Short-term slackline training improves task-specific but not general balance in female handball players

Slackline training has been shown to improve balance and neuromuscular performance. However, recent studies suggested that balance is task-specific, implying that transferability of balance skills is limited and might depend on the similarity of the tasks. This study therefore investigated if short-term slackline training could improve performance in balance tasks that are either more or less similar to the trained slackline task. Furthermore, we assessed potential transfer effects to other neuromuscular performance tests. 25 female handball players (23.7 ± 3.9 years) participated in our study and were matched to either a slackline training (SLT; n = 14) or a control group (CON; n = 11). The intervention comprised 12 sessions with overall 120 minutes of slackline training using single and double slacklines. Slackline standing time and measures of dynamic and static balance were assessed before and after the intervention, as well as power and sprint-related performance parameters. Two-way repeated-measures ANOVA found a significant group × time interaction for slackline standing time, indicating larger training effects for SLT. For the remaining dynamic and static balance tests, no significant interactions were found. With regard to neuromuscular performance, there was a significant group × time interaction only in change of direction. In essence, the study showed that slackline training induced task-specific balance improvements without affecting general balance. This adds further evidence to the task-specificity principle of balance, although the specificity of the sample as well as the briefness of the intervention should be taken into account when generalizing our findings. Nonetheless, this study contains practical implications for team sports interventions and future balance training studies, highlighting the importance of selecting appropriate balance exercises to yield rapid and the desired training outcomes.