The Effect of Proprioceptive Insoles on Gait Kinematics in Healthy Participants

Abstract

ABSTRACT Introduction Proprioceptive neuromuscular stimulating insoles (PNIs) enhance somatosensory information from the plantar region, thus modifying standing posture, balance, and ambulatory function. The present study investigated the short-term effects of customized PNIs on lower-limb kinematics during human locomotion. Materials and Methods Fifteen able-bodied volunteers were recruited and first examined with clinical evaluation of postural and feet behavior. Subjects performed 3-dimensional gait analysis (GA) while walking at self-selected speed in three different conditions: baseline, subjects barefoot; placebo, subjects wearing neutral insoles; and proprioceptive, subjects wearing PNIs. Spatiotemporal and kinematics data of the main lower-limb joints were acquired through a system of six photogrammetric infrared cameras acquiring at a sampling frequency of 100 Hz. Then, acquired parameters were compared in the three different conditions. Results We found a significant difference in the percentage of double-support phase (P = 0.022) and in ankle plantarflexion values during the toe-off phase of gait cycle (P = 0.022) between the three conditions. Post hoc analysis revealed that subjects wearing PNIs presented a significant reduction in percentage of double-support phase (P = 0.009) and reduced values of ankle plantarflexion during the toe-off phase of gait cycle (P = 0.02), compared with subjects in placebo condition. Conclusions Results suggest that proprioceptive insoles may induce modifications of gait biomechanics in able-bodied subjects, thus modulating movement strategies during human locomotion. Clinical Relevance These findings provide a basis for future investigation of the efficacy of these foot devices in a long-term period in able-bodied individuals and potentially in subjects with neurological impairment.