Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints

[Purpose] The purpose of this study was to determine the relationship between naviculardrop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints.[Subjects] Ten healthy young men participated in this study. [Methods] The Pearsonproduct-moment correlation coefficient was calculated to determine the relationshipbetween navicular drop and plantar flexion torque of the first and second-fifthmetatarsophalangeal joints. [Results] Significant negative correlations were observedbetween navicular drop and plantar flexion torques in the lengthened position of theintrinsic toe plantar flexion muscles, but no correlations were found between naviculardrop and plantar flexion torques in the neutral position of the ankle andmetatarsophalangeal joints. Moreover, the intrinsic toe plantar flexion muscles were foundto contribute to the formation of the medial longitudinal arch. [Conclusion] Naviculardrop correlates with metatarsophalangeal joint muscle strength in plantar flexion wherethe intrinsic toe muscles are capable of exerting force.Key words: Toe flexor strength, Intrinsic foot muscle, Medial longitudinal arch