Academic journal article Journal of Physical Education and Sport

Effect of Maximum Voluntary Isometric Contraction of Antagonist Muscles in Rate of Torque Development of Agonist Muscles

Academic journal article Journal of Physical Education and Sport

Effect of Maximum Voluntary Isometric Contraction of Antagonist Muscles in Rate of Torque Development of Agonist Muscles

Article excerpt

Introduction

The Rate of Torque Development (RTD) shows the change of torque in time, from the onset of torque to the time of appearance the maximum isometric torque. It is influenced both by neuronal and muscle factors as well (Andersen & Aagaard, 2006). However, it has been proposed (Grabiner, 1994) that RTD of agonist muscles is enhanced when a maximal contraction of the antagonist muscles is preceded, based on the phenomenon of the "reversal of antagonist muscles" (REV).

The idea of REV was introduced by Kabat (1950) and it was based on Sherrington's concept (1947) that elementary reflexes interact to trigger a more complex process to coordinate agonist and antagonist action. For this reason, REV was based on Golgi tendon organs (GTOs) function, which as previously has been reported (Carew, 1982), when a muscle is contracted inhibits the function of agonist muscle and facilitates the antagonist, through Ib afferent fibers.

The maximal inhibition from GTOs occurs between 1s after contraction (Moore & Kukulka, 1991; Garceau, Fauth, Hanson, Hsu, Yoon, Szalkowski, Lutsch & Ebben, 2010). That's why the duration of the antagonist contraction acting for the potentiation of agonist muscle in REV occurrence should last more than 1 s (Kamimura & Takenaka, 2007). The exact nature of this mechanism has not experimentally been identified thaw several neuronal or muscular mechanisms have been proposed (Roy, Sylvestre, Katch F.I., Katch V.L. & Lagassé, 1990).

Regarding the effect of REV on muscle performance two cases have been studied: the peak torque and the RTD. Initially the REV effect was tested in hemiparetic subjects were peak torque enhancement was observed (Bohannon, 1985). However, it was not the case for healthy people were conflicting results have been reported because in other cases enhancement was reported (Roy et al., 1990; Kamimura, Yoshioka, Ito, & Kusakabe, 2009; Kamimura et al., 2007) while in others not (Bohannon, Gibson & Larkin, 1986; Gabriel, Basford, & An., 2001; Grabiner, 1994).

The above mentioned studies did not measure the effect of the antagonist reversal on the phases of RTD so it is not known yet which part is affected more. So the primary aim of this study was to re-examine the effect of maximum voluntary isometric contraction of antagonist muscles on the rate of torque development of agonist muscles in the ankle joint. Secondary aim was to reveal in which time phases of RTD possible changes were observed.

Material and method

Participants

The sample consisted of 15 healthy women, who were students of the Department of Physical Education and Sport Science. They were aged from 19 to 26 years old (mean ± SD: 22.03 ± 1.78 years), body mass from 59 to 70.5 kg (mean ± SD: 62.89 ± 5.01 kg) and height from 153 to 174 cm (mean ± SD: 165.27 ± 6.03 cm). All participants were familiar with the testing protocol and they gave their written consent, having been informed of the process. The experimental process was complied with the Ethics standards provided by the Aristotle University of Thessaloniki.

Instrumentation

Dynamometry: The isokinetic dynamometer CYBEX Norm (Lumex Corporation, Ronkohoma, NY), according to manufacturing instructions regarding the alignment of the specific platform that has the dynamometer for the measurement of the ankle joint.

Experimental Protocol

The experimental protocol was consisted of two stages. Participants in the first stage performed 3 maximum isometric contractions of the plantar flexors for 2 s, 1 minute rest period and 3 maximum isometric contractions of the dorsiflexors for 2 s with 1 minute rest period between them. They rested for 10 minutes offthe machine and they performed the second stage of the protocol.

Participants in second stage performed 5 maximal plantar flexion isometric contractions for 2 s and 1 minute rest (phase1). Then they performed a maximal dorsiflexion isometric contraction for 2 s and immediately after it, a maximal plantar flexion for 2 s (phase2). …

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