Effects of Torso Weighting on Muscle Activation During Balance Tests in Individuals With and Without Multiple Sclerosis

Research Questions:

Question #1 - Is there a difference in EMG within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when not wearing weighted vest with eyes open? Question #2 - Is there a difference in EMG within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when not wearing weighted vest with eyes closed? Question #3 - Is there a difference in EMG within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when wearing weighted vest eyes open? Question #4 - Is there a difference in EMG within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when wearing weighted vest eyes closed? Question #5 - Is there a difference in SWAY within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when not wearing weighted vest with eyes open? Question #6 - Is there a difference in SWAY within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when not wearing weighted vest with eyes closed? Question #7 - Is there a difference in SWAY within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when wearing weighted vest eyes open? Question #8 - Is there a difference in SWAY within postural muscles (tibialis anterior and gastrocsoleus) and between healthy and MS when wearing weighted vest eyes closed? Research Design: Quasi-experimental design

Inclusion criteria

for Individuals with Multiple Sclerosis group:

• self-reported diagnosis of multiple sclerosis (MS)
• age 18 to 75 years old
• able to communicate in English
• able to provide informed consent
• able to tolerate up to three hours of testing with rest breaks
• able to walk 20 meters with or without assistive device and without resting (equivalent to Expanded Disability Status Scale of 6.5 or less).

Inclusion criteria

for the Healthy Control group:

• able to communicate in English
• able to provide informed consent
• physical criteria that matched each participant with MS which included age (within 7 years), height (within 12.7 cm [5 in]), mass (within 9.1 kg [20 lb]) and sex.

Exclusion criteria

for Individuals with Multiple Sclerosis group:

• exacerbation of MS within the past two months
• had a diagnosis of a concurrent neurological disorder (head injury, stroke, Parkinson's disease, etc.)
• reported pain that could be exacerbated by external perturbations during standing.

Exclusion criteria

for Healthy control group:

• Known diagnoses
• current pain that could affect balance.