Title: Body By Science
In Body By Science by Doug McGuff and John Little claim that exercise science research that has shown that very brief, high intensity cardiovascular or strength training can produce results equal to if not better than higher volume, low intensity training protocols. Does the science they cite support them? In this review I will show that in fact the science they cite does not support their claims.
The Body By Science protocol consists of doing 1 set for each exercise, and 1-2 sets each muscle group, once weekly or less, using a deliberately very slow movement taking ~5-10 seconds for both concentric and eccentric phases of motion.
McGuff and Little claim that exercise must be performed extremely slowly to prevent traumatic joint injury, and yet also that just one set of exercise lasting 2-3 minutes does so much damage to a muscle that most if not all people need at least 7 days to recover from a single bout.
On page 57 of BBS, McGuff and Little report:
“According to the medical literature, the more intensely the muscles are made to contract, the more damage or microtrauma takes place at a cellular level.”
While this is a true statement, their claim that this facst means that most people need to rest at least one week between training sessions is not supported by the studies they cite. Here I will review those studies.
In the first, by Clarkson and Nosaka , is entitled “Muscle function after exercise-induced muscle damage and rapid adaptation,” which signals right off that McGuff and Little are selectively interpreting this study, as they appear to have ignored the “rapid adaptation” aspect.
Clarkson and Nosaka start their paper by stating “It is well established that strenuous, unaccustomed exercise produces damage to muscle tissue.” The key word here is “unaccustomed,” which signals that damage occurs when the body is not adapted to the exercise; but McGuff and Little appear to have ignored a key finding of this study which was that muscles rapidly adapt to exercise so that this damage is minimal or non-existent.
The study involved subjecting the forearm flexors (primarily biceps) to a single bout of maximal effort eccentric actions consisting of “two sets of 35 maximal eccentric actions, with one every 15 s.” Five minutes of rest was provided between the two sets.
It should be obvious that this is not ordinary resistance exercise. This is high force eccentric exercise of an unusual volume, namely a total of 70 maximal eccentric actions! This is not a normal training session, which might have 15-30 total repetitions for a muscle group, of which only 1-6 involve near maximal or maximal concentric contractions, which involve loads about 40% less than what one would use for maximal eccentric contractions. Thus, this study is not informative about what happens to muscle after a normal training session, and does not support the claim that one needs at least 7 days to recover from a normal training session.
Clarkson and Nosaka did find that this extreme eccentric protocol resulted in muscle damage and inflammation, and that the muscles did not recover their pretrial strength even after 10 days of recovery without any exercise. However, Clarkson and Nosaka note that this does not apply to normal exercise because “unlike eccentric exercise, the strength loss after concentric and isometric exercise is restored in the next several hours.”
Moreover, Clarkson and Nosaka reported rapid adaptation to this extreme protocol.
“We have found that performance of one bout of high-force eccentric exercise produced an adaptation such that less damage was produced when the same exercise was performed up to several months later. This adaptation could also be produced when the first exercise was less stressful and produced little change in the indicators of damage compared with the second exercise. More specifically, when subjects performed 24 maximal eccentric actions, this exercise produced an adaptation such that less damage than expected was observed 2 wk later when subjects performed a second exercise bout consisting of 70 eccentric actions.”
“Exactly when and how this adaptation is produced is not known. We have found that subjects who performed the second exercise 5 d after the first exercise already showed an adaptation response…Thus, some adaptation has already been produced before the muscle is fully restored.”
The bottom line is that this study does not support the Body By Science claim that a normal training session produces such extensive muscle damage that one needs at least 7 days to recover from it. It only describes what happens after an extreme protocol of 70 maximal eccentric actions. On top of that, it showed that the body rapidly adapts to even this extreme protocol, such that much less damage is produced in subsequent training sessions.
The second study  cited by McGuff and Little in Body By Science to support their claims again involved untrained subjects who had not done any endurance or resistance training of the lower body within the 6 months preceding the study. These untrained subjects were made to do ten sets of 10 repetitions of unilateral knee extensions, with either eccentric or concentric action, with 85% of either the eccentric or concentric 1 RM respectively. When fatigue prevented completion of at least 7 repetitions, the resistance was reduced on subsequent sets. This again was an extreme protocol in both volume and intensity.
