3d force platform

Postural control was assessed during one-legged stance on the dominant leg using a 3D force platform (AMTI, USA). Total Center-of-Pressure (CoP) displacements were calculated according to the following formula:
$CoP[mm]=\sqrt{Co{P}_{AP}{}^2+Co{P}_{ML}{}^2}$ . CoP_AP represents CoP displacements in anterior-posterior and DTC_ML represent CoP displacements in medio-lateral direction. In addition, CoP velocity (in m/s), indicating the total distances covered by the CoP divided by the duration of the sampled period and sway area (in mm²), representing the ellipse area covered by the trajectory of the CoP with a 95% confidence interval were calculated [23 (link)]. The dominant leg was determined using the lateral preference inventory [24 ]. Participants were asked to stand on their dominant leg, hands akimbo and gaze fixated on a wall approximately 2.5 meters apart. Data was acquired over a time interval of 30 s at a sampling rate of 1,000 Hz. Previously, high intra- (ICC = 0.97; 95% CI: 0.91–0.99) and intersession (ICC = 0.94; 95%CI: 0.84–0.98) reliability were reported for the one-legged stance [25 (link)].

FUS test was performed out on the test participants in a laboratory. The kinematic and kinetic performance of the bilateral lower limbs during FUS was recorded using a 3D force platform (AMTI, United States of America) and an infrared Vicon motion capture system (Oxford Metrics Ltd, Oxford, UK). For kinematics, the frequency was 250 Hz, and for ground reaction force, it was 1000 Hz. Lower-limb stiffness (LLS), take-off height H), landing time (LT), ground reaction force (GRF), and lower-limb displacement (LLD) were the biomechanical indicators that were gathered. All data had been exported automatically by Vicon software.