Sant'Anna do Carmo Aprigio P, Ramathur Telles de Jesus I, Porto C, Lemos T, de Sá Ferreira A. Lower limb muscle fatigability is not associated with changes in movement strategies for balance control in the upright stance.
Hum Mov Sci 2020;
70:102588. [PMID:
32217206 DOI:
10.1016/j.humov.2020.102588]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 01/18/2020] [Accepted: 01/30/2020] [Indexed: 01/01/2023]
Abstract
BACKGROUND
Fatigue is a distressing symptom inversely related to postural stability in adults with neuromuscular and systemic diseases. However, there is no information about the effects of lower limb muscles fatigability on the movement strategies for balance control in the upright standing.
METHODS
This study enrolled 41 healthy subjects (female/male: 22/19; age 23 ± 3 years; body mass index 25.4 ± 3.7 kg/m2). Participants underwent posturography and surface electromyography of the gastrocnemius medialis muscle during a sustained, fatiguing voluntary contraction of the gastrocnemius preceded and followed by quiet standing (120 s). Amplitude of electromyograms and fatigability were evaluated using the root mean square (RMS) value and both the RMS and spectral median frequency (fmed) slopes. Balance control was evaluated using the center-of-pressure elliptic area (Area) and average velocity (Vavg). Movement strategies for balance control were evaluated using the number of high-density regions (nHDR) and spatial patterns of the three-dimensional statokinesigram.
RESULTS
Mean time to muscle fatigability was 258 ± 190 s. Area and Vavg but not nHDR increased after the fatiguing task. Single-centered spatial patterns were predominant in both tasks (pre-fatigue: n = 22/41; post-fatigue: n = 19/41), with no evidence of an association between the spatial patterns and tasks (γ = 0.237, 95%CI = [-0.338; 0.542]).
CONCLUSIONS
Lower limb muscle fatigability increases postural instability, but it is not associated with changes in movement strategies for balance control in the upright stance.
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