How does strength training increase muscle mass? | Fitness Science Fitness Science

How does strength training increase muscle mass?

The increase in muscle mass due to resistance exercise is a result of several hormone mechanisms. High intensity resistance training increases hormone concentrations of testosterone, growth hormone and IGF-1. These hormones stimulate protein synthesis and therefore increase muscle mass.

Men naturally produce more testosterone and growth hormone and these levels rise more strongly than in women as a result of resistance exercise. In men testosterone seems to be the most important regulator hypertrophy in muscle mass, in women, who produce much less testosterone, this role is reserved for growth hormone.

The amount of these hormones produced depends on several factors, the amount of muscle mass active during training, training intensity and rest periods between series. When more muscles are activated during training, anabolic hormone levels rise. The same applies to higher training intensity and shorter rest durations.

References:

-Heyward, V.H. (2010). Designing Resistance Training Programs. Advanced Fitness Assessment and Exercise Prescription Sixth Edition. USA. Human Kinetics