title: The effect of trunk flexion on lower-limb kinetics of able-bodied gait.
abstract: Able-bodied individuals spontaneously adopt crouch gait when walking with induced anterior trunk flexion, but the effect of this adaptation on lower-limb kinetics is unknown. Sustained forward trunk displacement during walking can greatly alter body center-of-mass location and necessitate a motor control response to maintain upright balance. Understanding this response may provide insight into the biomechanical demands on the lower-limb joints of spinal pathology that alter trunk alignment (e.g., flatback). The purpose of this study was to determine the effect of sustained trunk flexion on lower-limb kinetics in able-bodied gait, facilitating understanding of the effects of spinal pathologies. Subjects walked with three postures: 0° (normal upright), 25±7°, and 50±7° trunk flexion. With increased trunk flexion, decreased peak ankle plantar flexor moments were observed with increased energy absorption during stance. Sustained knee flexion during mid- and terminal stance decreased knee flexor moments, but energy absorption/generation remained unchanged across postures. Increased trunk flexion placed significant demand on the hip extensors, thus increasing peak hip extensor moments and energy generation. The direct relationship between trunk flexion and energy absorption/generation at the ankle and hip, respectively, suggest increased muscular demand during gait. These findings on able-bodied subjects might shed light on muscular demands associated with individuals having pathology-induced positive sagittal spine balance.
authors.affiliation: Northwestern University Prosthetics-Orthotics Center, Dept. of Physical Medicine & Rehabilitation, Feinberg School of Medicine, 680 N Lake Shore Dr., Suite 1100, Chicago, IL 60611, USA.
authors.forename: David
authors.initials: D
authors.lastname: Kluger
authors.affiliation: Northwestern University Prosthetics-Orthotics Center, Dept. of Physical Medicine & Rehabilitation, Feinberg School of Medicine, 680 N Lake Shore Dr., Suite 1100, Chicago, IL 60611, USA. Electronic address: Matthew-Major@northwestern.edu.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Major
authors.affiliation: Northwestern University Prosthetics-Orthotics Center, Dept. of Physical Medicine & Rehabilitation, Feinberg School of Medicine, 680 N Lake Shore Dr., Suite 1100, Chicago, IL 60611, USA.
authors.forename: Stefania
authors.initials: S
authors.lastname: Fatone
authors.affiliation: Northwestern University Prosthetics-Orthotics Center, Dept. of Physical Medicine & Rehabilitation, Feinberg School of Medicine, 680 N Lake Shore Dr., Suite 1100, Chicago, IL 60611, USA; Jesse Brown VA Medical Center, Dept. of Veterans Affairs, 820 S Damen Ave, Chicago, IL 60612, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Gard
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000503:physiopathology; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D004856:Postural Balance / Q000502:physiology*; D013122:Spinal Diseases / Q000503:physiopathology; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*
keywords: Gait; Kinetics; Posture; Trunk