Effects of isometric exercise on Achilles Tendinopathy
The findings of this study suggest that isometric exercises in individuals with Achilles Tendinopathy (AT) do not cause statistically significant or clinically relevant alterations in pain during a functional task, mechanical pressure pain thresholds or motor output.
The intervention utilized 5 sets of 45-second bent knee (90 degrees) isometric plantar flexor contractions at 70% maximum voluntary contraction (MVC), separated by 2-min rest intervals.
16 individuals with AT were included in the study. Outcome measures included pain during a functional task (bilateral or unilateral calf raise or unilateral hopping), mechanical pressure pain thresholds and isokinetic plantar flexor torque production.
The results demonstrate that subjects who experienced pain during the functional tests (9/16) did not experience a significant change in pain after the isometric exercises. Individuals with the highest NRS scores for pain appeared to experience worsening of the pain, whilst those with a NRS
Despite the mean concentric plantar flexor torque at 90 deg/ sec increasing significantly after the isometric exercise, this value did not exceed the minimum detectable change of the measure.
Compared to preliminary evidence for isometrics for patellar tendinopathy, the different results may be due to the varied tissue changes and different cortical response to exercises in AT.
This highlights that caution should be applied in suggesting widespread clinical implementation of isometric exercise in the treatment of tendinopathy in general, and particularly AT.
> From: O'Neil et al., Knee Surg Sports Traumatol Arthrosc (2018) (Epub ahead of print). All rights reserved to The Author(s). Click here for the online summary.