| Introduction. Neuromuscular control of the lower extremity has been proposed to be the primary contributor to the significantly increased risk for ACL injury exhibited by females. Multiple prevention programs have been suggested in the literature with varying effects. Interestingly, those prevention programs that appear to significantly decrease the risk of ACL injury employ technical instruction on landing from rotational jumps. However there exists a significant knowledge gap in the literature with respect to the rotational jump landing, a maneuver that occurs often in high risk sports. As an extension of this, there also exists a lack of research on the effects of temporal and spatial uncertainty on lower extremity positioning during a rotational jump-unanticipated cutting maneuver. Purpose. Thus the purpose of this study was to quantify the kinematics and kinetics of the knee during a rotational jump landing unanticipated cutting maneuver (RJLUC), with specific application to gaining insight into the ACL injury risk paradigm. Subjects. Twenty females (age: 21.3 +/- 0.733 y.o., ht.: 65.63 +/- 3.07 in., wt.: 144.2 +/- 19.81 lbs.) and nineteen males (age: 21.37 +/- 2.06 y.o., ht.: 70.96 +/- 3.39 in., wt.: 177.32 +/- 33.08 lbs.) with an age range of 18-25 were recruited from The University of Toledo and Toledo community. All participants reported a minimum of three years of playing experience in basketball, volleyball, or soccer. Methods. A 23 marker dynamic marker set was used with 8 Eagle cameras sampled at 120 Hz and processed with a low pass Butterworth cutoff filter of 6 Hz. Two AMTI force plates, sampled at 1200 Hz, captured the ground reaction force data. A VertecRTM was used to measure the subjects maximum rotational jump height. Subjects completed 12 RJLUC trials at 50% of their maximum rotational jump height during which video and force data were collected. Subjects rotated approximately 135° during the jump and upon reaching the vertical jump marker a personal computer program provided visual stimuli for the direction of cut. Peak knee flexion, genu valgum, vertical GRF, and proximal anterior tibial shear force at the knee were calculated for the landing phase of the RJLUC. Kinematic data were also calculated during the preparatory phase and at the initial contact during landing. Statistical Analysis. A one way MANOVA was run, as well as an intraclass reliability analysis, in SPSS v.15.0. Results. Females demonstrated significantly less knee flexion during the preparatory phase, F(1,37) = 9.77, p = 0.003 (Mean:-0.34° +/- 4.38 vs. -6° +/- 6.73), initial contact, F(1,37) = 18.44, p = 0.000 (Mean : -3.18° +/- 4.14 vs. -11.05° +/- 7.01), and peak knee flexion, F(1,37) = 10.83, p = 0.002 (Mean: -61.82° +/- 9.64 vs. -72.02° +/- 9.71). Males demonstrated significantly greater PPATSF F(1,37) = 7.349, p = 0.010 (Mean: 9.53 N +/- 1.88 vs. 7.63 N +/- 2.44). Intraclass Correlation Coefficients (ICC) were above 0.744 for all kinematic variables and above 0.456 for the two kinetic variables. All variables demonstrated significant intraclass reliability (p = 0.000). Conclusions. The RJLUC is a reliable high risk maneuver that may differentiate males and females in terms of neuromuscular control during the performance of this type of activity. Further research needs to be completed on the RJLUC to determine the implications that these results may have for the ACL injury paradigm. |
