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Titolo:
Is the VO2 slow component dependent on progressive recruitment of fast-twitch fibers in trained runners?
Autore:
Borrani, F; Candau, R; Millet, GY; Perrey, S; Fuchslocher, J; Rouillon, JD;
Indirizzi:
Univ Montpellier 1, Fac Sci Sport, Lab Sport Performance & Sante, UPRES EASport Performance Sante, F-34090 Montpellier, France Univ Montpellier 1 Montpellier France F-34090 -34090 Montpellier, France Lab Sci Sport, Unite Format & Rech Sci & Tech Act Phys & Sport, F-25000 Besancon, France Lab Sci Sport Besancon France F-25000 & Sport, F-25000 Besancon, France Univ Bourgogne, Grp Anal Mouvement, UFR STAPS, F-21000 Dijon, France Univ Bourgogne Dijon France F-21000 nt, UFR STAPS, F-21000 Dijon, France Fac Sci Sociale & Polit, Inst Sci Sport & Educ Phys, CH-1015 Lausanne, Switzerland Fac Sci Sociale & Polit Lausanne Switzerland CH-1015 usanne, Switzerland
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 6, volume: 90, anno: 2001,
pagine: 2212 - 2220
SICI:
8750-7587(200106)90:6<2212:ITVSCD>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
OXYGEN-UPTAKE KINETICS; QUADRICEPS-FEMORIS MUSCLE; HIGH-INTENSITY EXERCISE; GAS-EXCHANGE KINETICS; O-2 UPTAKE KINETICS; EMG POWER SPECTRUM; HEAVY EXERCISE; MOTOR UNITS; GLYCOGEN DEPLETION; ENERGY-COST;
Keywords:
VO2 kinetics; mean power frequency; electromyogram; power spectrum; O-2 uptake;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
66
Recensione:
Indirizzi per estratti:
Indirizzo: Borrani, F Univ Montpellier 1, Fac Sci Sport, Lab Sport Performance & Sante, UPRES EASport Performance Sante, 700 Ave Pic St Loup, F-34090 Montpellier, France Univ Montpellier 1 700 Ave Pic St Loup Montpellier France F-34090
Citazione:
F. Borrani et al., "Is the VO2 slow component dependent on progressive recruitment of fast-twitch fibers in trained runners?", J APP PHYSL, 90(6), 2001, pp. 2212-2220

Abstract

The goal of this study was to use spectral analysis of EMG data to test the hypothesis that the O-2 uptake ((V) over dot O-2) slow component is due to a recruitment of fast fibers. Thirteen runners carried out a treadmill test with a constant speed, corresponding to 95% of the velocity associated with maximal (V) over dot O-2. The (V) over dot O-2 response was fit with the classical model including three exponential functions. Electrical activity of six lower limb muscles (vastus lateralis, soleus, and gastrocnemius ofboth sides) was measured using electromyogram surface electrodes. Mean power frequency (MPF) was used to study the kinetics of the electromyogram discharge frequency. Three main results were observed: 1) a common pattern of the MPF kinetics in the six muscles studied was noted; 2) MPF decreased in the first part of the exercise, followed by an increase for all the musclesstudied, but only the vastus lateralis, and gastrocnemius muscles of both sides increased significantly (P < 0.05); and 3) the beginning of the MPF increase of the four muscles mentioned above corresponded with the beginningof the slow component. Our results suggest a progression in the average frequency of the motor unit discharge toward the high frequencies, which coheres with the hypothesis of the progressive recruitment of fast-twitch fibers during the (V) over dot O-2 slow component. However, this interpretation must be taken with caution because MPF is the result of a balance between several phenomena.

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Documento generato il 21/09/20 alle ore 16:17:55