2025

Biology

Journal year: 2025 | Journal volume: vol. 14 | Journal number: iss. 6

scientific article

english

EN This study assesses the actual recruitment of knee extensor muscle motor units at specific maximal voluntary contraction (MVC) thresholds in older adults and explores the divergence between perceived effort and actual muscle activation. We hypothesize that older adults may exhibit greater discrepancies between intended and actual motor unit recruitment, which could affect the quality of muscle activation and potentially increase the risk of falls. Forty-eight physically active older women participated in the study (65 ± 6 years, 164 ± 6 cm, and 76 ± 7 kg). The bioelectrical activity (EMG) of the vastus lateralis oblique (VLO) and vastus medialis oblique (VMO) muscles were assessed during isometric testing with the knee joint bent to 75 degrees. The participants were instructed to press against a stable bar for 5 s at a specific percentage of their perceived force level (at 15%, 30%, and 60% of MVC) when the EMG activity was recorded. Proprioceptive deficits in older adults may contribute to impaired motor control and reduced stability. Our results suggest that older adults experience deficits in muscle activation perception, leading to discrepancies between intended and actual muscle engagement, which may affect functional task performance and potentially increase fall risk. Future research should explore the effectiveness of targeted interventions on improving force control across different thresholds, ultimately aiding in fall prevention and enhancing functional independence in aging populations.

16.06.2025

703-1 - 703-12

10.3390/biology14060703

https://www.mdpi.com/2079-7737/14/6/703

Article Number: 703

CC BY (attribution alone)

open journal

final published version

at the time of publication

100

3,5 [List 2024]