Does isometric exercise improve leg stiffness and hop pain in subjects with Achilles tendinopathy? A feasibility study

Background: In Achilles tendinopathy (AT) the ability to store and recycle elastic energy during ground contact phase is often altered. A measure of this function is represented by leg stiffness (LS). Immediate responses in LS following therapeutic intervention have not been examined. Objective: The aim of this paper was to examine the feasibility of the protocol in participants with AT. Design: Single cohort feasibility study. Participants: Adults with persistent AT pain, symptoms on palpation and less than 80 points on the Visa-A questionnaire. Intervention: heavy isometric exercise sequence in plantarflexion. Outcome measures: Feasibility was assessed by evaluating: the willingness of participants to enroll into the study, the number of eligible participants, the recruitment rate, adherence to the intervention, the drop-out rate, the tolerability of the protocol. LS, reactive strength index, pain and rate of perceived effort were secondary outcomes. Results: 22 AT were eligible for data collection and 19 entered the statistical analysis. The intervention was well tolerated, no withdrawals. Pain scores were low during both the intervention and the assessment. Immediate improvements in LS and pain were recorded. Conclusions: The isometric exercise protocol was feasible. Future research should investigate its effectiveness.