Mechanism of Action Study to Explore the Footwear Components of the Leeds Ankle Stabilising Enhanced Rocker (Laser) Intervention Using a Williams Latin Square Cross-Over Experimental Design

Abstract

BackgroundThe Leeds Ankle Stabilising Enhanced Rocker (LASER) boot and foot orthoses (LASER intervention) have been used to manage haemophilia and blood-induced ankle arthritis, improving clinical outcomes. While clinical data supports using the LASER intervention, the individual and combined mechanical effects of the intervention component factors on the ankle, knee, and hip have not been examined. This study explored the biomechanical effects of the overall LASER intervention and its factor components.MethodsA single-centre, six-period, six-treatment (trainer, military boot, Solid Ankle Cushioned Heel (SACH), rocker sole, LASER boot, LASER intervention), Williams Latin-square cross-over design (within-participant comparison) was conducted to investigate the biomechanical effects of the component factors of the LASER intervention versus a standard trainer in 36 healthy male participants. Three-dimensional gait analysis was undertaken using an in-shoe biomechanical foot model to analyse lower limb kinetics and kinematics.ResultsThe LASER intervention significantly reduced ankle internal plantarflexion moment (1.37NmKg SD 0.17, 95% CI; 1.31,1.43) when compared to a standard trainer (1.55NmKg, SD 0.17, 95% CI; 1.49,1.60). Effects of the LASER components; the SACH (ankle plantarflexion moment of force), rocker sole (Progression CoP), military boot (ankle ROM) and foot orthoses (sagittal and frontal plane ankle kinetics) produce the hypothesised effect for all conditions when compared to a standard trainer. The proximal effect on the knee and hips was minimal.SignificanceThis study demonstrates that the mechanical effects of the individual and combined component factors of the LASER intervention reduced biomechanical demand on the ankle in the sagittal and frontal planes.

Note:
Funding Information: Richard Wilkins, Clinical Doctoral Research Fellow (ICA-CDRF-2015-01-012) was funded by Health Education England (HEE) / NIHR for this research project.

Conflict of Interests: There are no competing interests from any of the authors included in this paper

Ethical Approval: Ethical approval was obtained from the University of Leeds, School of Medicine Research Ethics Committee (MREC 16-087). All participants provided written informed consent before data collection commenced.

Keywords: ankle, footwear, kinetics, kinematics, foot orthoses, Williams Latin square cross-over experimental design