Applied anatomy and kinesiology; the mechanism of muscular movement . Fig. 105.^—Natural position when knees are Fig. 106.—Position used in Swedishbent while standing. gymnastics. other joint any force applied at one of them. If, however, wereplace the cords in the model shown in Fig. 107 by rubber bands,so as to bring to bear on the apparatus the natural tension of con-tracting muscles, the two-joint muscles acting alone will extendboth joints; still more surprising, if we replace either one Oi thetwo cords by a rubber band and leave the other cord in place, itwill extend both joints as befor
Applied anatomy and kinesiology; the mechanism of muscular movement . Fig. 105.^—Natural position when knees are Fig. 106.—Position used in Swedishbent while standing. gymnastics. other joint any force applied at one of them. If, however, wereplace the cords in the model shown in Fig. 107 by rubber bands,so as to bring to bear on the apparatus the natural tension of con-tracting muscles, the two-joint muscles acting alone will extendboth joints; still more surprising, if we replace either one Oi thetwo cords by a rubber band and leave the other cord in place, itwill extend both joints as before. We are thus confronted by theproblem, How can the hamstring-muscles, which are flexors of theknee, cause extension of the knee? How can a cord tied across two VASTUS INTERMEDIUS 185 joints give to a muscle that is primarily a flexor of a joint theability to extend it? Dr. Lombard has explained this apparent contradiction by show-ing that the two-joint muscles of the thigh have better leverage asextensors than as flexors. The hamstring muscles have betterleve
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