Despite the use of an extreme protocol with untrained subjects, “strength measures had returned to baseline by day 7 of recovery.” In fact, the authors state that “The most striking result of this study was the essential eradication of eccentric-exercise-induced decreases in strength by a prior bout of such actions.” In other words, untrained individuals rapidly adapt to resistance training so that the muscles are more resistant to damage and recover more quickly after subsequent bouts.
Again, this study does not support the Body By Science claim that trained individuals will need 7 days of recovery after performance of 1-2 sets of normal resistance training to failure.
The third study cited also involved untrained subjects performing either 24 or 70 maximal eccentric arm flexor actions . This study in fact showed that the 24-MAX condition did not produce the same damage nor require the same recovery period as the 70-MAX condition. Further, performing the 24-MAX session 2 weeks before the 70-MAX session markedly removed recovery from the 70-MAX session. After the 70-MAX session without prior training, isometric force did not return to baseline by day 5. However, after the 24-MAX session isometric force returned to baseline by day 2, and after the 70-MAX session that was performed 2 weeks after a 24-MAX session, isometric force returned to baseline by day 1. This study therefore showed that muscles rapidly adapt even to very extreme exercise protocols, reducing recovery requirements to 24-48 hours. Again this study does not support the Body By Science protocol.
The fourth study  again used untrained subjects who had not been involved in strength training during the year prior to the study. They were made to perform eccentric-only actions with their elbow flexors using a load equal to 90% of their maximum isometric force ability. They performed the eccentric actions “until the subject could no longer limit the rate of lowering so as to keep the lowering with the prescribe period” of about 5-9 seconds, which was 5-15 repetitions. After 2 minutes of rest the load was reduced by 10% and they performed a second set in the same fashion. Then another 2 minute rest and another 10% reduction of the load, they performed a third set. In other words, three maximal eccentric sets.
No surprise, these untrained subjects got very sore and only slowly recovered from this extreme training session. On the tenth post-exercise day the subjects had only recovered about 70% of their baseline strength. Again we are dealing with individuals unaccustomed to training and an extreme training protocol that does not represent a normal training plan. It does not support the Body By Science claim that a trained individual needs a week or more to recover from a normal resistance training session.
The fifth study was done with rabbits . “The muscles of the anterior compartment in the limbs of rabbits were cyclically activated as the ankle was simultaneously moved through passive plantar flexion every two seconds for thirty minutes. This treatment imposed acute passive lengthening (eccentric contractions) of the maximally contracted muscles of the anterior compartment.” One action every 2 seconds for 30 minutes equals about 900 high-load eccentric actions! Again, no relevance to a normal training session which might have 15-30 total repetitions, and no support for the Body By Science Protocol.
The sixth study only argues that delayed onset muscle soreness (DOMS) is caused by inflammation . If you have any experience training, you will know that DOMS usually occurs only after long layoffs or introduction of new exercises. If you train regularly you will find that DOMS is generally mild to non-existent, because you are adapted to training.
The seventh study involved inducing muscle soreness by subjects performing 170 repetitions with 80% of their 10RM . Again this is an extremely large number of repetitions to perform within a single training session with such a load. This study does not tell us anything about the effects of a training session wherein one performs only 10-30 total repetitions, nor the can it tell us how long it takes to recover from such a session.
In short, none of these studies really supports the Body By Science protocol of one set to failure once weekly for each muscle group.
On page 59 of Body By Science, McGuff and Little also claim that “other studies, as previously mentioned, have looked at training frequency macroscopically, examining the effects of training different groups of people (from senior citizens to younger subjects) with one, two, or more workouts per week. All of these studies have also come to the conclusion that training once a week produces all of the benefits to be had from a workout program and that training more frequently serves no additional purpose.”
To support this universal claim ("all studies") they cite the following several studies.
The first  aimed to find “a more acceptable program for some sedentary older adults.” The exercise groups performed three sets of eight exercises at 80% of their current one-repetition maximum either 1, 2, or 3 days per week (EX1, EX2, and EX3 respectively). Over 24 weeks of training, EX1, EX2, and EX3 increased strength by averages of 37, 42, and 40 percent respectively. However, the deviations from the mean were 15, 18, and 10 percent respectively, suggesting that as frequency increased, the variation in response may have decreased.
Most importantly, this study involved at minimum 3 sets per muscle group/exercises once weekly (EX1), up to 9 sets weekly (EX3). This study can’t be used to support the Body By Science claim that 1 set once weekly – the Body By Science protocol – is as good as 3 sets once weekly or 1 set thrice weekly.
