How much muscle mass and strength can an untrained female expect to gain upon entering the world of strength training? Quite a substantial amount, as it turns out.
Most strength-training research is still performed using male subjects. That being said, by now there is enough data to examine to get an idea of the effects of resistance training on strength and hypertrophy in women.
That’s just what a group of researchers did. They took the data from 24 studies lasting between 4 weeks and 12 months that looked at muscular hypertrophy, upper body strength and lower body strength in a total of 912 females and compiled it into a meta-analysis.
The results should be encouraging to any females looking to hit the gym for the first time. The review of the available research shows that strength training improves both strength and muscle mass in healthy women. And not by a small amount either.
Over a duration of 15 weeks, the women gained an average of 1.45 kilograms of muscle mass. This equates to about a 3.3% increase in lean body mass. In addition, the researchers observed strength gains averaging 25% in the upper body and 27% in the lower body. They didn’t compare these numbers to any previous data from studies with male subjects. However, they don’t sound very far off.
Younger women gained more than older women, which isn’t surprising. The data also shows that supervised training is more effective than unsupervised.
Trying to wrestle some recommendations from the data, it looks like women should train 2–4 days per week, shooting for a total of at least 250 repetitions for the best strength gains when starting out. The average training intensity was 70% of 1RM, but light or heavy weights doesn’t seem to matter. Regardless of intensity, the women in the studies gained about the same.
In summary, this is the first review of available scientific data examining strength gains and hypertrophy in previously untrained females. And the results are quite positive. Strength training is an effective method to increase muscle mass and strength, regardless of sex.
Sports Med (2019). pp 1–19. The Effect of Resistance Training in Women on Dynamic Strength and Muscular Hypertrophy: A Systematic Review with Meta-analysis.