Muscle Activity during Postural Stability Tasks: Role of Military Footwear and Load Carriage

Sachini N.K Kodithuwakku Arachchige,Reuben F Burch V,Daniel Carruth,Chip Wade,Jeffrey D Simpson,Samuel J Wilson,Harish Chander,Alana J Turner,Adam C Knight,John C Garner

doi:10.3390/safety6030035

Sachini N.K Kodithuwakku Arachchige, Reuben F Burch V + Show 8 more

Open Access

https://doi.org/10.3390/safety6030035

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Abstract

Decrements to postural control manifest as an increase in muscle activity, indicating continuous attempts to maintain body equilibrium and postural stability. Extrinsic factors such as footwear, and intrinsic factors such as muscle fatigue, can affect postural stability. The purpose of this study was to analyze the impact of two types of military footwear and a military-type load-carrying task on lower extremity muscle activity during various postural stability tasks. Sixteen males’ (age: 26.63 ± 3.93 years; mass: 87 ± 12.4 kg; height: 178.04 ± 6.2 cm) muscle activity from knee flexors, extensors, ankle dorsiflexors, and plantar flexors were measured using electromyography in standard (STD) and minimalist (MIN) military footwear, before (PRE) and after (POST) a simulated workload during sensory organization and motor control tests on the Neurocom EquitestTM. Mean muscle activity was analyzed using 2 (footwear) × 2 (time) repeated measures ANOVA with an alpha level of 0.05. Results revealed a requirement of significantly greater muscle activity in POST and STD. MIN demonstrated lesser balance decrements POST workload, which could be attributed to its design characteristics. Results will help in suggesting footwear design characteristics to minimize muscular exertion while eliciting better postural control, and to prevent postural instability due to overexertion in military personnel.

Highlights

Erect standing posture could be accomplished by a comparatively smaller degree of muscle activation
The current study addresses the impact of minimalist and standard types of military footwear and a load carriage workload on postural stability
In highly physically demanding occupations, such as military, special attention should be given to implementing measures to prevent physiological fatigue and enhancing postural stability performance, to prevent undue injuries

Summary

Introduction

Erect standing posture could be accomplished by a comparatively smaller degree of muscle activation. The regulation and maintenance of erect posture are more complex, which requires proper communication between the neuromuscular systems. Postural control is mainly acquired through the integration of sensory systems (visual, vestibular, and somatosensory systems), central control, and motor systems (neuromuscular system) [1,2]. When one or more of these systems. Safety 2020, 6, 35 are compromised, maintaining postural control will be challenged, leading to falls. Decrements to the postural control manifest as an increase in postural sway and increased muscle activity, indicating continuous attempts to maintain postural stability. The disruption to the postural control increases the demand for central control and peripheral muscles [3]

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