. Applied anatomy and kinesiology. action. Asthe body nears the bar the trunk and limbs are lifted by contrac-tion of the flexors of all the joints and the arm depressors and thenextended to the position shown in Fig. 182 by the extensors. Thehands hold to the pole long enough for the body to clear the barand for the feet to begin the downward movement due to gravity, PLAYS, GAMES AND SPORTS 297 then drop it with a pusli tliat will vary in force with the exactposition of the body and the pole. On aUghtiiig the extensormuscles of trunk and limbs come into action to lessen the jar bya lengthenin
. Applied anatomy and kinesiology. action. Asthe body nears the bar the trunk and limbs are lifted by contrac-tion of the flexors of all the joints and the arm depressors and thenextended to the position shown in Fig. 182 by the extensors. Thehands hold to the pole long enough for the body to clear the barand for the feet to begin the downward movement due to gravity, PLAYS, GAMES AND SPORTS 297 then drop it with a pusli tliat will vary in force with the exactposition of the body and the pole. On aUghtiiig the extensormuscles of trunk and limbs come into action to lessen the jar bya lengthening contraction, followed by a shortening contraction tobring the body to erect posture unless the balance is lost. Mou7itain climbing is essentially hke walking up stairs, using theflexors of the limbs to lift the feet and the extensors of trunk andlimbs to lift the body, the complete flexion giving the gluteusmaximus a chance to help. In going down the mountain theweight is lowered at each step by a lengthening contraction of the. Fig. 182.—The vault with the pole. extensor muscles. There is much turning and bending that variesthe work of the trunk muscles and brings all of them into action apart of the time. Climbing the rope or pole, using both hands and feet, starts bygrasping it with the hands, using the flexor group. Then the feetare lifted by action of the flexors of the trunk and limbs and thewhole body may be lifted at the same time with arm depressorsand flexors of the elbow. The rope is now grasped by the feet,using the adductors of both thighs and the flexors of one limbacting against the extensors of the other; then the hands are moved 298 PLAYS, GAMES AND SPORTS lip the rope by use of the arm-raising muscles and the extensors ofthe trunk and hips, after which the movement is repeated. In practically all forms of strimining the body is propelled alongor through the water by the use of the arm depressors and theextensors of the lower limbs. There are a few exceptio
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