Further, these were untrained elderly individuals. As such, they were not adapted or accustomed to exercise. A dosing of once weekly may produce similar results to thrice weekly in such a population. However, we know that the body adapts to all stimuli by becoming more resistant to those stimuli. Therefore, people who have become accustomed to training might be more resistant to its stimulus, and therefore need more frequent training to overcome this resistance.
The Body By Science program fails to acknowledge the fundamental principle of adaptation. A person who follows a Body By Science program will be less adapted to exercise than someone who trains with greater volume and frequency. Simple as that. And as I will discuss below, research shows that adaptation is likely a prerequisite for hypertrophy.
This leads us to the second study, which involved experienced trainees . In the note section of Body By Science, page 261, McGuff and Little seriously misrepresent the second study. They claim:
“In this study subjects who had an average training history of 5.7 years were put on a whole-body training program, consisting of nine exercises performed either one or three times per week. After the study, a post-test conducted on eight out of the nine strength measures indicated that there was no statistical difference between the two groups, which led the researchers to conclude that training once per week delivered the same results as training three times per week.”
In fact, the researchers stated clearly that there was a significant difference between 1DAY and 3DAY frequency:
“The 1DAY group achieved ~62% of the 1RM increases observed in the 3DAY group in both upper-body and lower-body lifts. Larger increases in lean body mass were apparent in the 3DAY group. The findings suggest that a higher frequency of resistance training, even when volume is held constant, produces superior gains in 1RM. However, training only 1 day per week was an effective means of increasing strength, even in experienced recreational weight trainers. From a dose-response perspective, with the total volume of exercise held constant, spreading the training frequency to 3 doses per week produced superior results.”
In this study, subjects performed either 1 set to failure of 9 exercises thrice weekly, or 3 sets to failure of the same exercises once weekly. So, either of these study groups performed a total of 3 sets per muscle group per week, which is 1.5 to 3 times the volume prescribed by McGuff and Little in Body By Science. Therefore, it doesn’t support the Body By Science claim that 1 set once weekly per muscle group produces results comparable to any other volume of exercise.
The researchers also concluded:
“This finding demonstrates a large contribution of volume per session for a given protocol design because total work volume was held constant. Also, greater increases in strength were observed in the higher frequency group with and equal volume of training per week, suggesting that frequency is a key factor in strength adaptations.”
The 1DAY group gained slightly less than 1 kg of lean body mass over the trial, which the 3DAY group gained 4.6 kg lean body mass. That’s a 4 times greater effect on lean body mass associated with increased frequency of training.
This study also found that the 1DAY group reported greater muscle soreness than the 3DAY group “possibly the result of greater detraining between sessions.” The 1DAY group had more muscle soreness but less hypertrophy. This means the 1DAY group was sustaining more muscle damage and yet less muscle growth. Below I will discuss a study which may explain why this happened: lower frequency produces less adaptation to exercise, which means a trainee will be sustain more muscle damage from training, and more resources will go to fixing that damage than to building new tissue.
Also, this study found “all upper-body exercises except the lat pull-down and all lower body exercises except the leg extension responded better to a higher frequency of training, with leg press and leg curl responding exceptionally well.”
This study does not support the Body By Science protocol. In fact, it provides evidence that if you want to train only once weekly rather than thrice, you have to perform in that one session the same number of sets you would have performed in three sessions, in order to get only about 62% of the strength results and 25% of the lean mass gains you would have gotten from three sessions. Moreover, it suggests that trained individuals will get better results in both strength and hypertrophy by training 3 days weekly than training 1 day weekly, which is consistent with what we would expect due to adaptation to the stimulus in trained individuals making increased dosing necessary.
According to McGuff and Little, resistance training is so stressful and does so much damage to muscles that people absolutely need at least 7 days recovery between sessions. Yet these two studies they themselves cited to support their protocol show both untrained and trained subjects gaining substantial strength and muscle mass training 3 times weekly with 48-72 hours between training sessions.
Strength gains can’t occur unless one recovers and grows between exercise sessions. Therefore, these studies actually provide evidence that people only need 48-72 hours between sessions to recover and progress. Thus, they actually provide evidence that the Body By Science Protocol may be not only unnecessary but suboptimal for trained individuals.
The third study  they cite in Body By Science to support infrequent training does state in the abstract that “performing a single set of the leg press once or twice per week results in statistically similar strength gains in untrained women.” However, this study only included a total of 21 women so it had a low statistical power to detect differences between the groups. Further, when you read beyond the abstract you find that the conclusion is acknowledged to be a misleading statistical artifact.
