The main muscle groups in the body care: chest, back, shoulders, legs, core, biceps and triceps. The back and the legs are the large muscle groups, where the smaller muscle groups are chest, shoulders, core, biceps and triceps. Yes there are MANY more muscles, but these are your general top level categories. See the diagram below for locations of each muscle group. Each muscle group can be worked with a series of pushing, moving the weight away from the body, and pulling, moving the weight closer to the body, movements.