Friday, April 20, 2012

All Men—and Women—Are Not Created Equal by Jerry Brainum

You see it all the time: Two people begin training at the same time, yet one of them seems to make gains in size and strength far more rapidly than the other. There are various explanations for the differences between hard and easy gainers. Men make faster initial muscle gains than women because men are usually larger and stronger than women. In addition, men secrete more of the anabolic hormones known to favor gains in muscular size and strength, such as testosterone. Age plays a role in how rapidly gains occur. Younger people make faster gains than older people for various reasons, especially a higher anabolic hormone level and greater recovery ability.

Back in 1954 physiologist Herbert Sheldon attempted to document the various human body-type variations. He came up with three basic types: 1) ectomorph, or thin; 2) endomorph, or fat; and 3) mesomorph, or muscular. Sheldon pointed out that humans are rarely any one exclusive type but usually are mixed, such as endo-mesomorph, or fat-muscular. The majority of bodybuilding champions are ecto-meso, or thin-muscular. Such people often start out thin, then gain muscle with training experience. When they stop training for an extended time, they revert to their dominant form. With age and metabolism changes, however, many formerly thin athletes get fat if they don’t maintain a strict diet and training schedule.

A recent study examined whether variations in gains occur in a large sample.1 The subjects included 585 people, 243 men and 342 women, ages 18 to 40. The cutoff age of 40 was set because the researchers felt that after that age the anabolic hormones needed to support muscular gains drop precipitously. In addition, none of the subjects took any drugs that might influence gains in size and strength, such as corticosteroids, which are catabolic and tend to produce losses in muscle size and strength. The subjects weren’t allowed any type of food supplement touted to boost gains, such as protein powders, creatine or pro-hormones.

The exercise consisted of one-arm preacher curls, done with the nondominant arm, for 12 weeks. Muscle gains were determined by magnetic resonance imaging, an expensive but accurate method. Strength gains were determined by baseline tests that used both isometric and dynamic exercise.
After 12 weeks individual variations in gains in muscular size and strength proved significant. Of the 585 subjects, 232 showed a 15-to-25-percent increase in cross-sectional area of muscle. Another 10 showed a gain of 40 percent, while 36 subjects gained only 5 percent muscle size. While the expected finding was that men would make greater size gains than women because of higher levels of testosterone, when relative size differences were taken into account, the women proved just as liable to gain muscle size as the men.

Nor did age affect the rate of muscle gains, since the older subjects made gains similar to those of their younger counterparts. The authors attributed that to a fairly stable level of testosterone secretion in the older subjects, noting that the hormone doesn’t drop enough to blunt muscle gains until about age 60; some would disagree.

As for strength, 232 subjects increased their one-rep maximum by 40 to 60 percent. That means their ability to lift a weight for one rep improved by 40 to 60 percent. Another 36 subjects made gains of 100 percent in one-rep max, while 12 subjects gained less than 5 percent. Similar figures held for gains in isometric strength, although one subject made gains of 150 percent in that area.
Women showed greater variability in dynamic strength, or the type of lifting most often done in bodybuilding workouts—eccentric and concentric muscle contractions. The greater variability could be explained by women’s naturally greater joint flexibility. In addition, the women were less skilled on average than the men in performing preacher curls at the start of the study, and with continued skill acquisition some might have made better gains than others. In total, the women made better strength gains than the men. Thus, the men made better gains in muscle size, while the women proved superior in strength gains, likely because they were much weaker at the start of the study.

The study shows that most people make significant gains in muscle size and strength when they begin regular training. Men show faster muscle size gains on average, while women may get stronger faster than men. The unanswered question of the study is why the variations in the gains occurred. Why did one trainee show a 40 percent muscle-size gain after 12 weeks of training, while another had only a 5 percent gain?

Factors not discussed in the study could explain the wide variations: diet, how intensely you train, how much rest you get, and so on. Also, genetic factors certainly play a dominant role in who makes the fastest gains. Perhaps some people have genes that favor muscle gains that are activated when they begin training. Somebody else may not produce as much myostatin, a protein that inhibits muscular growth, or may produce other proteins that block the activity of myostatin, which would favor rapid gains in size and strength. Although the study suggested that testosterone didn’t play a major role in the gains made by the male subjects, other studies show that higher initial levels of testosterone and other anabolic hormones favor more rapid muscle gains.

1 Hubal, M.J., et al. (2005). Variability in muscle size and strength gain after unilateral resistance training. Med Sci Sports Exer. 37:964-72.

©,2012, Jerry Brainum.Any reprinting in any type of media, including electronic and foreign is expressly prohibited.

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