavier warm-up sets in the weight room, increasingly faster pickups in sprinting, etc), static stretching appears to not be quite the absolute no-no that many have made it out to be.

Quoting from the researchers conclusions:

The most important findings from this study were that a dynamic warm-up routine is superior to static stretching when preparing for powerful performance; however, these differences can be eliminated if followed by a moderate to high intensity sport specific skill warm-up.

Summing Up: Basically, static stretching is only a problem if it’s done too extensively (e.g. stretches held for very extended periods) and is not followed by appropriate sport-specific warm-ups between the end of static stretching and maximal performance (testing or training).  Which isn’t how real athletes generally train anyhow.  Which is something any performance coach who has actually worked with athletes should know anyhow.

Mercader J. Mozambican grass seed consumption during the middle stone age. Science. (2009) 326(5960):1680-3.

The role of starchy plants in early hominin diets and when the culinary processing of starches began have been difficult to track archaeologically. Seed collecting is conventionally perceived to have been an irrelevant activity among the Pleistocene foragers of southern Africa, on the grounds of both technological difficulty in the processing of grains and the belief that roots, fruits, and nuts, not cereals, were the basis for subsistence for the past 100,000 years and further back in time. A large assemblage of starch granules has been retrieved from the surfaces of Middle Stone Age stone tools from Mozambique, showing that early Homo sapiens relied on grass seeds starting at least 105,000 years ago, including those of sorghum grasses.

My Comments: In recent years, there has been quite an explosion in interest in the supposed diet of our paleolithic ancestors, essentially in an attempt to explain part of why humans are having so much trouble with the modern diet.  So far as I can tell the first paper was written in the Mid-80′s or so but even more recently it’s become quite the fad/cult/area of interest for a lot of people.

Now, while an entire article could be written about this, it’s important to note that nobody knows for sure what we ate during our evolution.  Even researchers in the field (Cordain and Eaton are two of the major ones) have arrived at rather drastically different conclusions about what our diets contained based on their assumptions because it’s all basically a lot of guesswork.  We end up with estimations based on a bunch of assumptions and not much more.

Much of it comes from an analysis of a book called the Ethnographic Atlas, a work done years ago by non-scientists who wrote down (sort-of) what extant non-modernized people were eating.  From that, various researchers, making various assumptions about the relative proportions of animal and vegetable foods in the diet have thrown out some ideas about what our evolutionary diet contained.  Those researchers have often reached utterly differing ideas based on which built-in assumptions they started with.  Other suggestions about our ancestral diet have been made by examining the current intake of extant hunter-gatherer tribes with the implicit assumption that their food intake is representative of our intake during our evolution.

I’d note that it’s unlikely that there was any singular evolutionary diet in the first place.  Humans have shown the ability to adjust to all but the most extreme environments and show an amazing ability to adapt to drastically differing diets as well.  Human ancestors evolving in say Alaska would have had far different foods available than someone living in the arid plains in Africa.  Even examining the extant hunter-gatherer tribes demonstrates this in spades: the diet of an Alaskan Inuit is radically different from say an African Bushman simply due to the difference in environment and what is available to them.  So there is no single ancestral diet in terms of the quantities, proportions or types of food that would have been eaten in the first place.

At best we can probably say with some degree of certainty that our ancestors didn’t have many of the foods available to us today.  That is, Cap’n Crunch, Ben and Jerry’s Ice Cream and Bud Light weren’t part of our evolutionary diet because they didn’t exist (much to the loss of our ancestors).  Beyond that, we can’t say with much certainty what they did eat; it’s mostly guessing because folks weren’t alive to say for sure.  And while it may be safe to assume that extant hunter-gatherer tribes are representative, it’s still an assumption.

Now, while there are many different interpretations to the ‘paleo-diet’ craze, at least one thing that most seem to agree on was that refined grains were absolutely not part of the evolutionary diet.   Bloggers, apparently unclear on the concept of irony, go on constantly about how ‘Paleo man didn’t have grains, so you shouldn’t eat them.’  Apparently that same logic doesn’t apply to the computers they use to blog with, the Internet that they blog on, their Blackberries that they use to Twitter about their blog updates, modern cars that they use to get to work or the houses they live in.  Paleo man didn’t have those either but I don’t see these folks giving those up.  Guess they only want to give up the easy stuff when it’s convenient.  But I digress.

That is, it’s generally assumed that refined grains (being currently blamed for much of modern health problems) weren’t a major part of our diet until the agricultural revolution, about 10,000 years ago.  It’s also assumed that that span of time is insufficient for man to have evolved to deal with them.  I’ll only address this second assumption by pointing readers to a new book called The 10,000 Year Explosion: How Civilization Accelerated Human Evolution wherein the authors make a rather good argument that, contrary to common belief, not only did human evolution continue once humans became civilized, that it accelerated.

Rather, in looking at today’s second paper, I want to address that first assumption: that our evolutionary diet was devoid of any type of refined cereal grain.  I imagine that, if you’ve read this far, you can guess what I’m going to say about it and what the second study concluded.

The researchers were examining cave artifacts in a cave site in Mozambique which have been dated to somewhere between 42000 and 105,000 years ago.   They mention that excavation in 2007 retrieved 555 artifacts.  Of those, 70 stone tools were analyzed and were chosen to represent the broadest range of potential plant uses.  This includes scrapers, grinders, points, flakes and miscellaneous tools.  These were analyzed and while 20% contained no starch residue, the other 80% were found to contain starch granules with the number on each tool ranging from 1 to 650.  It’s worth noting that the quantity of granules found on the scrapers was massively larger than what is found naturally in the cave, that is, they were brought into the cave.

The majority of starch granules (89%) were identified as sorghum, a grass showing a large complex of cultivated, wild and weedy types.  The researchers note that the starch granules found on the tools analyzed are structurally identical to modern sorghum plants.  As the researchers state:

The Mozambican data show that Middle Stone Age groups routinely brought starchy plants to their cave sites and that starch granules go attached to and preserved on stone tools.  I cannot prove that starch from all stone tools represents direct tool function…These early grinders are simply modified cobbles and core tools, with a suspected use that conforms to the technological action of “diffuse resting percussion” and “pounding”, which allows the grinding of plant materials.

Put differently, while more research will certainly be needed to verify or refute this claim, data that is a bit more direct than “Assumptions based on a book some guys wrote years and years ago” suggest that as far back as 100,000 years ago, humans had found a way to refine and consume at least some grains for their diet.  Or as the researchers state more directly in the abstract above:

A large assembly of starch granules has been retrieved from the surfaces of Middle Stone Age tools from Mozambique, showing that early Homo Sapiens relied on grass seeds starting at least 105,000 years ago, including those of sorghum grasses.

