Too many choices can leave you confused. This is often the case with abdominal exercises. Many core movements are performed with knee raises or straight leg raises, but you have the choice of body positions. You can do knee or leg raises from a hanging, semi-hanging, lying or bench position. The decision comes down to your abdominal strength, goals and personal comfort.
Hanging Knee Raise
The most challenging way to perform knee or leg raises is from a hand-hanging position. In this exercise, you hold onto an overhead bar with your hands positioned slightly wider than shoulder-distance apart. Begin with your legs hanging straight below you. Tighten your stomach to prevent any swaying during the raise. If you are a beginner, bend your knees and raise your knees toward your chest. The goal is to completely flex your hips so your stomach contracts. As your strength improves, keep your legs straight and lift your legs until they are higher than your hips.
A mid-level place to perform leg raises is in the Captain's chair. The chair resembles a high-backed chair with strong arm rests and no seat. To position yourself, step onto the platform and rest your back against the pad. Place your forearms on the arm rests and hold onto the handles. Support yourself with your upper body and release your feet so you are in a hanging position. Keep your stomach tight as you exhale, bend your knees and raise them toward your chest. Inhale as you lower your legs. When your core strength improves, transition to lifting your straight legs. One way to do this is to alternate one knee raise with one straight leg raise until you can complete your desired number with your legs straight.
The easiest way to improve your core and learn the knee and leg raise movements is from a lying position. Lie face up on the floor with your hands behind your head or along side of you. Bend your knees to create 90-degree angles in your knees and hips. Your feet are off the floor with your ankles crossed, or un-crossed, whichever feels comfortable. Exhale and bring your knees toward your chest as your abdominal muscles contract. When your strength improves, straighten your legs toward the ceiling and then lower them toward the floor to tone your core. You can progress to performing these movements on a flat weight bench -- the benefit of this is you can lower your legs beyond the parallel of the floor.
The point of this challenging exercise is to strengthen your abdominal muscles. The main muscle in your abdomen is the rectus abdominis. The RA is placed down the center of your abdomen and is most known for resembling the "six pack". The RA contracts each time you shorten the distance between your ribs and hips as you do when you lift your knees and legs. Your obliques are along the sides of your abdomen and also contract when you flex your waist. The deepest layer of abdominal muscles, the transverse abdominis, contracts when you tighten your stomach by pulling your belly button toward your back.
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