Is There a Role for GPS in Determining Functional Ankle Rehabilitation Progression Criteria? A Preliminary Study

Greig, M., Emmerson, H., McCreadie, J.

Contemporary developments in GPS technology present a means of quantifying mechanical loading in a clinical environment with high ecological validity. However, applications to date have typically focused on performance rather than rehabilitation.

To examine the efficacy of GPS micro-technology in quantifying the progression of loading during functional rehabilitation from ankle sprain injury, given the prevalence of re-injury and need for quantifiable monitoring. Furthermore, to examine the influence of unit placement on the clinical interpretation of loading during specific functional rehabilitation drills.

Repeated measures.

University athletic facilities.

22 female intermittent team sports players.

All players completed a battery of 5 drills (anterior hop, inversion hop, eversion hop, diagonal hop, diagonal hurdle hop) designed to reflect the mechanism of ankle sprain injury, and progress functional challenge and loading.

Main Outcome Measures:
GPS-mounted accelerometers quantified uni-axial PlayerLoad for each drill, with units placed at C7 and the tibia. Main effects for drill type and GPS location were investigated.

There was a significant main effect for drill type (P < 0.001) in the medio-lateral (ɳ^2 = 0.436), anterio-posterior (ɳ^2 = 0.480), and vertical planes (ɳ^2 = 0.516). The diagonal hurdle hop elicited significantly greater load than all other drills, highlighting a non-linear progression of load. Only medio-lateral load showed evidence of progressive increase in loading. PlayerLoad was significantly greater at the tibia than at C7 for all drills, and in all planes (P < 0.001, ɳ^2 ≥ 0.662). Furthermore, the tibia placement was more sensitive to between-drill changes in medio-lateral load than the C7 placement. Conclusions: The placement of the GPS unit is imperative to clinical interpretation, with both magnitude and sensitivity influenced by the unit location. GPS does provide efficacy in quantifying multi-planar loading during (pre)rehabilitation, in a field or clinical setting, with potential in extending GPS analyses beyond performance metrics to functional injury rehabilitation and prevention.

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