Spine Intersegmental Flexion and Muscular Responses to Sudden Loading at the Hands Altered by Cognitive Dual-Tasking and Abdominal Bracing

Norrie, Jarrett
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University of Guelph

Basic movement and muscle activation patterns greatly influence fundamental mechanisms of lumbar spine injury in response to sudden spine flexion perturbations. This thesis aims to explore the influence of cognitive dual-tasking and abdominal bracing on the kinematic and neuromuscular response of the spine and paraspinal musculature during studies 1 and 2, respectively. Neuromuscular control was assessed by delivering an unexpected perturbation to the hands of participants to induce sudden spine flexion. Study 1 employed cognitive dual-tasking through serial-7 subtraction while study 2 focused on abdominal bracing. Dual-tasking and bracing resulted in opposite kinematic responses where greater and lesser flexion occurred during the cognitive and bracing conditions, respectively. Dual-tasking caused delayed muscle onsets while bracing increased baseline activation in all abdominal muscles. These investigations highlight that cognitive loading and abdominal bracing can influence trunk muscle activation and reflex dynamics to modify spine motion in response to unexpected perturbations.

Spine, Biomechanics, Sudden Loading, Abdominal Bracing, Cognitive Loading