Knee and trunk biomechanics during a single leg drop vertical jump. The effects of horizontal distance, sex, and limb dominance.

BACKGROUND

The drop vertical jump (DVJ) is used to identify biomechanical risk factors associated with non-contact anterior cruciate ligament (ACL) injuries, which often occur during eccentric loading. However, the influence of the horizontal jump distance, sex, and limb laterality on lower extremity and trunk biomechanics remains unclear.

METHODS

This cross-sectional study recruited 132 adolescents (83 males, 49 females, 15.0 ± 1.6 y) from a school strength and conditioning program. Athletes jumped from a 0.30 m box at two distances (0.15 m and 0.45 m). Kinematic and kinetic data were collected using markerless motion capture and force plates. Statistical Parametric Mapping analyzed the effects of sex, leg, and jump distance on lower extremity and trunk biomechanics during the eccentric phase landing.

FINDINGS: Greater horizontal distance increased frontal plane knee moments, with males and the non-dominant limb exhibiting greater moments. Females showed less sagittal plane trunk flexion than males. Greater horizontal jump distance led to an increase in frontal trunk lean over the ipsilateral limb.

INTERPRETATION: Horizontal distance, leg dominance, and sex are important factors in landing mechanics of DVJ. The increased frontal plane knee abduction moments (KAM), and ipsilateral trunk lean associated with longer distances, along with the asymmetries observed between legs indicate that increasing horizontal jump distance can magnify high-risk biomechanical patterns, which could make DVJ protocols more sensitive to identifying at-risk athletes. This information could make screening tools, such as single-leg DVJs with longer horizontal components, more sensitive to exposing deficits and could also be used to guide targeted neuromuscular training interventions.