One of the most common concerns I hear from trainees about lifting weights is that they will become “too big” or “bulky.” This doesn't seem to just be a concern for women, but also men. Though I believe that adding muscle does nothing but good for aesthetic, performance, and health; I understand the mindset that people with this concern may have. Luckily, this isn't something to worry about. Significant gains in muscle mass do not happen by accident, evident by the lack of people that complain to me about how muscular they have actually become. In fact, building muscle is pretty hard to do. Below are a couple of reasons why we don't pile on muscular bodyweight after a few RT sessions.
The first is specific to women, and a fact I have mentioned before in blog posts. Women who train hard with weights will not “get jacked” because of their lack of the hormone testosterone. Testosterone tells our body to grow muscle after lifting, and men have way more than women do. This is why men can become very large from a muscular standpoint. The women that you see who would be considered “big and bulky” are almost certainly using drugs. The most likely candidate would be steroids. What are steroids? Synthetic testosterone, the same hormone that tells our body to build muscle when we lift weights.
This second fact applies to men and women. Though our body will secrete hormones like testosterone in response to lifting weights, it needs enough energy (food) to actually add muscle. Most people will need to eat lots and lots of food in order to gain significant muscular bodyweight. Think if you wanted to build an addition to your house. It's pretty clear that you would need lots of extra building materials in order to do so. Your body is no different, if you want to add structural tissue (muscle) you must have extra materials (protein and excess calories) to make it happen.
Hopefully at this point it is clear why adding muscle doesn't just happen by accident. Anyone concerned with this happening almost certainly isn't eating enough of the right foods to support muscular growth. If this person is a female, they also lack the appropriate amount of hormones to become the next Ms. Olympia. Resistance training is a great activity for health and fitness and most people who do it consistently will build some muscle. But, unless someone is committed to (and knowledgeable about) what it takes to put on significant muscle, they will never have too worry about getting “too big” from lifting weights.