Trainer tip: If you need a break, just lower your knees and rest for a moment.

Trainer tip: Hold on to the back of a chair if you feel unsteady.

Trainer tip: When you lower into the lunge, don't let your back knee touch the floor.

Trainer tip: To help with balance, keep eyes focused on a single point.

Trainer tip: Do the move slowly at first, then speed up as you gain strength and control.

Trainer tip: Think about bringing each knee toward your nose.

Trainer tip: As you get comfortable, create your own combination of punches.

Trainer tip: For best results, keep the movement slow and controlled.

Trainer tip: For more of a challenge, do a push-up after each rep.

Trainer tip: Because of their size, chest muscles are surprisingly strong.