Isokinetic tests are commonly used in laboratory settings to measure trunk muscular strength and endurance, as they are considered important for both athletic performance and health care (Ho et al., 2005; Mayer et al., 1995). The aim of this study was to analyze the reliability of a new flexion-extension isokinetic trunk test to measure trunk muscular strength and endurance, and to examine the effect of repetition on the measurements. Methods: Forty physically active volunteers (28 men and 12 women) participated in this study. The isokinetic test (Biodex•) consisted in performing 4 trials of 15 maximal flexion-extension exertions at 120º/s (range of motion =50º). In order to assess the repetition effect on the measurements, the test was performed 4 times, with 7 days between sessions. Peak torque (PT) and total work (TW), and their decrease over trials, were used to assess trunk muscular strength and endurance, respectively. Results: Extension and flexion PT and TW showed high ICC and low SEM values between trials (PT: 0.87 < ICC < 0.96, 4% < SEM < 8%; TW: 0.73 < IC < 0.98, 4% < SEM < 16%) and sessions (PT: 0.81 < ICC < 0.96, 5% < SEM < 11%; TW: 0.81 ? ICC < 0.95, 7% < SEM < 16%). ANOVA for extension PT didn`t show significant differences between trials. On the other hand, the maximal extension TW was found in the first or second trial in all sessions. After the second trial, the extension TW decreased due to fatigue, although differences between the third and fourth trials were not statistically significant for session 1 and 4. Overall, the maximal flexion TW and PT were found in the first trial. Afterward, Flexion TW and PT decreased progressively from trial 1 to 4. ANOVA for extension and flexion PT and TW didn`t show significant diferences between sessions, with the exception of the comparison between sessions 1 and 2 for the first two trials of flexion TW. Discussion: These results showed good absolute (SEM) and relative (ICC) isokinetic test reliability. In addition, there was no repetition effect due to learning, training and/or fatigue across sessions for most measures. Therefore, one recording session could be enough to evaluate trunk muscular strength and endurance. In order to achieve the maximal PT and TW, at least 2 trials of the isokinetic test are required. The decreases of PT and TW seem useful parameters to analyze trunk flexion endurance. However, only the decrease of TW seems suitable to assess trunk extension endurance. In general, 3 trials of the isokinetic test are needed to obtain reliable measures of trunk endurance.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.