Medicine and Health Sciences Commons^™

Co-Contraction Of Ankle Muscle Activity During Quiet Standing In Individuals With Incomplete Spinal Cord Injury Is Associated With Postural Instability, Kai Lon Fok, Jae W Lee, Janelle Unger, Katherine Chan, Kristin E Musselman, Kei Masani

Physical Therapy Publications

Previous findings indicate that co-contractions of plantarflexors and dorsiflexors during quiet standing increase the ankle mechanical joint stiffness, resulting in increased postural sway. Balance impairments in individuals with incomplete spinal cord injury (iSCI) may be due to co-contractions like in other individuals with reduced balance ability. Here we investigated the effect of co-contraction between plantar- and dorsiflexors on postural balance in individuals with iSCI (iSCI-group) and able-bodied individuals (AB-group). Thirteen able-bodied individuals and 13 individuals with iSCI were asked to perform quiet standing with their eyes open (EO) and eyes closed (EC). Kinetics and electromyograms from the tibialis anterior (TA), …

Reactive Stepping After A Forward Fall In People Living With Incomplete Spinal Cord Injury Or Disease, Katherine Chan, Jae Woung Lee, Janelle Unger, Jaeeun Yoo, Kei Masani, Kristin E Musselman

Physical Therapy Publications

STUDY DESIGN: Cross sectional.

OBJECTIVES: To compare the reactive stepping ability of individuals living with incomplete spinal cord injury or disease (SCI/D) to that of sex- and age-matched able-bodied adults.

SETTING: A tertiary SCI/D rehabilitation center in Canada.

METHODS: Thirty-three individuals (20 with incomplete SCI/D) participated. Participants assumed a forward lean position in standing whilst 8-12% of their body weight was supported by a horizontal cable at waist height affixed to a rigid structure. The cable was released unexpectedly, simulating a forward fall and eliciting one or more reactive steps. Behavioral responses (i.e., single step versus non-single step) were compared …

Selectivity Of Conventional Electrodes For Recording Motor Evoked Potentials: An Investigation With High‐Density Surface Electromyography, Alessio Gallina, Sue Peters, Jason L. Neva, Lara A. Boyd, Jayne Garland

Physical Therapy Publications

Introduction

The objective of this study was to determine whether motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation and measured with conventional bipolar electromyography (EMG) are influenced by crosstalk from non-target muscles.

Methods

MEPs were recorded in healthy participants using conventional EMG electrodes placed over the extensor carpi radialis muscle (ECR) and high-density surface EMG (HDsEMG). Fifty MEPs at 120% resting and active motor threshold were recorded. To determine the contribution of ECR to the MEPs, the amplitude distribution across HDsEMG channels was correlated with EMG activity recorded during a wrist extension task.

Results

Whereas the conventional EMG identified …