Resistance training is an important component of women’s health. The strengthening of the muscle structure is fundamental for multiple reasons, one of which is to reduce the risk of osteoporosis. However, some females fear that the execution of weight lifting exercises can excessively enlarge their muscular form. Is this really the case?
The effects of resistance exercise on muscular tissue in women
In order to understand the effects of weight lifting in females, it is important to understand the effects of resistance exercise on muscular tissue. Muscular growth results from the action of anabolic hormones, such as androgens (especially testosterone) and the grow hormone (GH). Androgens have been shown to drive muscle hypertrophy in a dose-dependent manner. The female body typically provides minimal doses of testosterone, about 15 to 20 times lower than men, this is part of the reason why muscular growth in females can be more difficult in comparison to men. It has been documented that, resistance exercise has been shown to increase total testosterone concentrations in men, while in young women no change may take place. Moreover, men have greater muscle size and strength than women, due to greater body size and higher levels of anabolic hormones.
In a recent study, strength and the cross-sectional diameter of the upper-arm musculature was compared between 243 men and 342 women aged 18-40, before and after 12 weeks of resistance training. Men experienced 2.5% greater gains for cross-sectional area in comparison to women. Despite greater gains of muscular size in men, increases in strength were greater in women. These results explain how muscular size, or alternatively known as hypertrophy, is not directly related to the strength gain. Indeed, in the process of strength improvement, different mechanisms take place such as neuromuscular factors and the increase in motor unit recruitment.
Hormonal factors and training methods that influence muscular growth in women
Studies confirm that strength training affects women in different ways depending on body type. In fact, some women are genetically predisposed to gaining muscle more readily than others. Mesomorphs, who are more muscular, build muscle mass faster than ectomorphs, who are naturally slim in shape, even when they follow the same training program. The training method also influences the muscular adaptation, the most important difference between hypertrophy and simple strength gain is the training volume. Volume is a combination of the number of sets and repetitions executed during the workout and the load that is used. In order to increase muscular size, the training volume should be high.
With this considered it is necessary to use a moderately heavy weight but with the need to execute several repetitions, this load should theoretically be lighter than the load used for building absolute strength. Strength development requires heavier loads, close to maximal effort, with fewer repetitions. Taking this methodology into account, women that do not want to gain too much muscle mass or volume, would be advised to perform strength specific training, executing fewer reps at a higher load. This way, absolute strength can be improved with a minimal hypertrophic effect. An example is to execute three sets for three repetitions of weight lifting, with two to three minutes of rest between sets.
However, women have to consider hormonal factors, training method and diet when focusing on muscular development.
References:
- Hubal MJ, Gordish-Dressman H, Thompson PD, Price TB, Hoffman EP, Angelopoulos PM. Variability in muscle size and strength gain after unilateral resistance
- training. Med Sci Sports Exerc. 2005 Jun;37(6):964-72.
- TJ, Gordon PM, Moyna NM, Pescatello LS, Visich PS, Zoeller RF, Seip RL, Clarkson
- Kraemer WJ, Ratamess NA. Hormonal responses and adaptations to resistance exercise and training. Sports Med. 2005;35(4):339-61. Review.
