KLNEMATICS OF FREE THROW SHOOTING BY CLASS 1.0 WHEELCHAIR BASKETBALL PLAYERS

  • L.A. Malone
  • P.L. Gervais
  • J.P. Baudin
  • R. Steadward

Abstract

Wheelchair basketball players classified as 1.0 are those players who have the greatest degree of disability. In order to identify if there are s i d a r patterns in free throw (FT) shooting technique across these players and to identify kinematic differences between successful and missed FTs, three-dimensional video data was collected during the 1994 World Wheelchair Basketball Championship held in Edmonton, Alberta. Two SVHS cameras were used to record the right side of players attempting FTs at one basket. Ten successful and ten missed shots were randomly selected for analysis. Joint centers, body landmarks and points on the wheelchair were digitized. The 2D coordinate data reconstruction was performed using the DLT method, followed by smoothing with a quintic spline. Results indicate that maximum wrist extension (cocking of the wrist) before release was similar for both successful and missed shots (1 15.85 = 9.04"), as was maximum wrist flexion occurring just after release (14.01 + 5.60'). However velocity of wrist flexion at release was greater for missed shots (955.59 = 342.37'/sec) in contrast to that of successful shots (899.43 + 296.43,"/ sec). Maximum elbow velocity and elbow extension were greater at release for successful shots as compared to unsuccessful attempts. Al1 but one of the subjects, demonstrated a backward lean during shooting which would be due in part to a tiited sitting position in the wheelchair to compensate for lack of balance. Head movement ranged from 0-9' prior to release with a tendency towards less movement during successful shots. Wheelchair position in relation to the FT line was quite variable between subjects, with some players directly facing the basket while others were at an angle as great at 50" to the FT line. The ball was propelled towards the basket with similar angles of release for both successful and missed shots (57.86 ± 2.04 º and 58.65± 2.37 º, respectively), with height of ball release raging from 1.56m to 1.88m between subjects. Velocity of the ball at release was found to be greater for successful shots (7.39 = .25 m/sec)as compared to missed shots (7.28±2.7m/sec). The overall results indicate that although there are individual differences in shooting technique between class 1.0 wheelchair basketball players, there are certain kinematic variables which are important in determining the outcome of a free throw for all players.
Section
Coaching and Sports Activities