The word definition refers to the shapeliness of one's muscles. When your body has excess fat on it, it looks bulky and out of shape. Fat lacks definition, and it can be all over the place — your belly wobbles, your thighs are flabby, and your upper arms jiggle. In comparison, muscle has shape.

Women are often afraid of lifting weights because they think it's unladylike or not natural. However, unless you decide to spend hours and hours lifting very heavy weights, you will not get bulky. First of all, women do not have enough natural testosterone to produce major muscle size. And secondly, men build bulk only if they spend many hours each week lifting extremely heavy weights. As you will learn, there are many other ways to lift weights that will not produce such an effect.

Strength training exercises isolate muscles and muscle groups, and, as mentioned previously, builds muscular strength and endurance. Muscular strength and endurance enable you to perform such tasks as carrying groceries and suitcases, taking out the trash, moving light boxes of papers or small pieces of furniture, picking up children or pets, or assisting older adults.

Improvements in muscular strength cause the body to burn more calories, even at rest.

Strength Training and Overload

Strength training exercises include weight training, calisthenics, and sometimes activities like yoga or ballet. We stimulate muscle growth by applying the overload principle, pushing your muscles a bit beyond what they are accustomed to. To strengthen muscles, we have the muscles experience resistance, or an opposing force. The terms resistance training and strength training are used interchangeably, and simply mean the process (just described) used to produce strength; the term weight training refers to using weight or weights as a form of resistance that produces gains in strength.

No Weights Required

A muscle gets stronger when it is stressed, i.e., when it is asked to work harder than it is used to. This occurs because the stress creates microscopic tears in the muscle, and then when the muscle is given time to rest afterward, it knits itself back together to become stronger and better than ever.

Muscle doesn't necessarily have to lift more weight to be challenged. If you lift your arm to the side right now and try to hold it up gracefully like a ballerina, you'll notice that after just a few seconds, your arm begins to feel tired. And that's because you don't normally hold your arm that way, so your arm is being “stressed.”

If you continued to hold your arm up that way, oh, let's say, for 10 minutes a day, in about a week your arm would feel stronger, and it wouldn't be as difficult for you to repeat this exercise during the next week. Your arm would be stronger even though you didn't lift a weight.

The point is that you can build muscle without lifting weight. Ballerinas do it, gymnasts do it, and all kinds of other athletes become stronger in the very specific ways they challenge their muscles. For example, runners build strong legs; swimmers build strong backs, arms, and legs; and bowlers build one strong arm. Sounds silly, but it's true.