From the first time I stepped in to a gym as a trainer I have reassured hundreds of women that resistance training is good for them. “But I don’t want to get big and bulky like the men do!” – a reply I usually get 99% of the time. I’d often smile and tell them they won’t, it’s a myth and women cannot build as much muscle as men. I said this for years. Studies from 40 years ago suggest that In terms of absolute strength, women generally have about two-thirds the strength of men (13). But is that really the full picture? Maybe I am wrong…
Now before you think of how many women I have turned in to the Hulk, let me clarify that I have always used resistance training with women and I have never had a woman complain about her body, nor did they look anything remotely like the Hulk.
You see, originally I thought that women had less testosterone than men, and I’m right! In fact women only have 15-20 fold lower concentrations of testosterone than men do, although some women secrete higher concentrations of adrenal androgens (1). But testosterone isn’t necessarily the reason why we build muscle. Recent research has suggested that despite testosterone being recognised as one of the biggest hormones in building muscle (8, 9), it may not be the case. Most people have heard of protein synthesis – a process where protein tissue is repaired and rebuilt (1), but it’s the signalling pathways that promote this response that gives us the clues. It’s been found that this pathway doesn’t involve testosterone (2). I could go on here, but that’s a whole article in itself. It’s important to note, we are still learning about the responses of testosterone to resistance training (1) and i’ll update you guys as soon as i know more.
But back to why I was wrong. Firstly, women can increase strength and muscle size at the same rate as men (3). Previous studies have found gender differences in either strength or size changes after resistance training (4, 5) whereas studies have documented similarities in relative strength and size changes after training (7, 12). It is hypothesised that the disparities in results may be down to sample size, as the majority of previous studies have no more than 20 men or women. However, when performing a 12 week set programme of preacher bicep curls on the non-dominant arm with 585 subjects, a study found no difference in hypertrophy between men and women, thus possibly giving further evidence that testosterone isn’t the key factor in building muscle (6). Interestingly this study stated that although the gain in muscle size was similar (20% and 17% in men and women, respectively) women had larger increases in strength (40% and 64% in men and women, respectively). That’s over 20% more strength gains! However, the researchers did note that although women had larger increases in strength when compared to men, the fact that women may have been more uncoordinated in their original testing may have caused them to appear much weaker than men. Stereotypically, probably due to societal influences on women in regards to strength training, women may have less experience of resisted bicep curling. As explained in the Maximum Strength programme booklet, one of the components that may help increase strength initially is our body’s ability to increase synchronisation within in the motor units of the muscle, therefore causing further increases in the female subjects as they improve more via the skill aspect of a bicep curl.
In the beginning, during puberty, the production of estrogen in girls increases fat deposition and breast development, whereas testosterone production in boys increases bone formation and protein synthesis (1). Though estrogen also stimulates bone growth, boys have a longer growth period, and therefore adult men tend to achieve greater stature than adult women. On average, adult women tend to have more body fat and less muscle and bone than adult males. Furthermore, women tend to be lighter in total body weight than men. The broader shoulders in men can support more muscle tissue and can also provide a mechanical advantage for muscles acting at the shoulder. When considered on a relative basis, sex-related differences in muscular strength are greatly reduced (as is power). Because the average man and woman differ considerably in body size, it is useful to compare sex differences in strength relative to body weight, fat-free mass, and muscle cross-sectional area (1). When expressed relative to fat free mass, the lower body strength of women is similar to that of men (11, 12), while the upper body strength of women is still somewhat less (in relative bodyweight). Muscle hypertrophy increases are approximately the same in both sexes (1, 6).
Since the physiological characteristics of muscle in the sexes are the same, there is no sensible reason why resistance training programs for women need to be different from those for men. In fact, because the muscle groups involved in a particular sport are obviously the same for men and women, resistance training programs should be designed to improve the performance of the muscles needed for successful sport performance, regardless of sex (1). Women are also capable of tolerating and adapting to the stresses of resistance exercise and the benefits are substantial (10). The fear of ‘getting too big’ or ‘looking like a man’ should not even be considered.
Considering that most women have low levels of lean tissue, developing a bit of muscle will drastically improve the female body. Muscle adds curves, it shapes the bum and the legs. I’m not saying women need to shift weights every day for 5 years, I’m saying that women will greatly benefit from adding resistance training to their regime. And that’s just from an aesthetics viewpoint. The fact that resistance training has many benefits physiologically (such as decreasing fat mass, strengthening muscle and tendons, increasing coordination) (1), resistance trained women have been found to have improved bone mineral density (15) and are less prone to ACL injuries (16).
So ladies, in a nutshell – Don’t be afraid of the weight room. The strength and size gains are similar to men BUT next time you see a man with bulging pecs and delts, understand that he has developed them over years and years of hard work in the weight room. You won’t turn out like that overnight and if you feel you’re putting on too much mass, decrease the volume (sets and reps). Resistance training will give you a healthier, stronger, sexier body than any other training regime. So get off of the treadmills and in to the squat racks.
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