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Titolo:
Electrical and mechanical H-max-to-M-max ratio in power- and endurance-trained athletes
Autore:
Maffiuletti, NA; Martin, A; Babault, N; Pensini, A; Lucas, B; Schieppati, M;
Indirizzi:
Univ Bourgogne, Fac Sci Sport, UFR STAPS, Grp Anal Mouvement, F-21078 Dijon, France Univ Bourgogne Dijon France F-21078 nal Mouvement, F-21078 Dijon, France Univ Bourgogne, Grp Etud & Rech Handicap, Ctr Convalescence & Reeduc, F-21078 Dijon, France Univ Bourgogne Dijon France F-21078 ence & Reeduc, F-21078 Dijon, France Univ Pavia, Ist Fisiol Umana, I-27100 Pavia, Italy Univ Pavia Pavia Italy I-27100 a, Ist Fisiol Umana, I-27100 Pavia, Italy Fdn Salvatore Maugeri, I-27100 Pavia, Italy Fdn Salvatore Maugeri Pavia Italy I-27100 Maugeri, I-27100 Pavia, Italy
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 1, volume: 90, anno: 2001,
pagine: 3 - 9
SICI:
8750-7587(200101)90:1<3:EAMHRI>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
SKELETAL-MUSCLE; FIBER TYPES; REFLEX; HUMANS; CONTRACTIONS; ADAPTATIONS; RESPONSES; EXERCISE;
Keywords:
soleus muscle; maximal H-reflex-to-maximal M-wave ratio; maximal H-reflex and maximal M-wave twitch; motor units; power training; endurance training;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Maffiuletti, NA Univ Bourgogne, Fac Sci Sport, UFR STAPS, Grp Anal Mouvement, BP 27877, F-21078 Dijon, France Univ Bourgogne BP 27877 Dijon France F-21078 ijon, France
Citazione:
N.A. Maffiuletti et al., "Electrical and mechanical H-max-to-M-max ratio in power- and endurance-trained athletes", J APP PHYSL, 90(1), 2001, pp. 3-9

Abstract

The aim of this study was to compare the mechanical and electromyographic (EMG) characteristics of soleus motor units activated during maximal H reflex and direct M response among subjects with different histories of physical activity. Power-trained athletes produced stronger twitches, with a higher rate of twitch tension buildup and relaxation, than their endurance counterparts for both maximal H-reflex and maximal M-wave responses. The maximalH-reflex-to-maximal M-wave ratios for both force output (twitch) and EMG wave amplitude were significantly lower in power-trained than endurance-trained athletes. However, power-trained athletes exhibited a significantly greater twitch-to-EMG ratio for the reflexly activated motor units with respect to the entire motor pool, whereas endurance-trained athletes had comparable twitch-to-EMG ratios for both reflexly and directly activated units. Power training increases the force output of the whole ensemble of the motor units, thereby compensating for the lower efficacy of the reflex transmission between Ia spindle afferent input and soleus alpha -motoneuron. On the other hand, the lower level of force evoked by the reflexly activated units in endurance-trained athletes is associated with a greater motor pool reflexexcitability. Therefore, endurance-trained athletes produce the necessary force by recruitment of more slow-twitch units than do other subjects for comparable levels of force and type of task.

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Documento generato il 04/06/20 alle ore 01:29:30