Not Resting Long Enough May Ruin Your Gains! 1 vs. 5 min Cut Post-Workout Increase in Protein Synthesis by 50% !

Not Resting Long Enough May Ruin Your Gains! 1 vs. 5 min Cut Post-Workout Increase in Protein Synthesis by 50% !

build muscle gains gainz hypertrophy inter-set rest muscle protein synthesis protein synthesis rest rest intervals

Rest is not a waste of time ;-)

You may remember Schoenfeld et al's 2015 study with the telling title "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men" (Schoenfeld. 2015) and Henselmann's and Schoenfeld's previous review of "The Effect of Inter-Set Rest Intervals on Resistance Exercise-Induced Muscle Hypertrophy" stating that "the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard" (Henselmann. 2004).

Eventually, it can thus not be surprising that James McKendry and colleagues write in their latest paper that "short rest (1 min) between sets of moderate-intensity, high volume resistance exercise blunts the acute muscle anabolic response compared with a longer rest period (5 min), despite a superior circulating hormonal milieu," and conclude that their "data have important implications for the development of training regimens to maximize muscle hypertrophy" (McKendry).

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What may be surprising, though, is the extent (see Figure 2) to which the post-exercise protein synthesis the researchers measured in young male subjects who habitually performed lower-limb resistance training at least once per week for ≥1 year prior to study enrollment and were deemed ‘recreationally trained’, when they had them do the same leg workout

• 4 sets of leg press and 4 sets of knee extension exercise at 75% of 1RM
• performed w/ a lifting-lowering cadence of ~1 sec in both concentric & eccentric phases, 
• without pause, until momentary muscular failure (i.e. 9-10 on the Borg CR-10 scale). 

with either five minutes or one minute of passive rest between sets and gave them 25g of whey protein isolate (MyProtein, Cheshire, UK) right after the workout to kickstart the protein synthesis.

Figure 1: Overview of the initial (Trial 1) and next morning procedures (Trial 2 | McKendry. 2016).

After having ingested the whey protein shake, the participants rested in both trials supine for 240 minutes. After those 4h, another muscle biopsy was obtained ~3cm proximal to the second biopsy to determine MPS rates over the ‘early’ phase (0-4 h) of post-exercise recovery. The data from this phase was complemented by data from a last, fourth muscle biopsy on the next morning and after consuming an identical protein shake after 10h of fasting (lunch and dinner on the day before were standardized, so that this would not mess with the results).

Figure 2: Protein synthetic (myofibrillar) and hormone response after working out with 1 vs. 5 min rest (McKendry. 2016).

Whether and to which extent the sign. difference in protein synthesis of which the scientists say that it is an 76% vs. 152% increase in the 0-4h time-window after the workout is related or even triggered by the significantly higher GH response in after the 5-min rest trial is questionable, but if you recall the seminal paper by West et al. (2012), you will certainly remember that GH and cortisol are the only hormones the levels of which after a workout show any correlation with muscle gains (see Figure 3).

Figure 3: Sign. associations between PWO hormone levels and lean mass, as well as fiber size increases (West. 2012).

With that being said, you may consider this odd, because usually the metabolically more demanding short-rest workout will yield greater GH increases (Kraemer. 1990; Goto. 2004; Bottaro. 2009) - this and the fact that the previously hinted at association exists, but the incline or, in other words, the effect on fiber size per unit increase in GH is low (too low to fully explain the 5-minute-advantage) suggest that there must be more to it than the small GH increase with 5 minutes vs. 1 minute rest.

Why do other studies not confirm this finding? I guess that depends on the study. An often-cited paper by Kraemer, et al. for example found 1 minute of rest to outperform 3 minutes hypertrophy-wise - probably because the 1-min rest protocol involved 3 sets of 8 exercises with a 10-RM load, while the 3 minute protocol involved "only" five sets of five exercises, performed with a 5-RM load, so that the two workouts were not volume equated and the study no comparison of workouts with different rest times, but rather one of hypertrophy vs. strength workouts.

