Muscle Strengthening Exercises for the Foot and Ankle: A Scoping Review Exploring Adherence to Best Practice for Optimizing Musculoskeletal Health.

backgroundFoot and ankle muscle strengthening exercises are common interventions for many musculoskeletal conditions that are associated with pain and limited function in the lower limb. The scientific literature has a multitude of strengthening exercises recommended, and they have been criticized for not adhering to best practice and for being poorly reported. The aims of this scoping review were to (i) describe what foot and ankle strengthening exercises have been recommended in the scientific literature, (ii) compare the prescription of these exercises to best practice recommendations, and (iii) assess the completeness of the reporting of these exercises and exercise programs.

methodsThis scoping review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews. A systematic search of peer-review journal articles was conducted on 23 February 2023. Study designs that were included were experimental, quasi-experimental, feasibility, pilot studies, and observational. For each study included in the review, study design and participant details such as age, sex, and conditions treated were noted. To describe the foot and ankle strengthening exercises, each exercise was noted, which included its name, the number of sets and repetitions recommended, the load type and its magnitude, and whether there were any progression strategies. Exercises were grouped according to primary movement and a general exercise descriptor. To compare to best practice, each program's prescription parameters of frequency, intensity, and time were compared to the American College of Sports Medicine's (ACSM) guidelines. To assess completeness of reporting, each study was assessed with the Consensus on Exercise Reporting Template (CERT).

resultsThe search yielded 1511 documents, and 87 were included after full-text screening. Of the included studies, most were randomized controlled trials, and the most common participants were healthy adults (mean age range: 18-83 years). Across all studies, a total of 300 foot and ankle exercises were prescribed. The most common strengthening exercise category involved ankle plantar flexion (25% of 300 exercises), followed by plantar foot intrinsics (16%). The most common prescription of strengthening exercises included 3 sets (37%) of 10 repetitions (38%) performed 3 times per week (34%), often without a prescribed load (66%). Prescribed sets per muscle group met ACSM recommendations for novice lifters in 93% of studies. In contrast, load intensity (for increasing muscle strength) was prescribed at the recommended dose of 60% of 1 repetition maximum or greater in only 2% of exercises. The median score for completeness of reporting according to the CERT checklist was 31% of all items.

conclusionsThis scoping review found that the studies predominantly included ankle plantar flexion and plantar foot intrinsic muscle strengthening exercises, typically prescribed at 3 sets of 10 repetitions, 3 times per week. When compared to best practice recommendations, load intensity in exercise prescription is commonly less than recommended or is not reported. In addition, the review highlights deficiencies in the reporting of exercise programs. We propose using established best-practice exercise prescription guidelines like those from the ACSM and the adoption of CERT for reporting exercises in the scientific literature.