Throughout the past few years, I have become a growing member of the world of CrossFit where I have been immersed into a community of avid athletes hungry to achieve their fitness goals and become stronger competitors in this sport. As I have become more engaged in athletic performance and discussed with many experienced and knowledgeable coaches, nutritionist s and athletic trainers, I have become aware of the delicateness and precision required when designing training programs for other athletes. Although nutrition, training frequency and many other factors are at play in muscle tissue anabolism, one of the most interesting factors to consider when designing workout programs are hormones and how such fluctuations differ with certain intensities in resistance training. So, which type of resistance training maximizes muscle gains? There is a great debate in the exercise science world about this topic and in exercise training protocols.
Kraemer and Ratamess (2005), suggest that during high volume, high intensity resistance training such as a high rep count of front squats with minimal resting, there is an elevation post-exercise in testosterone, growth hormones (GH), both anabolic hormones as well as cortisol (a catabolic hormone) compared to when a person performs low-volume, high-intensity resistance exercises with lots of rest in between intervals. Additional anabolic hormones, insulin and insulin-like growth factor-1 (IGF-1), were also found to be elevated during resistance training. Interestingly, IGF-1 was found to be upregulated in response to GH hepatic secretions which also promotes muscle tissue anabolism.
A 2010 study by West and Phillips, however, contradicts these assumptions that testosterone and GH facilitate anabolic processes to promote skeletal muscle hypertrophy. In fact, they argue that neither of these hormones is really necessary nor do they play a significant role to enhance muscle hypertrophy, but rather that local mechanisms within the skeletal muscle tissue involved in the resistance training are what is responsible for stimulating anabolism.
The lack of clarity between the role hormones play in regulating muscle mass and the physiological adaptations of skeletal muscle to resistance training pose a challenge when trying to support a certain exercise prescription to making those, “gains.” Continuous research on this topic would be integral in enhancing athletic performance and provide evidenced-based training to all exercisers from the competitive CrossFit Games athlete to the everyday, average exerciser at your local gym.
References:
Kraemer, W. J., & Ratamess, N. A. (2005). Hormonal Responses and Adaptations to Resistance Exercise and Training. Sports Medicine,35(4), 339-361. doi:10.2165/00007256-200535040-00004
West, D. W., & Phillips, S. M. (2010). Anabolic Processes in Human Skeletal Muscle: Restoring the Identities of Growth Hormone and Testosterone. The Physician and Sportsmedicine,38(3), 97-104. doi:10.3810/psm.2010.10.1814
Does low rep, high intensity produce the same increase in testosterone? Or must it be high volume, high intensity with high rep count? I ask this because lower rep count often means you are able to push more weight and exert about the same amount of energy while working out?
ReplyDeleteThis is an intriguing post. I personally enjoy working out very much. I preferred to do heavy resistance training starting in high school and early into college. However, I noticed I hit sort of a wall, where I couldn't go up any more in weight. So I decided to switch off routines, meaning I would do light weight and higher reps for a few weeks, and then a few weeks of heavy lifting. I noticed that I wasn't hitting the wall as much and could lift a lot more weight. It is interesting that different forms of exercise actually release different hormones that help with muscle growth. Although further research obviously needs to be done to get a definitive answer, switching up routines really helped me out!
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