The hurdler stretch, involving one leg extended and the other bent backward, has long been a standard flexibility exercise. Physical therapists and fitness professionals now largely agree that this classic stretch is suboptimal and potentially unsafe for many individuals. The position’s biomechanics create significant stress on two major joints: the pelvis and the knee.
The Asymmetrical Load on the Pelvis
The asymmetrical nature of the hurdler stretch imposes a twisting force on the pelvis and lower back that joints do not tolerate well. The leg bent backward forces the hip into extreme external rotation and hyperextension, resulting in a backward rotation of the pelvis, known as a posterior pelvic tilt. This uneven rotation places unnatural strain on the sacroiliac (SI) joint, which connects the hip bones to the base of the spine.
This forced misalignment can destabilize the SI joint, which is designed for minimal movement, potentially leading to inflammation or chronic pain. The lumbar spine must compensate for the uneven pelvic position, stressing the vertebral discs and surrounding ligaments. Furthermore, the twisting motion while bending forward can increase the risk of nerve compression or lower back discomfort, especially for those with pre-existing SI joint dysfunction or lumbar disc issues.
Excessive Torque on the Bent Knee
The bent leg in the hurdler stretch generates significant rotational stress on the knee joint. The hip is forced into a combination of extreme external rotation and deep flexion, which the knee joint is not structurally designed to follow under load. The knee’s primary function is to hinge, built for flexion and extension, with only minimal rotational capability when bent.
This stretch forces the tibia to rotate outward relative to the femur, applying shear forces and torque across the joint. This rotation can strain the medial collateral ligament (MCL), which acts as a restraint against outward-directed forces. The menisci are also placed under abnormal compressive and rotational stress, increasing the potential for tearing or cartilage damage over time.
Safe Alternatives for Hamstring Flexibility
Since the goal of the hurdler stretch is typically to increase hamstring flexibility, several safer alternatives can achieve this benefit without risking the knee or pelvis. These alternatives prioritize joint stability and spinal neutrality, making them superior choices for long-term flexibility gains.
The supine hamstring stretch is one of the best options. You lie on your back and loop a strap or towel around the sole of your foot, gently pulling the straight leg toward the ceiling. This position keeps the pelvis in a neutral, supported alignment against the floor, eliminating the asymmetrical rotation and torque on the joints.
Another effective alternative is the seated straight-leg stretch, often called a long-sitting stretch, where both legs are extended forward. By focusing on hinging forward from the hips while maintaining a neutral, straight spine, the stretch targets the hamstrings without forcing the lower back to round excessively. You can modify this by bending the non-stretching knee and placing that foot flat on the floor to better stabilize the pelvis.
For a dynamic approach, a standing single-leg hamstring stretch involves placing one heel on a low surface, like a chair or step, and gently leaning forward from the hips. This variation allows for fine-tuning the stretch intensity and ensures that the pelvis remains level and symmetrical, avoiding the problematic rotation of the hurdler position.