To prevent injury, your muscles should be balanced. This is an often heard expression that has some basis.
There is no questioning the fact that muscles should be balanced in relation to the agonists (muscles responsible for the movement) and antagonists (muscles opposing the movements). The antagonists are located on the opposite side of the limb or body and contract during the movement but not enough to stop the movement. For example, the biceps and other muscles on the front side of the upper arm bend the elbow, bringing the forearm closer to the upper arm. The triceps, which is located on the back of the upper arm, straightens the arm. If the biceps contracts, the triceps also contracts but lengthens to not only allow the movement, but to control and eventually stop the movement. The reverse occurs when the triceps contracts in a shortening action to extend the arm. Thus the muscle development of the biceps and triceps (and all other “pairs” of muscles) should be balanced so they can carry out their functions without injury to the joint. Problems, however, arise when muscle balance is interpreted to mean equal strength or equal muscle size.In general, the body is not constructed in a manner that allows opposing muscle groups to be equal in size or strength. In general, the body is not constructed in a manner that allows opposing muscle groups to be equal in size or strength. The extensor muscles, such as the triceps, are usually larger and stronger for a good reason.
extensor muscles, such as the triceps, are usually larger and stronger for a good reason. These muscles play a major role in maintaining upright posture and in execution of most sports skills.For example, throwing, hitting, kicking, jumping, and running skills involve extension of the body and/or upper and lower extremities. Jumping requires extension of the legs while throwing and hitting involve extension of the arms, trunk, and, in many cases, the legs.Running involves hip, trunk, and leg extension. Some of the sports skills also involve active or strong flexion movements, as, for example, bringing the swing leg thigh forward in running. However, most often flexion type movements are not strongly executed and usually occur in backs wing movements. Because of this, there should not be equal strength between opposing muscles groups as is commonly advocated.Because of this, it is important to focus attention on the main muscle groups involved in your sport when preparing for the competitive season. In the off-season it is important to work the muscles on both sides of every joint, both the flexors and extensors, in order to maintain strong j oints and to keep the proper strength ratios between the flexors and extensors.Some of the joints must get equal attention. An example is the flexors and extensors of the spine. These are used almost equally in sports such as gymnastics, football, baseball and tennis.
If rotary actions are involved in the throwing and hitting, then attention should be given to development of the muscles in these actions as opposed to simply flexion or extension.You must develop the muscles in a manner similar to the way that they will be used in the sport. Simply developing strong muscles does not equate to better performances in the sport. Specificity of training is the key to success.