Lower extremity joint angle, moment, and coordination throughout a double limb drop vertical jump in individuals with anterior cruciate ligament reconstruction.

Individuals with anterior cruciate ligament reconstruction (ACLR) utilise different landing biomechanics between limbs, but previous analyses have not considered the continuous or simultaneous joint motion that occurs during landing and propulsion. The purpose of this study was to compare sagittal plane ankle/knee and knee/hip coordination patterns as well as ankle, knee, and hip angles and moments and vertical ground reaction force (vGRF) between the ACLR and uninjured limbs during landing and propulsion. Fifteen females and thirteen males performed a drop vertical jump from a 30 cm box placed half their height from force platforms. Coordination was compared using a modified vector coding technique and binning analysis. Kinematics and kinetics were time normalised for waveform analyses. Coordination was not different between limbs. The ACLR limb had smaller dorsiflexion angles from 11 to 16% of landing and 24 to 75% of landing and propulsion, knee flexion moments from 5 to 15% of landing, 20 to 31% of landing, and 35 to 91% of landing and propulsion, and vGRF from 92 to 94% of propulsion compared with the uninjured limb. The ACLR limb exhibited smaller dorsiflexion angles to potentially reduce the knee joint moment arm and mitigate the eccentric and concentric demands on the ACLR knee during landing and propulsion, respectively.

Lower extremity and trunk sagittal plane coordination strategies and kinetic distribution during landing in males and females.

Force attenuation during landing requires coordinated motion of the ankle, knee, hip, and trunk, and strategies may differ between sexes. Sagittal plane coordination of the ankle/knee, knee/hip, and knee/trunk, and lower extremity and trunk kinematics and kinetics was compared throughout landing between 28 males and 28 females. Coordination was assessed with a modified vector coding technique and binning analysis. Total support moments (TSM), each joint's percent contribution, and timing of the TSM were compared. Females landed with less isolated knee flexion in the ankle/knee, knee/hip, and knee/trunk couplings, but more simultaneous ankle/knee flexion, less simultaneous knee flexion/hip extension, and more simultaneous trunk/knee flexion. Females landed with larger plantarflexion angles from 0-16% and smaller trunk flexion angles from 0-78%. In females, absolute TSM were larger from 0-6% and smaller from 42-100%, and normalized TSM were larger from 0-8% and 26-42%. Females had greater ankle contribution to the TSM from 14-15% and 29-35%, smaller absolute peak TSM, and the peak TSM occurred earlier. Females compensated for less isolated knee flexion with greater simultaneous ankle/knee flexion early in landing and knee/trunk flexion later in landing. Coordination and TSM differences may influence force attenuation strategies and have implications for knee injury disparity between sexes.

Lower extremity coordination strategies to mitigate dynamic knee valgus during landing in males and females.

Frontal and sagittal plane landing biomechanics differ between sexes but reported values don't account for simultaneous segment or joint motion necessary for a coordinated landing. Frontal and sagittal plane coordination patterns, angles, and moments were compared between 28 males and 28 females throughout the landing phase of a drop vertical jump. Females landed with less isolated thigh abduction (p = 0.018), more in-phase motion (p < 0.001), and more isolated shank adduction (p = 0.028) between the thigh and shank in the frontal plane compared with males. Females landed with less in-phase (p = 0.012) and more anti-phase motion (p = 0.019) between the thigh and shank in the sagittal plane compared with males. Females landed with less isolated knee flexion (p = 0.001) and more anti-phase motion (p < 0.001) between the sagittal and frontal plane knee coupling compared with males. Waveform and discrete metric analyses revealed females land with less thigh abduction from 20 % to 100 % and more shank abduction from 0 to 100 % of landing, smaller knee adduction at initial contact (p = 0.002), greater peak knee abduction angles (p = 0.015), smaller knee flexion angles at initial contact (p = 0.035) and peak (p = 0.034), greater peak knee abduction moments (p = 0.024), greater knee abduction angles from 0 to 13 % and 19 to 30 %, greater knee abduction moments from 19 to 25 %, and smaller knee flexion moments from 3 to 5 % of landing compared with males. Females utilize greater frontal plane motion compared with males, which may be due to different inter-segmental joint coordination and smaller sagittal plane angles. Larger knee abduction angles and greater knee adduction motion in females are due to aberrant shank abduction rather than thigh adduction.