And even if you don’t buy the argument of the book I referenced above, that 10,000 years is more than sufficient to allow adaptation to changes in diet, it would be hard to argue that 105,000 years isn’t time enough to adapt to some degree.

With the sheer volume of research appearing on a weekly basis, this will at least help me to look at data in a more timely fashion.  I’d mention that, for anyone who wants an even better look at a lot of studies, you’d be well served to consider Alan Aragon’s monthly Research Review which I reviewed in the confusingly titled Alan Aragon Research Review – Product Review.

In any case, today I want to look at two recent studies which are:

1. Deglaire et al. Hydrolyzed dietary casein as compared with the intact protein reduces postprandial peripheral, but not whole-body, uptake of nitrogen in humans. Am J Clin Nutr. (2009) 90(4):1011-22.
2. West et. al. Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors. J Appl Physiol. 2009 Nov 12.

For each study I’ll give a brief background to the topic, look at what was done and then jump straight to the conclusions with some final summing up.  As noted above, some of the detail will be left out but I figure that anyone who is that interested in the details of methodology and such will simply get ahold of the full paper and read it themselves.

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Deglaire et al.  Hydrolyzed dietary casein as compared with the intact protein reduces postprandial peripheral, but not whole-body, uptake of nitrogen in humans. Am J Clin Nutr. (2009) 90(4):1011-22.

BACKGROUND: Compared with slow proteins, fast proteins are more completely extracted in the splanchnic bed but contribute less to peripheral protein accretion; however, the independent influence of absorption kinetics and the amino acid (AA) pattern of dietary protein on AA anabolism in individual tissues remains unknown. OBJECTIVE: We aimed to compare the postprandial regional utilization of proteins with similar AA profiles but different absorption kinetics by coupling clinical experiments with compartmental modeling. DESIGN: Experimental data pertaining to the intestine, blood, and urine for dietary nitrogen kinetics after a 15N-labeled intact (IC) or hydrolyzed (HC) casein meal were obtained in parallel groups of healthy adults (n = 21) and were analyzed by using a 13-compartment model to predict the cascade of dietary nitrogen absorption and regional metabolism. RESULTS: IC and HC elicited a similar whole-body postprandial retention of dietary nitrogen, but HC was associated with a faster rate of absorption than was IC, resulting in earlier and stronger hyperaminoacidemia and hyperinsulinemia. An enhancement of both catabolic (26%) and anabolic (37%) utilization of dietary nitrogen occurred in the splanchnic bed at the expense of its further peripheral availability, which reached 18% and 11% of ingested nitrogen 8 h after the IC and HC meals, respectively. CONCLUSIONS: The form of delivery of dietary AAs constituted an independent factor of modulation of their postprandial regional metabolism, with a fast supply favoring the splanchnic dietary nitrogen uptake over its peripheral anabolic use. These results question a possible effect of ingestion of protein hydrolysates on tissue nitrogen metabolism and accretion.

My Comments: Ever since the pioneering work in the 90′s on fast and slow proteins, there has been continued interest in the digestion speed of proteins and how that impacts on metabolism, performance and, of course, muscle growth. In recent years, there have been many claims made for the superiority of faster proteins to slower in terms of ‘speeding amino acids to muscle’ in terms of promoting growth.

As well, as many may note, a recent commercial product (T-nations Anaconda), who’s anabolic claims were analyzed in perhaps the most commented article on the site in Alan’s Aragon’s guest article Supplement Marketing on Steroids, has recently been released to the market.

For background, hydrolysates are simply whole proteins that have been pre-digested (through the addition of enzymes during production) to some degree.  The theory being that, due to this pre-digestion, the hydrolysate will be digested in the stomach faster, getting aminos into the bloodstream faster and, presumably, having a better effect on skeletal muscle than slower proteins.

But is it true?  Guess.

The above study examined this issue by feeding 21 subjects 2 test meals containing ~26.5 grams of either intact casein or it’s hydrolysate; the protein had been marked with radioactive nitrogen so that it’s fate after ingestion could be tracked over the next 8 hours.  The test meals also contained 96 grams of carbohydrate and 23 grams of fat; this is worth noting as adding other nutrients to fast proteins often makes them behave more like slow proteins.  I’ll spare you the methodology, sufficed to say that tracking protein after it enters the body is brutally complicated and involves a lot of modelling and various measurements of blood amino acid levels and such.

Here’s what the study found.  Over the time course studied (8 hours after ingestion), the hydrolyzed casein product showed greater losses from digestion (that is, less was absorbed).  As well, a greater amount of the hydrolysate was oxidized for energy through deamination (a process by which the amino group is stripped off the carbon backbone).  Finally, a larger amount of the casein hydrolysate was used by the splanchnic bed (gut and intestines) with significantly less of the total protein reaching the bloodstream or peripheral tissues (muscles).

To quote the researchers:

Despite similar overall net postprandial protein utilization, our results indicate important differences in metabolic partitioning and kinetics between protein sources characterized by a preferential utilization of dietary nitrogen by for splanchnic protein syntheses after HC [hydrolyzed casein] ingestion at the expense of the incorporation into peripheral tissues.

Translating that into English: hydrolyzed casein is digested more poorly, gets burned for energy to a greater degree and gets used more by the gut than intact casein; the end result of this is that hydrolyzed casein provides LESS amino acids to skeletal muscle after ingestion than intact casein protein.

So not only is the claim that hydrolysates are better at providing aminos faster to skeletal muscle wrong, the reality is actually exactly reversed: intact casein is better for providing aminos to the muscle.  I’d note that other studies have found this as well: in one, intact protein provided MORE branched-chain amino acids into the bloodstream than a hydrolyzed form.

I’d add to this that, as I discussed in The Protein Book, other data supports the idea that slower proteins may actually be superior to faster proteins for muscle growth; in one set of studies, for example, milk protein (a mix of slow and fast proteins) resulted in greater hypertophy than soy (a fast protein) over 8 weeks of training and supplementation.  As well hydrolyzed proteins tend to taste like bleach; it’s no coincidence that Anaconda has to come with a separate flavoring intensifier: hydrolysates are gag-inducing.  They can’t be consumed straight.

Summing up: Hydrolysates are not only not superior to intact protein in terms of providing amino acids to skeletal muscle, they are distinctly inferior.  Their fast digestion speed leads to greater digestive losses, more oxidation via deamination and provides less amino acids to skeletal muscle.  That’s on top of tasting like vomit.  Or at least making you want to.

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West et. al. Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors. J Appl Physiol. 2009 Nov 12.

