Foot Dorsum Height is Moderately to Strongly Correlated with Foot and Leg Muscle Size

Arch height and arch flexibility play important roles in foot and walking mechanics. For example, a highly flexible foot with a low arch (overpronation) is a common foot condition that can negatively impact foot function. Understanding relationships between dorsum height (DH), arch flexibility (AF), and muscle size provides important information in the development of treatment plans and assessment of pathology. PURPOSE: This study aims to investigate the association between foot DH, AF, and muscle size. METHODS: 26 adults (age=56±4.73 years, Ht=166.24±9.18cm, Wt=82.24±19.61kg, DH left sit=6.75±0.65mm, DH left stand=6.32±0.63mm, DH right sit=6.82±0.64, DH right stand= 6.48±0.64, AF left =0.18±0.43, AF= 0.08±0.07) had cross-sectional ultrasound images of leg and foot muscles collected to assess muscle size, DH, and AF while sitting and standing. RESULTS: A weak to moderate negative correlation was observed between AF and muscles size ranging from r=0.02 to r=-0.43 (p= 0.03). However, moderate and strong positive correlations were found between muscle size and DH in both sitting and standing positions (r ranging from 0.41 to 0.83, p<0.001). The muscles that showed the strongest correlation with DH were the abductor hallucis, flexor digitorum brevis, quadratus plantae, fibularis brevis, fibularis longus, tibialis anterior, and extensor digitorum longus. CONCLUSION: Muscle size in the leg and foot is more strongly associated with DH than with AF in static positions. Perhaps a stronger association would be seen between AF and muscle size during dynamic movement. Understanding this association informs decisions regarding strengthening protocols focused on arch control and an individuals function and mobility.