Effect of Foot Muscles Training and Foot Orthosis on the Medial Arch in Flatfoot Subjects

Study design: A parallel, active-control study design was used to conduct a single-blinded randomized controlled trial.

Method: The toe rising test, the "too many toes" sign, and the navicular drop test was used to select 30 participants with flexible flatfoot. Participants was randomly assigned either to an experimental group (n = 15) or a control group (n = 15). The experimental group received short foot exercises (SFE) and insoles, and the control group received only insoles. SFE was implemented 30 times for a duration of three minutes each day over the course of six weeks. The exercise progressed from sitting to standing and finally to one leg stance position within every two weeks. The participants wore shoes containing orthotic insoles for eight hours per day for six weeks. The EMED-x system was used to measure plantar pressure distribution (force, area, and pressure) at baseline and at two-week intervals throughout the six-week intervention. The Lower Extremity Functional Scale (LEFS) was used to evaluate restriction in participants' functional abilities, and the navicular drop test (NDT) was used to assess the medial longitudinal arch (MLA) height. Both variables were measured at baseline and at the sixth week.

Statistics: Mixed-effects ANOVA was used to test for significant interactions between the two groups across time and within-subject observations of the outcomes.

Inclusion criteria

• Females and males aged between 18 and 36
• Bilateral symptomatic flexible flatfoot, with symptoms including foot pain and lower limb fatigue
• Participants must show positive physical examination findings, including a positive result for the "too many toes" sign, the navicular drop test, and the foot toe raising test (Carr et al., 2016). A positive result for the "too many toes" sign occurs when more toes can be seen on the lateral side of each foot due to external rotation and abduction of the feet, and the positive result for the toe rising test is the reconstruction of the medial longitudinal arch secondary to the tightness of the plantar fascia (Carr et al., 2016). A positive result for the navicular drop test is an arch height more than or equal to 10 mm(Aenumulapalli et al., 2017)

Exclusion criteria

• An anatomical discrepancy in leg length
• Pathologic or neurologic disorders of the feet
• A history of traumatic foot injury or surgery within the last six months
• History of wearing foot orthoses within the past two years