The tag team of Mother Nature and Father Time can be cruel. As we age, we spend more time on our behinds, getting heavier, weaker—and wobblier. Pregnancy, too, can affect posture and coordination, increasing the risk of falls. But no matter your age, weight or fitness level, balance training can strengthen your trunk muscles, improving flexibility and balance. How to shore up your core:

Take a class
Pilates, yoga and tai chi enhance our flexibility and body awareness, building balance. Tai chi, often called “meditation in motion,” consists of a series of postures or movements performed slowly, each flowing into the next. Tailor-made for older folks, it’s often taught at senior centers.

Train at home

Do these exercises in-house, with no equipment other than your body:

Plank: Kneel and lean forward, with your arms bent at 90 degrees and shoulders directly over elbows. Extend your legs behind you and raise your hips to form a straight line from shoulders to ankles. Imagine your body as a plank and engage your abs, pulling navel to spine to keep from collapsing in the middle. Hold this position for 10 seconds; work up to 30 seconds. Do four repetitions. Beginners: Instead of extending your legs, stay kneeling and lean forward. Your body will be on an incline. Keep your abs pulled up toward the ceiling.

Side plank: Lie on your right side, supporting yourself on your right forearm, with lower arm bent perpendicular to body and right shoulder directly over right elbow. Stack left foot on top of right, keeping legs straight. Tighten your core muscles to keep shoulders, hips and knees aligned. Raise your body by pressing down through right arm. Hold for three deep breaths (five to eight seconds). Do four reps per side. Beginners: Instead of stacking feet, rest top foot on the floor in front of bottom foot.

Quadruped: Start on your hands and knees with hands directly below shoulders, head and neck aligned with your back (like a table). Engage abs. Raise and extend your right arm and left leg parallel to body; hold for three breaths. Do eight reps per side. Beginners: Raise each arm and leg separately, one at a time.

Cool Tools to Ward Off the Wobbles

Exercising with these pads, balls and boards will keep you rocking steady. Instructional DVDs and booklets offered with each item help you use them correctly and safely. From $40 up;

Stability ball: Whether you do crunches while lying on the ball or use it in place of a bench while strengthening your upper body with hand weights, exercising on a stability ball helps target your abs, waist and back.

Balance pads: Doing squats, lunges, push-ups and balance moves on these foam pads builds ankle stability and strength.

Balance boards:
These are designed to improve coordination and ankle and core strength. Beginners should use square rockers; advanced exercisers can try the more challenging round wobble or rectangular bongo boards. Everyone: Enlist a spotter.