Myoelectric fatigue profiles of three knee extensor muscles.
Int J Sports Med
; 30(6): 408-17, 2009 Jun.
Article
em En
| MEDLINE
| ID: mdl-19199219
ABSTRACT
Aims of the present study were to 1) investigate the differences between the myoelectric fatigue profiles of the vasti muscles of the quadriceps during electrically evoked contractions; 2) compare the myoelectric fatigue profiles of the vasti muscles between sedentary subjects and rowers; 3) analyze motor unit activation order during stimulation of the vasti muscles. In nine sedentary subjects and nine rowers surface EMG signals were detected during electrically elicited contractions of the following three muscles vastus medialis obliquus (VMO), vastus lateralis (VL), and vastus medialis longus (VML). M-waves were recorded as the muscles were stimulated with both variable (increasing-decreasing) and constant stimulation intensities. Changes in M-wave conduction velocity (CV) during trains with non-constant current were adopted for the study of the motor unit recruitment order. Rates of change of myoelectric signal variables were adopted to assess myoelectric manifestations of fatigue during stimulation trains with constant current. We found that 1) VL muscle was more fatigable than vastus medialis muscles; 2) VL and VML muscles of rowers resulted less fatigable than sedentary subjects; and 3) in the three muscles, motor units tended to be recruited in order of increasing CV and derecruited in order of decreasing CV with increasing/decreasing stimulation current.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fadiga Muscular
/
Músculo Quadríceps
/
Contração Muscular
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Int J Sports Med
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Itália