Influence of pole position on trunk angle in seated shotput

Background. Presently, the coaching of seated throwing technique and design of the throwing frame and is largely based on a trial-and-error approach. This case study focuses on one aspect of frame design (pole position) and how it might influence trunk angle in the power position (where the greatest forces can be generated resulting in a fast powerful transition to release) (Figure 1).Methods. The subject was a Class F55 elite level athlete, conducting their usual warm-up and using their own throwing frame. Kinematics were collected using (55) reflective markers on the major joints and on the shot put. A 10-camera motion capture system (Qualisys, 250Hz) was placed around the subject and throwing frame. The subject threw a 4kg shot put for 5 trials from 2 different throwing frame configurations (longer and shorter pole distances). The longer distance was at the left front side of the frame. The shorter distance was a position 5cm closer to the back of the frame. After each trial the distance thrown was recorded. Kinematic analysis involved creating a 6DOF Model (Visual 3D) enabling analysis of the trunk angle (difference between pelvis and thorax segments about the vertical axis) which was identified at the power position (Table 1, Figure 2).Results. Table 1 provides a description of statistics of trunk angle in Degrees and distance thrown in Meters for Long and Short Pole Positions. Figure 2 provides the trunk angle in power position in Degrees against distance in Meters for long and short pole positions.Discussion. The degree of trunk angle at the power position is thought to increase “trunk whip” and positively influence trunk muscle stretch, producing greater force and promoting muscle contraction. It should be as large as possible when the athlete is just exiting the power position. A positive correlation between trunk angle and performance shows for the Short Pole distance, suggesting the short pole allows more trunk angle variability which appears to be correlated with variability in performance. Pole position is just one of the frame characteristics that a coach might have to consider when working with a seated shot putter