If 'Size' is Your Goal, 30s Rest & 20 Reps Beat 3 Min Rest & 8 Reps to Failure -- Extra 100% Biceps Gains in 8 Week Study

Do women have to complain that training makes them "bulky", because they're doing it right (high rep, low weight, short rest) while their boyfriends don't?... What? Don't worry, I am just kiddin'.

As a loyal SuppVersity readers, you will remember my 2016 article: "Not Resting Long Enough May Ruin Your Gains! 1 vs. 5 min Cut Post-Workout Increase in Protein Synthesis by 50%!" (read it). Now, back in the day I already pointed out that "the study at hand only proves what we already knew - training volume is more important than metabolic stress when it comes to hypertrophy gains" (SV. 2016) and still many people (mis-)interpreted the results in their black-and-white world as "final evidence" that you'd have to turn your workout into a coffee (or intra-workout) party to make the gains you feel you deserve. That's a mistake you should not repeat by taking the publication of a recent study from the Nippon Sport Science University as a reason to stop resting (and using heavy weights) altogether.

Don't fool yourselves, there is no single best workout for the rest of 'us life -- periodize!

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Mix Things Up to Make Extra-Gains

Linear vs. Undulating Periodization

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But before we get to the implications, let's first take a look at the study itself. The corresponding experiments were conducted by Julius Fink, Naoki Kikuchi and Koichi Nakazato (Fink. 2016); and the authors did two things McEndry et al. the authors of the previously cited acute-phase study of the protein anabolic response to exercise failed to do in their study:

• Fink et al. investigated the effects of volume-matched resistance training (RT) regimen, and
• they tested both, the acute responses and long-term muscle and strength gains

McEndry et al. (2016) had stuck to the acute protein response to non-volume matched training regimen. That's not necessarily worse, but it limits the significance of the study results in a different way than the design of the more recent study by Fink et al., in which

More protein helps more?!

"[t]wenty young athletes (members of a university gymnastics club) volunteered to participate in this study [with previous] weight training [experience of >2 years] were randomly assigned to either the SL group (30-s rest, 20 RM) or the long-rest and LH group (3-min rest, 8 RM) and performed the same number of sets and exercises for the arm muscles three times per week for 8 weeks" (Fink. 2016).

Both groups performed each set to failure and used the same set of exercises: three biceps and three triceps exercises in form of

• barbell curl,
• preacher curl,
• hammer curl,

• close grip bench press,
• French press and
• dumbbell extension

Even though I doubt that this was necessary for the majority of the experienced trainees, all participants were familiarized with the exercises 2 weeks prior to the start of the experiment by qualified trainers. The same goes for the differential training styles, the authors describe as follows:

• The SL group did each exercise with a rest of 30 s between sets and exercises at 20 RM. 
• The LH group rested 3 min between sets and exercises with a training intensity of 8 RM. 
• In both groups, each set was performed to failure with a cadence of 1 s for the concentric and 2 s for the eccentric part of the movement. 
• The training sessions were performed three times per week for 8 weeks and supervised by a staff of qualified personal trainers.

Over the course of the 8-week study, the weight was increased by 10%, whenever, the participants, whose training experience of >2 years and body fat % of 10.9 and 13.3%, in the SL and LH group, respectively qualifies them as fitness enthusiasts, could perform more than 20 repetitions for the SL group or more than eight repetitions for the LH group. As previously pointed out, the volume (reps x load) was supposed to be identical and that worked out quite well - with one exception, the barbell curl, where the SL group trained at a sign. higher volume (see Table 1), of which one must, however, doubt that it alone could explain the already hinted at SL advantage.

Table 1: Total training volume, calculated as number of repetitions x training load ( SD) for three sets of each exercise; SL, short rest with the low-load protocol; LH, long rest with the high-load protocol (Fink. 2016).

The acute change in muscle thickness (MT) was assessed before and immediately after a single bout of RT via ultrasound imaging (Prosound 2; Hitachi Aloka Medical, Ltd., Tokyo, Japan | same method as in Schoenfeld et al., 2015a,b), the chronic adaptation was measured with MRI (AIRIS II; Hitachi, Ltd., Tokyo, Japan) 72–96 h after the last RT session (learn why this is important).

Figure 1: Acute growth hormone response to SL and LH workouts and the lack of correlation between acute GH increases and gains in terms of actual muscle circumference gains (CSA, right | Fink. 2016).

The analysis of the hormonal response to exercise (plotted in Figure 1), is unsurprising. We already knew from previous studies that the SL protocol would produce greater increases in growth hormone (GH) than the LH protocol with its long rest-times. The same must be said of the correlation (and implied effect) of these increases with the subjects' size gains which did - as in almost every previous study - not correlate with the hormonal response to the workouts (see Figure 1, right).

Should I change my workout style now? No. If you're still making progress, I would not hectically change everything. What I would do, however, is to read up on periodization (learn more) and plan to change your workouts regularly using both lower and higher weights and shorter and longer inter-set rest times periodically and for your own benefit.

Figure 2: Rel. size (top) and strength gains (bottom) over 8 weeks (Fink. 2016)

If we compare the long-term effects on the muscle cross-sectional areas (CSAs), as well as the changes in muscle strength (measured as maximum voluntary contraction (MVC) of the biceps) between studies, however, the differences approach statistical significance.

Whether and in which way (corollary or mechanistically) the long-term extra gains in the SL group (see Figure 2, top) are related to the observation that the muscle thickness increased significantly only after a single bout of SL training  (35 .2 +/- 16- 9%, P<0 05) (ES = 3 17), but not after a bout of LH training (13. 7 +/- 10. 8%) would warrant further investigation.

What appears to be easier to understand than the hypertrophy advantage of the SL training is the fact that the lack of heavy resistance training in the SL group (the SL group showed a non-significant decrease in strength of 5 .9 +/- 8. 6%; ES = 0 46) lead to a decrease in MVC in this group of previously resistance trained individuals (see Figure 2, bottom).

