title: Medial-lateral centre of mass displacement and base of support are equally good predictors of metabolic cost in amputee walking.
abstract: Amputees are known to walk with greater metabolic cost than able-bodied individuals and establishing predictors of metabolic cost from kinematic measures, such as centre of mass (CoM) motion, during walking are important from a rehabilitative perspective, as they can provide quantifiable measures to target during gait rehabilitation in amputees. While it is known that vertical CoM motion poorly predicts metabolic cost, CoM motion in the medial-lateral (ML) and anterior-posterior directions have not been investigated in the context of gait efficiency in the amputee population. Therefore, the aims of this study were to investigate the relationship between CoM motion in all three directions of motion, base of support and walking speed, and the metabolic cost of walking in both able-bodied individuals and different levels of lower limb amputee. 37 individuals were recruited to form groups of controls, unilateral above- and below-knee, and bilateral above-knee amputees respectively. Full-body optical motion and oxygen consumption data were collected during walking at a self-selected speed. CoM position was taken as the mass-weighted average of all body segments and compared to each individual's net non-dimensional metabolic cost. Base of support and ML CoM displacement were the strongest correlates to metabolic cost and the positive correlations suggest increased ML CoM displacement or Base of support will reduce walking efficiency. Rehabilitation protocols which indirectly reduce these indicators, rather than vertical CoM displacement will likely show improvements in amputee walking efficiency.
authors.affiliation: School of Health Sciences, University of Salford, Salford, UK. Electronic address: r.a.weinert-aplin@salford.ac.uk.
authors.forename: R A
authors.initials: RA
authors.lastname: Weinert-Aplin
authors.affiliation: School of Health Sciences, University of Salford, Salford, UK; United National Institute for Prosthetics & Orthotics Development, UK.
authors.forename: M
authors.initials: M
authors.lastname: Twiste
authors.affiliation: School of Health Sciences, University of Salford, Salford, UK; Defence Medical Rehabilitation Centre Headley Court, Surrey, UK.
authors.forename: H L
authors.initials: HL
authors.lastname: Jarvis
authors.affiliation: Defence Medical Rehabilitation Centre Headley Court, Surrey, UK; Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; National Heart and Lung Institute, Faculty of Medicine, Imperial College London, UK.
authors.forename: A N
authors.initials: AN
authors.lastname: Bennett
authors.affiliation: School of Health Sciences, University of Salford, Salford, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Baker
mesh_terms: D000293:Adolescent; D000328:Adult; D000671:Amputation, Surgical / Q000534:rehabilitation; D000674:Amputees / Q000534:rehabilitation*; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology*; D006801:Humans; D035002:Lower Extremity; D010101:Oxygen Consumption / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D016138:Walking / Q000502:physiology; D055815:Young Adult
keywords: Efficiency; Gait; Prosthetic; Rehabilitation