title: Influence of the intensity of a conditioning contraction on the subsequent twitch torque and maximal voluntary concentric torque.
abstract: This study aimed to clarify the influence of the intensity of a conditioning contraction on subsequent isometric twitch and maximal voluntary concentric torques. Subjects (n=12men) performed voluntary isometric plantar flexion for six seconds as a conditioning contraction, at intensities of 40%, 60%, 80% and 100% of a maximal voluntary isometric contraction (MVIC). Before and immediately after the conditioning contraction, isometric twitch and maximal voluntary concentric (180°/s) plantar flexion torques were determined. Surface electromyograms were recorded from the triceps surae muscles and M-wave amplitudes and root-mean-square values of the electromyographic signals (RMS(EMG)) were calculated. The isometric twitch torque increased significantly after conditioning contraction at all intensities (P<0.05), whereas maximal voluntary concentric torque increased significantly only at 80% and 100% MVIC conditions (P<0.05). It is concluded that during a six second conditioning contraction, the effect of the intensity of a conditioning contraction on subsequent torque development is different between an isometric twitch and maximal voluntary concentric contractions, with the latter being less affected.
authors.affiliation: Graduate School of Sport Sciences, Waseda University, Mikajima, Tokorozawa, Saitama, Japan.
authors.forename: Atsuki
authors.initials: A
authors.lastname: Fukutani
authors.forename: Naokazu
authors.initials: N
authors.lastname: Miyamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanehisa
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Yanai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawakami
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D019415:Torque; D014836:Volition / Q000502:physiology*; D055815:Young Adult