Intrinsic vs. combined foot muscle strengthening for pes planovalgus in children aged 4-7 years: a randomized controlled trial.

This study aimed to compare the effects of an 8-week intrinsic foot muscle strengthening and a combined intrinsic-extrinsic foot muscle strengthening on foot posture, balance, and functional mobility in children aged 4 to 7 years with pes planovalgus. A total of 36 children with pes planovalgus were randomly assigned to either the intrinsic foot muscle strengthening group (IMSG) or intrinsic-extrinsic foot muscle strengthening group (IEMSG). Of these, 32 children completed the study. Both interventions lasted 8 weeks, consisting of supervised weekly sessions and a home exercise program. Outcome measures included foot posture assessments with navicular drop test (NDT) and foot posture index-6 (FPI-6), static and dynamic balance assessments with single-leg stance test (SLST) and timed up and go (TUG) test, and functional mobility assessments with sit-to-stand (STS) test and 6-min walk test (6MWT). Both groups showed significant within-group improvements in all parameters (p < 0.001). Between-group comparisons revealed significantly greater improvements in favor of the IEMSG across all parameters. The analysis of foot posture measurements revealed statistically significant group-by-time interactions in favor of the IEMSG for NDT and FPI-6 results on both right (NDT: ηp = 0.13, FPI-6: ηp = 0.13) and left sides (NDT: ηp = 0.15, FPI-6: ηp = 0.26). Furthermore, IEMSG showed superior effects in SLST (ηp = 0.27).   Conclusion: This study demonstrates that both intrinsic and extrinsic muscle strengthening programs can significantly enhance foot posture, balance, and mobility in children aged 4 to 7 years with pes planovalgus. The superior outcomes achieved by the IEMSG program underscore the importance of integrated muscle training in early physiotherapeutic interventions.Trial registration: This study was approved by the Bezmialem Vakif University Non-Interventional Clinical Research Ethics Committee (approval no: 168537, date: 12.10.2024) and registered with ClinicalTrials.gov under the registration number NCT06548750 (date: 08.08.2024).