A popular theory among fitness professionals is that taking short rest periods between sets maximizes muscular growth. The theory is primarily based on the hormone hypothesis, whereby limiting inter-set rest promotes greater elevations in post-exercise growth hormone, IFG-1 and testosteron...
April 11, 2014
I’m stoked to announce that my dissertation study, Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men, was just published ahead-of-print in the Journal of Strength and Conditioning Research. I had actually devised the protocol during my master’s degree course in research methods back in 2008. The study I ultimately carried out had some different wrinkles than the one originally proposed, but overall the essence remained the same. Most importantly, it investigated a topic that’s been debated for many years: What are the differences in muscular adaptations (strength and hypertrophy) between bodybuilding- vs powerlifting-type training programs? Here is an overview of the study and a discussion on its practical implications.
20 well-trained subjects (minimum of 1 year resistance training experience working out at least 3 days/week) were recruited to participate in the study. Subjects were randomly assigned to one of two groups: A hypertrophy group (HT) that performed a bodybuilding style routine or a strength group (ST) that performed a powerlifting-style routine. The HT protocol was a split routine where each muscle was worked once per week with 3 exercises per session, performing 3 sets of 10 reps and resting for 90 seconds. The ST protocol was a total body routine where each muscle was worked 3 times per week with 1 exercise per session, performing 7 sets of 3 reps. The volume load (sets x reps x load) was equated so each group essentially lifted about the same amount of total weight per week. Training was carried out over 8 weeks. All sets were performed to the point of momentary concentric muscular failure.
Strength was measured by 1RM in the squat and bench press. Muscle thickness of the biceps was measured with ultrasound. Testing was carried out pre- and post-study, and results were then compared between groups to assess differences in strength and hypertrophy.
3 of the subjects dropped out of the study before completion leaving 17 subjects for analysis (9 in the HT group, 8 in the ST group). Both groups significantly increased biceps muscle thickness by ~13% with no differences seen between groups. Both groups also significantly increased 1RM strength, but the ST group had greater increases in the bench press and showed a trend for greater increases in the squat.
On the surface, the study showed that muscle hypertrophy is similar between powerlifting and bodybuilding type routines provided that volume is equated between protocols. Moreover, the study showed that maximal strength is slightly greater in a powerlifting protocol. This could lead to the conclusion that if your goal is hypertrophy then it doesn’t matter what rep range you use (at least in the heavy to moderately-heavy range) as long as you perform equal volumes, but that maximizing strength requires lifting very heavy weights. From a mechanistic standpoint with respect to muscle hypertrophy, the study suggests that either 1) the increased mechanical tension in the ST group was offset by the greater metabolic stress in the HT group on a volume-equated basis or, 2) there is a threshold for mechanical tension and once the threshold is reached, it doesn’t matter as long as the stimulus is maintained for similar timeframes. With respect to strength, this would suggest that neural factors related to training are still relevant in well-trained individuals, and that using very heavy weights does indeed have a greater transfer to maximal lifts compared to moderate intensity loads.
But the devil is often in the details and that is the case here.
First, it is important to point out that total training time in the ST group was 70 minutes while that of the HT group was 17 minutes. So from a time-efficiency standpoint, the bodybuilding-type training produced similar hypertrophy (as well as nearly similar strength increases) in about a quarter of the time as the powerlifting routine. Moreover, exit interviews revealed that those in the ST group were fried by the end of the study. Almost all of them complained of sore joints and general fatigue, and the two dropouts from this group were because of joint-related injury (and these routines were highly supervised with respect to form, so we took every precaution for safety). On the other hand, the HT group all felt they could have worked substantially harder and done more volume.
This brings up an important take-away message: While mechanistically it appears that it does not matter whether heavy or moderately-heavy weights are used for hypertrophy, from an application standpoint it simply isn’t practical to train constantly with the volumes used in this study on multiple body parts. The grinding on the joints and the taxation of the neural system that is involved with repeated performance of very heavy loads ultimately has a negative impact on the lifter; I am certain that if we had continued this program for any longer, most of those in the ST group would have been overtrained and seen performance decrements. If nothing else, these finding reinforce the importance of periodizing programs so that cycles of deloading are interspersed with very heavy loading protocols.
Additionally, realize that only three major muscle groups were worked in the study: the pecs (upper body pushing); the back (upper body pulling) and the thighs. Thus, the HT group could have easily done a couple of extra sets for each muscle group without overtaxing their resources. Although impossible to say for sure, it certainly is plausible that additional work would have enhanced the hypertrophic response in the bodybuilding-style training group. Moreover, the HT group could have performed exercises for other muscle groups, including some targeted work with single joint movements. Working specific muscles (and aspects of muscles) such as the middle and posterior delts, the hamstrings and the calves alone would definitely have benefited overall muscle hypertrophy.
So bottom line: The study indicates that the best approach to building muscle is to perform a combination of heavy and moderately heavy loads. The “hypertrophy range” is applicable from the standpoint that it allows the performance of a greater amount of volume without overtaxing the body’s resources. Adding in loads in the 1-5 RM range can enhance strength (which ultimately allows the use of heavier loads during moderate rep lifting) as well as providing a potent hypertrophic stimulus.
It should be noted that.I made a conscious decision to investigate the two types of routines as lifters usually perform them. Thus, the HT routine was a split routine since the vast majority of bodybuilders train in this fashion, while the ST routine was a total body routine since this is the way most powerlifters train. While staying true to the usual performance gives insight into how muscular adaptations generally play out in everyday practice, they also obscure the ability to attribute results entirely to the set/rep scheme. I will be carrying out a follow up study that seeks to address this issue in the near future. Stay tuned!
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