The aim of our study was to determine whether resistance exercise-induced elevations in endogenous hormones enhance muscle strength and hypertrophy with training. Twelve healthy young men (21.8 +/- 1.2 y, BMI = 23.1 +/- 0.6 kg(.)m(-2)) independently trained their elbow flexors for 15 weeks on separate days and under different hormonal milieu. In one training condition, participants performed isolated arm curl exercise designed to maintain basal hormone concentrations (low hormone, LH); in the other training condition, participants performed identical arm exercise to the LH condition followed immediately by a high volume of leg resistance exercise to elicit a large increase in endogenous hormones (High Hormone, HH). There was no elevation in serum growth hormone (GH), insulin-like growth factor (IGF-1) or testosterone after the LH protocol, but significant (P < 0.001) elevations in these hormones immediately and 15 and 30 min after the HH protocol. The hormone responses elicited by each respective exercise protocol late in the training period were similar to the response elicited early in the training period indicating that a divergent post-exercise hormone response was maintained over the training period. Muscle cross-sectional area increased by 12% in LH and 10% in HH (P < 0.001) with no difference between conditions (condition x training interaction, P = 0.25). Similarly, type I (P < 0.01) and type II (P < 0.001) muscle fiber CSA increased with training with no effect of hormone elevation in the HH condition. Strength increased in both arms but the increase was not different between the LH and HH conditions. We conclude that exposure of loaded muscle to acute exercise-induced elevations in endogenous anabolic hormones enhances neither muscle hypertrophy nor strength with resistance training in young men. Key words: testosterone, growth hormone, IGF-1, anabolism.

My Comments: For several decades now, there has been intense focus on the acute hormonal response to training.  This started back in the 80′s where researchers, interested in growth did a rather cursory examination of elite powerlifters and bodybuilders, made some assumptions about muscle size, made some even bigger assumptions about how they trained, and then proceeded to reach some staggeringly poor conclusions.

Basically, what they observed was that bodybuilders were bigger than powerlifters, which is debatable in the first place.  They also observed that powerlifters typically used low reps and long rest periods and bodybuilders (remember: this was the Arnold era) trained with high reps and short rest periods.  Thus they concluded that high reps and short rest stimulated muscle growth and went looking for reasons why this was the case.  I’d note that this is not really how you’re supposed to do science: you don’t reach your conclusion and go find reasons why it’s right.  You test hypotheses and draw your conclusions from that.  But I digress.

And the main focus for a while was potential differences in hormonal response to training, primarily focusing on testosterone and growth hormone (GH).  The basic study design that was followed was to compare the acute hormonal response to either 3 sets of 5 repetitions with a long rest interval (3 minutes) to sets of 10 with a 1 minute rest interval.  Repeatedly, studies showed that the first type of training boosted testosterone and the second GH.  Entire training schemes have grown out of this but there was a problem: nobody ever bothered to see if these acute (usually less than 10-15 minute) bumps in hormones actually did anything.

Nevermind that this makes little sense anyhow for a variety of reasons.  Not the least of which is that women have higher GH levels than men and get a bigger GH response to training, yet they don’t grow better.  If anything, with the known impact of testosterone on muscle growth, if there was to be any benefit to this, you’d expect the lower rep/heavy work to be superior.  Yet the researchers were arguing that it wasn’t.   There was a logic missing in the argument (not the least of which being the assumption that powerlifters had smaller muscles than bodybuilders) that seemed to get skipped over.

In addition to the science, there is a long held belief, echoed in various places (including the comments section of another contentious article I wrote titled Squats vs. Leg Press for Big Legs) that certain movements, notably squats and deadlifts, will have full-body growth stimulating properties, generally mediated through the hormonal response.

It’s not uncommon to see people recommending things like “If you want big arms, squat/train legs.” for example.  Essentially, heavy leg work is touted as being the key to overall growth.  Nevermind that the same people who make this argument will often complain about “All those guys in the gym with huge upper bodies and no legs” without realizing that the two ideas contradict one another (that is, if leg training is required for growth, how can guys get huge upper bodies without training legs).  But I digress again.

In any case, this study examined the issue directly with a somewhat confusing study design: twelve healthy young men trained their biceps on different days of the week under different training conditions.  In what they called the low-hormone condition, the biceps were trained all by themselves; no other exercise was done.  In the other called the high-hormone condition, the biceps were trained and then a large-volume of leg training was done to elevate the supposedly anabolic hormones.

Does that make sense, all subjects trained both arms, but on different days and under different conditions.  And the training was far enough apart that the hormonal response from the leg training wouldn’t have impacted the low-hormone training session.  This training was followed for 15 weeks and subjects consumed protein both before and after the training (so there was nutritional support).

Hormone levels were measured and while there was no significant change in hormones in the low-hormone situation, in the high-hormone situation, there were increases in lactate, growth hormone, free and total testosterone and IGF-1 with the peak occurring approximately 15 minutes after the leg work.

And, if the hormonal response to heavy leg training actually has any impact, what you’d expect to see is that one arm, the one trained along with the leg training, would grow better.

Did it happen? Guess.

Both maximal strength and muscle cross sectional area increased identically in both arms to the tune of a 20% vs. 19% increase in strength for low- vs. high-hormones and an increase in skeletal muscle cross sectional area of 12% vs. 10% in low- vs. high-hormones.  These differences were not statistically significant. Quoting the researchers:

Despite vast differences in hormone availability in the immediate post- exercise period, we found no differences in the increases in strength or hypertrophy in muscle exercised under low or high hormone conditions after 15 weeks of resistance training. These findings are in agreement with our hypothesis and previous work showing that exercise-induced hormone elevations do not stimulate myofibrillar protein synthesis (36) and are not necessary for hypertrophy (37). Thus, our data ((36) and present observations), when viewed collectively, lead us to conclude that local mechanisms are of far greater relevance in regulating muscle protein accretion occurring with resistance training, and that acute changes in hormones, such as GH, IGF-1, and testosterone, do not predict or in any way reflect a capacity for hypertrophy.

I don’t think it gets any clearer than that and I’d note that another recent study titled “Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men.” by the same group found the exact same thing.

Summing Up: Leg training has no magic impact on overall growth, most of which is determined locally (through mechanisms of tension and fatigue mediated by changes in local muscular metabolism).  If you want big arms, train arms.  If you want big legs, train legs.

And if folks are wondering why empirically ‘folks who train legs hard’ seem to get big compared to those who don’t, I’d offer the following explanation: folks willing to toil on heavy leg work work hard.  Folks too lazy to train legs hard often don’t.  And it’s the overall intensity of the training that is causing the difference, not the presence or absence of squats per se. Which is why guys who only hammer pecs and guns get big pecs and guns even if they couldn’t find the squat rack in the gym: the small acute hormonal responses to training are simply irrelevant to overall growth.

