Lower-extremity kinematics during unanticipated side-cutting including before initial ground contact.

BACKGROUND

The biomechanical reasons why lateral ankle sprains (LAS) are more likely to occur during unanticipated side-cutting (UNA-SC) than under anticipated side-cutting (ANT-SC) are unclear.

RESEARCH QUESTION: Are there differences in lower-extremity kinematics between ANT-SC and UNA-SC that are relevant to LAS incidence?

METHODS

This is a cross-sectional study. Twenty-one male soccer players performed a 45° ANT-SC and UNA-SC. Their ankle, knee, and hip joints and foot segment kinematic data, from 0.2 s before initial ground contact (IC) to toe-off, were analyzed using paired t tests of statistical parametric mapping.

RESULTS

In the frontal plane, faster hip abduction and lateral movement of the foot segment before IC and faster ankle inversion immediately afterwards were characteristic of UNA-SC relative to ANT-SC. In the sagittal plane, smaller and slower ankle dorsiflexion and larger and faster knee and hip flexion after IC were also characteristic of UNA-SC.

SIGNIFICANCE: In the frontal plane, during UNA-SC, IC with increased lateral velocity of the foot segment, accompanied by immediate, rapid hip abduction, resulted in faster ankle inversion and an increased risk of LAS. Kinematic changes in the sagittal plane suggest that compensatory contributions of the hip and knee joints absorb landing impact and protect the ankle joint under UNA-SC.