Shall you forget about long rest times? I understand that you gravitate towards simple solutions. Unfortunately, those simple solutions are the reason you are not making the gains you could make if you finally got rid of the stupid idea that there was one ideal workout routine, you'd just have to find and could then follow for the rest of your life.

Strength Plateau? Try Daily Changing Loads: To Boost 6-Week Strength Gains on All Major Lifts by ~40%.

How's that wrong? It's what the study says SL is better than LH, right? Well, the study at hand does indeed suggest that training with more reps and low(er) rest builds more muscle (note that the results could be very different for other muscles, e.g. the legs, or other trainees, i.e. rookies), while training with long(er) rest and more weight will boost strength gains. Eventually, however, the differences are (a) not statistically significant and (b) not independent of each other. Strength and size gains are not like the two sides of the same coin. They are yet also not unrelated.

Accordingly, the question is not whether you want size or strength/ power and thus train with short(er) rest and low(er) weights or long(er) rest and high(er) weights. No, making optimal gains is rather a question of balancing all three domains of "gains", i.e. size, strength and anaerobic power (Pasiakos. 2015) within a well-planned periodization regimen that would - if the volume is controlled for - favor size gains during the short rest, high rep / low weight and strength gains during the long rest, low(er) rep / high(er) weight phases | Comment!

References:

• Fink et al. "Effects of rest intervals and training loads on metabolic stress and muscle hypertrophy." Clin Physiol Funct Imaging (2016) - Ahead of print.
• Pasiakos, Stefan M., Tom M. McLellan, and Harris R. Lieberman. "The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review." Sports Medicine 45.1 (2015): 111-131.
• Schoenfeld, Brad J., et al. "Effects of low-vs. high-load resistance training on muscle strength and hypertrophy in well-trained men." The Journal of Strength & Conditioning Research 29.10 (2015a): 2954-2963.
• Schoenfeld, Brad J., et al. "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men." Journal of strength and conditioning research/National Strength & Conditioning Association (2015b).

Resting as Long as You Think Fit Reduces Training Time W/Out Reducing the Workload & (Hopefully) Your Gains

The study provides only preliminary evidence, but it is evidence... 

You will certainly remember the SuppVersity article about the beneficial effects of long(er) rest times on strength and size gains from November last year (read more).

Now, after I posted this article, a discussion evolved about whether you actually have to wait that long (3 min) after exercises that don't leave you as winded as barbell squats; and if resting less than the "optimal" time wouldn't yield the exact same results if volume and weights you lift during set and individual rest time workouts were identical.

As the authors of a recent study from the Universidade Federal do Rio de Janeiro (Freitas de Salles. 2016), point out, there was, until now, no study that compared the "consequences of applying selfsuggested with fixed intervals in upper and lower body exercises performance". With said study, however, there's some data on what happens if you compare the effects of fixed (2 min) versus self-suggested rest intervals (RI) between sets in lower (squat and leg press) and upper body (bench press and biceps curl) exercises on experienced trainees' performance.

It would be interesting to see if rest periods should also be periodized!

30% More on the Big Three: Squat, DL, BP!

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Linear vs. Undulating Periodizationt

12% Body Fat in 12 Weeks W/ Periodizatoin

Detraining + Periodization - How to?

Tapering 101 - Learn How It's Done!

With at least 6 months of training experience at a frequency of three intense strength workouts per week, the subjects in Freitas de Salles's study are allegedly not as experienced as those in the previously discussed study by Schoenfeld et al. (2015), but they are by no means absolute rookies. If the scientists' initial hypothesis "that selfsuggested RI would result in similar performance to
the 2-min RI, with a shorter session" (Freitas de Salles. 2016) was confirmed in the study, there would thus be at least a good chance that the same results would be observed for better-trained athletes when they perform a workout the scientists describe as follows:

"Before the 1RM test, subjects performed standardization and familiarization set in each exercise, cor recting possible mistakes in the performance of exercises. Between different exercises a 5 min rest was given, and up to three attempts for each exercise with a three to 5 min RI were performed. Before each test a warm-up set in each exercise with 10 repetitions at 50% of 1RM self-perceived load was performed. After the 1RM test and retest a minimum interval of 48 h before ST sessions were adopted. All 1RM tests and all sets in ST sessions were closely super vised by an examiner to avoid facilitative movements or incomplete range of motion applied.  

The 75% 1RM load was stipulated, aiming to keep sets in the 8–12 repetition range. The participants were tasked to perform three sets to concentric failure and no specific velocity was determined to perform the exercises. Both groups attended the weight room on two separate days with an interval of 48 h between days for 2 min and self-suggested RI protocols. The order of different RIs applied was random and only the examiner had knowledge of what RI would be held before the sessions. The exercise sessions were accompanied by an experienced examiner who performed the count of the number of repetitions and controlled the RI duration without the participants knowing their rest time" (Freitas de Salles. 2016).

If you are now looking for the word "weeks" in the previous quote, you have already spotted a major problem with the design of the study at hand: Instead of evaluating the actual strength and size gains as it was done in the Schoenfeld study, Freitas de Salles et al. studied only the number of reps and the total volume (weight x reps) the subjects lifted on two different training days with either set or individual / selfdetermined inter-set rest periods.

Figure 2: Effective rest times (in s between sets) during the selfselected rest trial (Freitas de Salles. 2016).

Any statements about the effects on strength and size gains are thus necessarily based on the (scientifically not unwarranted) assumption that the total training volume (within the "optimal", i.e. "not overtraining" region) was the primary determinant of the adaptive response to exercise.

Figure 1: Repetition numbers for each exercise on three separate sets for 2 min and self-suggested RIs.
∗p < .05 from first set; #p < .05 from second set (Freitas de Salles. 2016).

So, if we assume that this stipulation was correct, the data in Figure 2 says: It doesn't make a difference, if you rest for the prescribed 2 minutes or start your next set after feeling recuperated - and since the selfdetermined rest times were >100 + X seconds, the study doesn't necessarily conflict with the previously cited study by Schoenfelt et al. (2016), because Schoenfeld's study tested "only" 60s and 180s. The 100 seconds + X of the selfdetermined rest in the study at hand is thus not so much off of the 3 minutes of rest in the Schoenfeld study or the 2 minutes, of which Willardson, et al. found in 2006 that they are sufficient to maximize the adaptive response to exercise.

