Yoga training enhances elastic biomechanics of trapezius and hamstrings: a quantitative SWE assessment

TL;DR

This study shows that regular yoga practice over six months improves the elasticity of the trapezius and hamstring muscles, as measured by shear-wave elastography.

Contribution

The study introduces a quantitative SWE-based method to assess posture-dependent biomechanical changes in muscles due to yoga training.

Findings

Yoga practice significantly reduced the Young’s modulus of trapezius and hamstring muscles over six months.

Longitudinal SWE measurements were more sensitive to changes in muscle elasticity than transverse measurements.

Cumulative yoga training duration was inversely correlated with muscle stiffness in both trapezius and hamstrings.

Abstract

To investigate the association between long-term Yoga practice and changes in trapezius and hamstring biomechanics using shear-wave elastography (SWE), and to identify reliable measurement conditions.

Eighty-one healthy women were assigned to a Yoga group (n = 51) or non-Yoga control group (n = 30). The mean Young’s modulus (Emean) of the trapezius, biceps femoris long head, and semitendinosus was assessed at baseline, 1, 3, and 6 months under standardized postures (neutral, flexed, extended, and 90° knee flexion) and imaging planes (transverse/longitudinal) using a Siemens ACUSON Redwood system.

Eighty-one healthy adult women were enrolled (Yoga: n = 51; non-Yoga: n = 30), with no significant baseline differences between groups (all p > 0.05). Muscle thickness did not differ between groups at any time point for any muscle (all p > 0.05). For the trapezius, significant main effects of position (p < 0.001) and time (p = 0.014), as well as a significant group × time interaction (p < 0.001), were observed, with a progressive reduction in Emean in the Yoga group only. In the hamstring muscles, significant group × time interactions were detected for both the biceps femoris long head (longitudinal: F (2.66, 210.24) = 12.11, p < 0.001; transverse: F (2.42, 191.04) = 9.19, p < 0.001) and the semitendinosus (longitudinal: F (2.05, 161.87) = 9.93, p < 0.001; transverse: F (2.47, 195.00) = 5.21, p = 0.002). Longitudinal measurements consistently showed greater sensitivity to temporal changes than transverse measurements, and weak inverse correlations were observed between cumulative yoga training duration and muscle elasticity (all p < 0.05).

Six months of regular Yoga was associated with improved muscle elasticity, while SWE provides a robust and quantitative assessment of posture-dependent biomechanical adaptations.

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