A comparison of the free moment pattern between normal and hyper-pronated aligned feet in female subjects during the stance phase of gait

Abstract

Background: Excessive range of adductory free moment of the ground reaction force may potentially increase the risk of lower extremity injuries by applying a higher torsional load transmitted to the proximal parts.Objective: It was hypothesized that the free moment pattern might be different between hyper-pronated and normal feet subjects. Moreover, a correlation would exist between peak adduction free moment and peak ankle-foot complex abduction at the stance phase of walking.Methods: Thirty female participants were divided into two groups of asymptomatic hyper-pronated and normal feet. Kinetic and kinematic data were collected using a single force plate and a six-camera motion analysis system during three successful free speed walking trials. Ensemble average curves were extracted from the time normalized individual trials of the stance phase for both free moment and peak ankle-foot complex abduction parameters.Results: Significant differences in peak adductory free moment, peak ankle-foot complex eversion and peak ankle-foot complex abduction were found between normal and hyper-pronated groups (4.90±0.97Vs. 5.94±0.88, P < 0.01), (3.30±0.95Vs. 6.28±1.47, P < 0.01) and (4.52±1.16Vs. 8.23±2.52, P < 0.01, respectively).A significant positive correlation was found between the peak adduction free moment and peak ankle-foot complex abduction in both groups, which was more strongly positive in hyper-pronated group (r = 0.745, p < 0.01, normal group, r = 0.900, p < 0.01, hyper-pronated group).Conclusion: As a good measure of torque which is transmitted to the lower extremity, may free moment be a useful biomechanical indicator for both clinical and research purposes.

Influence of altered torsional stiffness through sole modification of air pressure shoes on lower extremity biomechanical behaviour during side-step cutting maneuvers

“…Where Mz is the plate moment about Z-axis (vertical axis) in the force plate center, Fx is the GRF in X-direction (medio-lateral axis and positive direction to the right), Fy is the GRF in Y-direction (anterior–posterior axis, running direction is positive to Y-axis), ax is the X-coordinate of force application point (COP), and ay is Y-coordinate of force application point (COP) [ 64 ]. GRF and ankle and knee joint moments data were normalized to body weight (BW) [ 51 ], while the twisting moment was normalized to the product of body weight (BW) and body height (BH) multiplied by 10 -3 [ 65 ].…”

A review of musculoskeletal modelling of human locomotion

“…It is possible to conduct an inverse dynamics solution of the single support phase of walking with a single force plate (e.g. [111]), but extending the analysis to the double support portions of the stride is more difficult with one force plate because it would require estimation of the unknown contribution of the other stance foot. Consequently, any research that requires information about double support should optimally be conducted with multiple force plates.…”

Eight Weeks of Exercising on Sand Has Positive Effects on Biomechanics of Walking and Muscle Activities in Individuals with Pronated Feet: A Randomized Double-Blinded Controlled Trial

“…With regards to the biomechanics of walking, there is evidence that individuals with PF show a significantly lower second peak (propulsion phase) of vertical ground reaction force (GRF) [ 1 ], greater lateral-medial GRF [ 8 ], and greater [ 9 ] or similar [ 8 ] peak- free moment amplitudes. Of note, different researchers have observed that greater peak vertical GRF during heel contact and vertical loading rates are associated with walking and/or running-related injuries [ 8 , 10 ].…”