Unfortunately you’ve asked the wrong scientist here..I am a chemistry guy!
But I was also interested in your question so had a quick look around the web. Here follows a short description…
Bones, ligaments, and muscles are the structures that form levers in the body to create human movement. In simple terms, a joint (where two or more bones join together) forms the axis (or fulcrum), and the muscles crossing the joint apply the force to move a weight or resistance.
Basically, force is applied between the resistance (weight) and the axis (fulcrum). Picture someone using a shovel to pick up an object. The axis is the end of the handle where the person grips with one hand. The other hand, placed somewhere along the shaft of the handle, applies force. At the other end of the shovel (the bed), a resistance (weight) is present. One example of this type in the human body is the elbow. The joint is the axis (fulcrum). The resistance (weight) is the forearm, wrist, and hand. The force is the biceps muscle when the elbow is flexed.