Morton Toe and Neuromuscular Performance

Overview

This cross-sectional observational study investigated whether female football players with Morton toe morphology differ from those with normal foot morphology in neuromuscular contractile properties and kinetic performance characteristics. Morton toe is a congenital foot variation in which the second toe is longer than the first. A total of 47 female football players were classified into two groups based on bilateral foot morphology: Morton foot group (n = 24) and normal foot group (n = 23). Neuromuscular properties of the dominant vastus lateralis muscle were assessed using tensiomyography, and kinetic performance was evaluated through a 40-cm drop jump test on dual force plates. The primary outcomes were contraction time (Tc) and reactive strength index (RSI). Secondary outcomes included relaxation time, delay time, sustain time, maximal displacement, jump height, peak power normalized to body mass, and landing net peak force normalized to body mass. Multiple linear regression models adjusted for age, body mass index, and mean arch index were used to evaluate whether group differences were independent of potential confounders. This study aimed to determine whether Morton toe morphology is associated with distinct neuromuscular and kinetic performance profiles in female athletes.

Morton toe is a congenital foot morphology characterized by a longer second metatarsal relative to the first. Although traditionally regarded as a clinical or orthopedic variation associated with metatarsal stress fractures and balance difficulties, limited evidence from sprinter populations suggests that a longer second toe may be associated with superior athletic performance. However, no previous study has examined whether Morton toe morphology is related to neuromuscular contractile properties assessed via tensiomyography or kinetic performance derived from force plate testing in a controlled group comparison design. Participants were screened from 97 female football players. Exclusion criteria included BMI outside the 18.5-29.9 range, bilateral arch index outside the 14-29% range, inconsistent bilateral foot morphology, lower-extremity injury within the past 12 months, neurological or orthopedic conditions, performance-affecting pharmacological use, and menstruation on the measurement day. Morton toe classification was based on the palpation method described by Davidson et al. (2007) with a minimal detectable change threshold of ±0.30 mm. All measurements were conducted during the off-season to minimize training load interference. Testing followed a standardized sequence: foot morphology assessment, tensiomyography of the dominant vastus lateralis at rest, a 15-minute warm-up, and a 40-cm drop jump test. The assessor was blinded to group classification, and statistical analysis was performed by an independent researcher on a coded dataset. Primary outcome variables (Tc and RSI) were determined a priori. Secondary outcomes were corrected for multiple comparisons using the Holm-Bonferroni method. Regression analyses were performed to assess the independence of group effects from age, body mass index, and mean bilateral arch index.