In the body of the paper, the authors remark that “the lack of significant differences was likely due to the large variability within groups (Table I). The large standard deviations within groups indicated that some of the subjects in Group 1 (once per week) made larger strength gains that some of the subjects in Group 2 (twice per week).” This finding suggests the once-weekly group may have had a higher number of good responders and the twice-weekly group a higher number of low responders to resistance exercise.
Moreover, the authors add: “Both groups in the current study demonstrated large increases in strength, which was not surprising considering that subjects had little or no previous training experience….Due to the relatively short duration of the current study, these strength gains were likely due to neural adaptations rather than muscular hypertrophy.” Thus, this study does not bear on long-term adaptations based on muscle hypertrophy.
Finally, the authors recommended caution in interpreting their results, noting:
“From a statistical standpoint, the differences between the once per week group and the twice per week group were not significant (P=0.757). However, from a practical standpoint, the percentage of strength gained by the twice per week group (60%) was higher than that gained by the once per week group (38%). Therefore, individuals with performance related goals, such as athletes, might consider performing the leg press exercise two or more times per week.”
McGuff and Little appear to have ignored this caution and the details of this study. Its failure to find a statistically significant difference between training once and twice weekly was most likely due to its inclusion of only 21 subjects, not evidence that training once or twice weekly produce the same results. Moreover, like the previously discussed studies, this one proved that people make excellent progress training a muscle group twice weekly, and better than training only once weekly, which should not occur if resistance training is as stressful and the body is as fragile and limited in adaptation ability as McGuff and Little claim in Body By Science.
In summary, the research that McGuff and Little cite in Body By Science fails to provide much support for their claims that a single set of normal resistance exercise produces extreme muscle damage requiring at least a week to repair, and that one set per muscle group per session produces effects similar to multiple sets per muscle group per session, or that one training session per week produces the same results as multiple session per week. In short the studies they have cited provided no support for their protocol at all; in fact, the studies they have cited disprove their key claims about resistance training volume, frequency, and recovery.
Although it has been proven that most published research findings are false and probably merely report the biases and opinions of the researchers, reviewers, and scientific community at time of publication , the studies on resistance training frequency and volume are rather consistent in giving the advantage to greater frequency.
Consider the formation of callouses. Resistance training is akin to callous formation, NOT akin to wounds (such as burns or lacerations). The body forms callouses very readily if a surface is exposed to sufficient but not excessive stress, even if the stress is daily. Further, infrequent exposure to callous forming activity results in...no callous or minimal callous formation. Greater frequency results in greater callous formation. This is not rocket science.
A 2018 study by Gentil et al reported that individuals with at least 12 months of training experience produced similar (and minimal) improvements in strength and muscle mass whether they trained twice weekly or only once weekly . In fact, only the once-weekly group produced an improvement in muscle mass as measured by elbow flexor muscle thickness. However, this could have been measurement error or bias. Moreover, the once weekly group performed 6 sets of exercise for each muscle group, every set to momentary muscular failure (the twice weekly group spread the same 6 sets over two training sessions, i.e. three sets each session). This is six times the volume prescribed in Body By Science, so once again this study does not provide support for the BBS protocol. At best this study showed that so long as one does at least 6 sets weekly for a muscle group, it doesn't matter whether you do it all in one session or spread it over two sessions. Most people would probably find it easier to complete the shorter sessions performed twice weekly, versus the much longer session performed only once weekly, because longer training sessions are just harder to complete. It is difficult to determine whether this volume was excessive or necessary for the minimal improvement in muscle mass that occurred in these subjects. It is possible the subjects in both groups were doing too much exercise to progress; and also possible that they were doing too little exercise to progress.
This is why I maintain that ultimately every individual must experiment to find out what frequency and volume of exercise produces the best results (progress) for him/her self.
It is interesting to notice the fact that all of this research they cited suggests that muscles adapt to training very quickly so that muscle damage is no longer a concern. Does this adaptation make muscles more resistant to progression? If so, one might need more frequent stimulus, not less frequent training, as one progresses.
