Levels of Agreement for the Direction of Inter-Limb Asymmetry during Four Simple Change-of-Direction Tests in Young Male Handball Players: A Pilot Study

The purpose of this pilot study was to investigate the effects of change-of-direction (CoD) angle (90 degrees vs. 180 degrees) and the inclusion of acceleration approach on total task time, CoD deficit, and agreement regarding inter-limb asymmetry direction across CoD tasks. The sample included 13 young male handball players (age: 22.4 +/- 3.2 years). The CoD tasks were performed over a 10 m distance with 90 degrees and 180 degrees turns. Both CoD tasks were performed under two conditions: (1) from the standing start and, (2) with a 10 m prior acceleration approach. Linear sprint times over a 10 m distance were also recorded for the purpose of determining the CoD deficit. The differences between the outcomes of different test variants were assessed with pairwise t-tests and associated Cohen's d effect size. The agreement in terms of inter-limb asymmetry direction was assessed descriptively, using percentage of agreement. Results showed that the inclusion of the 10 m approach reduced the total task time (mean differences ranging between 0.26 and 0.35 s; d = 2.27-4.02; p < 0.002). The differences between 90 degrees and 180 degrees turn times were statistically significant under both conditions: (a) without approach (0.44-0.48 s; d = 4.72-4.84; all p < 0.001), and (b) with approach (0.50-0.54 s; d = 4.41-5.03; p < 0.001). The agreement regarding inter-limb asymmetry direction among the tasks was 30.7-61.5%. The differences between the tasks could be explained by the angle-velocity trade-off. The results of this study imply that the CoD tasks should not be used interchangeably when assessing inter-limb asymmetries.