Sprint and jump performance responses to curvilinear sprint training with and without a weighted vest in youth female soccer players

Objectives: Evidence on the effects of curvilinear sprint (CS) training in female soccer players is limited. This study examined the effects of adding a weighted vest during CS training on sprint and vertical jump performance in youth female soccer players. Methods: Sixteen players were randomly assigned to a CS training group (CON; n = 8) or a weighted vest CS training group using 10% body mass (WV; n = 8) for six weeks (one session per week). Pre- and post-intervention testing included a 30-m linear sprint (LS), CS performed to the left and right sides, squat jump (SJ), and countermovement jump (CMJ). Peak sprinting speed (S _peak ) measured via Global Navigation Satellite System during LS, weaker-side, and stronger-side CS, as well as jump height, were analysed as primary outcomes. Curvilinear sprint asymmetry (CS _ASY ) was calculated as a secondary outcome. Results: Paired-samples t-tests showed significant improvements in weaker-side CS for CON (+3.5%) and WV (+5.3%), accompanied by significant reductions in CS _ASY . Significant decreases in SJ and CMJ height were observed only in the CON group (−7.6 and −7.7%, respectively). The ANCOVA revealed greater post-intervention S _peak in stronger-side and weaker-side CS for the WV group. Conclusion: Curvilinear sprint training improved weaker-side CS performance in youth female soccer players, whereas training with a weighted vest additionally mitigated declines in jumping performance. Curvilinear sprint training with or without a weighted vest may enhance direction-specific sprint speed in youth female soccer players.