Kouri EM, et. al.Fat-free mass index in users and nonusers of anabolic-androgenic steroids.  Clin J Sport Med. (1995) 5(4):223-8.

We calculated fat-free mass index (FFMI) in a sample of 157 male athletes, comprising 83 users of anabolic-androgenic steroids and 74 nonusers. FFMI is defined by the formula (fat-free body mass in kg) x (height in meters)-2. We then added a slight correction of 6.3 x (1.80 m – height) to normalize these values to the height of a 1.8-m man. The normalized FFMI values of athletes who had not used steroids extended up to a well-defined limit of 25.0. Similarly, a sample of 20 Mr. America winners from the presteroid era (1939-1959), for whom we estimated the normalized FFMI, had a mean FFMI of 25.4. By contrast, the FFMI of many of the steroid users in our sample easily exceeded 25.0, and that of some even exceeded 30. Thus, although these findings must be regarded as preliminary, it appears that FFMI may represent a useful initial measure to screen for possible steroid abuse, especially in athletic, medical, or forensic situations in which individuals may attempt to deny such behavior.

Background

Last Thursday, I published a guest article by Alan Aragon entitled Supplement Marketing on Steroids, which was a scientific and technical analysis of recent claims regarding rates of muscle mass gain and potential maximum size by the website Testosterone.nation.  In a different context, this topic was previously covered on this site in the article What Is my Genetic Muscular Potential?

As expected, this caused quite an uproar as can be seen in the comments section of that article.

Of course, similar discussion has gone on on the T-nation site itself although, I should note that the term ‘discussion’ is debatable at best.  The moderators at T-nation are very censorship heavy, controlling information flow with an iron fist.  They ensure that only certain responses will be seen to keep their readers from the truth of their nonsensical claims.  My friend Matt Perryman made two posts to his site AmpedTraining which are worth reading in this regards:

Monday Morning Censorship Protest Real T-Men Speak Out

Real T-Men Speak Out Part 2

But I’m getting a bit off topic.

In the article What Is my Genetic Muscular Potential, one of the models presented is that of Casey Butt, who did an analysis of top bodybuilders over many years to develop an equation that predicts maximum potential for muscle growth.  There are several assumptions inherent in his model including that the bodybuilders are natural, along with the idea that bodybuilders represent the pinnacle of muscle building potential.

I’d note that Casey’s model lined up quite well with the models presented by myself, Alan Aragon and Martin Berkhan.  We all approached it from a slightly different direction but, based on our combined experience over the years, all ended up at basically the same place.

But among other gems of argument on T-nation was criticism that Casey’s model was inaccurate because it only examined bodybuilders from ages past (another was that athletes with better muscular potential would go into sports that weren’t bodybuilding).

That is, that current improvements in nutrition and training will have improved the muscular potential for natural bodybuilders beyond what Casey’s analysis shows.  Never mind that the three other models presented by myself, Alan and Martin and that includes top natural bodybuilding competitors completely line up with it perfectly as well.

Which brings us to today’s paper.

As another piece of background, I assume that readers are familiar with the concept of the Body Mass Index (BMI).  BMI gives a relationship of weight to height and is often used to determine things like under-, normal and over-weight.  With certain caveats, discussed in Body Composition Methods Part 1 BMI can be a reasonably accurate measure but it suffers from a major problem for athletes: it doesn’t distinguish between fat mass and lean body mass.

Towards this goal, researchers have tried to develop what they call a Fat-Free Mass Index (FFMI) conceptually similar to the BMI but a measure of fat free mass (another term for lean body mass) relative to height.  Which is what this study looked at…in both users and non-users of steroids.  They wanted to see if there were any fundamental differences in the FFMI that either occurred or were achievable between users of steroids and nonusers.  Clearly this ties in to the current debate over genetic maximums along with rates of muscle gain.

Just for completeness FFMI is defined as fat free mass / height squared.

Where fat free mass is in kg and height is in meters.

If you want to calculate your current FFMI (for example, to compare it to the values I’m going to discuss below), there is an easy to use online

FFMI Calculator.

The Study

The researchers recruited 156 men, athletes, from gyms in the Boston and Los Angeles area, of those 156 men 134 data points were used.  A full physical examination was given including measurements of height, weight and body fat, the latter computed from the sum of 6 skinfold measurements and the Jackson and Pollock equation.  A history of previous steroid use was obtained by personal interview along with urine testing. Now we might quibble with this as athletes are known to lie about drug use.

But as the researchers state:

Briefly, no evidence suggested that any athlete had deliberately misrepresented his steroid use, nor did any urine test contradict an athlete’s verbal report.

Of course, that still doesn’t prove anything, athletes have been beating drug tests for years.  But within the context of this paper, that’s as good as it’s going to get.

To the above data set of 156 men, an additional 23 men were recruited from a separate study examining the impact of testosterone cypionate, the same measurements were given to them.  So of the total 157 individuals (134 from the first group, 23 from the second group), 74 (47%) had never used steroids and 83 (53%) had used steroids.  Fifty-two of the subjects had used steroids within the past year.

Adding to the validity of the data set, in the context of Alan’s article and this debate, the researchers state (bold added for emphasis) that:

The nonusers included many dedicated bodybuilders. Several had competed successfully in “natural” bodybuilding contests, two held world records in strength events, and many others were recognized by their associates as highly successful weightlifters.  Thus the nonuser group probably included individuals who closely approached the maximum limits of muscularity that could be attained without drugs.

I’m quoting that bit in full so that people can’t try to dismiss this in the comments section or on forums by trying to argue that these were recreational lifters or that they didn’t train hard: these guys were near the top of the heap in terms of natural competitors.

Results

In any case, with this data set in tow, the researchers calculated the FFMI for both the steroid user and nonuser groups.   I’ve reproduced the results in full in the table below; please note that I added the column for lean body mass which I simply calculated by taking weight in kg by body fat percentage (without the error bars).

Table 1: Characteristics of Steroid Users and Nonusers

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Now, as the results above show, even with steroid use, the users were still considerably lighter on average than even the typical IFBB pro with only 175 pounds of lean body mass.  Contest weights in the 200′s are common nowadays; of course modern bodybuilders use far more than just anabolic steroids.  Growth hormone, IGF-1 and all kinds of ancillaries are in use now.

And, again, look at the nonusers.  An average lean body mass of 158 pounds.  Of course, that’s not taking into account the error bars. Some of the subjects in each group were larger than this and some smaller.

Just for the hell of it, let’s see what the absolute best values we can get out of the above are.

