Figures & data
Table 1 Averaged values of four kinematic parameters during landing phase and maximum value of knee flexion angle during the landing phase
Figure 1 (A) Anatomical coordinate systems of the pelvis, thigh and shank segments; (B) depiction of the calculation of the thigh tilt and knee-hip distance variables.
Notes: (A) Coordinate systems of the pelvis, thigh, and shank segments as well as the hip joint center (HJC), knee joint center (KJC), and ankle joint center (AJC) locations. The pelvis origin was the mid-point of the anterior superior iliac spines of the pelvis, the thigh origin was the KJC and the shank origin was the AJC. Hip adduction was calculated by rotating Xthigh relative to Xpelvis. Knee flexion was calculated by rotating Zshank relative to Zthigh. (B) The customized foot coordinate system held at the AJC and associated calculation of the thigh tilt and knee–hip distance variable. ZYhip and ZYknee were the Z and Y coordinate values in the customized foot coordinate system of the HJC and KJC, respectively. The thigh tilt angle was the angle to the vertical of the ZYhip−ZYknee vector. The knee–hip distance was the scalar distance between Zhip and Zknee.
Figure 2 Beta values from the linear regressions of the kinematic parameters (hip adduction, thigh tilt, and knee–hip distance) from the single-leg squat as predictors of the respective variable in the ballet movement. *p<0.05, **p<0.01.
Table 2 Correlations between the kinematic parameters and the turnout and knee flexion angles