Electrical and mechanical Hmax-to-Mmax ratio in power- and endurance-trained athletes
1 Groupe Analyse du Mouvement, Unité de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives, and 2 Groupe d'Etudes et de la Recherche sur le Handicap, Centre de Convalescence et de Rééducation, Université de Bourgogne, 21078 Dijon Cedex, France; and 3 Ist...
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Published in | Journal of applied physiology (1985) Vol. 90; no. 1; pp. 3 - 9 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
Am Physiological Soc
01.01.2001
American Physiological Society |
Subjects | |
Online Access | Get full text |
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Summary: | 1 Groupe Analyse du Mouvement, Unité de Formation et
de Recherche en Sciences et Techniques des Activités
Physiques et Sportives, and 2 Groupe d'Etudes et de la
Recherche sur le Handicap, Centre de Convalescence et de
Rééducation, Université de Bourgogne, 21078 Dijon
Cedex, France; and 3 Istituto di Fisiologia Umana,
Università degli Studi di Pavia and Fondazione Salvatore
Maugeri, I-27100 Pavia, Italy
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 maximal H-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
-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 reflex excitability. 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.
soleus muscle; maximal H-reflex-to-maximal M-wave ratio; maximal
H-reflex and maximal M-wave twitch; motor units; power training; endurance training |
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ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/jappl.2001.90.1.3 |