Why women don’t get ‘bulky’ lifting weights (REPOST)

It’s a very common question in my gym. “Will lifting all these weights make me bulky”. As much as I try and refrain, I can’t help but meet this enquiry with a standard ‘face to palm’ response. Partly due to the fact that in all my years (and all the years of the trainers gone before me) the fitness industry has still not addressed fully the ongoing myth that women lifting weights = huge man-featured brutes. However many times I explain why squatting your body weight won’t give you huge legs, I have to constantly reassure my female clients that I’m not trying to turn them into Geoff Capes. So here it is. Once and only once will I address this in my blog, (with references I might add) the reasons why women don’t get huge from lifting weights.

The difference between men and women.

Men and women are equal, but not the same. This is one of my favourite quotes although I can’t remember where I heard it from. I train my male and female clients in a very similar fashion in that I expect hard work and dedication to their goals. I expect them to give me maximum effort and to strive to be the best they can. I also expect them to get as strong as possible. Not only for life benefits but to help them achieve their goal, as I’ve not heard of a goal yet where getting stronger wouldn’t bring them closer to accomplishment.

However, with all this in mind we must highlight there are fundamental biological differences between male and females. And this is where our journey begins, ladies and gents, welcome to the endocrine system.

Hormones hormones hormones…

The endocrine system is responsible for all the hormones in our bodies. It is responsible for maintaining homeostasis (our stable maintenance environment). Hormones are found in glands around the body and are released into our bloodstream to regulate cellular activity. Hormones influence the rate of cellular reactions by altering the rate of enzyme activity. Basically in the instance of muscle growth they facilitate or inhibit the uptake of substances into cells. In terms of protein synthesis (think of this as muscle growth) the hormone testosterone plays a vital role in facilitating cellular uptake and thus influencing muscle growth.

How we build muscle

Now not to oversimplify it, but before we go any further it’s important we understand the basics of how our muscles grow. So here it is in 3 easy steps!

Activate motor units through movement. Lets take the squat for example. When we squat we have to stimulate muscle fibres to produce movement. Nw if I squat with 100kg on my back, this task becomes much harder, so my body needs to stimulate the larger muscle fibres.
When we stimulate these muscle fibres, signals are sent to our muscles that stimulate growth and repair.
An activation of muscle satellite cells and an increase in protein synthesis leads eventually to larger, stronger muscles.

So theoretically if we follow the stages above, both males and females should be able to simply get infinitely stronger and bigger as a direct correlation of the amount of weight they are lifting, right? Well no actually, it’s much more complicated than that and that’s where hormones come into play.

Remodelling and growth of muscular tissue is dependant on the hormonal response to resistance exercise. Here is a quick rundown of the key players:

Testosterone (T)

Secretion gland: testes in men, and adrenal cortex in women
Responsible for: growth and protein synthesis
What we know: testosterone is a steroid hormone. It is anabolic in nature and is produced mainly in the testes. It’s responsible for protein synthesis in the cells, and helps contribute to bone growth.

A acute bout of resistance exercise can increase levels of T briefly, and prolonged resistance exercise has been linked greater resting levels of T in men. Coincidentally low levels of resting T have been found in endurance athletes, so if you want to get big and strong guys, steer clear of the marathons. High volume high repetition training has the greatest response in terms of T. Most strength improvements will be neural at lower volume and higher intensity (<6 reps). This means that your brain simply becomes better at activating already existing muscle fibres and will not build new muscle. Also in terms of the subject we are discussing today, it's important to note that T production in males is 20x greater than in females. So men have 20x the amount of this magical muscle-builder compared to their female training companions. Why is this? Well let's remember where the T is produced... Growth hormone (GH)

Secretion gland: pituitary gland
Responsible for: amino acid transportation, protein synthesis, growth of bones and increases our ability to use fatty acids (burn fat).
What we know: like T, GH is effected by volume and intensity of training. High volume and moderate intensity has been shown to increase GH. It is also suggested that GH is probably more responsible for muscle growth in females due to their lack of T. Resting levels of GH do not appear to be effected by prolonged resistance training.

Secretion gland: adrenal gland
Responsible for: mobilises fatty acids, inhibits protein synthesis, has been related to stress, sleep and other factors
What we know: overtraining or high volumes over time can increase cortisol secretion. High levels of aerobic training have also been shown to raise cortisol. Effective rest and stress reduction are great ways to ensure that cortisol doesn’t inhibit your training.

So what does this mean to any aspiring female bodybuilders out there? Well if you want to get big, you better increase your T levels of up to 20x… Alright I’m being facetious, you ladies basically lack the hormonal profile required to increase significant muscle mass. No matter how hard you try, how much weight you lift and how strong you try to become, you simply lack the hormones responsible for hypertrophy (muscle mass gain). On a side note, EVEN IF you trained as hard as possible everyday lifting lots of heavy weights, the chances are you would eventually increase your cortisol levels and INHIBIT your ability to build muscle. Wow lucky I was born a man…

So there it is ladies, my definitive although not exhaustive post on why you won’t be getting big from lifting weights. So I will leave you with a list of benefits from lifting heavy weights.

You will be strong and able to do things that make mere mortal females wince
You will have lean, defined muscles
You will have an improved body image and increased feeling of self esteem.

Thanks for reading, now lets ever bring this up again…


Leave a Reply to Nick Vacalo