These at-home preventive exercises can give you more stability at the playground. Do them with a spouse or in a gym when possible; it's easier to keep up the routine if you do it with others.

Half Squats:
Bend legs at knees and hips, lower torso until upper legs are parallel to the ground, then return to standing. Add resistance by holding phone books or tomato cans. Benefits: flexes Achilles tendon, strengthens calves and rear, requires balance, and develops trunk muscles including obliques, abdominals and lower back.

Lateral Arm Raises:
Stand with feet slightly apart, arms at your side, palms facing in. Raise arms to head level, hold, and lower. Add resistance with cans of vegetables. Benefits: Strengthens shoulder girdle, trunk, quad, rear.

Source: Dr. Robert Schoene, professor at the University of California-San Diego School of Medicine.