You’ll feel it in your middle
This move, called the “hundred,” is a signature exercise developed by Pilates founder Joseph Pilates to stimulate breathing and strengthen core muscles. If you are new to Pilates or have a sensitive back, be sure to practice the modified and easier bent-leg version before trying the more advanced straight-leg variation.
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Modified beginning version
Lie on your back on a mat with your arms by your sides, palms down. Bend both knees directly above your hips. Press your back flat against the mat and raise your arms above the floor alongside your body; point your fingertips forward and keep your elbows straight. Inhale, then on the exhale curl your torso forward, lifting your head, neck and shoulders away from the mat. Maintain this position while you inhale and vigorously pump your arms up and down five times. Exhale, then pump your arms five more times. On each exhale, concentrate on pressing your navel down toward your spine.
Classic version
Lie on your back with your arms by your sides, palms down. Straighten your legs in a 45-degree angle from the floor. If you cannot keep your back pressed against the floor, lift your legs higher to get your lower back pressed down. Raise your hands above the floor and inhale. Exhale as you curl your chest, head and shoulders off the floor. Maintain this position as you inhale, then vigorously pump your arms up and down five times; exhale, pumping your arms five more times. Every time you exhale, concentrate on pressing your navel toward your spine, keeping your abdominals flat. Continue to pump your arms until you reach 100 pumps.
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-- Karen Voight