Calf raise: Stand on a flat surface or, for more of a challenge, on the edge of a step or stair. On the latter, keep toes on edge of stair and let heel come off. Rise up onto toes, squeezing calf muscles tightly, and lower heel to start position; repeat. Do one leg at a time if you can.

Clean and press: (Do this with a trainer's supervision until you get comfortable with it.) Stand with feet under a light barbell or just behind a Body Bar, feet about shoulder-width apart. Squat down and grasp bar with hands slightly wider than shoulders and palms facing behind you. Shoulders should be aligned over the bar and your back should be flat. Straighten legs and push hips forward to stand up; keep bar close to shins as you rise up. Shrug shoulders and bend arms out to sides to pull bar up in front of chest, then flip hands over so arms are underneath bar and it rests under your chin (bend knees to cushion the impact). Press bar straight overhead. Slowly lower bar until it's in front of thighs and then squat to lower it completely to floor, keeping it close to shins again.

Crunch on a stability ball: Lie back with a stability ball centered under your back, hands resting lightly behind head with elbows out to sides and feet about shoulder-width apart. Lift hips so body is straight from head to knees. Slowly crunch head and shoulder blades off ball, then lower back to start and repeat. The farther the ball is from your head, the more challenging the move.

Fast feet: With hands out to sides for balance, stand with feet about hip-width apart. Lower into a half-squat, then step right foot out to right and left foot out to left then bring them back in to the start position again, right then left. Repeat, trying to move feet as quickly as possible.

High knees: Stand with feet about hip-width apart, hands on hips or at sides as if jogging. Jog in place, lifting knees as high as you can in front of you.