This exercise stretches and strengthens the spine and abdominal muscles, and improves posture. Start on your hands and knees, with knees under your hips and wrists under your shoulders, fingers pointing forward. Keep your neck in line with your spine and contract your abdominal muscles to prevent your back from sagging.

Holding a weight in your right hand, extend your right arm in front of your body, in line with your right shoulder, palm down. Lift your left leg off the floor to hip level. Inhale for four counts and bring your right elbow and left knee together until they touch. Exhale for four counts and return to extended position so your right arm and left leg are stretched out again. Repeat 16 times. Then switch sides and repeat.

This exercise works the large muscles of the glutes and quads, and tones the deltoids. Stand with feet hip-width apart. Pull your abdominal muscles inward; feel your tailbone drop down. Hold dumbbells in your hands with palms facing in toward your sides. Slowly lower yourself into a squat as if you're sitting on a chair, raising your arms out to shoulder height. Do three sets of 10 to 30 repetitions.

This exercise stretches and engages the core muscles and chest. Lie on your back with your feet off the ground and your legs bent in a 90-degree angle (or rest your feet on a chair). Holding a weight in each hand, start in a closed position above your chest with knuckles touching and arms slightly curved. Open arms smoothly and slowly out to the sides and then close. Exhale as you open your arms; inhale as you close. Repeat exercise 16 times.

This exercise simultaneously engages major muscle groups in your upper and lower body. It also increases your heart rate. Start in a lunge, your right foot 2 to 3 feet in front of your left. Holding a weight in each hand, tuck your elbows in by your sides with palms facing each other. Engage your core and inhale for four counts, and then exhale for four counts as you go deeper into the lunge, lowering your right thigh until it's parallel to the ground (your left knee should almost touch the floor); lift weights toward your shoulders. Return to starting position, inhaling as you come up, and repeat. Do 16 repetitions, and then switch sides.