Damas et al.  have recently shown that resistance training (3 sets per muscle group, twice weekly) causes significant muscle damage only in untrained subjects, that signs of post-training damage diminish by the 3rd week of regular training, and that by the 10th week of regular resistance training signs of post-training muscle damage are minimal. Moreover, they provided evidence that muscle hypertrophy ensues only after the muscles have adapted to exercise to the extent that repeated bouts of exercise no longer cause muscle damage.
In short they provided some evidence that muscles must be made accustomed to training and therefore resistant to damage before they will hypertrophy. If so, this would explain why higher training frequency has been reported more effective for hypertrophy [9, 12, 13].
Lower frequency training such as the Body By Science program means the muscles will be less accustomed / adapted to the training stimulus, in which case each (weekly) bout may result in more muscle damage, and the post-training protein synthesis is primarily directed to repairing that damage, not to hypertrophy.
Therefore, while low frequency training will provide some benefits, it may provide less progress than more frequent training, at least in some individuals.
In the words of Damas et al. “individuals who present more muscle damage do not necessarily have a greater hypertrophic response.” Damas et al. have essentially called into question the idea that muscle damage is the stimulus for hypertrophy. This has important implications for designing effective resistance training programs.
Most people measure the effectiveness of a routine by how sore or exhausted they feel afterwards, but this research suggests that the more sore you get, the more damage you have done to the muscles, and the less effective the bout has been for increasing strength and muscle mass.
Instead of designing resistance training programs with a goal of trying to damage muscle as much as possible with extremely intense protocols or “deep inroad” in order to get a response, training should be designed to promote adaptation to training and resistance to muscle damage, so that little or none of post-training protein synthesis goes to repairing damage done in training, and more to building new muscle.
This means training with less extreme efforts with greater frequency, using the same exercises over and over so that you minimize muscle damage (DOMS) and maximize muscular adaptation. It means coaxing your body to grow, not trying to force it to grow.
McGuff and Little outline two Body By Science basic full body training routines: The Big 3 and The Big 5. The Big 3 consists of pulldown, chest press and leg press. The Big 5 adds the overhead press and rowing. They recommend novices perform The Big 5 once weekly.
In Body By Science, McGuff and Little suggest that the leg press provides adequate training for the hamstrings. In fact, as explained by Greg Nuckols in "Hamstrings – The Most Overrated Muscle Group for the Squat," the hamstrings get little activation during the leg press or squats, because these movements involve flexing or extending at both the knee and the hip simultaneously. On the descent, the hamstrings shorten at the knee end while lengthening at the hip end, which means there is no net lengthening; then, on the ascent, as you extend at the knee and hip simultaneously, the hamstrings are lengthening at the knee while shortening at the hip – again no net change in length. EMG studies also show very low levels of contraction in the hamstrings during leg presses or squats.
Hence, I think a well-designed strength training routine should include an exercise that directly trains the hamstrings, such as back arch ups, straight leg deadlifts, or some types of leg curls. Otherwise you may create a strength imbalance between the knee extensors (quadriceps) and the knee flexors (hamstrings), which may increase your risk of knee injuries.
If you don’t have access to machines, McGuff and Little suggest using the barbell bent over row, bench press, deadlift, overhead press, and squat for a Big 5 training routine. I don’t like this selection of exercises. Here’s what I suggest instead and why:
The bent over row only trains the upper back and biceps through a limited range of motion, with very poor loading for the biceps, and puts a lot of unnecessary strain on the lower back. I would recommend using rings to perform feet-assisted chin ups, progressing to full chin ups, instead. These train the upper back through a greater range of motion and provide excellent loading for the biceps.
The barbell bench press is a relatively dangerous exercise unless done in a power rack with safety bars set to catch the bar in case of muscular failure. Push ups on the floor (for novices) or on rings (for intermediate or advanced trainees), with bands for additional resistance, or bar dips, are safer and just as effective as barbell bench presses. You can do incline push ups on rings or a suspension trainer to start, and this allows progressive resistance by gradual decrease in the height of the rings or handles.
The conventional deadlift doesn’t train any upper back, hip or thigh muscle group through a full range of motion. Moreover, it is very fatiguing, requiring much more recovery time than other exercises. Its an over-rated lift with a high risk to benefit ratio. Squats (including single-leg squats) sufficiently train the hips and quadriceps through a greater range of motion and more safely than the deadlift (and, arguably, the leg press), obviating the need for this aspect of the deadlift.
