"I don't lift weights because I don't want to bulk up" said way too many women, wa

Sadly, the misconceptions that surround resistance training cause many women to shy away from lifting weights and miss out on the numerous benefits that this type of training has to offer.

One of the most frequent hesitations I hear has to be the fear of getting big and bulky. I want to quash this myth here, today, once-and-for-all.

Firstly, how many women do you really see walking around who have biceps, backs or abs so ripped that you can't help but think thank God I don't look like that; Far better to avoid the gym altogether than run the risk of building muscles like those!

At the risk of sounding like an arse, I think that sometimes the I don't want to get big and bulky claim is an excuse... And we tend to use excuses when we feel threatened, intimidated, or simply don't know enough about something to provide a more legitimate reason for why we don't want to do it.

So let's get down to the physiology of it all.

As women we don't produce enough testosterone to build that much muscle.

Muscle growth is the result of an increase in muscle protein synthesis, which is governed largely by the hormone testosterone.[i],[ii]

Testosterone is produced by the testes in males, the ovaries in females, and in small amounts by the adrenal glands in both sexes. Generally, the testes produce much more testosterone than the ovaries, leading to average plasma concentrations of 16.7±14.8 nmol/L in men, compared to just 2.1±1.6 nmol/L in women.[iii]

Yes, arguably there is variability between individuals, but on the whole, women have considerably lower plasma concentrations of testosterone and so a reduced capacity to build muscle... regardless of how much weight they might be lifting, or how many protein shakes they may be consuming.

It’s also worth being aware that a very low body fat percentage is required for any significant muscle definition to be visible.

Bodybuilders for example, follow a strict and complex diet plan in order to maintain lean mass and strip body fat during the weeks prior to competition. Similarly, in sports where bodyweight affects performance, such as gymnastics, boxing, long distance running or rock climbing, athletes might reduce their energy intake or increase their energy expenditure in order to closely control their weight.

Take a look at the table below, which shows percentage body fat ranges and the associated health risks in women and men (and notice how the essential body fat percentage for a woman is much higher than for a man). Maintaining such low body fat puts women at increased risk of infertility, anaemia, osteoporosis, hormonal imbalances and amenorrhea. These negative health implications means that most women will aim to regain any weight they lost immediately following competition.

Body fat percentages and associated health risks among women. Adapted from the ACSM position statement on nutrition and athletic performance.[iv]

We're moving out of an age where women's bodies are regarded merely as ornaments and we're waking up to the realisation that women can be strong, able and confident too.

So either come up with a decent excuse, or don't let a silly, old-fashioned misconception put you off doing something that can have such positive effects on your physical and mental health!

[i] Griggs, R. C., Kingston, W., Jozefowicz, R. F., Herr, B. E., Forbes, G., & Halliday, D. (1989). Effect of testosterone on muscle mass and muscle protein synthesis. Journal of Applied Physiology, 66(1), 498-503.

[ii] Tipton, K. D., & Wolfe, R. R. (2001). Exercise, protein metabolism, and muscle growth. International journal of sport nutrition and exercise metabolism, 11(1), 109-132.

[iii] Torjesen, P. A., & Sandnes, L. (2004). Serum testosterone in women as measured by an automated immunoassay and a RIA. Clinical chemistry, 50(3), 678-679.

[iv] American College of Sports Medicine, & American Dietetic Association. (2000). Joint Position Statement: nutrition and athletic performance. American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada. Medicine and Science in Sports and Exercise, 32(12), 2130.