The psoas, or iliopsoas, are the muscles that connects your upper body to your legs according to Yoga Journal. When you sit with your hips flexed, the psoas muscles become tight if you don't move around. This can cause pain in the lower back and create reduced range of motion. Pilates exercises to stretch the psoas can strengthen and release tight psoas.
The psoas stretch exercise isolates one psoas muscle at a time for stretching. This is a simple Pilates exercise, but the Pilates principles of zip and hollowing and anchoring the scapula still apply. To perform this exercise, lie on your back with your legs bent, feet on the floor, and press your shoulder blades into the floor. This is anchoring the scapulas. Pull your right knee into your chest and then slide your left leg straight. The psoas stretches as one leg slides forward as the other is in the bent position. Pull in the abdominals. Repeat by switching legs.
Constructive Rest Position
The constructive rest position releases tension in the hips, pelvis and lower back. Gravity works to lengthen the psoas muscle automatically. To assume the constructive rest position, lie on your back with your arms at your sides, your knees bent, your heels 12 to 16 inches from your butt and your feet about hip-width apart. By lying in this position for 10 to 20 minutes and relaxing, the psoas muscle releases and the body will sink into the floor. No forcing down of the back is necessary, according to Pilates Digest.
The hundred is a challenging core Pilates exercise. The hundred is also one of the most popular exercises in Pilates, though many practitioners cannot execute it with correct form, according to SelfGrowth.com. Beginners hold their legs, using their arms and not their psoas muscles, to keep their hips flexed. Others can bend their knees or raise their legs above a 45 degree angle to the floor, which is easier. To perform the hundred correctly and work the psoas, sit on the floor with your legs straight in the air so your feet are at eye level. Lean the upper body back with a straight spine and flutter your arms at your sides as you reach forward, palms down. This works the ab and back muscles too.
The side-kick-kneeling is a mat Pilates exercise that strengthens the hips and core. This exercise is a variation of the side kick. To begin, kneel and place your right hand on the floor next to your right knee as you place your left hand behind your head and lean to the right to lift your left leg straight into the air at your side. Swing the leg backwards and then kick the leg forward. The psoas muscle helps bring the leg forward into hip extension at this point. Repeat on the other side. Maintaining the abdominals stabilizes the trunk during this exercise.