Abstract
Objectives:
A high prevalence of lower limb injuries has been observed in women’s football with ACL-injuries and thigh injuries on the rise [1, 2]. Injury analyses highlight horizontal movements such as sprinting and change-of-direction manoeuvres as well as stopping and lunging as main risk factors for non-contact ACL injuries. Lack of regular exposure to high-speed football actions during training was found as one of the main modifiable risk factors for hamstring injuries in female soccer [3]. Optimizing plyometric abilities and improving lower limb alignment control should therefore be one of the key objectives of an injury prevention program in women's football. Evidence supports the effectiveness of multicomponent prevention programmes in reducing the incidence of lower limb injuries among female football players [4, 5]. Therefore, Stop X—a neuromuscular training programme developed by the German Knee Society to address key risk factors and enhance muscle groups critical to knee stability—was implemented and evaluated in this study.
Methods:
Female players from a professional team, U20 and U17 squads were included in this study. The Stop X prevention programme was integrated as a part of the warm-up routine during the 2022–2024 seasons and performed five to six times per week for 15–20 minutes at the start of training. Injuries during the seasons were documented by the club's medical staff. Additionally, countermovement jump (CMJ), single leg drop jump (SLDJ), and isokinetic strength tests were conducted pre- and inseason to assess potential improvements of injury risk factors.
Results:
A total of 147 players participated in the 2022/23 and 2023/24 season: 58 players (39%) from the U17 team, 34 (24%) from the U20 team, and 55 (37%) professionals. In-season CMJ and SLDJ tests revealed significantly improved jump performances across all teams compared to preseason tests with a significant improvement in SLDJ height and reactive strength index (RSI), especially in young-elite players. The U20 team significantly improved peak-propulsive force of the non-dominant leg (p = 0.04). The functional H/Q ratio stagnated at a high level or slightly deteriorated from pre- to in-season analyses. Players who sustained an ACL injury showed a non-significant trend toward increased knee valgus during preseason jump testing. In isokinetic testing, injured players had a significantly lower in-season HQ ratio in the dominant leg than uninjured players (0.54 vs. 0.59, p = 0.03).
Conclusion:
The Stop X prevention programme increases the jumping performance and propulsive forces in female soccer players, thereby enabling female players to develop strategies for injury prevention. A larger sample size is needed to evaluate the programme’s effect on actual injury risk reduction. Additionally, targeted hamstring strengthening should be emphasized to address observed declines in the HQ ratio.