SLR - July 2023 - Irene Limratana, DPM
Title: The Effects of the Short-Foot Exercise on Foot Alignment and Muscle Hypertrophy in Flatfoot Individuals: A Meta-AnalysisReference: Huang C, Chen LY, Liao YH, Masodsai K, Lin YY. Effects of the Short-Foot Exercise on Foot Alignment and Muscle Hypertrophy in Flatfoot Individuals: A Meta-Analysis. Int J Environ Res Public Health. 2022 Sep 22;19(19)
Level of Evidence: Level 2
Scientific Literature Review
Reviewed by: Irene Limratana, DPM
Residency Program: SUNY Downstate, Brooklyn, NY
Podiatric Relevance: Flatfoot is a common foot condition affecting up to 23% of adults and is characterized by medial longitudinal arch collapse, rearfoot eversion, and forefoot abduction. Intrinsic foot muscles such as the abductor hallucis, flexor digitorum brevis, and quadrates plantae play a role in supporting the medial longitudinal arch. The short-foot exercise (SFE) involves contracting the intrinsic foot muscles by pulling the 1st MTPJ towards the calcaneus without flexing the toes. It is a recently developed, yet widely recognized, intervention in balance training, intended to strengthen the intrinsic foot muscles. This study aimed to conduct a meta-analysis of randomized controlled trials to examine the effects of the SFE compared to foot orthosis or other types of interventions in the treatment of flatfoot.
Methods: The meta-analysis included 6 RCTs, with a total of 201 participants. Relevant articles were identified from PubMed, Cochrane, Embase, and other resources, using the following MeSH and free-text terms and Boolean operators: (flatfoot OR pronat*) AND (short foot OR intrinsic foot muscle). Eligibility criteria involved participants with flatfoot engaging in the SFE compared to other forms of intervention or control groups without specific intervention. The outcome measures were foot alignment (including navicular drop and foot posture) and muscle hypertrophy. All parameters were continuous variables which were analyzed by mean difference (MD) and standard MD (SMD) with 95% confidence intervals (CIs).
Results: Five RCTs assessed navicular drop by the navicular drop test and their results showed that those in the SFE group had significantly decreased values of navicular drop (mean difference -0.23mm). Three RCTs assessed foot posture by the foot posture index and found that the SFE group had significantly lower FPI values compared to the control group, indicating a more neutral foot position in rhe SFE group (MD -0.67 score). Two RCTs assessed muscle hypertrophy and found no significant differences post-intervention between the SFE group and control group (SMD 0.03).
Conclusions: The authors concluded that the short-foot exercise (SFE) significantly contributed to normalizing foot alignment, with a tendency towards decreased navicular drop and more neutral foot position. As the SFE has only been popular for less than a decade, there is a lack of research and evidence regarding its long-term benefits and the RCTs included in this meta-analysis were individually limited by their small sample sizes. Additional large-scale RCTs are necessary to determine a proper and specific protocol as well as to investigate the long-term outcomes of incorporating SFEs into the treatment of flatfoot. Based on the results of this meta-analysis, SFE seems to be promising in its ability to strengthen muscles of inversion, which could make it a valuable addition to not only the treatment of flatfoot but the same principles could also be applied in other physical rehabilitation regimens. SFE combined with orthosis may prove to be effective in the long-term treatment of flatfoot for patients who prefer conservative treatment.