I’ll assume the heaviest body weight for both the steroid and non-steroid users and the lowest body fat percentage so it’s an equal comparison; this calculation will show the absolute biggest guys in both groups in terms of how much lean body mass that they can carry.

All I’ve done is taken the average weight plus the error bar for weight and average body fat percentage minus the error bar for body fat percentage.  I’ve shown the numbers in the table below.

Table 2: Maximum Lean Body Mass in the Sample Group

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Those are the two biggest guys in the sample size, again using the highest body weight and lowest body fat percentage.  Notice anything, for example how the values line up if you go back and look at Supplement Marketing on Steroids or What Is my Genetic Muscular Potential?

In this MODERN sample of top level bodybuilders using drugs or not, the steroid users are about what Arnold was at his peak (average competition weight of 235).   And not a single one of the nonusers exceeds the maximums set by my, Alan, Martin or Casey’s model in What Is my Genetic Muscular Potential.

This is despite being world record holders and top level competitors in natural bodybuilding.   Presumably they are using every modern nutritional and training trick available.  And they still can’t break the model’s predictions.  Not a single one of them.

The researchers concluded, based on this that the upper limits of FFMI in non-steroid users is roughly 25 with an abrupt stopping point; steroid users can surpass this with FFMI values as high as 32 occurring in this study for the largest individual.  But for nonusers, 25 is it.

In support of this, the researchers obtained other data, similar to Casey’s original analysis.  Using data on the Mr. American winners from the years of 1939-1959 (a time when presumably training and nutrition was improving) an estimated FFMI was done.  With one or two outliers, none exceeded a FFMI of 25.

My Comments

Now the researchers were using this whole approach to basically try to find a way, more or less, to determine whether or not a given individual was on steroids.  Basically, they found through their sample that, without drugs, there is simply a cap on how much fat free mass an individual can carry.

And a FFMI of roughly 25 represents the natural limit.  And this value hasn’t changed since 1930.  Because human genetics haven’t changed.  And no amount of training or nutrition will EVER change that.

Of course that’s not really why I choose to analyze this study.  This paper represents a meticulously analyzed modern data set showing that, assertion by T-nation moderators to the contrary, the potential for muscular gain in natural athletes has not gone up or changed due to improvements in training, nutrition or anything else.  Claims that ‘We have naturals exceeding 230 pounds of lean body mass on our forums’ are either delusion, lies, or both.  Ok, not exactly.

In that context, it is worth noting a specific comment by the researchers which I will again quote in full:

Fourth, our formula may not be satisfactory for fat individuals.  Because a gain in the fat component of the body is consistently accompanied by some gain in the lean component, it is possible that fat individuals might be able to exceed substantially an FFMI of 25 without steroids.

It is amusing to note that, invariably the pictures of T-nation members held up as ‘proof’ that LBM can go higher than what’s in my, Alan, Martin or Casey’s models are invariably carrying a tremendous amount of body fat.  But the reality is that, dieted down, the loss of connective tissue, etc. that accompanied the development of their frank obesity would bring them right back down to the numbers predicted by the various models.  They wouldn’t end up with more than 200 pounds LBM after the two plus years of dieting it would take to get the fat off.

And, while I’m sure this paper will do nothing to quell the claims of the T-nation moderators or the folks who want to believe that they are the lone exception, the evidence and research based facts speak for themselves.  Natural limits exist and no amount of magic pills, powders or potions will let you exceed them unless those magic pills are anabolic steroids.  That’s reality folks, it may not be pretty or sexy but it is true.

Please not that, again, I’ve turned off moderation for this article to encourage discussion and meaningful debate (in direct contrast to the T-nation approach).  Please keep it civil and I will be keeping an eye for outright trolling or what have you.

Tabata I. et. al.  Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.  Med Sci Sports Exerc. (1996) 28(10):1327-30.

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P < 0.01) (mean +/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d.wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Background

In recent years, training and the Internets have become interval crazy.  Everybody wants to do nothing but interval training all the damn time (with some even proclaiming that any non-interval training is not only useless but downright detrimental).

Now, I’ve written extensively about this in what must be about a 12 part series on Steady State vs. Interval Training here on the site.  I’m not going to rehash the entirety of that series, mind you; go read it.  But simply, both intervals and steady state have their place in training.  Arguments that one is inherently or always superior to the other has more to do with marketing than reality.

But among other aspects of this particular meme, the idea of the Tabata protocol (often abbreviated Tabatas) gets bandied about all the time.  And the problem is that people are using the term to describe something that they don’t really understand.  What has happened is that a bunch of people who don’t really know what they are talking about have written so much about the protocol that what it actually is or accomplishes has been completely diluted.

So I figured I’d undilute it by actually examining the study that the whole set of claims and supposed ‘protocols’ are based on.  Because, as is so often the case, what people think they are doing as ‘Tabatas’ are nothing like what the actual study did.  And most people who think they are doing the Tabata protocol are doing absolutely nothing of the sort.

As a bit of history, the protocol was actually originally developed by a Japanese speed skating coach and later studied by researchers; I bring this up because speed skating is actually a very peculiar sport in a lot of ways (something that I have insight into as I’ve spent the last 5 years training full time as a skater).  But I’m not going to get that into detail here; I simply mention it for completeness.

The Study

The study set out to compare both the anaerobic and aerobic adaptations (in terms of one parameter only, VO2 max) to two different protocols of training.  The study recruited 14 active male students who were, at best moderately trained (VO2 max was roughly 50 ml/kg/min which is average at best; elite endurance athletes have values in the 70-80 range).

All work including the pre- and post tests were done on a mechanically braked bicycle ergometer; this is an important point that is often ignored and I’ll come back to in the discussion.  Every test or high-intensity workout was proceeded by a 10 minute warm-up at 50% of VO2 max (This is maybe 60-65% maximum heart rate).

The two primary tests were VO2 max and the maximal accumulated oxygen deficit (this is a test of anaerobic capacity, basically people with higher anaerobic capacity can generate a larger oxygen deficit) and then subjected to one of two training programs.

The first program was a fairly standard aerobic training program, subjects exercised 5 days/week at 70% of VO2 max for 60 minutes at a cadence of 70 RPMs for 6 straight weeks.  The intensity of exercise was raised as VO2 max increased with training to maintain the proper percentage.  VO2 max was tested weekly in this group and the maximal accumulated oxygen deficit was measured before, at 4 weeks and after training.

The second group performed the Tabata protocol.  For four days per week they performed 7-8 sets of 20 seconds at 170% of VO2 max with 10 seconds rest between bouts, again this was done after a 10 minute warm-up.  When more than 9 sets could be completed, the wattage was increased by 11 watts.  If the subjects could not maintain a cadence of 85RPM, the workout was ended.