Resting 3 vs. 1 Min. Between Sets Pays Off: Greater Size + Strength Gains - Probably Mediated by 15% Higher Volume | Learn more!

Bottom line: This is not the "we've proven it once and for all that you can rest as long as you see fit and make the optimal gains"-study. Why's that? Well, firstly, the study at hand did not directly investigate the long-term effects of resting only as long as it takes you to feel recovered (much less than 2 minutes) on the strength and size gains of the subjects.

The lack of significant effects on the overall training volume are - without question - a very good indicator that there wouldn't be a difference in the adaptive response, but it is not as reliable as the actual size and strength measures Schoenfeld et al. conducted in their 2015 study.

Moreover, there's secondly, the fact that the selfdetermined rest times in the study at hand were still pretty long. I personally know that some people will, if you tell them to rest only as long as it takes for the to recover from the previous set, rest for only 30s and that's quite certainly a bit too little rest ... you don't believe it? Record your set and rep numbers + weights and see if the total volume of your workouts sucks or not w/ only 30s of rest - 30s which are only 1/6 of the 3 minutes it takes for your ATP stores to recover to 85% of the initial levels (Ratamess. 2007) | Comment!

References:

• De Salles, Belmiro Freitas, et al. "Effects of fixed vs. self-suggested rest between sets in upper and lower body exercises performance." European Journal of Sport Science (2016): 1-5.
• Ratamess, Nicholas A., et al. "The effect of rest interval length on metabolic responses to the bench press exercise." European journal of applied physiology 100.1 (2007): 1-17.
• Willardson, Jeffrey M., and Lee N. Burkett. "The effect of rest interval length on bench press performance with heavy vs. light loads." The Journal of Strength & Conditioning Research 20.2 (2006): 396-399.

Resting 3 vs. 1 Min. Between Sets Pays Off: Greater Size + Strength Gains - Probably Mediated by 15% Higher Volume

Resting long enough to maximize your training volume could be the key to success, i.e. strength and size gains.

If you have been following the various affords to ascribe differences in strength and, even more so, size-increases to a specific training variable, you will remember that the only promising parameters that appear to be supported by more than the literal "outlier study" are training load and volume.

Of these, the former is pretty much uncontested. The latter, however, is still questioned by a camp of inconvincible skep- tics, who simply ignore the fact that there's ample evidence that "[h]igher-volume, multiple-set protocols have consistent- ly proven superior over single set protocols with respect to increased muscle hypertrophy" (Schoenfeld. 2010).

It would be interesting to see if rest periods should also be periodized!

30% More on the Big Three: Squat, DL, BP!

Block Periodization Done Right

Linear vs. Undulating Periodizationt

12% Body Fat in 12 Weeks W/ Periodizatoin

Detraining + Periodization - How to?

Tapering 101 - Learn How It's Done!

What still isn't clear, though, is the role of other training parameters, such as the time you take to recover between multiple sets and exercises aka the "rest intervals". As Schoenfeld et al. point out in the introduction to their most recent study, "several studies have investigated the effects of varying rest interval length on muscular adaptations," (Schoenfeld. 2015) albeit with contradictory results: While Ahtiainen et al (2005) were unable to find a significant inter-group size or strength difference in well-trained subjects (6.6 +/- 2.8 years of continuous strength training) who rested 2 minutes compared to those who rested only 5 minute in response to their 21-week training intervention, Buresh et al (2005) reported more recently that significantly greater size increases of the arms and a trend for greater muscle hypertrophy in the legs in young, albeit untrained subjects who rested for 2.5 minutes instead of just one.

Figure 1: Previous studies found "conflicting" evidence. While Ahtiainen et al. found no effects of 2 vs. 5 minutes in trained, Buresh et al. found effects of 2 vs. 1 minutes rest in untrained subjects. With different subjects, different workouts and most importantly different rest times that were compared it is yet not exactly right to say that the studies contradict each other.

Now, obviously, the ostensible "contradiction" I alluded to in the previous paragraph does eventually not exist. With trained vs. untrained subjects, different workout protocols and most importantly different rest intervals (1 vs. 2 minutes and 2 vs. 5 minutes) the studies by Ahtiainen and Buresh cannot really contradict each other. The same must be said of an even more recent study by Villanueva et al. (2014) the surprising findings of which, i.e. "longer rest periods compromise the gains of older trainees", I've discussed last year, already.

What about the lack of different increases in strength endurance? I have to admit that I do not discuss this finding of the study in detail. While one would expect that shorter rest intervals would produce greater strength endurance adaptations, the researchers observed the opposite, an - albeit non-significantly larger increase in strength endurance in the 3-minute-rest group that correlated with the increase in 1RM strength. Further studies will have to show what the underlying mechanism of this counter-intuitive observation is and whether it may be muscle specific, i.e. occur only in the upper, but not in the lower body.

Eventually, however, this does not change that there is, as Schoenfeld et al. write that "a need for more research to provide greater clarity on the topic" (Schoenfeld. 2015). A "clarity" Schoenfeld et al. sought to find with a study that "used current rest interval recommendations for hypertrophy and strength of 1 versus 3 minutes, respectively, and employed validated measures to directly assess site-specific changes in muscle thickness" (ibid). In that, the researchers speculated that ...

"[c]onsistent with generally accepted guidelines on the topic (Willardson. 2006), we hypothesized that short rest intervals would produce greater increases in muscle growth and local muscle endurance while long rest intervals would result in superior strength increases" (Schoenfeld. 2015).

As you will know if you didn't miss the headline of this SuppVersity article, this hypothesis was only partly validated. The data in Figure 2 confirms that the subjects, "experienced lifters (defined as consistently lifting weights for a minimum of 6 months and a back squat / body weight ratio ≥ 1.0)" (Schoenfeld. 2015), gained significantly more strength, when they rested 3 versus just 1 minute between the 3 sets of their three weekly workouts (Figure 2 does also tell you that the strength endurance increases were identical in both groups).

