Many non-contact anterior cruciate ligament (ACL) injuries in rugby players occur during sidestep cutting. Females unfortunately have a non-contact ACL injury rate 2–8 times higher than their male
counterparts. However, the exact mechanisms of how prolonged activity increases the risk for ACL injuries are not clear. Firstly, The objective of this study was to identify the stance phase of a
sidestep cutting maneuver that place rugby players at a greater risk for ACL injuries. Secondly, we try to find the difference between male players and female players during the stance phase of an
unanticipated side-cut maneuve.
Three-dimensional motion analysis was performed using a marker-based, 11-camera digital motion capturing system (250 Hz; Qualisys, Gothenburg, Sweden). Ground reaction force data were obtained using a
force platform (1500 Hz; AMTI, Newton, MA, USA) embedded into the floor. Bipolar superficiall EMG sensors (Blue Sensor; MEDICOTEST, Olstykke, Denmark) were placed over the muscles.
Fifteen healthy Chinese national female rugby athletes and ten healthy male athletes were asked to perform an unanticipated side-cut maneuver; the hip , knee flexion and valgus angles ,GRF as well as
the electromyographic activity of the vastus lateral, vastus medial, biceps femoris, and semimembranosus muscles of the dominant leg were analyzed during the maneuver. A kinematic and inverse dynamic
model was used to calculate the three-dimensional hip, knee postures .
The mean knee valgus angle peak , hip abduction and internal tended to be greater for females than males(P<0.05). Moreover, the ratio of hamstring to quadricepsmuscle activation for female players was
significantly lower than that for male players(P<0.05). Females demonstrated greater lateral and medial gastrocnemii activity for the early stance phases of the side-cut(P<0.05). A rectus femoris
activation difference was identified with females having an earlier and more rapid rise in muscle activity during the stance phase(P<0.05). The differences suggest that the activation patterns
observed in females might not be providing adequate joint protection and stability, thereby possibly having a contributing role towards increased non-contact ACL injuries in females.
Female rugby athletes have a higher risk for ACL injury during the stop phase. Moreover, these data further suggest that the hip may play a different role during cutting to smaller and larger angles
and also illustrate a pattern of engagement in the sagittal and frontal planes that has not been described previously.