JMMBS
Open Access • ISSN 3070-3662 • Volume 2 • Issue 1
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The Biomechanical Fallacy of Maximal Abduction: Why “Knees Out” Induces Lateral Compartment Pathology and Reduces Squat Depth

DOI: 10.5281/zenodo.18063977
Lead Authors: Neeraj Mehta; Karun Jain; Steve Henderson
Published: 2025 • Pages: 71–(set last page)

Abstract

For over a decade, the cue “knees out” (maximal hip abduction and external rotation) has been the dominant corrective strategy to prevent dynamic knee valgus. However, emerging data suggests this cue has resulted in an industry-wide overcorrection. From 2023 to 2025, MMSx Authority analyzed 870 subjects using the MMSx-SCAN™ protocol. The data indicates that forced excessive abduction creates pathological varus torque, lateral patellofemoral compression, and loss of foot stability. This paper presents evidence that while preventing valgus is critical, the “knees out” strategy reduces squat depth and increases joint reaction forces in the majority of lifters. We introduce BPIT and the “5-Line Principle” as a new standard for neutral tracking.

Dynamic Knee Valgus Pathological Varus Patellofemoral Pain Squat Biomechanics BPIT Principle MMSx-SCAN

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Recommended Citation

Mehta, N., Jain, K., & Henderson, S. (2025). The Biomechanical Fallacy of Maximal Abduction: Why “Knees Out” Induces Lateral Compartment Pathology and Reduces Squat Depth. Journal of Movement Mechanics & Biomechanics Science, 2(1). https://doi.org/10.5281/zenodo.18063977