Figure 2: Changes in markers of strength and strength endurance; * denotes significant pre- vs. post difference, # denotes significant inter-group difference (here in favor of long(er) rest periods | Schoenfeld. 2015).

What was Schoenfeld et al. did not find, however, were increased size gains in the short-rest period group whose 24 workouts that were performed on non-consecutive days over the course of the 8-week study period, were otherwise identical with those of the long-rest period group and comprised a total of 7 exercises for all major body parts, namely...

• three leg exercises, i.e. barbell back squats, plate-loaded leg presses, and plate-loaded leg extensions), 
• two exercises for the anterior torso muscles, i.e. flat barbell presses and seated barbell military presses, and 
• two exercises for the posterior torso muscles, i.e. wide-grip plate-loaded lateral pulldowns, and plate-loaded seated cable rows

This is a highly significant result even for you who is - according to an older SuppVersity Poll - probably training according to a split regimen, albeit most likely with very similar exercises. What may be different from the some, but obviously *smile* not your workout though, is that the supervision by members of the research team ensured that the subjects stuck to the prescribed cadence of 1 second for the concentric and "approximately 2 seconds" (ibid.) for the eccentric part of every the exercise. This as well as the imperative progression to higher weights, whence the prescribed number of 8-12 reps per set could be performed is unfortunately overlooked by many recreational trainees - with disappointing consequences in the form of inferior or even no size and strength gains, by the way... but I am digressing, let's rather take a look at the already mentioned, unexpectedly superior strength size gains in the long(er) rest interval group (Figure 3).

Figure 3: Changes in muscle thickness and corresponding effect sizes; * denotes significant pre- vs. post-changes, # denotes significant inter-group differences; overall it is obvious that there's a long(er) rest advantage (Schoenfeld. 2015).

As the single "#" in Figure 3 tells you, the inter-group differences and thus the advantage of the long(er) rest intervals was statistically significant only for the quads, though. If we also take into account the lack of statistically significant effects on the sleeve sizes (biceps and triceps) in the short rest interval group, as well as the obvious differences in effect sizes (Figure 3, right), there's yet little doubt that the hypothesis that shorter rest intervals yield greater size increases must be considered falsified - at least under the given experimental conditions (trained subjects, three full-body workouts per week, standard hypertrophy set and rep-ranges, etc.).

So what's the verdict, then? At first sight it would appear as if the study at hand would totally refute the idea that shorter rest intervals, or I should clarify, rest intervals that are as short as 60s (*) should have a place in your training regimen altogether (*Schoenfeld, et al. rightly point out that Ahtiainen's result suggest that even 120s could have been enough time to rest - it is thus important to give precise recommendations for rest intervals, not something as arbitrary "short" vs. "long"). We should not forget, though, that even a thoroughly conducted study like the one at hand has its limits and definite conclusions should not be drawn hastily based on a single study result - even if it is, as in this case, corroborated by the results of Buresh et al (2009).

Figure 4: The total training volume in the long(er) rest period group (3 vs. 1 minutes of rest) was on average 15% higher. Due to the relatively high inter-individual differences and the relatively low number of participants (N=21) a statistically significant correlation between the weight lifted per week (total volume in kg as in the figure) and the surprisingly superior gains in the 3-min-rest group could not be established (based on Schoenfeld. 2015).

With that being said, a secondary outcome of the study provides a reasonable explanation for why both, the strength and the size gains benefited from long(er) rest intervals: The total training volume I've plotted in Figure 4. As Schoenfeld et al. point out, the latter has previously been suspected to mediate the effects of inter-set rest on strength and hypertrophy on total training volume and strength (Henselmans. 2014). A correlation between the visible differences in training load (see Figure 4) and the magnitude of training adaptations, however, could not be found in the study at hand. As the authors highlight, the reason for this lack of statistical significant correlations may yet be a simple lack of statistical power, so that one "cannot rule out the possibility that the greater training load achieved by the longer rest period group was responsible for the greater training adaptations" (Schoenfeld. 2015 | Buresh et al. found such an effect for the upper, yet not for the lower body).

Personally, I tend to believe that, with a higher number of subjects, a correlation between the total training volume that was on average 15% higher in the 3 vs. 1 minute rest group could have been established. This, in turn, would support the notion that long(er) rest periods - maybe, as Schoenfeld et al. suggest based on the data from Ahtiainen's study, at least 120s - are necessary to maximize the total training volume and thus the overall = strength and hypertrophy response to workouts. Whether that is true for all types of workouts (e.g. split- vs. full-body), all subject groups (e.g. people who are used to short rest periods vs. those who are not) as well as special athletic requirements (e.g. power vs. strength & hypertrophy) will have to be determined in future studies, however | Comment on Facebook!

References:

• Ahtiainen, Juha P., et al. "Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men." The Journal of Strength & Conditioning Research 19.3 (2005): 572-582.
• Buresh, Robert, Kris Berg, and Jeffrey French. "The effect of resistive exercise rest interval on hormonal response, strength, and hypertrophy with training." The Journal of Strength & Conditioning Research 23.1 (2009): 62-71.
• Henselmans, Menno, and Brad J. Schoenfeld. "The Effect of Inter-Set Rest Intervals on Resistance Exercise-Induced Muscle Hypertrophy." Sports Medicine 44.12 (2014): 1635-1643.
• Schoenfeld, Brad J. "The mechanisms of muscle hypertrophy and their application to resistance training." The Journal of Strength & Conditioning Research 24.10 (2010): 2857-2872.
• Schoenfeld, et al. "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance trained men." Journal of Strength and Conditioning Research (2015): Publish Ahead of Print.
• Villanueva, Matthew G., Christianne Joy Lane, and E. Todd Schroeder. "Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men." European journal of applied physiology (2014): 1-14.
• Willardson, Jeffrey M. "A brief review: factors affecting the length of the rest interval between resistance exercise sets." The Journal of Strength & Conditioning Research 20.4 (2006): 978-984.

