Resistance training follows a set structure; these key terms are used to describe the training protocol.

Exercise - A movement designed to challenge and develop the body.
Repetition - One complete movement of an exercise.
Set - A consecutive number of repetitions, e.g. 10 push ups.
Rest - Time taken between sets, e.g. 30 sec, 90 sec, 4 minutes,
Volume - The number of sets per exercise.
Exercise order - The order of exercises e.g. circuit training,

In practice you will perform a set of an exercise then take a certain rest period followed by one or more sets of that exercise before moving on to the next.

Physiological effects

The main effect of resistance training is changes in the hormones within the body. The biggest changes are seen in testosterone and growth hormone. The effect of training is to increase the amount and sensitivity to these which results in you being better able to build muscle as well as numerous other health benefits.

Another excellent benefit is the training teaches the body to coordinate the muscles better. This means the brain can activate more of each working muscle and relax the opposite muscle more thoroughly. The result is you become stronger. The repeated loads experienced when training also induces osteoblasts to build more bone to cope with the demands and thus improves bone density but not all resistance exercises increase bone density.

How Does Resistance Exercise Work?

Resistance training works by causing microscopic damage or tears to the muscle cells, which in turn are quickly repaired by the body to help the muscles regenerate and grow stronger. The breakdown of the muscle fiber is called "catabolism," and the repair and re-growth of the muscle tissue is called "anabolism." You're probably familiar with the term anabolic when used with steroids. Anabolic means to grow, and that's exactly what happens after you break down the muscle fibers with resistance exercise. In fact, many biological processes of growth in the body require some breakdown, or catabolism, prior to re-growth. For instance, bones must be broken down first before calcium and other growth factors repair the bone and make it stronger. With muscles, testosterone, insulin-like growth factor, growth hormone, protein, and other nutrients rush to the muscle after a resistance-exercise session to help repair the muscles to make them stronger. Importantly, your muscles heal and grow when you aren't working out, and so that's why it's necessary to leave time between workouts for recovery.