There are no planar perspectives and subsequently the images appear rather flat (or that every single limb is placed at the exact same distance from the eye which would be unlikely). I would recommend looking into foreshortening and perspective to fix that issue. Also make sure you are going from simple to detail, the muscles should be 'wrapped' around the forms (skeletal forms being the ribcage, pelvis and the head) rather than just drawn as enclosed areas like a box (Pectoralis Major).
Also, maybe look into shading so that you can give the forms a 3D appearance and a recognizable structure. Or failing that, maybe try to indicate the surface perspectives of the masses by drawing a line and using it to indicate how each muscle is rounded and the shapes they take.