On the use of spline functions for data smoothing.

The appropriateness of various numerical procedures for obtaining valid time-derivative data recently reported in the literature (Zernicke et a/., 1976: McLaughlin er al., 1977; Pezzack et u/., 1977) is discussed. A case for the use of quintic natural splines is presented. based on the smoothness of higher derivatives and flexibility in application. \‘ES; /\ . _J”P JGTc, SE=5 :;yz,s’sy = z7 ___ ‘/CL:2 _ OUINT Fig. 1. Second derivatives of cubic and quintic spline approximations to vertical jump data from Miller and Nelson (1973). CUBIC = cubic spline; QUINT = quintic spline; VALID = ground reaction force values.