Changes in the relationship between joint angle and torque production associated with the repeated bout effect
Deutscher übersetzter Titel: | Veränderungen des Verhältnisses zwischen Gelenkwinkel und Drehmomentproduktion verbunden mit dem wiederholten Belastungseffekt |
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Autor: | McHugh, Malachy P.; Tetro, Danielle T. |
Erschienen in: | Journal of sports sciences |
Veröffentlicht: | 21 (2003), 11, S. 927-932, Lit. |
Format: | Literatur (SPOLIT) |
Publikationstyp: | Zeitschriftenartikel |
Medienart: | Gedruckte Ressource |
Sprache: | Englisch |
ISSN: | 0264-0414, 1466-447X |
DOI: | 10.1080/0264041031000140400 |
Schlagworte: | |
Online Zugang: | |
Erfassungsnummer: | PU201001001154 |
Quelle: | BISp |
Abstract
A single bout of eccentric exercise induces a protective adaptation against damage from a repeated bout. The aim of this study was to determine whether this repeated bout effect is due to a change in the length–tension relationship. Twelve individuals performed an initial bout of six sets of 10 eccentric quadriceps contractions and then performed a repeated bout 2 weeks later. Eccentric contractions were performed on an isokinetic dynamometer at 1.04 rad/s with a target intensity of 90% of isometric strength at 70° of knee flexion. Isometric strength and pain were recorded before and after both eccentric bouts and on each of the next 3 days. Isometric strength was tested at 30°, 50°, 70°, 90° and 110° of knee flexion. On the days following the initial bout, there was a significant loss of isometric strength at all knee flexion angles except 110° (bout×angle: P <0.01). On day 2, strength averaged 86% of baseline for 30–90° and 102% of baseline for 110°. Strength loss and pain after the initial bout was contrasted by minimal changes after the repeated bout (pain: P <0.001; strength: P <0.01). The repeated bout effect was associated with a rightward shift in the length–tension curve; before the repeated bout, isometric strength was 6.8% lower at 30° and 13.6% higher at 110° compared with values before the initial bout (bout×angle: P <0.05). Assuming that torque production at 110° occurs on the descending limb of the length–tension curve, the increase in torque at 110° may be explained by a longitudinal addition of sarcomeres. The addition of sarcomeres would limit sarcomere strain for subsequent eccentric contractions and may explain the repeated bout effect observed here. Verf.-Referat