Fig 1.
Placement points of the reflective markers on the barbell’s right end.
Fig 2.
One of the video images for the marker-less auto-tracking.
Fig 3.
A representative bar trajectory of snatch (a) and horizontal and vertical position coordinates and velocity (b) The thick line represents the data from the 3D-MC system, whereas the circle indicates the data from 2D-AT. The direction of the lifter’s line of sight was set in the forward direction 3D-MC: Three-dimensional motion capture system, 2D-AT: Two-dimensional analysis.
Fig 4.
Linear relationship between the data from the 3D-MC and 2D-AT methods.
The dashed and the thick lines correspond to the linear regression and identity lines, respectively 3D-MC: Three-dimensional motion capture system, 2D-AT: Two-dimensional analysis. DxF: The displacement of forward direction, DxB: The displacement of backward direction, DyMH: The maximum vertical height, pVxF: The maximum horizontal linear velocity in the forward direction, pVxB: The maximum horizontal linear velocity in the backward direction, pVy: Maximum vertical linear velocity.
Fig 5.
The Bland–Altman plot of the mean differences across the 3D-MC and 2D-AT methods.
The data are plotted against the mean value for both methods (dot-dashed line), with the upper and lower 95% LoA shown as dotted lines 3D-MC: Three-dimensional motion capture system, 2D-AT: Two-dimensional analysis, LoA: Limits of agreement. DxF: The displacement of forward direction, DxB: The displacement of backward direction, DyMH: The maximum vertical height, pVxF: The maximum horizontal linear velocity in the forward direction, pVxB: The maximum horizontal linear velocity in the backward direction, pVy: Maximum vertical linear velocity.
Table 1.
Mean and standard deviation (std) values of variables, bias, and precision between the two methods in the Bland–Altman analysis.