The influence of dosing on effect size of exercise therapy for musculoskeletal foot and ankle disorders: a systematic review

OBJECTIVE: The purpose of this review was to identify doses of exercise therapy associated with greater treatment effect sizes in individuals with common musculoskeletal disorders of the foot and ankle, namely, achilles tendinopathy, ankle sprains and plantar heel pain. METHODS: AMED, EMBASE and MEDLINE were searched from 2005 to August 2017 for randomized controlled trials related to exercise for these three diagnoses. The Physiotherapy Evidence Database scale was used for methodological quality assessment. Exercise dosing variables and outcome measures related to pain and function were extracted from the studies, and standardized mean differences were calculated for the exercise groups. RESULTS: Fourteen studies met the final inclusion. A majority of the studies showed large effects and two small trends were identified. Patients with plantar heel pain may benefit more from a daily home exercise program than two supervised visits per week (SMD = 3.82), but this recommendation is based on weak evidence. In achilles tendinopathy, a relationship was also seen when sets and repetitions of eccentric exercise were performed as tolerated (SMD = 1.08 for function, −1.29 for pain). CONCLUSIONS: Session duration, frequency, total number of visits, and overall length of care may all be dosing variables with limited value for determining effective exercise prescription. However, the limited number of studies prevents any definitive conclusions. Further investigation is warranted to improve our understanding of the influence exercise dosing has on treatment effect sizes. Future randomized controlled trials comparing specific exercise dose variables should be conducted to clarify the impact of these variables.