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.
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.