No, not just like fat. If it’s not flexed and is really loose (after a long massage, not toned, hasn’t been used in a long while or is weak as it is in some elderly people, medicated with a relaxer, adequately warmed up) then it will jiggle some. But it’s an obviously more dense substance. Also, muscle is attached to bone, unlike adipose which is attached to only skin. So if the skin moves, the fat will move, but not necessarily the muscle.