Alteration in global motor strategy following lateral ankle sprain.

Maude Bastien,Marc Perron,Hélène Moffet,Laurent J Bouyer,Jean Leblond,Luc J Hébert

doi:10.1186/1471-2474-15-436

Abstract

BackgroundLateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system. Persistent chronic ankle instability and bilateral alterations in motor control after a first ankle sprain episode suggest that the origin of relapses might be a maladaptive reorganization of central motor commands. The objectives of this study were (1) to compare the quality of motor control through motor strategy variables of two groups (with and without LAS) from a military population (n = 10/group), (2) to evaluate the contribution of the lower limbs and the trunk to global body strategy and (3) to identify which global variable best estimates performance on the Star Excursion Balance Test (SEBT) for each group, reaching direction, and lower limb.MethodsPersonal and clinical characteristics of the participants of both groups were collected. Their functional ability was measured using questionnaires and they performed a series of functional tests including the SEBT. During this test, the maximal reach distance (MRD) and biomechanical data were collected to characterize whole body and segmental strategies using a 3D motion capture system.ResultsAt maximal lower limb reach, participants with LAS had a smaller variation in their vertical velocity in lowering-straightening and lowered the body centre of mass less for all injured limb conditions and some conditions with the uninjured lower limb. The global body centre of mass variables were significantly correlated to SEBT performance (MRD).ConclusionModifications in global motor strategies were found in participants with LAS as well as a decreased performance on the SEBT for the injured and uninjured lower limbs. These results support the hypothesis that following LAS, there may be a maladaptive reorganization of the central motor commands. Level of evidence: 3b.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-436) contains supplementary material, which is available to authorized users.

Highlights

Lateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system
The LAS group had, a lower level of functional ability as measured by two questionnaires (FADI sport module: 79.4 ± 18.4 compared to 98.1 ± 2.6; Lower Extremity Function Scale (LEFS): 73.3 ± 6.8 compared to 79.1 ± 1.4; p < 0.05)
Quality of motor control and comparison of global body strategies between groups Around “foot contact,” the LAS group shows a smaller magnitude of CoMgl lowering (MD, 95% confidence interval (CI): 4.17 cm, (0.51 to 7.82) to 5.92 cm, (1.56 to 10.28), p < 0.05) and a smaller peak-to-peak CoMgl vertical velocities than the healthy group in all directions (0.08 cm/s, (0.01 to 0.15) to 0.12 cm/s, (0.04 to 0.20), p < 0.05) (Figure 2A)

Summary

Introduction

Lateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system. Persistent chronic ankle instability and bilateral alterations in motor control after a first ankle sprain episode suggest that the origin of relapses might be a maladaptive reorganization of central motor commands. LAS causes swelling, pain and other peripheral damage This leads to altered sensory inputs, which trigger a reorganization in sensorimotor processing leading to long-term central modification in movement planning and execution [19,20,21]. Such a sensorimotor processing deficit could explain the bilateral effects observed in participants with chronic ankle instability. Regarding potential neural control mechanisms that could be altered after LAS, it is known that individuals with chronic ankle instability have impaired sensorimotor function [11,13,22,23,24,25,26], and differences in segmental motor strategies during walking, running and jump landing [26,27,28,29,30,31]

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