The key to bodyweight exercise is mixing it up. Challenge yourself. If you're not sore the next day, you didn't work out hard enough. "When you push yourself, you'll be building muscle, increasing bone density, strengthening ligaments, and burning calories for up to 36 hours after your workout," says Mark Lauren, author of 'You Are Your Own Gym.' When push-ups become too easy, switch to a different grip – wide, narrow, or staggered hands – or pause during the motion. Try one set on an incline, the next on a decline, and the next with one hand on a basketball. For all of the exercises below, aim for three sets of 10 reps unless noted otherwise. Time yourself and try to do them more quickly the next time around. If you can't finish a set, complete it with the easier version.
The No-Weights Workout: Push-Ups
Push-ups ignite more than 100 muscles, but few guys do them with proper form. Be sure to keep your back and neck straight, and glutes and core engaged. Always lower yourself slowly, bringing your chest almost to the floor before pushing up.
Make it Hard
Place one hand on a basketball and roll from hand to hand on each rep.
Credit: Photograph by John Loomis
Try a one-handed push-up by putting one hand behind your back and spreading your legs wide.