Effects of Modified Toe Spread Out and PNF Exercises on Abductor Hallucis Muscle Thickness, Plantar Pressure, and Balance Control Ability in Individuals with Hallux Valgus

Purpose: The purpose of this study was to compare the effects of a modified toe-spread-out (MTSO) exercise and a proprioceptive neuromuscular facilitation (PNF) leg pattern-emphasized hallux abduction exercise on the thickness of the abductor hallucis (AbH) muscle, plantar pressure, and balance control ability in individuals with hallux valgus. Methods:The sample size was determined based on the results of a pilot study, with an effect size of 1.33, a statistical power of 0.8, and a significance level of 0.05.Twenty participants were required, and, considering a 20% dropout rate, 24 participants were recruited.The participants were randomly assigned to either the MTSO group (n=12) or the PNF group (n=12).AbH muscle thickness, balance control ability, and plantar pressure were measured before and after the exercise interventions.Each exercise was performed for 12 minutes. Results:The MTSO and PNF exercises both resulted in significant improvements in AbH muscle thickness and hallux pressure compared to the pre-exercise measurements.However, there were no significant differences in AbH muscle thickness, balance control ability, or plantar pressure between the PNF and MTSO exercises.Additionally, the PNF exercise demonstrated a higher effect size for AbH muscle thickness (Cohen's d=0.94) and hallux pressure (d=1.11)than the modified TSO exercise (d=0.75 and 1.03, respectively).