On the fifth day of training, they performed 30 minutes of exercise at 70% of VO2 max followed by 4 sets of the intermittent protocol and this session was designed to NOT be exhaustive.  The anaerobic capacity test was performed at the beginning, week 2, week 4 and the end of the 6 week period; VO2 max was tested at the beginning and at week 3, 5 and the end of training.

Results

For group 1, the standard aerobic training group, while there was no increase in anaerobic capacity, VO2 max increased significantly from roughly 52 to 57 ml/kg/min (I say roughly because the paper failed to provide vaules, I’m going by what’s in the graphic below).  Frankly, given the lack of anaerobic contribution to steady state training, the lack of improvement in this parameter is absolutely no surprise.

For group 2, both the anaerobic capacity and VO2 max showed improvements.  VO2 max improved in the interval group from 48 ml/kg/min to roughly 55 ml/kg/min (see graphic below).  It is worth noting that the interval group was starting with a lower value and may have had more room for improvement.  Also note that they still ended up with a lower Vo2 max than the steady state group.

I’ve put Figure 2 from the paper (showing improvements in VO2 max) below

Click to Enlarge

As I noted, pay attention to the fact that the Tabata group (black line, filled circles) started lower than the steady state group, they also still ended up lower than the steady state group.  As well, note that pattern of improvement, the Tabata group got most of their improvement in the first 3 weeks and far less in the second three weeks.  The steady state group showed more gradual improvement across the entire 6 week period but it was more consistent.  As the researchers state regarding the Tabata group

After 3 wk of training, the VO2 max had increased significantly by 5+-3ml.kg/min.  It tended to increase in the last part of the training period but no significant changes [emphasis mine] were observed.

Basically, the Tabata group improved for 3 weeks and then plateaued despite a continuingly increasing workload.  I’d note that anaerobic capacity did improve over the length of the study although most of the benefit came in the first 4 weeks of the study (with far less over the last 2 weeks).

My Comments

First and foremost, there’s no doubt that while the steady state group only improved VO2 max, it did not improve anaerobic capacity; this is no shock based on the training effect to be expected.  And while the Tabata protocol certainly improved both, not only did the Tabata group still end up with a lower VO2 at the end of the study, they only made progress for 3 weeks before plateauing on VO2 max and 4 weeks for anaerobic capacity.

Interestingly, the running coach Arthur Lydiard made this observation half a century ago; after months of base training, he found that only 3 weeks of interval work were necessary to sharpen his athletes.  More than that was neither necessary nor desirable.  Other studies using cycling have found similar results: intervals improve certain parameters of athletic performance for about 3 weeks or 6 sessions and then they stop having any further benefit.

I’ve asked this question before but for all of the ‘All interval all the time’ folks, if intervals stop working after 3-4 weeks, what are people supposed to do for the other 48-49 weeks of the year.  Should they keep busting their nuts with supra-maximal interval training for no meaningful results?

On that note, it’s worth mentioning that the Tabata group actually did a single steady state workout per week.  Is it at all possible that this contributed to the overall training effect (given that 70% VO2 max training improved VO2 max in the steady state only group)?  Does anybody else find it weird that the Tabata promoters ignore the fact that the Tabata group was doing steady state work too?

It’s also relevant to note that the study used a bike for training.  This is important and here’s why: on a stationary bike, when you start to get exhausted and fall apart from fatigue, the worst that happens is that you stop pedalling.  You don’t fall off, you don’t get hurt, nothing bad happens.  The folks suggesting high skill movements for a ‘Tabata’ workout might want to consider that.  Because when form goes bad on cleans near the end of the ‘Tabata’ workout, some really bad things can happen.  Things that don’t happen on a stationary bike.

As well, I want to make a related comment: as you can see above the protocol used was VERY specific. The interval group used 170% of VO2 max for the high intensity bits and the wattage was increased by a specific amount when the workout was completed.  Let me put this into real world perspective.

My VO2 max occurs somewhere between 300-330watts on my power bike, I can usually handle that for repeat sets of 3 minutes and maybe 1 all out-set of 5-8 minutes if I’m willing to really suffer.  That’s how hard it is, it’s a maximal effort across that time span.

For a proper Tabata workout, 170% of that wattage would be 510 watts (for perspective, Tour De France cyclists may maintain 400 watts for an hour).  This is an absolutely grueling workload.  I suspect that most reading this, unless they are a trained cyclist, couldn’t turn the pedals at that wattage, that’s how much resistance there is.

If you don’t believe me, find someone with a bike with a powermeter and see how much effort it takes to generate that kind of power output.  Now do it for 20 seconds.  Now repeat that 8 times with a 10 second break.  You might learn something about what a Tabata workout actually is.

My point is that to get the benefits of the Tabata protocol, the workload has to be that supra-maximal for it to be effective.  Doing thrusters or KB swings or front squats with 65 lbs fo 20 seconds doesn’t generate nearly the workload that was used during the actual study.  Nor will it generate the benefits (which I’d note again stop accruing after a mere 3 weeks).  You can call them Tabatas all you want but they assuredly aren’t.

Finally, I’d note that, as I discussed in Predictors of Endurance Performance VO2 max is only one of many components of overall performance, and it’s not even the most important one.  Of more relevance here, VO2 max and aerobic endurance are not at all synonymous, many people confuse the two because they don’t understand the difference between aerobic power (VO2 max) and aerobic capacity (determined primarily by enzyme activity and mitochondrial density within the muscle).  Other studies have shown clearly that interval work and steady state work generate different results in this regards, intervals improve VO2 max but can actually decrease aerobic enzyme activity (citrate synthase) within skeletal muscle.

The basic point being that even if the Tabata group improved VO2 max and anaerobic capacity to a greater degree than the steady state group, those are not the only parameters of relevance for overall performance.

Summing Up

First, here’s what I’m not saying.  I’m not anti-interval training, I’m not anti-high intensity training.  I am anti-this stupid-assed idea that the only type of training anyone should ever do is interval training, based on people’s mis-understanding and mis-extrapolation of papers like this.

High-intensity interval training and the Tabata protocol specifically are one tool in the toolbox but anybody proclaiming that intervals can do everything that anyone ever needs to do is cracked. That’s on top of the fact that 99% of people who claim to be doing ‘Tabatas’ aren’t doing anything of the sort.

Because 8 sets of 20″ hard/10″ easy is NOT the Tabata protocol and body-weight stuff or the other stuff that is often suggested simply cannot achieve the workload of 170% VO2 max that this study used.  It may be challenging and such but the Tabata protocol it ain’t.

