Appendix A. Results for three different explanatory variables, for three different subjects, processed using three different filtering approaches: (1) unfiltered, (2) filtering the entire trial, through impact, and (3) the linear extrapolation technique described by Knudson and Bahamonde (2001). The extrapolation and unfiltered technique resulted in results that were very similar. Racquet Trajectory Before Impact (°o) Subject Filtered Extrapolated Unfiltered 1 27.54 28.38 28.38 2 34.01 31.54 31.30 3 41.70 37.67 37.71 Racquet Horizontal Velocity Before Impact (°m/s) Subject Filtered Extrapolated Unfiltered 1 19.20 19.81 19.20 2 8.58 10.37 10.34 3 10.22 12.22 12.13 Racquet Vertical Velocity Before Impact (°m/s) Subject Filtered Extrapolated Unfiltered 1 9.58 10.33 10.37 2 7.65 8.01 7.99 3 7.05 7.16 7.16