Optimising Physiotherapist Delivery Fidelity of Exercise and Physical Activity Advice for Achilles Tendinopathy: A Prospective Repeated-measures Observational Study

Objectives: To assess physiotherapist delivery fidelity and identify factors optimising delivery fidelity of an intervention based on recommended guidelines for Achilles tendinopathy.

Design: A prospective repeated-measures observational study of physiotherapist delivery fidelity with carefully defined exercise and physical activity advice.

Setting: An inter-disciplinary clinic in Melbourne, Australia, embedded in a randomised controlled trial.

Participants: Two physiotherapists delivering the intervention to five participants each, at three timepoints.

Intervention: All participants were expected to receive the same intervention. Feedback at timepoint one, guided boost-training to optimise delivery fidelity.

Main Outcome Measures: Proportion of exercise and physical activity advice components delivered as intended (high ≥80%; moderate 51-79%; low≤50%), with relationships between variables analysed using chi-square tests.

Results: Physiotherapist delivery fidelity improved significantly between timepoint one and two (χ = 83.3, p < 0.001), then sustained at timepoint three. At timepoint one, seven (70%) of intervention components were delivered with high fidelity, one (10%) with moderate fidelity and two (20%) with low fidelity. At timepoint two, after boost-training, nine (90%) were delivered with high fidelity and one (10%) with moderate fidelity. At timepoint three, all intervention components (100%) were delivered with high fidelity by both physiotherapists.

Conclusion: Physiotherapist delivery fidelity can be optimised with feedback, collaboration and boost-training.