BFR Preconditioning Not Better Than Placebo? Long Rest Periods For Sustained Testosterone Increase? Train One Leg, Grow Both? - Resistance Training Update October '14

Single-legged leg presses that make both legs stronger are only one of many topics, today.

Time for an update on the latest resistance training research - just the interesting stuff, obviously ;-) What exactly? Well, let's see: We'll take a look at how long rest periods sustain the exercise induced. Then, we'll dive right into a placebo-controlled study on blood flow restriction as a means of preconditioning before resistance training, only to top things off with a study that found that training your dominant leg will also increase the leg press strength of the untrained, non-dominant limb.

Ah, and since there was some space left in the bottom line, we will acknowledge that AM vs. PM training have identical effects on power, force and hormonal response in young men and pretend to be surprised that a three-set upper-body workout is much more energetically demanding than its one-set analog. All in all, a very balanced update on the latest resistance training research, I'd say.

Read more about exercise-related studies at the SuppVersity

Tri- or Multi-Set Training for Body Recomp.?

Aug '15 Ex.Res. Upd.: Nitrate, Glycogen, and ...

Pre-Exhaustion Exhausts Your Growth Potential

Full ROM ➯ Full Gains - Form Counts!

Body Pump, Cardio & Exercise Expenditure

Study Indicates Cut the Volume Make the Gains!

• Long rest periods prolong testosterone response to bench press exercise -- From various previous SuppVersity articles you know that resistance training triggers an acute increase in testosterone. That this increase may depend on the rest between sets, though, is news. News from a recent article in the Journal of Strength and Conditioning Research.
  
  The purpose of the study was to examine the influence of rest period duration (1 vs. 3-minute between sets) on acute hormone responses to a high intensity and equal volume bench press workout (5x3 sets at 85% of the 1RM, to be specific).
  

  

  Figure 1: Mean (left) and individual (right) free testosterone levels before and after performing bench presses with 1 min or 3 min rest (Scudese. 2015).

  To this ends, Scudese et al. (2015) recruited ten resistance trained men (25.2 +/- 5.6 years; 78.2 +/- 5.7 kg; 176.7 +/- 5.4 cm; bench press relative strength: 1.3 +/- 0.1 kg/kg of body mass) and had them perform two bench press workouts separated by one week. Each workout consisted of 5 sets of 3 repetitions performed at 85% of 1-repetition maximum, with either 1 or 3-minute rest between sets. The rates of perceived exertion and serum levels of growth hormone (GH), cortisol, free and total testosterone were sampled at three different timepoints right (PRE), right after (T0) before, 15 (T15) and 30 (T30) minutes after. The results were as follows:
  • For total testosterone, both rest lengths enhanced all post-exercise verifications (T0, T15 and T30) compared to PRE, with 1-minute showing decreases on T15 and T30 compared to T0.
  • For free testosterone, both 1 and 3-minute rest protocols triggered augmentations on distinct post-exercise moments (T0 and T15 for 1-minute; T15 and T30 for 3-minute) compared to PRE.
  • Since the the cortisol values did not change throughout any post-exercise verification for either rests, the total testosterone/cortisol ratio was significantly elevated for both rests in all post-exercise moments compared to PRE.
    The growth hormone values did not change for both rest lengths.
  Now, that's exciting, right? The free testosterone levels kept increasing... well, not exactly. If you look at the data in Figure 1 right, you will notice interpersonal differences that suggest that the elevation would not have lasted for much more than those 15 extra-minutes .
  
  What's of significantly greater importance for the interpretation of the study results is yet a study by West et al. (2012) who observed that the testosterone response (both free and total) to resistance training is not associated with either strength or size gains. So what? It is very likely that the results of the study at hand are of zero practical relevance for your gains (strength- and sizewise, as West's study indicates).
• Blood flow restriction before strength training? It works - just as well as placebo! -- You will probably remember my recent article about the benefits of using blood flow restricting cuffs before a sprint workout, right (click here if not)? With the publication of the results of Moacir et al.'s (2015) latest study, we do now know that similar benefits will be seen with subsequent resistance training, too.

  

  The study at hand should make you question the results of the previously discussed study which did not have a placebo group | learn more

  "Thirteen men participated in a randomized crossover design that involved 3 separate sessions (ischemic preconditioning, placebo and control). A 12-RM load for the leg extension exercise was assessed through test and retest sessions prior to the first experimental session. The IPC session consisted of 4 cycles of 5 minutes occlusion at 220 mmHg of pressure alternated with 5 minutes of reperfusion at 0 mmHg for a total of 40 minutes. The PLACEBO session consisted of 4 cycles of 5 minutes of cuff administration at 20 mmHg of pressure alternated with 5 minutes of pseudo-reperfusion at 0 mmHg for a total of 40 minutes. 

  The occlusion and reperfusion phases were conducted alternately between the thighs, with subjects remaining seated. No ischemic pressure was applied during the control (CON) session and subjects sat passively for 40 minutes. Eight minutes following IPC, PLACEBO or CON, subjects performed three repetition maximum sets of the leg extension (2min rest between sets) with the pre-determined 12-RM load. Four minutes following the third set for each condition, blood lactate was assessed" (Moacir. 2015)

  When the researchers analyzed the results, they found that for the first set, the number of repetitions significantly increased for both the IPC (13.08 +/- 2.11; p = 0.0036) and PLACEBO (13.15 +/- 0.88; p = 0.0016) conditions, but not the CON (11.88 +/- 1.07; p > 0.99) condition.
  

  

  Figure 2: Significant increases in the number of reps (left) were observed for both the placebo and IPC group. The fatique index (right) did not differ between treatments, but the large inter-individual variety in the IPC group clearly suggests that BFR as a means of preconditioning ain't for everyone (Moacir. 2015).

  Similarly, the IPC and PLACEBO conditions resulted in significantly greater repetitions versus the CON condition on the 1st set (p=0.015; p=0.007) and 2nd set (p=0.011; p=0.019), but not the 3rd set (p=0.68; p>0.99). No significant difference (p=0.465) was found in the fatigue index and lactate concentration between conditions.
  
