Warming up before exercise is the essential preparation needed to supplement the workout. A warm-up can be any physical activity that increases blood flow to working tissues, speed of nerve impulses to muscles, and delivery of oxygen and nutrients for energy release. This increase in blood flow also enhances the removal of waste products from muscle. Combined altogether, these changes prepare the body for vigorous exercise by enhancing the muscle’s metabolic properties and enhancing the mechanical efficiency of muscle contraction and force production.
Warming up is an imperative pre-exercise injury prevention component because it increases the elasticity of the muscle-tendon unit.
Contrariwise, the purpose of stretching is to increase the range of motion about a joint and group of joints. Pre-exercise stretching does NOT assist with injury prevention. It IS an extremely important part of fitness and crucial to include as part of a well-balanced exercise program BUT the timing of it should be reconsidered. You would be better off waiting until AFTER the workout is complete to conduct your stretching routine. Muscles are best stretched warm so this is an ideal time to also get the maximal stretching benefits.
Stretching after each vigorous workout also encourages mind and body relaxation.