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The Science of Performance |
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How Much Can You Improve? Part II
In part 1 of “How Much Can You Improve?” we reviewed data from a large research study that examined changes in VO2max in 481 healthy subjects. That study showed that there was a large range of response in VO2max to a three-days-per-week standardized training program, a range of -5% to 56%. Though the average change in VO2max was a 17% improvement, some subjects’ VO2max decreased as much as -5% while other increased VO2max by as much as 56%. This study clearly illustrated that individuals have widely different responses in aerobic capacity to a standardized training program. We also noted in part 1 that this study was not unique – other studies have examined variability in VO2max and found similar results. Does this same variability exist in other areas too? Just because there is a wide range of responses in aerobic capacity doesn’t mean that there is a similar range of responses in other adaptations to exercise. Perhaps the range of response in aerobic capacity is unique or uniquely large and that other known adaptations to exercise are either not variable or much less variable than changes in aerobic capacity. Let’s take a look at other research on this topic to see if other known adaptations to exercise also exhibit a similar range of response. In particular we will review a study that examined variability in changes in muscle fiber size and strength from a standardized training program. Research A group of researchers had a unique opportunity to study 585 subjects participating in the FAMuSS – Functional Polymorphisms Associated with Human Muscle Size and Strength study - a large, multi-institutional cooperative effort designed to identify genetic variations in humans and the relationship between these genetic variations and changes in muscle strength and size. In this study the researchers examined changes in bicep muscle strength and size following 12 weeks of resistance training (1). The researchers noted that “it has been commonly observed that some people who take up resistance training experience vastly different gains in strength and size” but that “no study has been undertaken with a large enough sample size of subjects to fully quantify the range of human responses to a given strength training program.” FAMuSS, therefore, offered a unique opportunity to conduct just such a study and fully measure the range of response to strength training. A total of 585 subjects – 243 males, 342 females – participated in and completed the study. The age range of the subjects was 18 – 40 years with an average age of 24.3 years. Training was conducted twice weekly using the non-dominant arm only and consisted of biceps preacher curls, bicep concentration curls, standing bicep curls, overhead triceps extensions, and triceps kickbacks. Subjects trained with 3 sets x 12 reps in weeks 1-4, 3 sets x 8 reps in weeks 5-8, and 3 sets x 6 reps in weeks 9-12. Each subject was tested for maximum voluntary contraction (MVC), 1 rep maximum (1RM), and muscle size pre- and post-training. Results A large range of responses was observed in changes in both strength and size, following a normal distribution (bell curve) for all measured changes. Similar variability was observed in men and women for changes in relative size and strength, with men showing a slightly greater gain in relative size and women showing a larger increase in relative strength. MVC: Changes in MVC strength ranged from -32% to 149% with an average increase of 19.5%. Of 585 subjects, 119 subjects increased strength between 15-25%, 60 subjects gained more than 40%, and 102 subjects gained less than 5%. Muscle Size: Changes in muscle size ranged from -2% to 59% with an average increase of 18.9%. Of 585 subjects, 232 subjects showed an increase in muscle size of between 15 and 25%, 10 subjects gained more than 40%, and 36 subjects gained less than 5%. 1RM: Changes in one rep maximum ranged from 0% to 250% with an average increase of 54.1%. Of 585 subjects, 232 increased 1RM 40-60%, 36 subjects gained over 100%, and 12 subjects gained less than 5%. Overall, there was a greater frequency of high responders than low responders. Table 1 summarizes the percent changes in MVC, 1RM, and muscle size for all the subjects. Table 1: Changes in size and strength in the trained bicep
Discussion The results of this study reveal several things. First, this study shows that the large variation in VO2max response to training observed in the HERITAGE study is not unique. This study showed an equal or larger variation in both muscle strength and size that that shown in VO2max in the HERITAGE study. These results support the belief that a large variability in response to training is likely the norm for all training adaptations. Also, this study shows a normal distribution in changes in muscle size and strength following a standardized training program. The results indicate that, just like normal distribution of changes in aerobic capacity, other adaptations to training also exhibit a normal distribution in range of response. Second, this study showed a larger variability in response in muscle strength (250%) than the variability of response in muscle size (61%) or the changes in VO2max (61%) shown in the HERITAGE study. This indicates a larger adaptability of muscle fiber strength than either muscle size or changes in aerobic capacity. Third, the fact that all 585 subjects followed the same standardized training program suggests that changes in muscle size and strength are due to genetic differences. Finally, the subjects were training just