Pushups

Regular pushups. Keep your back straight and be sure to go all the way down and all the way up.

   Chin-ups

Grab the bar using a shoulder-width grip, palms facing toward you. Hang so your arms are fully extended. Pull yourself up until your chin is above the bar, then lower to the full hanging position. Do not swing your legs to assist the motion.

   Air Squat

Stand with feet slightly more than shoulder-width apart, toes pointed slightly out. Sit back, squatting back on your heels keeping your back strongly arched, pushing your knees out to the sides, until your thighs go past parallel with the floor. Return to the standing position, being sure to keep your weight back.