Core exercises don’t get much better than the plank. It works your whole body at once and you don’t need any equipment, which makes it easy to do everywhere. Rotate plank exercises so you don’t get bored. Combine some explosive movements with static ones. Start with the plank crunch, the move to a side plank crunch. Add a few plank jacks for some cardio workout. Then finish with 30 seconds of plank jump crunches.