Anterior Pelvic Tilt (APT) is a common postural pattern where the pelvis rotates forward, tipping down at the front and up at the back. This rotation causes hyperlordosis (an increased arch) in the lower back, often leading to a visible “swayback” appearance. APT is frequently linked to prolonged sitting, which shortens the hip flexors and weakens the abdominal and gluteal muscles. Testing for this imbalance at home provides an initial indication of your posture and guides steps toward improving alignment.
Visual Self-Assessment Using Landmarks
The simplest way to check for APT is by visually assessing the relationship between two specific bony points on your pelvis. Stand sideways in front of a full-length mirror in your usual, relaxed posture. The goal is to compare the height of the Anterior Superior Iliac Spine (ASIS) and the Posterior Superior Iliac Spine (PSIS). Locate the ASIS at the prominent bony points near the front of your hips, and the PSIS at the small, paired dimples on the lower back, just above the buttock crease. In a neutral pelvis, these two landmarks are roughly level, or the ASIS is only slightly lower. With APT, the ASIS drops noticeably lower than the PSIS, indicating forward rotation.
Functional Alignment Check Against a Wall
This objective test checks the natural curvature of the lumbar spine against a flat surface to assess the degree of lower back arch. Stand with your back flat against a wall, ensuring your heels are a few inches away and your head, shoulders, and buttocks are touching the surface. The spine’s natural inward curve should create a small space between your lower back and the wall. This space should be just enough to slide the flat of your hand through. If you can easily fit your entire forearm or a closed fist into the gap, it suggests an excessive arch, a classic sign of APT. Maintain a relaxed stance and avoid consciously engaging your abdominal muscles, as this would invalidate the result.
Assessing Hip Flexor Tightness (The Modified Thomas Test)
The Modified Thomas Test assesses hip flexor tightness, which often drives APT. Begin by sitting near the edge of a sturdy table or bed, then lie back while pulling both knees toward your chest to flatten the lower back and neutralize the pelvis. Gently release and lower the leg being tested over the edge, allowing it to hang freely while keeping the opposite knee held firmly to your chest. If the hip flexors are not tight, the back of your thigh should rest flat against the surface, and the knee should bend to at least a 90-degree angle. If the thigh lifts off the surface or the knee cannot bend to 90 degrees, it suggests tightness in the iliopsoas or rectus femoris muscles. If multiple self-assessments suggest APT, consulting a physical therapist for a formal evaluation is recommended.