Article Text
Abstract
Background Anterior cruciate ligament (ACL) injuries pose serious short and long term consequences for athletes in team sports worldwide. Modifying technique is an important part of effective prevention programs, but the understanding of which technique that reduces potentially harmful joint loadings is limited. Prevention can likely be improved with better knowledge of technique effects.
Objective Study the effect of sidestep cutting technique on knee valgus moments.
Design Cross-sectional.
Setting Three sidestep cutting manoeuvres to each side in a 240 Hz motion analysis lab.
Participants 131 female elite handball back and wing players (22.4±4.0 years, 173±6 cm, 69±7 kg). Two excluded due to technical problems.
Assessment of risk factor Initial contact (IC) knee flexion, knee valgus, hip abduction, ankle pronation, torso lateral flexion, torso rotation, speed of torso rotation, inward rotation of foot relative to direction of motion and lateral distance from centre of mass of the body to the centre of pressure of the foot, as well as length of contact phase, cutting angle and approach speed.
Main outcome Maximum knee valgus moment during first 50 ms of contact phase.
Results Average maximum valgus moment was 1.54 ± 0.64 Nm/kg. Six variables had a pronounced effect in the linear regression model. An increase of knee valgus angle at IC of one SD gave a 0.20 Nm/kg (13%) increase in maximum valgus moment. Corresponding effect sizes was 0.14 Nm/kg (9%) for hip abduction, 0.22 Nm/kg (14%) for ankle pronation, 0.12 Nm/kg (8%) for cut width, 0.16 Nm/kg (10%) for cutting angle and 0.21 Nm/kg (14%) for approach speed.
Conclusion We have identified potentially harmful sidestep cutting technique components. ACL injury prevention programs should continue to focus on cutting techniques with small knee valgus angles, low ankle pronation and narrow stance, particularly for cuts that are performed with high approach speed and sharp direction changes.