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Titolo:
Neuromuscular changes after long-lasting mechanically and electrically elicited fatigue
Autore:
Avela, J; Kyrolainen, H; Komi, PV;
Indirizzi:
Univ Jyvaskyla, Dept Biol Phys Activ, Neuromuscular Res Ctr, SF-40100 Jyvaskyla, Finland Univ Jyvaskyla Jyvaskyla Finland SF-40100 r, SF-40100 Jyvaskyla, Finland
Titolo Testata:
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 3-4, volume: 85, anno: 2001,
pagine: 317 - 325
SICI:
1439-6319(200108)85:3-4<317:NCALMA>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAXIMAL VOLUNTARY CONTRACTIONS; STRETCH-REFLEX SENSITIVITY; SHORTENING CYCLE EXERCISE; MOTONEURON FIRING RATES; HUMAN SKELETAL-MUSCLE; TRICEPS SURAE; SOLEUS MUSCLE; INHIBITION; PERFORMANCE; ACTIVATION;
Keywords:
electromyography; low-frequency fatigue; neuromuscular fatigue; stretch-reflex;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Avela, J Univ Jyvaskyla, Dept Biol Phys Activ, Neuromuscular Res Ctr, SF-40100 Jyvaskyla, Finland Univ Jyvaskyla Jyvaskyla Finland SF-40100 00 Jyvaskyla, Finland
Citazione:
J. Avela et al., "Neuromuscular changes after long-lasting mechanically and electrically elicited fatigue", EUR J A PHY, 85(3-4), 2001, pp. 317-325

Abstract

Central fatigue was investigated under an isolated active condition whereby the possible effects of supraspinal fatigue were minimized. Therefore, ten subjects were fatigued by simultaneously and repeatedly mechanically stretching and electrically stimulating their calf muscles for 1 h. This was performed using an ankle ergometer. The active fatigue task included a total of 2400 muscle stretches with an intensity of 10% of the maximal voluntary contraction (MVC). This protocol clearly impaired neuromuscular function, as revealed by a significant reduction in MVC (P < 0.01) and the neural input to the muscle (average EMG) (P<0.01-0.001). The interpolated nerve stimulation compensated for this force loss by 4.28% (P < 0.05). Stretch-reflex recordings revealed a notable post-fatigue reduction in the peak-to-peak amplitude (59.1%, P < 0.01) and stretch-resisting force of the muscle (14.1%, P < 0.01). The maximal H-reflex declined by 50.5% (P < 0.001) and did not recover while the leg was kept ischemic. It is suggested that the existing protocol with minor metabolic loading can,induce central fatigue, which seems to be of reflex origin from the fatigued muscle. Although the role of presynaptic inhibition of la terminals is possibly reinforced, disfacilitationvia reduced spindle sensitivity cannot be excluded.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 11:59:46