I would replace the conventional deadlift with suspension leg curls, ball leg curls, Nordic leg curls, back arch ups, or very strictly performed, slow motion straight leg deadlifts to train the hamstrings and lower back. If performing leg curls or back arch ups, pair these with inverted rowing on rings to provide the training for the upper back that one would get from deadlifts.
Thus, my Big 6 with conventional equipment would be:
In Body By Science, McGuff and Little suggest direct neck work only for some athletes, such as football players, as injury prevention. I think everyone should include neck work because almost everyone either drives a car, bicycle or motorcycle, and is thus vulnerable to whiplash injuries; and many people also do a lot of desk work, which often causes chronic neck strain, which I have found responsive to regular neck training.
I give this book a reserved recommendation. It has valuable information on high intensity training, and its recommended exercise protocol will produce some benefits for most people. However, the program may be suboptimal for some or many people. While I agree with some of the general principles discussed by McGuff and Little in BBS – e.g. using controlled movement speed and only one set per exercise, and allowing adequate recovery time between training sessions – I doubt their prescription of one set per exercise, and 1-2 sets per muscle group, once weekly is optimal for all trainees.
1. Clarkson PM, Nosaka K, Braun B. Muscle function after exercise-induced muscle damage and rapid adaptation. Med Sci Sports Exerc. 1992 May;24(5):512-20. Review. PubMed PMID: 1569847.
2. Golden CL, Dudley GA. Strength after bouts of eccentric or concentric actions. Med Sci Sports Exerc. 1992 Aug;24(8):926-33. PubMed PMID: 1406179.
3. Clarkson PM, Tremblay I. Exercise-induced muscle damage, repair, and adaptation in humans. J Appl Physiol (1985). 1988 Jul;65(1):1-6. PubMed PMID:3403453.
4. Howell JN, Chleboun G, Conatser R. Muscle stiffness, strength loss, swelling and soreness following exercise-induced injury in humans. The Journal of Physiology. 1993;464:183-196. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1175380/?page=4>
5. Mishra DK, Fridén J, Schmitz MC, Lieber RL. Anti-inflammatory medication after muscle injury. A treatment resulting in short-term improvement but subsequent loss of muscle function. J Bone Joint Surg Am. 1995 Oct;77(10):1510-9. PubMed PMID: 7593059.
6. Smith LL. Acute inflammation: the underlying mechanism in delayed onset muscle soreness? Med Sci Sports Exerc. 1991 May;23(5):542-51. Review. PubMed PMID:2072832.
7. Tiidus PM, Ianuzzo CD. Effects of intensity and duration of muscular exercise on delayed soreness and serum enzyme activities. Med Sci Sports Exerc. 1983;15(6):461-5. PubMed PMID: 6656554.
8. Taaffe DR, Duret C, Wheeler S, Marcus R. Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults. J Am Geriatr Soc. 1999 Oct;47(10):1208-14. PubMed PMID: 10522954.
9. McLester JR, Bishop P, Guilliams ME. Comparison of 1 Day and 3 Days Per Week of Equal-Volume Resistance Training in Experienced Subjects. Journal of Strength and Conditioning Research 2000;14(3):273-281.
10. Burt J, Wilson R, Willardson J. A comparison of once versus twice per week training on leg press strength in women. J Sports Med and Phys Fit 2007 May;47:13-17.
11. Damas F, Phillips SM, Libardi CA, et al. Resistance training‐induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage. The Journal of Physiology. 2016;594(18):5209-5222. doi:10.1113/JP272472.
12. Schoenfeld BJ, Ogborn D, Krieger JW. Effects of Resistance Training Frequency on Measures of Muscle Hypertrophy: A Systematic Review and Meta-Analysis. Sports Med. 2016 Nov;46(11):1689-1697. doi: 10.1007/s40279-016-0543-8. Review. PubMed PMID: 27102172.
13. Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Tiryaki-Sonmez G. Influence of Resistance Training Frequency on Muscular Adaptations in Well-Trained Men. J Strength Cond Res. 2015 Jul;29(7):1821-9. doi: 10.1519/JSC.0000000000000970. PubMed PMID: 25932981.
14. Ioannidis JPA (2005) Why Most Published Research Findings Are False. PLoS Med 2(8): e124. https://doi.org/10.1371/journal.pmed.0020124
15. Gentil P, Fisher J, Steele J, et al. Effects of equal-volume resistance training with different training frequencies in muscle size and strength in trained men. Ramírez-Campillo R, ed. PeerJ. 2018;6:e5020. doi:10.7717/peerj.5020.