Term of Award

Summer 2025

Degree Name

Master of Science in Kinesiology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Health Sciences and Kinesiology

Committee Chair

Nicholas Siekirk

Committee Member 1

Jessica Mutchler

Committee Member 2

Li Li

Committee Member 3

Barry Joyner

Abstract

This study examined the effects of externally focused verbal instructions-cues (VIC’s) and upper extremity (UE) involvement on lower extremity (LE) electromyography (EMG) during recumbent stepping (RS) in middle-aged to older adults. Sixteen participants (M = 69 ± 10 years) completed 6 randomized stepping conditions on the NuStep T6 Pro: full body or legs-only RS, both with either a push, pull or no verbal cue (no VIC). EMG was collected bilaterally from the Rectus Femoris (RF), Tibialis Anterior (TA), Medial Gastrocnemius (MG) and Biceps Femoris (BF). EMG values were normalized to participants maximal voluntary contractions (MVC). Significant main effects for VIC were detected across all muscles (p < 0.05). RF excitation was greatest during the pull VIC, highlighting the role of the RF as a hip flexor during RS. TA excitation doubled under the pull VIC compared to push and no VIC, following previous literature on dorsiflexors role during the swing phase of RS. MG excitation was greater during the push VIC and no VIC compared to pull, highlighting the need for verbal cues during RS. The BF showed small changes in excitation due to VIC, indicating limited involvement during RS. Full body RS slightly increased RF activation compared to legs-only RS, however differences were modest. The results indicate that externally focused verbal cues can influence LE EMG during RS, with implications for optimizing muscle recruitment in middle-aged to older populations.

OCLC Number

1528654010

Research Data and Supplementary Material

Yes

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