I believe that you are supposed to notice that the striations in the contracted muscle fibers are much closer together than the striations in the uncontracted muscle. Therefore, it would appear that somehow the striated parts of the muscle are being pulled closer together somehow. Glycerinated muscle retains the organized structural array of myosin thick filaments and actin thin filaments, actin associated proteins like troponin and tropomyosin which regulate contraction, and the functional capacity for contraction.
