Muscles grow when you overload them with resistance that’s greater than what they’re accustomed to. Makes perfect sense doesn’t it? To handle a heavier load, muscles need to grow in size and become stronger. In response to training, muscle cells synthesis more contractile proteins, actin, and myosin, that let the muscle contract with more force. A number of hormones, activated in response to exercise, are called into play to theoretically help the muscles you’re training grow. In the fitness industry, these are referred to as “anabolic hormones,” and include such key players as testosterone, growth hormone and insulin-like growth factor.
You often hear people talk about tailoring their workout to maximize the release of these anabolic hormones. After all, hormones like testosterone, growth hormone and IGF-1 create an optimal environment for muscle growth. Some proposed ways to boost the release of testosterone and growth hormone include:
Using heavy resistance (80 to 90% of one-rep max)
Doing multiple sets
Using short rest periods (less than 60 seconds)
Focusing training on large muscle groups
No doubt anabolic hormones are important, but a 2010 study published in the Journal of Applied Physiology suggests that in the bigger scheme of things, the transient rise in these hormones after a workout have little effect on muscle growth or strength gains. This study, involving 12 healthy, young men, showed workouts using heavy resistance, high volume training and large muscle groups DID lead to a hefty increase in anabolic hormones during the post-exercise period.
Unfortunately, the rise in post-workout anabolic hormones WAS NOT linked with an increase in muscle protein synthesis nor did the men make greater gains in strength or muscle size when they were exposed to higher levels of these hormones post workout. To verify even small changes in muscle size, the researchers used MRI muscle imaging, and to ensure the guys had adequate protein, they drank a beverage with 18 grams of protein before each training session and another 18 grams whey protein beverage afterward.
Their conclusion? The surge of “whole body” anabolic hormones you experience immediately after a high-intensity, high-volume workout doesn’t significantly boost strength or hypertrophy gains. What matters most for muscle growth are “local factors,” as the local release of hormones and the activation of signaling pathways that promote muscle growth due to the mechanical stress of resistance training. The anabolic hormone surge weight lifters try to achieve may not boost muscle growth after all, at least based on this study.
Does This Mean “Anabolic Training” is Worthless?
Don’t be too quick to put down the heavy weights though – this was a small study in young men and it didn’t look at the effects of “anabolic training” on women. Why does this matter? Men have higher baseline levels of testosterone than women naturally. In fact, men produce 15 to 20 times more testosterone than women. Therefore, any increase in testosterone in response to anabolic weight training using heavy resistance could conceivably benefit women more than men since they have lower levels of testosterone at baseline. The post-workout spike in testosterone might be just what a woman, who makes little testosterone naturally, needs to build strength and lean mass.
It would be interesting to see whether a similar study in women would yield the same results. Plus, you have to take into consideration the other benefits that release of anabolic hormones after a workout offers. For example, growth hormone increases fat oxidation – something you want to take advantage of if you’re trying to lose body fat. In addition, growth hormone also enhances immune function, cartilage growth, and collagen synthesis. Growth hormone levels decline with age, and high-intensity exercise is one of the best ways to transiently increase growth hormone production naturally.
Whether or not a transient rise in anabolic hormones has benefits or not should not change how you work out. The same type of training that boosts the release of anabolic hormones – heavy resistance, high volume, shorter rest periods etc. – maximizes the mechanical stress you place on muscle fibers. So regardless of the impact, such training has on anabolic hormones, it’s STILL an effective approach for building strength and lean body mass and for improving body composition.
The Bottom Line
High volume, heavy resistance, short rest periods and training large muscle groups elevate blood levels of anabolic hormones, but it’s not clear whether this increase leads to greater gains in strength and mass, as is widely believed. What seems to be more important for strength and mass gains is the release of LOCAL hormonal factors and signaling molecules related to the mechanical aspects of lifting.
All in all, heavy resistance and low reps, regardless of the underlying mechanism, is most conducive to strength development, while medium to high resistance and higher volume training is optimal for mass gains. In practice, it’s best to vary the intensity, volume and rest periods of your workouts to challenge your muscles in different ways. You can do this by periodizing your workouts so that you expose your muscles to high loads and low reps during some cycles and lighter loads and higher reps during others. Through periodization, you can increase muscle strength, size, and muscle endurance as well as prevent plateaus. Periodization will also help you circumvent excessive muscle fatigue, prevent injury and avoid overtraining. A number of studies suggest that periodization leads to superior gains in strength and mass relative to non-periodized workouts.
The take-home message? Heavy lifting, doing multiple sets and focusing on large muscle groups is an effective training strategy, but maybe not due to the post-workout release of anabolic hormones.
Essentials of Strength Training and Conditioning. Second edition. Baechle and Earle. (2000)
Journal of Applied Physiology Published 1 January 2010 Vol. 108 no. 1, 60-67 DOI: 10.1152/japplphysiol.01147.2009.
Periodization: Latest Studies and Practical Applications by Christopher C. Frankel and Len Kravitz, Ph.D.
Periodized Training for the Strength/Power Athlete Jay R. Hoffman, Ph.D., FACSM, CSCS D.
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