The hanging leg raise works several muscles in your hips and midsection. To perform this exercise, hang from a fixed pullup bar with your arms and legs extended. With your legs together, contract your abdominal muscles and lift your knees as high as possible by rolling up your spine and bringing your pubis toward your sternum. Slowly lower your legs to return to the starting position. Hold a dumbbell between your feet to increase the difficulty of the exercise.
The iliopsoas is a composite of two muscles -- the iliacus and the psoas major. These muscles, also known as the hip flexors, are the prime movers for flexing the thigh and flexing the trunk. The iliopsoas is the primary muscle worked during a hanging leg raise.
The rectus femoris the is one of the four quadriceps muscles and is the most superficial muscle in the middle of the anterior thigh. This muscle works with the iliopsoas to flex the hips during a leg raise. The rectus femoris also crosses the knee joint and assists the other quadriceps muscles in extending the knee.
Tensor Fascia Lata
The tensor fascia lata is a synergist of the iliopsoas and rectus femoris muscles during hip flexion. The muscle is located on the upper lateral thigh and is enclosed between layers of connective tissue known as fascia.
The adductors are a group of muscles located on the inner thighs and consist of the adductor magnus, adductor longus and adductor brevis. These muscles along with the pectineus work to press the thighs together as you raise your legs.
The rectus abdominis are the most superficial and medial muscles of the abdomen. The muscles flex and rotate the lumbar region of the vertebral column, stabilize the pelvis during walking, and increase intra-abdominal pressure. The rectus abdominis muscles are not engaged during a hanging leg raise until your knees rise above hip level and you life your pubis toward your sternum.
The external and internal obliques are worked to some extent once your knees reach horizontal when performing a leg raise. When the obliques work individually, they aid the muscles of the back in trunk rotation and lateral flexion. You can, therefore, put more emphasis on your obliques by alternately raising your legs to the left and right during a hanging leg raise rather than straight to the front.
The muscles of your forearms, shoulders and back are used to grasp the bar, support your weight and stabilize your back and shoulder joints when you perform hanging leg raises.