Willardson, J.M. A brief review: Factors affecting the length of the rest interval between resistance exercise sets. J. Strength Cond. Res. 20(4):978-984. 2006

Research has indicated that multiple sets are superior to single sets for maximal strength development. However, whether maximal strength gains are achieved may depend on the ability to sustain a consistent number of repetitions over consecutive sets. A key factor that determines the ability to sustain repetitions is the length of rest interval between sets. The length of the rest interval is commonly prescribed based on the training goal, but may vary based on several other factors. The purpose of this review was to discuss these factors in the context of different training goals. When training for muscular strength, the magnitude of the load lifted is a key determinant of the rest interval prescribed between sets. For loads less than 90% of 1 repetition maximum, 3-5 minutes rest between sets allows for greater strength increases through the maintenance of training intensity. However, when testing for maximal strength, 1-2 minutes rest between sets might be sufficient between repeated attempts. When training for muscular power, a minimum of 3 minutes rest should be prescribed between sets of repeated maximal effort movements (e.g., plyometric jumps). When training for muscular hypertrophy, consecutive sets should be performed prior to when full recovery has taken place. Shorter rest intervals of 30-60 seconds between sets have been associated with higher acute increases in growth hormone, which may contribute to the hypertrophic effect. When training for muscular endurance, an ideal strategy might be to perform resistance exercises in a circuit, with shorter rest intervals (e.g., 30 seconds) between exercises that involve dissimilar muscle groups, and longer rest intervals (e.g., 3 minutes) between exercises that involve similar muscle groups. In summary, the length of the rest interval between sets is only 1 component of a resistance exercise program directed toward different training goals. Prescribing the appropriate rest interval does not ensure a desired outcome if other components such as intensity and volume are not prescribed appropriately.

My Comments

When you look around the weight room, it’s not uncommon to see folks using rest intervals that are wholly inappropriate for their stated goals.  The paper I want to look at today was a good overall review of how rest intervals should be structured for different training goals including maximal strength, hypertrophy, power production or local muscular endurance.

Maximal Strength

Looking first at maximum strength training (typically defined as low repetition, heavy weight), the review points out that most strength-oriented programs place a primary emphasis on maintaining training intensity (defined in most research as the percentage of 1 rep max) throughout the sets.

That is, when the goal is maximal strength, you want to be able to use the heaviest weight for the number of reps you intend to do in any given set.  This means avoiding a lot of cumulative fatigue and that means complete rest intervals although there are occasional exceptions to this.

Examining a variety of studies along with some theoretical concerns involving ATP regeneration and the nervous system, the review recommends a fairly standard rest interval of 2-5 minutes between sets for maximal strength work.  I’d say that this is a recommendation that is certainly consistent with empirical experience.

When training with a system such as 5X5 (discussed in more detail in The 5X5 Program) or even something like 6 sets of 3, rest intervals of 3-5 minutes between maximally heavy sets would be a common recommendation; again this ensures that the heaviest weights can be handled on each set without too much accumulated fatigue.

The paper suggests, however, that when the intensities go above 90% of maximum (generally 3 reps per set or less) short intervals can sometimes be used.  In premise, very low reps sets don’t generate much in the way of metabolic fatigue; basically a set of 5 will generate more metabolic fatigue than a set of 1-2 reps.   This may make shorter rest intervals workable.

Related to this, some studies have found that short rest intervals can be used when testing 1 repetition maximum, for the same reason; there is less metabolic fatigue from only a single repetition set.  Practically I tend to question this a bit , most people testing a true 1 rep max tend to take fairly long rest intervals, 5 minutes or more aren’t uncommon for individuals moving very heavy weights (as well, I’ve seen some claim that you can train yourself to need lest rest on maximum attempts).

I think this is because, even if there is less metabolic fatigue generated, factors of neural fatigue in addition to psychological factors play a role. Testing a true 1 rep max requires an extreme amount of focus and I prefer longer recoveries on test days for this reason.

An additional variable here is the type of movement being done.  Olympic lifters will often use fairly heavy weights with, relatively speaking anyhow, shorter rest intervals.   This is probably because with the exception of the front squat recovery, a maximal Olympic lift has very little ‘grinding’ to it.  A single repetition typically either goes or doesn’t go.

Powerlifters, in contrast, who tend to grind a bit more often require longer rest intervals due to the nature of the lift they are doing.  Grinding out a near maximum single tends to be very neurally fatiguing and requires longer rests.

I should note that, while the paper didn’t mention it explicitly, I have seen folks for whom too long of a rest interval actually does more harm than good.  This is especially true for highly technical movements, especially when technique isn’t completely stable.  Lifters will lose their groove (and this happens most often on Olympic lifts) if they sit around too long between repetitions.  As well, some lifters seem to cool down between sets if you let them rest too long.  So there can be some individual variance in the length of time taken between heavy sets.

Muscular Power

Muscular power training is generally performed to improve how quickly a muscle can generate force.  Typically speaking, power training takes the form of moving sub-maximal weights fairly quickly.  Various types of medicine ball throws, jumps, the Olympic lifts, or even traditional weight exercises (e.g. squat, bench, deadlift), can be performed in this fashion.

Since the focus, as with maximal strength, is on the quality of movement, fatigue should generally be avoided during this type of training. And the paper suggests similar long rest intervals of 3-5 minutes between sets of power work.  This allows maximal quality in each set without accumulated fatigue hampering movement speed.

This is especially true for higher rep efforts such as high rep bounding or higher rep sets of power weight training.  Someone performing power endurance work, performing 10 or more fast repetitions per set needs to be fully rested for each set to ensure that movement speed doesn’t slow down.  That requires full recovery between sets.

I should note that lower repetition sets are sometimes used (in powerlifting and Olympic lifting) for power work and this won’t require the same long rest intervals since the fatigue from each set tends to be lower.    For example, the Westside Barbell approach to dynamic work is multiple low rep sets (10-15X1 for deadlift, 8-10X2 for squat, 8-10X3 for bench) with relatively short rest intervals (45-60 seconds) and a sub-maximal weight (anywhere from 40-60% of 1RM.  Since each set is very short and relatively unfatiguing, shorter rest intervals can be used with the quality of work being maintained.

Hypertrophy

The section on hypertrophy is the one in the paper that I had the most potential disagreement on in terms of their recommended rest intervals.  Based on some of the hormonal stuff (Growth Hormone primarily) that’s been floating around for years (but in my opinion has never really been shown to play much role in the growth response), the paper argues for relatively short rest intervals of 30-90 seconds between sets for hypertrophy.

From a real-world perspective, the issue I have with that is that the biggest guys are usually the strongest and often use fairly long rest intervals between heavy sets.  As I’ve commented on before, dieted down many big powerlifters have as much if not more muscle size than folks training strictly as bodybuilders.

