skeletal muscle is a system of pairs that relax and contract to move a joint
{"Image DocumentName": "Skeletal muscle is a system of pairs that relax and contract to move a joint.", "Image ImageDescription": "For example, when front leg muscles contract, the knee extends. (straightens) while back leg muscles relax. Conversely, to flex (bend) the knee, back leg muscles contract while front leg muscles relax.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}