The reliable examination of isokinetic parameters in young athletes is important for the establishment of appropriate strength testing protocols. The purpose of this study was to examine the reliability of peak moments, non-preferred/preferred leg and reciprocal ratios during isokinetic knee efforts in young soccer players. Thirteen circumpubertal (age = 13.0 ± 0.4 years) soccer players performed maximum knee extension and flexion efforts at 30, 120 and 180°·s1 in two occasions, a week apart. The reliability of the peak moments was high, with reliability coefficients ranging from 0.71 to 0.98. The non-preferred/preferred leg and reciprocal ratios demonstrated moderate to high reliability (coefficients ranged from 0.42 to 0.87). The reliable examination of moments of force and ratio measurements during eccentric tests and at fast angular velocities in young soccer players requires extensive familiarization of the subjects prior to the main test.
Eleftherios Kellis, Spiros Kellis, Vasilios Gerodimos and Vasiliki Manou
Theophanis Siatras, Georgios Papadopoulos, Dimitra Mameletzi, Vasilios Gerodimos and Spiros Kellis
Although warm-up and stretching exercises are routinely performed by gymnasts, it is suggested that stretching immediately prior to an activity might affect negatively the athletic performance. The focus of this investigation was on the acute effect of a protocol, including warm-up and static and dynamic stretching exercises, on speed during vaulting in gymnastics. Eleven boys were asked to perform three different protocols consisting of warm-up, warm-up and static stretching and warm-up and dynamic stretching, on three nonconsecutive days. Each protocol was followed by a “handspring” vault. One-way analysis of variance for repeated-measures showed a significant difference in gymnasts’ speed, following the different protocols. Tukey’s post hoc analysis revealed that gymnasts mean speed during the run of vault was significantly decreased after the application of the static stretching protocol. The findings of the present study indicate the inhibitory role of an acute static stretching in running speed in young gymnasts.
Panagiotis Ioakimidis, Vasilios Gerodimos, Eleftherios Kellis and Spiros Kellis
Fifteen young basketball players (aged 14.4 – 0.5 yrs) underwent two identical testing sessions spaced one week apart, to determine the reliability of maximum isometric force and force-time parameters during a maximal bilateral isometric leg press effort. The maximal isometric force (MIF), the ratio of maximal force to time (T MIF) to attain maximal force (ARMIF), starting strength (F 50), and on a relative scale the time taken to increase the force from 10% to 30%, 60%, and 90% of maximal force were calculated. High intraclass correlation coefficients (ICC) were found for MIF (0.96), ARMIF (0.85), and F50 (0.90). On the relative scale, the ICCs for the times to produce 30%, 60%, and 90% of maximum force were 0.94, 0.95, 0.95, respectively. The present results indicate that maximum isometric force and the force-time parameters during a bilateral leg press can be measured reliably in pubertal basketball players.