The relationship between psychological, cognitive, and contextual factors and rehabilitation outcomes in Achilles tendinopathy: A prospective feasibility cohort study.

OBJECTIVES: This study aimed to investigate the feasibility of conducting a full-scale study investigating the influence of patient-related factors on rehabilitation outcomes in Achilles tendinopathy (AT). A secondary aim was to investigate preliminary relationships between patient-related factors and clinical outcomes at 12- and 26- weeks. DESIGN: feasibility cohort. SETTING: Australian healthcare settings. METHODS: Participants with AT receiving physiotherapy in Australia were recruited via treating physiotherapists and online. Data were collected online at baseline, 12- and 26-weeks. Progression criteria for a full-scale study were recruitment rate of ≥10 per month, conversion rate ≥20%, and response rate to questionnaires ≥80%. The relationship between patient-related factors and clinical outcomes was investigated using Spearman's rho correlation coefficient. RESULTS: The average recruitment rate was 5/month, conversion rate was 97%, and response rate to questionnaires was ≥97% at all timepoints. There was a fair to moderate correlation (rho = 0.225 to 0.683) between patient-related factors and clinical outcomes at the 12-week, but no to weak correlation at the 26-week (rho = 0.002 to 0.284). CONCLUSIONS: Feasibility outcomes suggest a future full-scale cohort study is feasible with the caveat of utilizing strategies to improve recruitment rate. Preliminary bivariate correlations at 12-weeks warrant further investigations in larger studies.

The acute effects of higher versus lower load duration and intensity on morphological and mechanical properties of the healthy Achilles tendon: a randomized crossover trial.

The Achilles tendon (AT) exhibits volume changes related to fluid flow under acute load which may be linked to changes in stiffness. Fluid flow provides a mechanical signal for cellular activity and may be one mechanism that facilitates tendon adaptation. This study aimed to investigate whether isometric intervention involving a high level of load duration and intensity could maximize the immediate reduction in AT volume and stiffness compared with interventions involving a lower level of load duration and intensity. Sixteen healthy participants (12 males, 4 females; age 24.4±9.4 years, body mass 70.9±16.1 kg, height 1.7±0.1 m) performed three isometric interventions of varying levels of load duration (2 s and 8 s) and intensity (35% and 75% maximal voluntary isometric contraction) over a 3 week period. Freehand 3D ultrasound was used to measure free AT volume (at rest) and length (at 35%, 55% and 75% of maximum plantarflexion force) pre- and post-interventions. The slope of the force-elongation curve over these force levels represented individual stiffness (N mm-1). Large reductions in free AT volume and stiffness resulted in response to long-duration high-intensity loading whilst less reduction was produced with a lower load intensity. In contrast, no change in free AT volume and a small increase in AT stiffness occurred with lower load duration. These findings suggest that the applied load on the AT must be heavy and sustained for a long duration to maximize immediate volume reduction, which might be an acute response that enables optimal long-term tendon adaptation via mechanotransduction pathways.