Given the paucity of research pertaining to the landing technique of adolescent ballet dancers, the aim of this study was to compare the three-dimensional lower limb joint angles and peak vGRF
between female adolescent ballet dancers and non-dancers during single limb drop-landings from 30 cm.
Such variables include the kinematics of trunk flexion, joint kinematics of the lower body, kinematics of the upper extremities, orientation of the golf club, VGRF
, and COP.
When walking at increased speeds in LBPP simulated hypogravity, VO2 is maintained as similar to normal weight walking, while vGRF
is significantly reduced.
As shown in Figure 2, with increase of the dropping height, peak vGRF
increased significantly (P < 0.001).
Use of monolimbs with elliptical shank pylons decrease peak vGRF
ACC 85.1064 MCC 0.6822 Sensitivity 0.8966 Specificity 0.7778 Area Under Curve 0.902 Using the above listed data, 0.9 as area under the curve indicates an excellent performance of skewness in discriminating normal from Parkinson using VGRF
from sensor 5.
The variables for the stiffness of the lower extremity included: 1) vertical stiffness ([k.sub.vert]) = [F.sub.max] /Ay (Granata et al., 2002), where [F.sub.max] is the maximum vGRF
, and Ay is the maximum vertical displacement of the center of mass based on the pelvis and greater trochanter anatomical landmarks; 2) average joint stiffness ([k.sub.joint]) = [DELTA]M/RoM (Butler and Davis, 2003), where [DELTA]M is the change in hip, knee, and ankle joint moments during the landing period (from the initial contact to the maximum knee flexion), and the RoM is the joint range of motion.
The corresponding VCRF and VGRF
in the same STS task performed by the healthy subject and the patient in STS rehabilitation were, respectively, shown in Figures 6(a) and 6(b), which were used to offer the referenced standard point (seat-off) within whole STS to synchronize the three trials of a task to the same percentage metric.
Reduced proprioceptive feedback due to the amputation may have prevented the generation of adequate afferent stimuli to organize an appropriate response to the VGRF
perturbation in the short time from TD to [F.sub.2] .
In order to evaluate the body stability, the weight distribution (WD) and the vertical ground reaction force (VGRF
) were computed according to the vertical direction of the arrow from the force plate exerted on the body during foot contact.
Condition NB SB SRB Dynamic Postural Stability .32 (.01) .32 (.01) .31 (.01) Index (DPSI) Anterior-posterior stability .14 (.01) .13 (.01) .13 (.02) index (APSI) Medial-lateral stability .03 (.01) .03 (.00) .03 (.01) index (MLSI) Vertical stability index .29 (.02) .29 (.03) .28 (.03) (VSI) vGRF
max (%BW) 1.90 (.23) 1.90 (.24) 1.84 (.25) Effect Observed P-value Size Power Dynamic Postural Stability .014 .38 .78 Index (DPSI) Anterior-posterior stability .315 .12 .23 index (APSI) Medial-lateral stability .508 .07 .15 index (MLSI) Vertical stability index .005 .44 .88 (VSI) vGRF
max (%BW) .037 .31 .66 NB, Non Brace; SB, Soft supoort Brace; SRB, Semi/rigid support Brace; vGRF
max, maximum vertical grand reaction force; %BW, % body weight.
A multicomponent force plate (Kistler Type 9286BA; Winterthur, Switzerland) was used to measure VGRF
. The signal was amplified with a gain of 2x by using a universal measurement amplifier (UMVE, uk labs; Kempen, Germany).