Warming Up Performance is improved

Warming Up

Performance is improved if the muscles have been slightly warmed up just before the activity. Most baseball pitchers, for example, work better on warm days. Failure to warm up before vigorous activity may lead to an actual tearing loose of muscle fibers from their tendinous attachments.

Observations on the contraction of isolated muscles provide a clue to the nature of the warming up process. If the muscle is warmed, the speed with which the muscle contracts and relaxes and the force of contraction are all increased. If a previously inactive muscle is stimulated repeatedly, the first few contractions are often small and irregular and relaxation is incomplete. After this, the contractions become stronger and relaxation is complete. It is probable that warming up is due in part to these changes in the muscle itself, involving a local rise in temperature and the accumulation of metabolic products. It is possible that the viscosity of the muscle is thereby decreased, allowing contraction and relaxation to occur with greater promptness. In the body these same factors also increase the local blood flow through the muscle by dilating the small blood vessels. This improves the functional condition of the muscle by increasing its oxygen supply.

The muscles most frequently torn during strenuous activity which has not been preceded by a warming up period are the antagonists to the strong contracting muscles. These "cold" antagonistic muscles relax slowly and incompletely when the agonists contract and thus retard free movement and accurate coordination. At the same time, the force of contraction of the agonists and the momentum of the moving part exert a terrific strain on the unyielding antagonists with consequent tearing of the muscle fibers or their tendinous attachments.