Exercise in education and medicine / by R. Tait McKenzie.

  • R. Tait McKenzie
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: Exercise in education and medicine / by R. Tait McKenzie. Source: Wellcome Collection.

    30/418 (page 30)
    3° severe athletic test. The lack of this precaution in cold weather is the cause of most ruptured muscles and tendon strains. Galen recognized this fact in the second century and writes: “If any one immediately after undressing proceed to the more violent move¬ ments before he has softened the whole body and thinned the excretions and opened the pores, he incurs the danger of breaking or spraining some of the solid parts, . . . but if beforehand you gradually warm and soften the solids and thin the fluids, and expand the pores, the person exercising will run no danger of breaking any part.” The overproduction of heat is fairly well equalized by evap¬ oration through the skin and lungs, although general massage is followed by a slight rise in temperature, and there is always some fever attending and following a long distance race. The effects of the three kinds of exercise described in the previous chapter on the structure and behavior of the muscle vary widely. Single and complete contraction, however mild the resistance, improves the nutrition if frequently repeated, as shown by an increase in size and efficiency. When, however, the tension is habitually excessive, minute ruptures occur in its substance and sheath, fibrous deposits are formed, and the muscle itself becomes shortened, hard, and inelastic. Even when at rest, the specialist on the horizontal bar will show the rounded shoulders, the bent arms, and curved fingers developed by too exclusive devotion to this exercise. The number of muscles involved in a simple movement multi¬ plies with the intensity of the effort. The trial of grasping power by the hand dynamometer is designed to test the flexors of the hand and forearm, but in the strife for additional force, muscular contraction spreads to the arm and shoulder and throughout the entire muscular system until its intensity is expressed by the face. If, however, skill is an important factor in the exercise, the em¬ phasis on alacrity and accurate control cultivates in the muscle economy of effort and promptness in responding to the will. In other words, the latent period is shortened. In exercises of endurance each movement is comparatively