Written by Michael J. Rudolph, Ph.D.
12 April 2019

19freeweights

Free Weights Boost Anabolic Hormone Levels

Build Muscle and Increase Testosterone

 

 

All forms of resistance training induce an anabolic-hormonal response, which contributes to adaptations associated with weight training such as muscle growth and strength. Weight training also causes an increase in the two most prominent muscle-building hormones, testosterone and growth hormone (GH). Testosterone drives muscle growth by stimulating muscle protein synthesis1 and inhibiting muscle protein degradation. GH triggers greater muscle growth primarily by stimulating the production of the insulin-like growth factor 1 (IGF-1), which has been shown to also potently stimulate muscle growth by increasing muscle cell protein synthesis.2

      That said, not all weight-training protocols are as effective at inducing an increase in anabolic hormone levels— suggesting that the increase in anabolic hormone from weight training is dependent on factors associated with training program variables such as exercise intensity, training volume, as well as the type of training equipment used such as free weights or exercise machines. 

Free Weights More Effectively Increase Anabolic Hormone Levels

      Because the apparent discrepancy between free weights and machines on the anabolic hormone response to training had been unexamined, Shaner et al.6 investigated the effect of a similar free-weight movement (squat) and machine exercise (leg press) on anabolic hormone response. In this study, 10 young men with weight-training experience completed six sets of 10 repetitions of squats or leg presses at the same relative intensity one week apart. After each exercise session, blood samples were analyzed for testosterone, GH and cortisol concentrations.   

      The results of the study by Shaner et al. showed that testosterone levels were considerably higher after performing the squat when compared to the leg press. The authors suggest that this difference may be due to the greater amount of muscle mass recruited during the squat8 that has clearly been shown to be an important factor that enhances testosterone production.9 In addition, while GH concentrations were elevated after the squat and leg press, the increase was much greater after performing the squat. Because lactate production has been shown to trigger GH secretion10, the authors propose that the larger increase in GH from squatting is also likely due to the greater amount of activated muscle mass, which generates more lactate and triggers more GH release.

      Although this study clearly demonstrated that squatting increased testosterone and GH levels more effectively than the leg press, cortisol levels were also increased to a greater degree from squatting. As a result, the increased level of cortisol induced from free-weight squatting may actually mitigate some of the positive impact that squats have on muscle hypertrophy and strength.

Free Weights and Machines Surprisingly Increase Muscle Size and Strength Similarly

      For those trying to gain strength and size, free weights are typically the preferred training method over machines. The preference for free weights is based on the well-established fact that free weights activate greater levels of muscle mass, boosting more testosterone for enhanced gains in muscle hypertrophy and strength. However, as previously mentioned, free-weight training has also been shown to increase the muscle-depleting hormone cortisol. In order to understand the influence that greater cortisol levels have on muscle growth and strength, a study by Schwanbeck et al.7 investigated the comparative influence of free weights versus machines on muscle growth and strength as well as the production of testosterone and cortisol.

      In this study by Schwanbeck et al., 15 young males and 21 young females with weight-training experience worked out with only free weights or machines, performing an entire body workout for eight weeks. Cortisol and testosterone concentrations were assessed, before and after working out, throughout the entire study. Muscle size and strength were measured at the beginning and the end of the study.

      The results surprisingly showed that muscle size and strength increased significantly in both the free weight and machine groups, with no difference between each group. In addition, another remarkable finding was that the males in the free-weight group had a large increase in testosterone of 21.7 percent after training. However, the increase in testosterone also corresponded with a sizable increase in cortisol, resulting in a similar ratio of testosterone to cortisol in both male training groups.

Nutritional Supplements That Reduce Cortisol

      Although the results from the previous studies6-7 collectively propose that training with free weights or machines generates similar gains in muscle mass and strength, largely because of a similarly induced testosterone to cortisol ratio, the ability of free-weight training to stimulate a higher amount of testosterone relative to machines makes it a potentially more effective training method for packing on size and strength— especially when combined with the right nutritional supplements that diminish exercise-induced cortisol production.

      There are a few supplements that have been shown to be rather effective at thwarting exercise-induced cortisol production. One of those being phosphatidylserine, which is a phospholipid normally found within the cell membrane where it regulates many different cellular signaling cascades. Although the exact mechanism of phosphatidylserine regulation of cortisol production is unknown, a study by Starks et al.13 showed that 600 milligrams of phosphatidylserine per day causes a considerable reduction in cortisol production after exercise, which led to a much better testosterone to cortisol ratio.

      In a second study by Sharp et al.14, the researchers demonstrated that branched-chain amino acid (BCAA) supplementation maintained a net anabolic hormonal profile by decreasing cortisol levels while increasing testosterone levels following high-intensity resistance training. Finally, another study done by Marsit et al.15 showed a decrease in cortisol levels in a group of elite weightlifters taking an additional gram of vitamin C per day. This study also showed an improved testosterone to cortisol ratio by over 20 percent.

      For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a Research Scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biology of exercise as a fellow at Harvard Medical School and Columbia University for over eight years. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK— leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a scientist working at the New York Structural Biology Center doing contract work for the Department of Defense on a project involving national security.

 

 

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