Date of Award
5-10-2026
Date Published
June 2026
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Exercise Science
Advisor(s)
Kylie Harmon
Keywords
Action observation;Limb immobilization;Motor imagery;Muscle atrophy;Muscle strength;Neuromuscular electrical stimulation
Subject Categories
Kinesiology | Life Sciences
Abstract
Short-term limb immobilization induces rapid declines in muscle strength that exceed reductions in muscle size, suggesting a dominant role of neural mechanisms in early functional decline. Interventions capable of simultaneously targeting central neural and peripheral muscular pathways may therefore offer superior protection during disuse, yet such combined approaches remain unexamined in upper limb immobilization models. To investigate the effects of combined action observation with motor imagery (AOMI) and neuromuscular electrical stimulation (NMES) (AOSTIM) on muscle strength, size, and quality during 7 days of upper limb immobilization, we conducted a study in healthy young adults. Forty-three healthy young adults were randomly assigned to one of four groups: immobilization with AOSTIM (n=10), immobilization only (n=10), AOSTIM without immobilization (n=11), and no immobilization no intervention (n=12). Participants in immobilization groups wore a hand and wrist brace on the non-dominant limb for 7 consecutive days. Intervention groups completed daily 30-minute AOMI + NMES sessions targeting the abductor pollicis brevis (APB). Grip strength, cross-sectional area (CSA), and echo intensity (EI) of APB were assessed pre- and post-intervention. Data were analyzed using one-way ANCOVA with baseline values as covariates and paired-samples t-tests for within-group changes. Analysis revealed a significant effect of group on post-intervention grip strength of the experimental hand, with both non-immobilized groups demonstrating significantly greater grip strength than both immobilized groups, and no difference between immobilization conditions. A significant effect of group was also observed for APB CSA, with AOSTIM showing significantly greater CSA than immobilization only group (p = 0.011). Within-group analyses revealed a significant decline in muscle CSA in the immobilization-only group (−7.13%), which was attenuated in the immobilization with AOSTIM group (+0.49%). No significant effects were observed for muscle EI or contralateral hand grip strength. Combined AOMI + NMES attenuated muscle atrophy but did not prevent strength loss during short-term upper limb immobilization, reinforcing the dissociation between structural and functional adaptations and the predominance of neural mechanisms in early disuse-induced strength decline.
Access
Open Access
Recommended Citation
Pourhatami, Zahra, "EFFECTS OF COMBINED ACTION OBSERVATION, MOTOR IMAGERY, AND NEUROMUSCULAR ELECTRICAL STIMULATION ON MUSCLE STRENGTH AND SIZE DURING SHORT-TERM UPPER LIMB IMMOBILIZATION" (2026). Theses - ALL. 1027.
https://surface.syr.edu/thesis/1027
