The hanging knee raise is a challenging bodyweight exercise performed while suspended from a pull-up bar. It requires muscular endurance, grip strength, and precise motor control to execute effectively. This movement targets the abdominal muscles in a way that traditional floor exercises cannot, by requiring the core to stabilize the entire lower body against gravity. The exercise builds functional strength that transfers to other complex movements and improves overall body stability.
Primary Muscle Focus
The hanging knee raise primarily engages the abdominal muscles and the hip flexors to lift the legs upward. The main muscle targeted is the rectus abdominis, the long, flat muscle that runs vertically along the front of the abdomen. This muscle is responsible for spinal flexion, pulling the rib cage and the pelvis closer together.
The hip flexors, specifically the iliopsoas, are the initial and strongest movers. These muscles connect the lower spine and pelvis to the femur and are responsible for lifting the thighs toward the torso. In the early stage of the raise, the hip flexors perform the majority of the work, with the abdominals working isometrically to stabilize the trunk. As the knees are pulled higher than a 90-degree angle, the abdominals contract more strongly to cause the necessary posterior pelvic tilt.
Several other muscle groups act as stabilizers throughout the exercise. The obliques (internal and external) are engaged to prevent rotational movement and maintain a stable torso. The forearm muscles and the muscles of the shoulder girdle are continuously active to maintain the hang and prevent the body from swinging or collapsing. Grip strength is a significant limiting factor for many individuals, as the forearms must endure the entire body weight for the duration of the set.
Proper Technique and Execution
Begin by taking an overhand, pronated grip on the pull-up bar, with hands positioned approximately shoulder-width apart. Establish an active hang rather than a passive hang by slightly depressing the shoulder blades down and back, engaging the lats to stabilize the upper body. This engagement minimizes excessive swinging and protects the shoulder joints.
The movement should be initiated by bracing the core and performing a slight posterior pelvic tilt before the knees begin to rise. As you raise your knees, exhale forcefully, driving them toward the chest until the thighs are at least parallel to the floor. Raising the knees higher than 90 degrees of hip flexion maximizes the concentric contraction of the abdominal muscles.
During the lowering, or eccentric, phase, inhale slowly as you return your legs to the starting position, maintaining core tension to prevent a free fall or pendulum swing. The descent should be deliberate and take roughly twice as long as the ascent, which increases time under tension. Return to a stable, non-swinging hang before initiating the next repetition.
Common Mistakes and Form Adjustments
Using momentum, or swinging the body, to assist the leg lift significantly reduces the work done by the abdominal muscles. To correct this, slow down the repetition tempo and ensure the movement is initiated by the core’s contraction, not by a backward swing of the legs.
Over-reliance on the hip flexors without achieving sufficient spinal flexion is a common issue. This mistake is characterized by lifting the legs with a straight or slightly arched back, which primarily fatigues the hip flexors and places minimal stress on the rectus abdominis. The fix is to consciously focus on the pelvic curl at the top of the movement, aiming to bring the knees toward the chest while rounding the lower back slightly.
Poor grip endurance or shoulder instability can derail the exercise. If the grip is the limiting factor, focus on the active hang by pulling the shoulder blades down away from the ears to engage the lats. Utilizing ab straps that cradle the elbows can be a temporary adjustment, allowing the core to be trained fully before grip strength catches up.