Everyone knows about crunches and leg raises, but the most effective ab exercise is something simple that no one is doing.
Take your warm up seriously. It's the best way to prevent injury while also helping get your head in the game.
Core strength is not as simple as getting a 6-pack. It's the muscles behind the 6-pack that makes all the difference.
Pushups are a staple move in calisthenics, but adding one simple tweak can make them much more effective.