Acute effect of different rest intervals between sets over the number of repetitions maximum (RM). Values expressed as RM (de Salles. 2009)

Conflicting results from other studies, e.g. Villanueva, et al. (2015) who found sign. greater muscle gains in with 1 vs. 4 minutes of rest, may be explained by differences in the study population (elderly in Villanueva, et al.) and/or the training protocol, which did not involve training to failure and thus probably didn't produce significant volume advantages for the 4-minute rest group. Eventually, volume appears to be, within sustainable limits, the most sign. determinant of the hypertrophy response to exercise, so if you do something to increase it (e.g. myoreps or real vs. volume- equated drop sets, etc.) you may still benefit. If you simply cut the rest, however, the volume suffers from not resting long enough (cf. table on the left) and this may affect your gains.

The existing differences in  anabolic signaling protein phosphorylation (e.g. p70S6KThr389, rpS6Ser240/244, 4EBP1Thr37/46, etc.) can likewise not serve as a mechanistic explanation. After all, these are the switches that trigger the growth. Saying they are responsible would be tantamount to saying that the light switch is the reason the light went out, when someone actually switched it off.

So, what is it that makes the difference? Well, in view of the results of previous studies that suggest that, ultimately, it's not hormones, not protein phosphorylation, but rather the total volume of weight that is lifted (at least unless that's so much that you do more harm than good) that determines the hypertrophy response to resistance training (Schoenfeld. 2013), we should look at a different study outcome: the total volume in kilograms (see Figure 4):

Figure 4: Set- and total volume when subjects trained with 1 vs. 5 minutes rest (McKendry. 2016).

That the sign. difference in volume on set 3 and 4, and the significant difference in total volume are actually the explanation, is obviously speculative, but at least for me it is the most likely explanation for a difference (see red box, as well).

The ineffectiveness of drop-sets in Fisher's recent study may in fact also have been a result of a lack of difference in training volume | more

Bottom line: Eventually, the study at hand only proves what we already knew - training volume is more important than metabolic stress when it comes to hypertrophy gains.

Any training regimen / modification that reduces the total volume of weight lifted may thus potentially compromise your gains... if the volume is in fact all that is to the effects of shortening rest times will obviously still have to be determined. As of now, volume is yet the best explanation for the differences or lack of differences and effects scientists observed in this and previous studies such as the recently discussed dropset study by Fisher et al. where the set-volume standardization may have blocked any sign. advantage of real-world (=add-on) dropsets | Discuss!.

References:

• Bottaro, Martim, et al. "Effects of rest duration between sets of resistance training on acute hormonal responses in trained women." Journal of science and medicine in sport 12.1 (2009): 73-78.
• de Salles, Belmiro Freitas, et al. "Rest interval between sets in strength training." Sports Medicine 39.9 (2009): 765-777.
• Goto, Kazushige, et al. "Muscular adaptations to combinations of high-and low-intensity resistance exercises." The Journal of Strength & Conditioning Research 18.4 (2004): 730-737.
• 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.
• Kraemer, WJ, Marchitelli, L, Gordon, SE, Harman, E, Dziados, JE, Mello, R, Frykman, P, McCurry, D, and Fleck, SJ. Hormonal and growth factor responses to high intensity resistance exercise protocols. J Appl Physiol 69: 1442-1450, 1990.
• Schoenfeld, Brad J. "Postexercise hypertrophic adaptations: a reexamination of the hormone hypothesis and its applicability to resistance training program design." The Journal of Strength & Conditioning Research 27.6 (2013): 1720-1730.
• 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 (2015).
• 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 115.2 (2015): 295-308.
• 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.
• Willardson, Jeffrey M. "A Brief Review: How Much Rest between Sets?." Strength & Conditioning Journal 30.3 (2008): 44-50.

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

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

build muscle build strength rest rest times

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!

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Linear vs. Undulating Periodizationt

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

build muscle build strength hypertrophy rest rest intervals rest periods rest times

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

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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.