  As the researchers point out, their results "indicate that IPC and PLACEBO ischemic preconditioning may have small beneficial effects on repetition performance over a CON condition" (Moacir. 2015). It is thus not completely logical that they suggest "that ischemic pre-conditioning might be practiced gradually to assess tolerance and potential enhancements to exercise performance" (ibid.). What? Oh, you think your clients would notice that their blood flow is not actually impaired and the placebo effect would be lost? Right, now I understand why you should keep using it. Unfortunately that does not exclude that it is still a placebo effect which seems not unlikely in view of the larg(er) inter-individual differences in the IPC vs. any other group. Further studies are necessary... obviously!
• Train your right leg, and your left leg will become stronger, too - on leg presses, at least -- What sounds like a joke (or magic) is actually science. Science that is going to be presented in an article in a future edition of the Journal of Strength and Conditioning Research; and more precisely from a study that assessed the cross education of strength and changes in the underlying mechanisms (muscle size, activation, and hormonal response) following a 4-week unilateral resistance training (URT) program.
  
  In said study by Beyer et al. (2015), a group of nine untrained men completed a 4-week URT program on the dominant leg (DOM), while cross education was measured in the non-dominant leg (NON); and were compared to a control group (n=8, CON).

  "Unilateral isometric force (PKF), leg press (LP) and leg extension (LE) strength, muscle size (via ultrasonography) and activation (via electromyography) of the rectus femoris and vastus lateralis, and the hormonal response (testosterone, growth hormone, insulin, and insulin-like growth factor-1) were tested pre- and post-training" (Beyer. 2015).

  In all strength and size related measures, the trained group improved significantly better than CON. Significant group x time effects for PKF, LP, LE, and muscle size were observed only in the dominant leg (DOM), the non-dominant (NON = untrained leg), on the other hand, the scientist observed not just a trend, but rather an actual and statistically significant increase in leg press strength.
  

  

  Figure 3: Relative leg press and leg extension strength relative to body weight; the values above the post-bars indicate the relative difference between post and pre-test (2015).

  Whether that's related to the acute hormonal response to URT, the scientists observed, is more than questionable, after all the strength increase in the non-dominant leg didn't just occur in the absence of "detectable changes in muscle size, activation (EMG), or the acute hormonal response" it did also occur only during leg presses - if it was the result of any of the aforementioned factors one would expect to see at least something like a trend for leg extensions, as well.
  
  Against that background it should also be clear that you must not neglect one leg or arm when you train in the definitely false hope it would grow and the almost certainly false hope it would get stronger as you train your "favorite" limb. 

There's more: In view of the fact that the bottom lines to the individuals studies discussed in SuppVersity Research Overviews are always provided at the end of the respective item, I have room for mentioning two other interesting results at least briefly.

Figure 4: Energetic demands of 5x3 vs. 5x1 set upper body workout in men and women. Needless to say that the inter-group difference between 3 vs. 1 sets and the inter-group difference between men and women (not shown) were significant (Mookerjay. 2015).

Firstly, Hatfield et al.'s study of the "Effects of circadian rhythm on power, force, and hormonal response in young men" that indicates that "high force and power exercises utilizing  bench press-throws or jump squats may be performed any time of day without detrimental decreases in acute performance" (Hatfield. 2015). And secondly, Mookerjay et al.'s "[c]omparison of energy expenditure during single vs. multiple-set resistance exercise" (Mookerjay. 2015) that yielded a very obvious result which was that the multi-set protocols yield greater metabolic and cardiovascular demands than single set protocols when the number of exercises performed are the same (see Figure 4). In the study 5 upper-body exercises of either 1 or 3 sets per exercise performed in random order the gross and net energy expenditure was determined for the workout + 5 minutes of recovery. You can see the exact data in Figure 4, in case you're interested | Comment on Facebook!

References:

• Beyer, et al. "Short-Term Unilateral Resistance Training Results in Cross Education of Strength without Changes in Muscle Size, Activation, or Endocrine Response." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Hatfield, et al. "Effects of circadian rhythm on power, force, and hormonal response in young men." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Moacir, et al. "Ischemic preconditioning and placebo intervention improves resistance exercise performance." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Scudese et al. "Long rest interval promotes durable testosterone responses in high intensity bench press." Journal of Strength and Conditioning Research (2015): Ahead of print.
• West, Daniel WD, and Stuart M. Phillips. "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training." European journal of applied physiology 112.7 (2012): 2693-2702.

Training to Failure and Modifying Rest Times: Two Ways to Maximize Muscle Activity? Two Studies, Similar Implications

This is what science looks like... Well, at least in the Hiscock study, where the subjects, 10 young men with at leas 12 months of training experience did regular and hammer dumbbell curls on the preacher bench - (photo | Hiscock. 2015).

In today's SuppVersity feature article, I am going to address not one, but two potentially highly relevant articles from the Journal of Strength and Conditioning Research (Looney. 2015) and the European Journal of Sport Science (Hiscock. 2015). What makes these papers interesting is the fact that both investigated the effect of commonly prescribed remedies to "bust a plateau" by providing novel growth triggers: (a) Training to failure and (b) modifying rep schemes and whether you fail or don't fail on every set.

If you believe in what you can read in many articles on strength training, both, training to failure and decreasing rest times / drop sets should significantly increase the muscle activity and thus - this is the most important thing - the number of motor units that are recruited during the exercises.

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But is this actually true? I mean, is there a link between EMG activity, the number of motor units that are firing and the way you train? I guess, it would be wise to take a brief look at the pertinent research before we get to design and results of the individual studies. So, what do we have? As Looney et al. point out, motor unit activity can be measured through electromyography (EMG) which is commonly considered to reflect the neural drive to the muscle. Since the electrical impulse should be proportional to the number of motor units that are firing and in view of the fact that the latter determines the acute force output, it should be obvious that increasing force demands result in higher EMG amplitude due to the greater recruitment of motor units and faster firing rates necessary to increase the contractile force.

