Abstract
Anterior cruciate ligament (ACL) ruptures are among the most severe injuries in football, with
female athletes facing a disproportionately high risk due to anatomical, hormonal, and
biomechanical differences (Mancino et al., 2024). A significant proportion of these injuries
occur during non-contact defensive scenarios, particularly side-step cutting movements
(Kaneko et al., 2016). While injury prevention programs exist, their effectiveness remains
limited (Weitz et al., 2020), highlighting the need for more targeted and innovative approaches.
Virtual reality (VR) has emerged as a promising tool in sports training and rehabilitation,
offering immersive, controlled environments for movement practice (Li et al., 2025). However,
before VR-based interventions can be confidently implemented, it is essential to establish
whether movement patterns performed within a virtual environment are comparable to those
in real-world conditions.
This study investigates whether lower-limb kinematics during a football-specific side-step
cutting task differ between a virtual reality environment and a real-world setting in female
football players. A VR scenario was developed in the Unity game engine to simulate a scenario
in which a virtual character approaches the athlete and he has to perform a side-step cut to
block them.
70 female athletes without prior ACL injury history from various recreational football levels will
perform 15 trials of this scenario in both the real-world and VR setting. Sample size was
determined by an a prior power analysis for a repeated-measures comparison (α = .05, power
= .80, medium effect size d = 0.4–0.5), yielding a minimum of ~60 completers, inflated to 70 to
account for an anticipated 15% dropout rate, while also generating approximately 1,000
biomechanical data samples sufficient for machine learning analyses in future studies. During
the tasks in the VR athletes wear a head-mounted display and consumer grade VR trackers
to capture the motion of the lower limbs and to display the athlete’s motions in the VR
environment. Additionally, motion capture data will be recorded simultaneously using multiple
cameras and analyzed with the post-processing software Theia3D, serving as the gold-
standard reference for kinematic variables known to be associated with ACL injury risk,
including knee and hip joint angles. Following the VR session participants will complete the
Igroup Presence Questionnaire to evaluate their subjective experience of immersion, usability,
and fatigue.
The primary aim of this study is to determine the ecological validity of the VR scenario by
identifying potential differences in biomechanical movement patterns between real-world and
VR conditions like approach velocity, ground contact time, movement onset / reaction time and
the step width at initial contact. Proofing the equivalence is a critical prerequisite for the
subsequent studies in further projects, which will use VR as a platform for individualized motor
learning interventions targeting ACL injury prevention. If movement patterns in VR closely
mirror those observed in real-world settings, this would provide a strong foundation for using
immersive virtual environments as a safe, scalable, and ecologically valid training and
assessment tool for female football players at risk of ACL injury.
References
Kaneko, S., Sasaki, S., Hirose, N., Nagano, Y., Fukano, M., & Fukubayashi, T. (2016).
Mechanism of Anterior Cruciate Ligament Injury in Female Soccer Players (Research
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https://doi.org/10.5812/asjsm.38205
Li, Y., Peng, J., Cao, J., Ou, Y., Wu, J., Ma, W., Qian, F., & Li, X. (2025). Effectiveness of
virtual reality technology in rehabilitation after anterior cruciate ligament
reconstruction: A systematic review and meta-analysis. PLOS ONE, 20(3), e0314766.
https://doi.org/10.1371/journal.pone.0314766
Mancino, F., Kayani, B., Gabr, A., Fontalis, A., Plastow, R., & Haddad, F. S. (2024). Anterior
cruciate ligament injuries in female athletes: Risk factors and strategies for
prevention. Bone & Joint Open, 5(2), 94–100. https://doi.org/10.1302/2633-
1462.52.BJO-2023-0166
Weitz, F. K., Sillanpää, P. J., & Mattila, V. M. (2020). The incidence of paediatric ACL injury
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