Differences in foot muscle morphology and foot kinematics between symptomatic and asymptomatic pronated feet

Abstract

Purpose: This study aimed to determine the differences in foot muscle morphology and 3D multisegmental foot kinematics during walking between symptomatic and asymptomatic individuals with pronated feet (pronators) in a physically active population. Methods: A total of 30 young physically active adults with pronated feet participated in this study, with 15 of them having recurring overuse injuries in the lower extremity in the 6 months prior to the test. A pronated foot was identified as having a foot posture index score between 6 and 12. An ultrasound system was used to measure the cross-sectional area and thickness of foot muscles of interest, including peroneus muscles, flexor digitorum longus and brevis, and abductor hallucis. Foot kinematic data during walking was collected using a 3D motion capture system incorporating the Oxford Foot Model. Results: The symptomatic pronators demonstrated smaller cross-sectional area of flexor digitorum longus and abductor hallucis, and thinner peroneus muscles and abductor hallucis than their asymptomatic counterparts. The symptomatic pronators also displayed higher forefoot peak abduction during the stance phase of walking. Conclusion: There are differences in both extrinsic and intrinsic foot muscle morphology between symptomatic and asymptomatic pronators in a physically active adult population. Strengthening foot muscles may contribute to injury prevention in pronators. Large forefoot abduction instead of large rearfoot eversion during walking might be the indicator of pain in physically active pronators. Findings of this study may have implications on the underlying mechanisms of overuse injuries in individuals with pronated feet. K E Y W O R D S foot posture, forefoot abduction, intrinsic foot muscle, multisegment foot model, recreational runners | 1767 ZHANG et Al.

The biomechanical effects of pronated foot function on gait. An experimental study

“…Both similarities and differences were found between FF and FP, demonstrating that static foot type and dynamic foot function are separate entities. Our results also confirmed that both the forefoot and rearfoot are involved in global foot pronation 3,41 : a combination which could increase knee internal rotation and alter pelvic motion during gait. These kinematic changes are consistent with biomechanical variables that have been shown to increase the risk of MSD.…”

“…The kinematic changes in the whole lower limb caused by FP might increase the risk of pathology in the lower limb joints and muscles 3 . Increased forefoot abduction, as found in the FPg, has recently been reported as a predictive factor for lower limb MSD 12,41 . Similarly, higher knee internal rotation (also found in the FPg) has been shown to be a risk factor for the development of MSD of the knee and tibia 7,10,42 .…”

“…This work also confirmed the importance of studying transverse plane forefoot motion in pronated foot function. The results suggest that individuals with pronated foot function, though asymptomatic, may have a greater risk of lower limb MSD due to the increase in forefoot abduction 12,41 . Studies are therefore required to fully elucidate the relationship between FP and MSD.…”

“…3 Increased forefoot abduction, as found in the FPg, has recently been reported as a predictive factor for lower limb MSD. 12,41 Similarly, higher knee internal rotation (also found in the FPg) has been shown to be a risk factor for the development of MSD of the knee and tibia. 7,10,42 The increased pelvic ROM in the sagittal and transverse planes observed in the FPg could accentuate the lumbar lordosis and increase the risk of low back pain.…”

“…The results suggest that individuals with pronated foot function, though asymptomatic, may have a greater risk of lower limb MSD due to the increase in forefoot abduction. 12,41 Studies are therefore required to fully elucidate the relationship between FP and MSD. In addition, the increase in forefoot dorsiflexion in the FPg is a mechanism for foot collapse when the foot is in a flat position on the ground.…”