Sex Difference in Hypertrophy Training

Regarding resistance training, there are differences between males and females regarding muscle size, recovery, and optimal training frequency. In this article, we'll take a closer look at these differences and how they affect the way women should approach their training.

Firstly, females tend to have higher levels of essential fat mass than males, which means that at the same body weight, they tend to have lower lean and higher fat mass. However, this doesn't mean women can't increase muscle size and strength to similar degrees as men through resistance training. Studies have shown that males and females can experience similar gains in muscle size and strength when following a well-designed resistance training program.

One key difference between males and females is in their recovery rate. Females tend to recover faster than males between sets and between training sessions. This is partly because males, on average, have larger and stronger muscles, which take longer to recover. Additionally, psychological differences may contribute to this difference in recovery rate, with females being less driven by the desire to display their physical abilities. This may mean that women get less growth out of each training session, but it also means they can have more back-to-back stimulative sessions and less risk of injury.

Females also tend to clear metabolites better and faster than males, likely due to their muscle size to vascularization ratio. This means that women experience less fatigue from a given set/rep/rest scheme and can recover faster, shortening their SRA curves (the stimulus, recovery, and adaptation cycle that determines how much and how quickly the body can adapt to a given training stimulus).

These factors suggest that females can benefit from higher training frequencies than males. While every individual's training needs and capacities are unique, a good starting point for female clients might be to add one training session per week compared to what you would program for a male. This means that if your male clients train three times per week for a given muscle group with 3-10 sets per session, your female clients might benefit from training four times per week with the same volume and intensity.

Of course, individualized prescription and adjustment are always best, especially as there can be large muscular females and small, not-so-muscular males. However, these general guidelines can be helpful for female athletes and trainers looking to optimize their training programs. With the right approach, women can achieve impressive gains in strength and muscle size and enjoy faster recovery times and a reduced risk of injury.

References:

Ansdell, P. et al. Sex differences in fatigability and recovery relative to the intensity–duration relationship. J. Physiol. 597, 5577–5595 (2019).

Hunter, S. K. Sex differences in human fatigability: mechanisms and insight to physiological responses. Acta Physiol. 210, 768–789 (2014).

Miller, A. E. J., MacDougall, J. D., Tarnopolsky, M. A. & Sale, D. G. Gender differences in strength and muscle fiber characteristics. Eur. J. Appl. Physiol. Occup. Physiol. 66, 254–262 (1993).

Roberts, B. M., Nuckols, G., & Krieger, J. W. (2020). Sex differences in resistance training: a systematic review and meta-analysis. The Journal of Strength & Conditioning Research, 34(5), 1448-1460.