Figure 1: Previous studies show that the motor unit recruited (or at least it's indicator, the mean EMG values) increases over the duration of sustained or repeated muscle actions at a constant force level (Masuda. 1999 - l; Mottram. 2005 - r)

Unfortunately, more does not necessarily help more. If you take a closer look at the existing research you have to realize you cannot stretch this proven increase of the EMG amplitude (Carpentier. 2001; Fuglevand. 1993; Lind. 1979; Masuda. 1999; Mottram. 2005; Petrofsky. 1982) infinitely. Over prolonged exercise / contraction times, the initially increasing firing rates will eventually decrease. That this is the case is interpreted by many scientists as evidence of the the fact that the initial rise in EMG amplitude is just a compensatory mechanism for sustaining contractile force as fatigue accumulates (when the individual fibers fatigue, more are recruited to sustain the same force). This hypothesis appears to be confirmed by numerous investigations that have demonstrated that EMG amplitude increases during dynamic exercise as the extent of the effort, or number of repetitions performed, increases (Hasani. 2006; Spreuwenberg. 2006; etc.).

Why is it even important that all muscle fibers contract? The reason should be obvious, but I am happy to explain it once more. It is the contraction that's responsible for the exercise induced increase in GLUT-4 receptor expression and mTOR phosphorylation. In view of the fact that the latter determine the increase in glucose uptake and protein synthesis after a workout, you obviously want as many muscle fibers to contract as possible. Or, to put it differently: If you don't use it you won't grow it, bro... well, at least not to the same / optimal extent.

This is where the "train to failure to maximize motor unit recruitment"-theory comes from. After all, this observation indicates that usually inactive motor units are going to fire only during prolonged training at high intensities (best to failure). As usual, though, there are problems with this theory:

"While the increase in EMG amplitude observed during repeated muscle actions has been explained by increased central drive necessary to sustain force as fatigue accumulates, it is inconclusive whether fatigue derived from earlier performed exercise induces greater EMG amplitude during subsequent exercise. Previous studies have shown EMG amplitude diminishes after strenuous resistance exercise protocols. In contrast, Smilios et al. demonstrated progressive increases in EMG amplitude over a series of 20-repetition sets with gradually decreasing resistance interspaced with 2-minute rest periods. Further uncertainly exists pertaining to consecutive maximal effort sets with progressively lighter resistance performed without allotted rest periods. This frequently incorporated training technique, commonly known as a “drop set”, has remained relatively uninvestigated" (Looney. 2015).

Needless to say that we all expect that lighter weights can stimulate greater motor unit recruitment, if you use them in dropsets, but as Looney et al. say, the science that would conclusively confirm that is simply not there (yet). The goals of Looney's study were thus as follows:

• Firstly, confirm / refute the assumption that EMG amplitude would be significantly greater in light resistance exercise (50% 1RM) performed in rested conditions to a maximal number of repetitions than to a submaximal number of repetitions. 
• Secondly, assess whether the EMG amplitude would be significantly lower in maximal repetition sets performed in rested conditions with 50% 1RM resistance than with heavy resistance (90% 1RM). 
• Thirdly, test whether the EMG amplitude would be greater in maximal repetition 50% 1RM resistance sets performed in pre-fatigued conditions (no prior rest period) than in rested conditions. 

As the authors rightly point out, the "findings of this investigation would provide critical information on understanding the changes in neuromuscular physiology during dynamic exercise related to variable levels of target repetitions, resistance, and fatigue" (Looney. 2015) and may thus be of great value to scientists (initially, because the would have to still check the practical consequences of any increases in motor recruitment) and coaches + athletes (later). What the Hiscock study in which the researchers evaluated the rate of perceived exertion (RPE) and its correlation with muscle activation and lactate levels can add to the table is information on the effect of another parameter: Different rest times.

If you don't do them as an intensity add-on / finisher don't do partial reps at all - "Full Rom, Full Gains" | more

Don't forget that form, time under tension and the range of motion matter, as well. In 2013, for example, I discussed the results of a study by McMahon et al. that leaves little doubt that the increased mechanical stress and workload (remember work is the product of force x time) from doing exercises over the full range of motion will trigger greater morphological and architectural adaptations in response to resistance training than doing the same exercises over only a partial range of motion. Unfortunately, the evidence in favor of the significance of optimal form (beyond going over the full range) and the time under tension for optimal gains is less convincing and in parts contradictory.

In order to avoid any confusion, though, let's initially look at the Looney study in isolation. In said study ten resistance trained men (age, 23±3 yr; height, 187±7 cm; body mass, 91.5±6.9 kg; squat 1RM, 141±28 kg) had EMG electrodes attached to their vastus lateralis and vastus medialis muscles on two occasions:

• A drop set day, on which he subjects performed three consecutive maximal repetition sets at 90%, 70%, and 50% 1RM to failure with no rest periods in between. 
• A single set day, on which the subjects performed a maximal repetition set at 50% 1RM to failure (no "dropping" involved). 

The analysis of the EMG data yielded overall unambiguous results: The maximal repetition sets to failure at 50% and 70% 1RM resulted in higher peak EMG amplitude than during submaximal repetition sets with the same resistance. In view of the fact that the peak EMG amplitude was significantly (P ≤ 0.05) greater in the maximal 90% 1RM set than on any of the other sets the subjects performed, the classic drop set with 90%, 70% and 50% 1RM should thus still have an edge over any regular "low intensity + high rep to failure" single set training. The question remains, however, whether it will also have the edge over conventional training?

Figure 2: Very general summary of the research interests and designs of the two studies discussed in today's SuppVersity article by Looney et al. (2015) and Hiscock et al. (2015)

We will get back to that question in the bottom line. In the mean time, let's briefly take a look at another, quite surprising result, one that will also lead us to the results of the previously mentioned study by Hiscock et al. (2015): The lack of association between the ratings of perceived exertion (CR-10). In contrast to what most of you certainly expected, the fatigue levels did not differ over the intensity range of loads and did not reflect the degree motor unit recruitment in any way (see Figure 3). You as an individual without the necessary technical equipment are thus probably unable to tell hor many motor units you've actually recruitment in a workout; and - even more importantly - the mere fact that you have to crawl instead of walk out of the gym is not a sign of a productive workout.

