Andersson Link May 2026

For clinicians, the lesson is clear:

Andersson link, biomechanics, sacroiliac joint, lumbar spine, biceps femoris, sacrotuberous ligament, low back pain, force closure. andersson link

If you suffer from chronic low back pain that clicks, shifts, or feels unstable, ask your physiotherapist about the Andersson Link. It might be the missing piece of your rehabilitation puzzle. This article is for informational and educational purposes only. It does not constitute medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment of musculoskeletal conditions. For clinicians, the lesson is clear: Andersson link,

In the world of orthopedic physical therapy and sports rehabilitation, few concepts have sparked as much debate and practical application as the Andersson Link . For practitioners specializing in the lumbar spine, sacroiliac (SI) joint, and lower quadrant dysfunctions, understanding this biomechanical phenomenon is not just an academic exercise—it is a clinical necessity. This article is for informational and educational purposes

The core hypothesis of the Andersson Link is this: When the hamstrings contract eccentrically or isometrically (e.g., during a forward bend or deadlift), tension is transmitted through the sacrotuberous ligament to the sacrum, influencing the position and stability of the sacroiliac joint and the lumbar lordosis. To understand the Link, you must understand the "myofascial sling" it creates. 1. The Starting Point: The Thoracolumbar Fascia (TLF) The posterior layer of the TLF is a dense connective tissue that covers the deep muscles of the back. It attaches medially to the spinous processes of the lumbar vertebrae and laterally to the iliac crest. 2. The Intermediate Link: The Sacrotuberous Ligament (STL) This is the keystone of the Andersson Link. The STL is a large, fan-shaped ligament that runs from the posterior superior iliac spine (PSIS) and the lateral border of the sacrum down to the ischial tuberosity (the "sit bone"). Crucially, the long head of the biceps femoris (a hamstring muscle) attaches directly to the ischial tuberosity. 3. The Terminal Link: The Biceps Femoris This is the lateral hamstring muscle. Its long head originates from the ischial tuberosity, merging with the sacrotuberous ligament fibers. Therefore, tension in the hamstring pulls directly on the STL, which pulls on the sacrum. Biomechanical Function: How the Link Works The Andersson Link serves a protective and stabilizing function during forward flexion (bending over). The "Sling" Effect When you bend forward (hip flexion with a neutral spine), your hamstrings are stretched. To prevent you from falling over, your hamstrings contract eccentrically. Via the Andersson Link, this contraction pulls the sacrotuberous ligament taut. This ligament then pulls the lower sacrum anteriorly (forward) and the ilia posteriorly (backward), effectively closing the sacroiliac joint.