Deficits in neuromuscular control of increasing force in patients with chronic lateral epicondylitis

Objective: This study investigated the neuromuscular control of increasing and releasing force in patients with chronic lateral epicondylitis (CLE). Methods: Fifteen patients with CLE (10 males, 5 females, 46.5 ± 6.3 years) and fifteen healthy participants (9 males, 6 females, 45.3 ± 2.5 years) part...

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Bibliographic Details
Published in:Frontiers in physiology 2023-08, Vol.14, p.1178557-1178557
Main Authors: Chen, Yueh, Hu, Chia-Ling, Hong, Chih-Kai, Hsu, Kai-Lan, Kuan, Fa-Chuan, Chen, Wei-Li, Su, Wei-Ren, Chen, Yi-Ching, Hwang, Ing-Shiou
Format: Article
Language:English
Subjects:
EMG
force variability
motor unit
muscle strength
Physiology
tennis elbow
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Summary:Objective: This study investigated the neuromuscular control of increasing and releasing force in patients with chronic lateral epicondylitis (CLE). Methods: Fifteen patients with CLE (10 males, 5 females, 46.5 ± 6.3 years) and fifteen healthy participants (9 males, 6 females, 45.3 ± 2.5 years) participated in this study. In addition to power grip and maximal voluntary contraction (MVC) of wrist extension, force fluctuation dynamics and characteristics of inter-spike intervals (ISI) of motor units (MUs) with various recruitment thresholds in the extensor carpi radialis brevis (ECRB) and extensor carpi radialis longus (ECRL) during a designated force-tracking task with a trapezoidal target (0%–75%–0% MVC) were assessed. Results: Besides a smaller MVC of wrist extension, the patients exhibited significantly greater task errors ( p = 0.007) and force fluctuations ( p = 0.001) during force increment than the healthy counterparts. Nevertheless, no force variables significantly differed between groups during force release ( p > 0.05). During force increment, the amplitudes of the motor unit action potential of the ECRB and ECRL muscles of the patients were smaller than those of the heathy counterparts ( p < 0.001). The patient group also exhibited a higher percentage of motor units (MU) with lower recruitment threshold (40% MVC) in the ECRB muscle, compared to the healthy group. During force increment, the patient group exhibited a higher rate of decrease in inter-spike intervals (ISIs) of motor units with lower recruitment thresholds (
ISSN:1664-042X
1664-042X
DOI:10.3389/fphys.2023.1178557