Figure 4: Mean number of repetitions (left, top), rate of perceived exertion (RPE | left, bottom), and peak EMG amplitude as a measure of motor recruitment (Looney. 2015).

You don't want to believe that? Well, bad luck for you: This result appears to be confirmed by Hiscock's study, in which 10 recreationally trained (>12 months of previous resistance training) did DB Curls and DB Hammer Curls on the preacher bench for three sets with their preferred arm at a constant load of 70% of their individual 1-RM over 4 trials:

1. 3 sets × 8 repetitions × 120 s recovery between sets; 
2. 3 sets × 8 repetitions × 240 s recovery; 
3. 3 sets × maximum number of repetitions (MNR) × 120 s recovery; 
4. 3 sets × MNR × 240 s recovery.

After each of the exercises the participants rated their overall and active arm muscle rate of perceived exertion (RPE-O and RPE-AM) and the data was correlated with the biceps brachii and brachioradialis muscle EMG activity during each set for each trial.

Figure 5: Despite sign. higher volumes (see boxes) and a 100% increase in rate of perceived local muscular exertion there was no significant increase in muscle activity with lifting 70% of the 1RM for 8 vs. to failure (Hiscock. 2015).

Just like in the Looney study, the measured rates of perceived exertion in the Hiscock study had did not correlate with with either the muscle activation or the lactate accumulation in the biceps. Rather than that, it appears as if the subjects' bicepses didn't even care about rep schemes and failure. While the RPE increased significantly, when the subjects trained to failure, the mean and peak EMG activity levels in Figure 5 are more or less identical for all rep x intensity (+/- failure) schemes.

So what's the significance of the results, then? If you put some faith into Looney's conclusion, it is that the results of his (and I may add Hiscock's study, too) confirm "previous recommendations for the use of heavier loads during resistance training programs to stimulate the maximal development of strength and hypertrophy" (Looney. 2015).

SuppVersity Suggested Topical Article: "Failure, a Necessary Prerequisite for Max. Muscle Growth & Strength Gains? Another Study Says 'No Need to Fail, Bro!'" | read more

Reducing the load and training to failure (Looney's "single set" day) or reducing the rest times and or switching from a set rep number to training to failure (Hiscock's groups A-D), on the other hand, has no effect on motor recruitment and could, in view of potentially increased recovery times due to higher rates of perceived exertion w/ training to failure, rather hinder than facilitate rapid strength and size gains. Whether the same is the case for the drop-set, though, is not 100% clear. With the peak muscle activity occurring in the first set, you cannot argue that the stimulus was weakened. On the other hand, there's a proven reduction in total volume (reps x weight | Melibeu Bentes. 2012) of which long-term studies would have to investigate whether the can impair your strength and size gains.

Overall, there is still little doubt that the results of the two studies I discussed today support the notion that "going heavy" is still the way to activate a maximal number of muscle fibers. Whether this does also mean that it is necessarily the best way to make those fibers grow and or increase their glucose uptake, however, is still not fully proven. The same goes for the usefulness of training to failure, of which some studies suggest that failure does not matter, while others appear to indicate that "failing" is almost necessary to maximize your gains - as usual, I've written about both of them and will continue to do so in the future, so stay tuned if you want to be among the first to learn what works best for strength and hypertrophy training ;-) | Comment on Facebook!

References:

• Carpentier, Alain, Jacques Duchateau, and Karl Hainaut. "Motor unit behaviour and contractile changes during fatigue in the human first dorsal interosseus." The Journal of physiology 534.3 (2001): 903-912.
• Fuglevand, A. J., et al. "Impairment of neuromuscular propagation during human fatiguing contractions at submaximal forces." The Journal of physiology 460.1 (1993): 549-572.
• Gibson, A. St Clair, E. J. Schabort, and T. D. Noakes. "Reduced neuromuscular activity and force generation during prolonged cycling." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 281.1 (2001): R187-R196.
• Hassani, A., et al. "Agonist and antagonist muscle activation during maximal and submaximal isokinetic fatigue tests of the knee extensors." Journal of Electromyography and Kinesiology 16.6 (2006): 661-668.
• Hiscock, Daniel J., et al. "Muscle activation, blood lactate, and perceived exertion responses to changing resistance training programming variables." European Journal of Sport Science ahead-of-print (2015): 1-9.
• Lind, Alexander R., and Jerrold S. Petrofsky. "Amplitude of the surface electromyogram during fatiguing isometric contractions." Muscle & nerve 2.4 (1979): 257-264.
• Looney, David P., et al. "Electromyographical and Perceptual Responses to Different Resistance Intensities in a Squat Protocol: Does Performing Sets to Failure With Light Loads Recruit More Motor Units?." The Journal of Strength & Conditioning Research (2015).
• Masuda, Kazumi, et al. "Changes in surface EMG parameters during static and dynamic fatiguing contractions." Journal of Electromyography and Kinesiology 9.1 (1999): 39-46.
• McMahon, Gerard E., et al. "Impact of range of motion during ecologically valid resistance training protocols on muscle size, subcutaneous fat, and strength." The Journal of Strength & Conditioning Research 28.1 (2014): 245-255.
• Mottram, Carol J., et al. "Motor-unit activity differs with load type during a fatiguing contraction." Journal of neurophysiology 93.3 (2005): 1381-1392.
• Petrofsky, Jerrold Scott, et al. "Evaluation of the amplitude and frequency components of the surface EMG as an index of muscle fatigue." Ergonomics 25.3 (1982): 213-223.
• Smilios, Ilias, Keijo Häkkinen, and Savvas P. Tokmakidis. "Power output and electromyographic activity during and after a moderate load muscular endurance session." The Journal of Strength & Conditioning Research 24.8 (2010): 2122-2131.
• Spreuwenberg, Luuk PB, et al. "Influence of exercise order in a resistance-training exercise session." The Journal of Strength & Conditioning Research 20.1 (2006): 141-144.