Experiencing discomfort in the front of your hips when trying to work your abdominal muscles is a common issue. This burning or aching sensation is not typically a sign of injury, but rather an indication of muscle compensation. It means that the muscles intended to perform the work are not fully engaging, causing other, more powerful muscles to take over. This article will explain the mechanism behind this compensation and provide strategies for resolving the issue.
Understanding Muscle Compensation
The difference between abdominal work and hip flexor work lies in the movement they create. Abdominal muscles, especially the rectus abdominis, are responsible for spinal flexion—curling the torso forward. Hip flexors, including the iliopsoas group, are responsible for hip flexion, which involves lifting the legs toward the torso or bringing the torso toward the legs while keeping the spine relatively straight.
When performing an abdominal exercise, if the core is not properly activated, the body recruits the strong hip flexors to complete the movement. The iliopsoas group is prone to this compensation because it connects the lower spine and pelvis to the femur, acting as a powerful lever. This over-reliance causes the hip flexors to become overworked and strained, leading to the burning sensation. The strong pull of the hip flexors can also cause an anterior pelvic tilt, which may accentuate the curve in the lower back and lead to discomfort.
Immediate Technique Adjustments for Core Work
Adjustments during your workout can shift the effort away from the hip flexors and back onto the core. The most direct way to reduce hip flexor involvement is to decrease the range of motion. Only move through the arc where you actively feel your abdominal muscles contracting, stopping the moment the hips begin to take over.
Focusing on a posterior pelvic tilt at the start of the exercise is also effective. This involves pressing your lower back firmly into the floor, which shortens the abdominal wall and pre-engages the core stabilizers. For exercises performed on the back, such as leg raises, bending the knees reduces the leverage and load placed on the hip flexors.
When performing a curl-up or crunch, ensure the movement is a curl of the upper body toward the hips, not a straight lift of the torso. Avoid pulling on your neck with your hands, as this indicates compensation for a weak core. Consider substituting hip-flexor-dominant exercises, like straight-leg raises or full sit-ups, with alternatives that better isolate the abdominal muscles, such as the dead bug or traditional crunches.
Addressing Underlying Weakness and Tightness
The long-term solution involves addressing tightness in the hip flexors and weakness in the core and glutes. Tight hip flexors, often caused by a sedentary lifestyle, are constantly shortened, making them prone to overactivity during exercise. Static stretching helps lengthen these muscles to restore a neutral resting position.
Stretching Techniques
The kneeling hip flexor stretch is effective. Kneel with one leg forward at a 90-degree angle and gently shift your weight forward while squeezing the glute on the back leg. The couch stretch is another option, placing the back leg’s shin and foot against a wall or couch for a deeper stretch.
Strengthening the Core and Glutes
Strengthening exercises for the glutes and core prevent future compensation. Glute bridges strengthen the glutes and hamstrings, opposing the hip flexors, by engaging the glutes to lift the hips from a lying position. The bird dog exercise strengthens deep core stabilizers and improves control without heavily recruiting the hip flexors. Consistently incorporating both lengthening and strengthening work teaches the correct muscles to fire, allowing you to perform abdominal exercises with less hip discomfort.