Despite its name, the straight leg raise isn't an exercise for the leg muscles. It actually targets the iliopsoas muscles of the hips, though it also engages the thighs and abs. You won't be stuck in a rut with one version of this classic exercise -- you can change the degree of your leg raise to suit your own preferences or comfort level, or to target different muscle groups.
For the lying straight leg raise -- the standard variation of this exercise -- begin supine on the ground or a workout bench with your back flat, legs extended and your hands tucked under your lower buttocks. With a smooth, controlled motion, raise both your legs by flexing at the hips, keeping your toes pointed and knees straight. At the top of the motion, your body should form about a 90-degree angle between your thighs and torso. Return to the starting position and repeat.
Grip a pull-up bar overhand with your hands just a bit wider than shoulder-width and hang with your body extended. For the straight-legged variation of this exercise, lift your legs up from the hip, keeping your knees straight. At the top of the raise, your legs should be angled a bit inward toward your body, forming an angle slightly less than 90 degrees between your thighs and torso. Return to neutral and repeat.
To work the all important tummy -- namely the rectus abdominis and obliques, or outer abs -- you have to achieve full flexion of the waist during your leg raises. This means that a 90-degree angle of the lying straight leg raise -- which engages the abs as secondary muscles, but doesn't engage them dynamically -- won't cut it for ab-focused exercisers. For ab workouts, stick with hanging straight leg raises. To prep your body for this stretch, try a set of leg-hip raises before launching into your straight leg raises.
For lying and hanging varieties of the leg raise, you can decrease the challenge by bending your knees as you raise your legs. If you prefer to go straight-legged but can't quite hit the 90-degree angle, simply lift your leg to a 45-degree angle, or as high as you can. Exercise at your own pace, lifting your legs a little higher each time you workout. Lifting one leg at a time and keeping the other leg bent at the knee also helps reduce intensity. On the flip side, add ankle weights, starting with 1/2 to 1 pound per ankle, to increase the challenge.
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