Samuel J. Wilson

Impact of alternative footwear on human balance

Alternative footwear are those that are most commonly used for casual or recreational purposes, over the course of the day. The purpose of this study was to examine the effects of three forms of alternative footwear (thong style flip-flops, clog style Crocs®, and Vibram Five-Fingers®) on balance with a low-intensity workload. Eighteen healthy male adults (age: 22.9 ± 2.88 years; height: 179 ± 6.0 cm; mass: 81.3 ± 8.8 kg) participated in this study. Balance performance along with electromyographic (EMG) measures was assessed with sensory organization test (SOT) and motor control test on the Neurocom Equitest, while donning alternative footwear, prior to and after a one-mile walk at a self-selected pace. Sway velocities and root-mean-square sway, SOT equilibrium scores, postural response latencies, and EMG measures from lower leg muscles were analysed using a 3 × 2 (footwear × time) repeated-measures ANOVA. Results from balance variables revealed a significant main effect difference for footwear in the eyes closed and eyes open sway-referenced vision conditions and a significant main effect difference for time in the eyes open, eyes open sway-referenced vision, and eyes open sway-referenced platform conditions. Pairwise comparisons revealed MIN demonstrating significantly greater balance performance in the pretest condition and the post-test demonstrating significantly lower balance performance. Greater balance performance from MIN could be attributed to the barefoot design suggesting an increase in somatosensory feedback from the plantar surface, particularly during absent or conflicting visual feedback. The lower balance performance seen in post-test could be attributed to the one-mile walk, suggesting that even a transient physiological workload could be sufficient to cause balance decrements in alternative footwear.

The influence of multiple sensory impairments on functional balance and difficulty with falls among U.S. adults.

OBJECTIVE Studies have looked at the individual associations of sensory impairment on balance, but no population-based studies have examined their combined association on balance and difficulty with falls. Thus, the purpose of this study was to examine both the independent associations and combined associations of visual impairment, peripheral neuropathy, and self-reported hearing loss with the odds of reporting difficulty with falls and functional balance. METHODS Data from the 2003-2004 National Health and Nutrition Examination Survey were used. Vision and peripheral neuropathy were objectively measured, and hearing was self-reported. Balance testing consisted of a modified Romberg test. After exclusions, 1662 (40-85years of age) participants provided complete data on the study variables. RESULTS Sensory impairment was associated with perceived difficulty of falls and functional balance. Participants who presented a single sensory impairment had 29% reduced odds of having functional balance (95% CI=0.54-0.93, p=0.01) and increased odds of reporting difficulty with falls by 61% (95% CI=0.99-2.60, p=0.05). Moreover, our multisensory models showed some evidence of a dose-response relationship, in that sensory impairment of multiple sensory systems was associated with worse balance (OR =0.59, CI=0.35-1.00, p=0.05) and perceived difficulty of falls (OR =5.02, 95% CI=1.99-12.66, p=0.002) when compared to those with less sensory impairment. CONCLUSION Multiple sensory impairment is associated with significantly higher odds of both reporting difficulty with falls and balance dysfunction, which may lead to a subsequent fall, ultimately compromising the individuals health.

The Influence of an Acute Bout of Whole Body Vibration on Human Postural Control Responses

ABSTRACT The use of vibrating platforms has become increasingly available, and popular at sports and rehabilitation institutes. Given the discrepancies in the literature regarding whole body vibration (WBV) and human reflexive responses, the purpose of this study was to examine the acute effects of WBV on postural response latencies, as well as associated electromyography measures of the lower extremities during balance perturbations. Reflexive responses during backward and forward balance perturbations were examined before, after, and 10 min after a bout of WBV. The findings suggest that following an acute bout of whole body vibration, muscle activity of the lower extremities is decreased during a reflexive response to an unexpected perturbation, and may be associated with faster reaction time.

Impact of Military Type Footwear and Load Carrying Workload on Postural Stability

Abstract Postural stability has been shown to be impacted by footwear and task performed. This study analysed the impact of two military footwear, standard boot (STB) and minimalist boot (MTB) on postural stability, before (PRE) and after (POST) a load carriage task. Sixteen participants were tested for postural stability using sensory organisation and motor control tests on Neurocom Equitest™. Postural sway, equilibrium scores and postural latencies were analysed using a two-factor repeated measures ANOVA: boot type (STB-MTB) × time (PRE-POST) load carriage task. Significantly greater postural sway variables, lower balance scores and slower postural latencies were seen in STB and POST load carriage conditions (p < .05). The results suggest that MTB exhibited greater balance compared to STB in balance conditions that rely on somatosensory feedback and that balance is lowered after a load carriage task. Decrements in postural stability could be attributed to boot design characteristics and muscular exertion due to the load carriage task. Practitioner Summary: Maintaining optimal postural stability is crucial in military. Impact of military footwear types and load carriage task on postural stability are addressed. Findings provide footwear design and physical exertion implications on postural stability leading to potential interventions that reduce postural stability decrements; thereby, reducing potential falls and fall related injuries.