An analysis of a discrete complex skill using Bernstein's stages of learning

The purpose of this study was to provide quantitative data about changes in coordination after practicing a racquetball forehand drive serve. Novice w omen (N = 10) were videotaped before and after 10 min, of practicing a racq uetball forehand drive serve on Day 1, and after 10-min. practice sessions on consecutive Days 2 through 5. The PEAK5 Motion Measurement System was us ed to evaluate the following dependent variables: (a) range of motion of th e wrist, elbow, upper torso, and pelvis from backswing to ball contact; (b) racket head velocity at ball contact; and (c) coordination. Coordination w as evaluated based on analysis of the angular velocity graphs of each perfo rmance to assess sequencing and timing of the segmental contributions. Shar ed positive contribution was assessed between adjacent 2-segment combinatio ns: pelvis-torso and elbow-wrist. A repeated-measures analysis of variance indicated racket velocity, pelvic rotation, and upper torso rotation signif icantly increased over the 5 days of practice. Although participants increa sed their pelvic and torso ranges of motion and racket velocity, improvemen t in coordination was not documented.