One of the most important arm muscles is the triceps brachii (the triceps, for short). You use your triceps to extend your arm. It opposes the biceps muscle, which is used to flex the arm. You also ...

The donkey kick is one of those aptly-named exercises — like the bear crawl or crab walk — that looks exactly how you’d expect it to. So yes, it involves getting on all fours and kicking your leg back ...