The effect of manual therapy on gastrocnemius muscle stiffness in healthy individuals

Document Type


Publication Date



Study Design: Randomized clinical trial. Background: Muscle stiffness is a potential complication after injury and has been shown to be a risk factor for injury in healthy individuals. Objectives: The primary purpose of this study was to assess the short-term effects of manual therapy (MT) on muscle stiffness of the gastrocnemius in both a relaxed and contracted state. The secondary purpose was to assess the reliability of a novel clinical tool (MyotonPRO) to measure muscle stiffness in the gastrocnemius in both a passive and contracted state. Methods: Eighty-four consecutive healthy individuals were randomized to receive Manual Therapy (MT group) directed at the right-side ankle and foot or no treatment (CONTROL group). Muscle stiffness of the gastrocnemius was assessed bilaterally in all participants at baseline and then immediately after intervention in a relaxed and contracted state. Group (MT vs. CONTROL) by side (ipsilateral vs. contralateral) by time (pre vs. post) effects were compared through a 3-way interaction utilizing mixed model ANOVA. Reliability of the MyotonPRO was assessed with two-way mixed model intraclass correlation coefficients. Results: There was a significant 3-way interaction for muscle stiffness of the gastrocnemius in a relaxed state (p <.01), but not contracted state (p =.54). All conditions had increased resting muscle stiffness from pre to post measures except for the ipsilateral limb of the MT group. There was not a significant interaction for muscle stiffness in a contracted state. Reliability estimates (ICC) for muscle stiffness measures ranged between.898 and.986. Conclusion: The change in muscle stiffness of the gastrocnemius in a relaxed state depended upon whether individuals received MT. Muscle stiffness measures were highly reliable based on single measurements. Level of evidence: Therapy, level 2.

This document is currently not available here.