In any activity some muscles will be causing movement while others will be checking movement in order to stabilize the body. The muscles causing movement are working isotonically, and those checking movement are working isometrically. Take care when training isometrically, such as supporting a heavy weight or your own body weight for several seconds without moving, as this increases blood pressure dramatically. Muscular strength and endurance training can be carried out without weights. One method is calisthenics, which involves gymnastic exercises that boost strength and encourage graceful movement. Many techniques used in aerobic step or circuit training also increase strength and endurance. Muscles must be pushed beyond their previous levels in order to stimulate them to improve. They can be worked with the same weight, or resistance, but for a longer duration in order to improve muscular endurance, or with a greater weight but the same duration to improve strength. Flexibility is crucial to ensure a complete range of movement, good posture, reduced muscle stiffness, and lower risk of injury. The key to developing and keeping flexibility is to stretch often. However, stretches should be performed only after the muscles of the body are warmed up. In sports that involve a lot of stretching, such as swimming, it is important to warm up and do stretching exercises before participating. |
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