We are used to defining movement in the body in terms of muscles. This makes sense when describing the act of lifting a mug from the table to your mouth. However, the moment you begin describing full body motions like running, sports, dancing, etc, it makes sense to drop the lens of muscles and apply the lens of muscle chains.
Traditional training is comprised of movements that, while engaging many muscles simultaneously(in the case of compound lifts), all the muscles are engaging individually in a more-isolated fashion.
This is contrasted to many sports and more functional movements that rely on elastic recoil and force transmission through whole muscle chains
In all of the following, see if you can spot the elements of rotation, elastic recoil, and force transfer.
Connected moves like these do not put pressure on the joints involved in the movement, because the force flows through the joints via muscle chains( assuming you are well enough connected). Contrast the spike to a bench press, where because force can not be carried through the joint to the next muscle it can not help but strain the shoulder.
Elastic recoil from muscle chains are our gift from nature to be able to move efficiently with low caloric expenditure. The chemical and physical makeup of the myofascia that constitues our chains allows for it to have elastic recoil, just like a common rubber band. We either train in ways that strengthen the integrity and connectivity of these chains and make them more like whippy rubber bands, or in ways that lead to the disconnection and fragmentation of them, leading to joint pain and stiffness.
A great way to build muscle mass is to isolate it, and while pure isolation is impossible you can definitely isolate a muscle in training more than it would be isolated in nature. And guess what? This is a great way to build muscle mass, which our culture loves. The problem is it’s training the muscle to work alone and not to connect to the tissues above and below that would otherwise link to it in movements that are more natural.
Think of your body like a bow and arrow. Each muscle chain is a possible bow string you can use to shoot an arrow. In this metaphor, the arrow is the direction you are moving. All of these bow strings are designed to be tensioned and then release force in a horizontal direction over the ground, like in the below two gifs. But what happens in the gym? We take our bowstring and try to shoot the arrow straight up, at 90 degrees, essentially perpendicular to the direction the bowstring is pointing the arrow.