Flexing is a process in which the muscle tissues in a specific muscle or group of muscles contract. This contraction causes a joint in the body to bend in a specific way but also causes the muscles to reduce in length and increase in width. Flexing is crucial when performing weightlifting exercises because it is what causes the body to move and lift the weight. The other benefit of flexing is that the change in the shape of the muscle can draw attention to it. Bodybuilders utilize various flexes to emphasize the size of their muscles.
Flexing occurs when the body's neuromuscular system recruits the muscle tissue and causes the tissue to contract. This causes the muscle's length to decrease, which, in turn, causes the joint to which the muscle is attached to move. For instance, when an athlete performs a biceps flex, the biceps muscles contract, causing the arm to bend at the elbow.
When a flex encounters resistance, such as during weightlifting exercises, it stimulates muscle growth. For this reason, the harder an athlete must flex a muscle during a lift, the more that lift will help to stimulate growth of the muscle tissue. Without flexing, then, weightlifting would not be possible.
In addition to making weightlifting possible, flexing also enables an athlete to show the benefits of his or her weight training in a more dramatic fashion. Bodybuilders use a variety of flexes to emphasize different muscle groups and to show off the size of their muscles. For instance, during one of the most common types of flexes, the biceps flex, the biceps muscle bulges out from the body. As a result, biceps flexing draws attention to the size of the athlete's biceps and even makes them look slightly larger than they would look if they were relaxed.
It is possible to flex every muscle in the body, but bodybuilders typically utilize a few specific types of flexes during competition. Typical flexing in bodybuilding aims to create the most dramatic effect possible. In addition to biceps flexes, athletes will tend to flex muscles that are part of large muscle groups, such as the quadriceps and triceps. Abdominal flexes also are quite common, as are flexes of the back muscles. All of these flexes, in addition to recruiting some of the most visible muscle groups, also coincide with the muscles groups that some of the most common weightlifting exercises tend to target.