And at least part of the powerlifter’s training is usually performed with very heavy weights and relatively long rest intervals.  Of course, many powerlifters also perform higher reptition work (often with shorter rest intervals) as well so it’s hard to draw a line in the sand between the types of training being done.

I guess my point is that there is more to hypertrophy than giving a simple short or long rest interval can properly address.  The interaction of tension with fatigue/metabolic work and tonnage are all involved in the growth stimulus and by the time you get into issues of sarcoplasmic vs. myofibrillar hypertrophy, it starts getting complicated.  Some of those issues are addressed in the series on Periodization for Bodybuilders.

Put simply, I think that both longer (complete or near complete) and shorter (incomplete) rest intervals have their place in hypertrophy training.  In general, I’ll typically use longer rest intervals when the goal is primarily a tension stimulus (e.g. rest interval of 2-3 minutes for sets of 5-8 reps) and shorter rest intervals when the goal is a fatigue stimulus (e.g. 60 seconds for sets of 12-15 reps).

Finishing up, I will say that i think people who always use 10-15 seconds between sets so that they ‘get real tired’ or ‘get a good pump’ or what have you are shortchanging themselves when it comes to growth.  Outside of some specific applications (usually involving rest pause or drop sets), very short intervals tend to drastically decrease how much weight can be used.

As I discuss in Reps Per Set for Optimal Growth, tension is the primary stimulus for growth and very short rest interval systems tend to be fatigue dominant instead of tension dominant.  If anything, that hurts growth.

Local Muscular Endurance

Local muscular endurance refers to a muscle’s ability to resist fatigue (usually against high levels of acid production) and, as such, fatigue is a more important stimulus than tension or intensity.  Generally high repetitions (15-25 ore more) very short rest intervals (30-60 seconds or less) and circuit type training (to get a more metabolic effect) are used with this type of training.

Although they aren’t necessarily performance oriented, many of the currently popular ‘metabolic weight training’ programs for fat loss actually make a pretty good model for local muscular endurance training.

Summing Up

Summing up this review, practically folks may manipulate rest intervals for different goals according to the following guidelines:

1. Maximal strength training: 2-5 minutes between sets. Possibly shorter when intensity is above 90% and reps are three or less.
2. Testing 1 rep max: the paper recommends short rest of 1-2 minutes. From a real-world perspective, I’m not sure I agree with this as a general rule.
3. Muscular power: generally 3-5 minutes although shorter rests of 30-45 seconds can be used with very short sets (multiple sets of doubles and triples).
4. Hypertrophy: the paper recommends incomplete rest intervals of 30-90 seconds but I disagree somewhat with this.  I feel that both complete and incomplete rest intervals have their place in hypertrophy training.
5. Muscular endurance: Short rest intervals of 30-60 seconds performed in circuit fashion.

BACKGROUND: Due to occupational restrictions many people’s recreational endurance activities are confined to the weekends. We intended to clarify if cumulating the training load in such a way diminishes endurance gains. DESIGN: We conducted a longitudinal study comparing training-induced changes within three independent samples. METHODS: Thirty-eight healthy untrained participants (45+/-8 years, 80+/-18 kg; 172+/-9 cm) were stratified for endurance capacity and sex and randomly assigned to three groups: ‘weekend warrior’ (n=13, two sessions per week on consecutive days, 75 min each, intensity 90% of the anaerobic threshold; baseline lactate+1.5 mmol/l), regular training (n=12, five sessions per week, 30 min each, same intensity as weekend warrior), and control (n=13, no training). Training was conducted over 12 weeks and monitored by means of heart rate. Identical graded treadmill protocols before and after the training program served for exercise prescription and assessment of endurance effects. RESULTS: VO2max improved similarly in weekend warrior (+3.4 ml/min per kg) and register training (+1.5 ml/min per kg; P=0.20 between groups). Compared with controls (-1.0 ml/min per kg) this effect was significant for weekend warriors (P<0.01) whereas there was only a tendency for the regular training group (P=0.10). In comparison with controls (mean decrease, 3 beats/min), the average heart rate during exercise decreased significantly by 11 beats/min (weekend warriors, P<0.01) and 9 beats/min (regular training, P<0.05). There was no significant difference, however, between the weekend warrior and regular training groups (P=0.99). CONCLUSION: In a middle-aged population of healthy untrained subjects, cumulating the training load at the weekends does not lead to an impairment of endurance gains in comparison with a smoother training distribution.

My comments: As the introduction to the abstract mentions, some people, due to their scheduling find that training during the week is nearly impossible. And while the standard dogma in terms of endurance training is that you have to train at least 3X/week (generally for a minimum of 20 minutes), preferably on non-consecutive days, this study brings that into question.

As indicated, subjects were either placed on a traditional training program (5 days/week for 30 minutes at 90% of lactate threshold) or given weekend warrior training (75 minutes at 90% of LT done on Sat/Sun) and monitored for 12 weeks.

Note: lactate threshold (LT) is generally defined as the highest intensity that you can maintain without fatigue, above LT fatigue generally occurs fairly quickly (in a few minutes anyhow). I want to mention that the argument over LT (as opposed to competing concepts such as anaerobic threshold, onset of blood lactate accumulation, threshold power, critical power) is neverending but ultimately kind of tangential to this study. Just think of LT as the highest intensity you can maintain without fatigue; LT is a pretty challenging intensity. 90% of LT is doable and some believe that working in that range gives the optimal endurance adaptations. But I digress.

In any case, over the 12 weeks of the study, at least in this population (untrained middle aged individuals), both training programs gave identical results. As above, this goes against the commonly held belief and may represent a workable schedule for folks who simply can’t train during the week.

Alternately, someone might be able to train twice on the weekends and fit in a third workout during the week; it wouldn’t entire surprise me if this gave even greater adaptations. In any case, this shows that getting most of your aerobic training done (again, in untrained individuals) can stimulate adaptations similar to spreading it out.

An interesting question is whether a weekend warrior pattern of weight training might be as effective as more frequent weekly workouts? Could someone train full body 2 days in a row and then take the next 5 days off and make gains?

Perhaps more interesting is that this ties in with a current trend in aerobic training methodology which is usually called block training. In block training, rather than spreading out hard workouts through the week, they are done in series. So a cyclist might do 2-3 days of high intensity interval work in a row followed by multiple days of rest (for recovery). In highly trained athletes, this may be a way to stimulate further adaptation by accumulating fatigue/training stimulus over several consecutive days and then allowing the body to adapt. I’ve had a couple of the bodybuilders on my forum use this kind of approach for bodybuilding with good results; I hope to write up the idea at some point in the future.