Errors in force generation and changes in controlling patterns following agonist muscle fatigue.
The purpose of this study was to evaluate whether agonist muscle fatigue changed the coactivation time and the co-contraction magnitude of the agonist and antagonist muscle, and if the agonist muscle fatigue produced bias (constant error: CE) and inconsistency (variable error: VE) of the force. Subjects are 10 healthy people and one person with impaired proprioception. EMG and force for fast (0.19 +/- 0.06 s) and slow (1.20 +/- 0.44 s) targeted isometric dorsiflexions were recorded before and after fatigue of the dorsiflexors. The results revealed that the coactivation time increased after fatigue only in the slow contractions but the co-contraction magnitude did not change. The postfatigue increment of the CE was greater in the fast contractions than in the slow ones. We conclude that the postfatigue compensatory strategy can reduce the fatigue-induced bias. The change of muscles activation level after fatigue might be under the influence of the common drive. Impaired proprioception is a possible cause of the fatigue-related increase in bias and inconsistency.
Huang
Yi-Ming
YM
National College of Physical Education and Sports, Taiwan;
Chang
Ya-Ju
YJ
Hsu
Miao-Ju
MJ
Chen
Chia-Ling
CL
Fang
Chia-Ying
CY
Wong
Alice May-Kuen
AM
D000843:Ankle Joint / Q000503:physiopathology*; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance; D011597:Psychomotor Performance; D020886:Somatosensory Disorders / Q000503:physiopathology*; D013314:Stress, Mechanical; D055815:Young Adult