Sensory Organization Test Conditions Influence Postural Strategy Rather than Footwear or Workload.

Harish Chander,Alana J Turner,Reuben F Burch V,John C Garner,Sachini N K Kodithuwakku Arachchige,Chip Wade,Adam C Knight,Jennifer C Reneker

doi:10.3390/ijerph181910511

Abstract

Background: Postural strategies such as ankle, hip, or combined ankle-hip strategies are used to maintain optimal postural stability, which can be influenced by the footwear type and physiological workload. Purpose: This paper reports previously unreported postural strategy scores during the six conditions of the sensory organization test (SOT). Methods: Fourteen healthy males (age: 23.6 ± 1.2 years; height: 181 ± 5.3 cm; mass: 89.2 ± 14.6 kg) were tested for postural strategy adopted during SOT in three types of occupational footwear (steel-toed work boot, tactical work boot, low-top work shoe) every 30 min during a 4-h simulated occupational workload. Postural strategy scores were analyzed using repeated measures analysis of variance at 0.05 alpha level. Results: Significant differences among postural strategy scores were only evident between SOT conditions, and but not between footwear type or the workload. Conclusions: Findings indicate that occupational footwear and occupational workload did not cause a significant change in reliance on postural strategies. The significant changes in postural strategy scores were due to the availability of accurate and/or conflicting sensory feedback during SOT conditions. In SOT conditions where all three types of sensory feedback was available, the ankle strategy was predominantly adopted, while more reliance on hip strategy occurred in conditions with absent or conflicting sensory feedback.

Highlights

In the event of an induced postural perturbation, the body’s postural control system selects and executes either one or a combination of postural strategies to provide counteracting measures to the postural perturbation, to regain postural stability and prevent falls
Even with prior findings from the current study demonstrating that occupational footwear and/or occupational workload significantly influenced postural stability based on center of pressure (COP) postural sway variables [15], Sensory organization test (SOT) EQ scores [17], and lower extremity EMG muscle activity [20], the current findings indicate that occupational footwear and occupational workload did not cause a significant change in reliance of ankle or hip strategy
Based on the results from this study, and comparing postural stability findings from the same study from previously published literature [15,17], it is evident that while postural stability quantified by COP-derived postural sway variables and SOT EQ scores were influenced by the type of occupational footwear and workload, individuals did not have to significantly change postural strategy from a predominant ankle strategy to relying more on hip strategy to maintain postural stability

Summary

Introduction

In the event of an induced postural perturbation, the body’s postural control system selects and executes either one or a combination of postural strategies to provide counteracting measures to the postural perturbation, to regain postural stability and prevent falls. Postural strategies are usually classified as fixed support strategies which include ankle strategy, hip strategy, and a combination of ankle and hip strategy, and change in support strategies, which include stepping and grasping strategies [1,2,3]. While stepping and grasping strategies are usually resorted to only when the postural perturbation is large and causing the body’s center of mass (COM) to move outside of the base of support (BOS), ankle and hip strategies are more commonly used in static bilateral stance, with ankle strategy being selected with small perturbations and hip strategy being selected with larger perturbations [1,2].

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