{"id":2575,"date":"2025-06-09T12:24:38","date_gmt":"2025-06-09T09:24:38","guid":{"rendered":"https:\/\/runzy.com\/blog\/?p=2575"},"modified":"2025-06-09T12:24:39","modified_gmt":"2025-06-09T09:24:39","slug":"functional-vs-structural-leg-length-difference","status":"publish","type":"post","link":"https:\/\/runzy.com\/blog\/functional-vs-structural-leg-length-difference\/","title":{"rendered":"Functional vs Structural Leg Length Difference"},"content":{"rendered":"\n<p>About 85% of running-related overuse injuries affect only one side of the body at a time. Understanding what causes these issues is essential for maintaining a long and healthy running career. A common source of these injuries is a leg length discrepancy, which can fall into one of two main categories\u2014each requiring different treatment approaches.<\/p>\n\n\n\n<h3>1. <strong>Structural Leg Length Difference<\/strong><\/h3>\n\n\n\n<ul><li>This refers to an actual difference in bone length.<\/li><li>It typically affects the tibia and fibula, though sometimes the femur is involved.<\/li><li>The most accurate way to diagnose it is through an x-ray, but simple at-home tests can help identify it:<\/li><\/ul>\n\n\n\n<p><strong>Test 1:<\/strong> If your knees are at different heights when sitting or lying down&#8230;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" src=\"https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-1024x643.webp\" alt=\"\" class=\"wp-image-2576\" width=\"494\" height=\"310\" srcset=\"https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-1024x643.webp 1024w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-300x188.webp 300w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-768x482.webp 768w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-750x471.webp 750w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32-1140x716.webp 1140w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.32.webp 1520w\" sizes=\"(max-width: 494px) 100vw, 494px\" \/><\/figure>\n\n\n\n<p><strong>Test 2:<\/strong> If your kneecaps line up but your ankles don\u2019t (or vice versa)&#8230;<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" src=\"https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-1024x726.webp\" alt=\"\" class=\"wp-image-2577\" width=\"494\" height=\"350\" srcset=\"https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-1024x726.webp 1024w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-300x213.webp 300w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-768x544.webp 768w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-120x86.webp 120w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-750x531.webp 750w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42-1140x808.webp 1140w, https:\/\/runzy.com\/blog\/wp-content\/uploads\/2025\/06\/Screenshot-2025-06-09-at-12.00.42.webp 1524w\" sizes=\"(max-width: 494px) 100vw, 494px\" \/><\/figure>\n\n\n\n<p>If your knees and ankles are misaligned in opposite ways, it likely points to a structural difference.<\/p>\n\n\n\n<h3>2. <strong>Functional Leg Length Difference (More Common)<\/strong><\/h3>\n\n\n\n<ul><li>The bones are the same length, but one hip may be tilted or rotated differently than the other.<\/li><li>In Test 2, both the knees and ankles are off\u2014but by the same amount\u2014which indicates a functional difference.<\/li><\/ul>\n\n\n\n<h3>What to Do Next<\/h3>\n\n\n\n<ul><li><strong>Structural<\/strong> differences are typically addressed with orthotic inserts or modified footwear to compensate for the bone length variation. Note: While orthotics can help, they may change your mechanics and bring new risks. Strengthening and balancing your musculoskeletal system can sometimes reduce the need for orthotics.<\/li><li><strong>Functional<\/strong> differences are best corrected by improving muscle balance, flexibility, and movement in the hips and surrounding tissues.<\/li><\/ul>\n\n\n\n<h3>Special Case: Scoliosis<\/h3>\n\n\n\n<p>People with scoliosis may also show signs of a leg length discrepancy due to the tilt caused by spinal curvature. Though unique, this condition is often treated similarly to a structural leg length difference.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>About 85% of running-related overuse injuries affect only one side of the body at a time. Understanding what causes these issues is essential for maintaining a long and healthy running career. A common source of these injuries is a leg length discrepancy, which can fall into one of two main categories\u2014each requiring different treatment approaches. [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":2578,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v19.13 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Functional vs Structural Leg Length Difference - RUNZY<\/title>\n<meta name=\"description\" content=\"About 85% of running-related overuse injuries affect only one side of the body at a time. 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