twice each week, following a traditional type strength training program. There was nothing particularly unusual about the training program followed by these subjects and the workout is quite similar to the recommendations of many modern training programs. Despite this fact, a small number of subjects lost strength from this program with the largest loss being a decrease of 32% in MVC and a 2% decrease in muscle size. Additionally, a significant number of other subjects failed to gain either strength or size. The loss of strength and size by some subjects and the failure to gain either strength or size by other subjects can not be due to inadequate training since a significant number of other subjects increased both size and strength by as much as 59% and 250% respectively. Training Implications With some subjects gaining strength and size and other subjects experiencing either no change or a loss in performance, the question must be asked as to whether training recommendations should be standardized for a population. Should training recommendations be the same for all humans, despite obviously large differences in genetic talent? If you were coaching the high responders, what training modifications might you make? An anecdotal review of the training program of the elites in the strength and bodybuilding sports reveal that elites tend to train with a relatively high volume, intensity, and frequency. Based on the superior response of high responders in this study, it is reasonable to assume that these individuals might respond even better to a higher volume or more frequent training schedule. While it is possible that 2 x week is an optimal training frequency for the high responders in this study, it is not unreasonable to suggest that the high responders in this study seem to posses elite level genetic talent and, based on the training programs of elites in the strength and bodybuilding sports, that these high responders might also benefit from a greater intensity, volume, and frequency than those with average genetic talents. Conversely, if you were the coach of those subjects who actually lost strength and size from twice weekly training, what training modifications would you make? How do you train someone who loses strength and muscle size after taking up a traditional, modest strength training program? Would you increase training volume, frequency, or intensity? Would you decrease it? Unfortunately, the answer is not provided from this study. However, since loss of strength and size are known to be associated with overtraining and based on the positive results achieved by others in this study it is not unreasonable to suggest that the training intensity, duration, and frequency were excessive for the negative responders in this study. I once worked with a trainee, a low responder, who quickly stopped gaining strength and size following a 2 x week full body training program. After just 4 months of strength training this individual stopped gaining both strength and size. Despite his best efforts over the next several months, his strength levels and size did not increase at all. Out of frustration at his total lack of progress, he was ready to give up training completely. Instead, I had him decrease his training frequency to once per week. His strength instantly and dramatically increased (a 25% increase in the number of reps he could press) and from that moment on he made steady gains in strength for more than 1.5 years. Though this example is clearly anecdotal and not scientifically rigorous, it does serve to illustrate the point that training that is suitable for those with average genetic talents might not be optimal for those with either above or below average genetic talents. Finally, consider the issue of elite training methods. Elites are clearly high responders. It is a very common argument to suggest that the results enjoyed by elites prove that elite training methods are best – i.e. all other trainees should strive to emulate the training program of elites because the results of the elites prove the superiority of their particular training method. The results of this study suggest this advice could well be flawed. The results the elites experience are due much more to superior genetic talent than superior training. This is not to say elites don’t train hard as clearly no elite became elite without hard training. That being said, hard training won’t overcome less than elite genetic talent and to accurately evaluate the effectiveness of a training program requires making a distinction between results due to training and results due to genetic talent. Additionally, even if elite training methods are optimal for those with elite genetic talent it does not follow that the same training methods are optimal for those with less than elite level genetic talents. Summary Changes in muscle strength and size following 12 weeks of resistance training were examined in 585 subjects. A large, normal distribution in range of response for both strength and size was revealed. Changes in MVC strength ranged from -32% to 149% and changes in muscle size ranged from -2% to 59%. Similar variability was observed in both men and women, with men gaining slightly more relative size and women gaining more relative strength. I suggest these results support the idea that training recommendations should not be standardized for all trainees and should instead be varied to account for differences in genetic talent. Reference: 1. Hubal M, Gordish-Dressman H, Thompson P, et al Variability in Muscle Size and Strength Gain after Unilateral Resistance Training Med Sci Sports Exerc 2005, 37(6), 964-972
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