TIMER AND 35 MM CAMERA INSTRUMENTATION TO INVESTIGATE THE RELEASE OF BASEBALL PITCHERS' FASTBALLS AND CURVEBALLS

The purpose of this study was to develop the instrumentation to investigate the moment of release and the sequential release pattern of baseball pitchers' fastballs and curveballs. A portable six-channel timer was constructed with accuracy of 10('-4) seconds and with the capability of being triggered by either the opening or closing of microswitches. Microswitches were constructed for the thumb, index and middle fingers using 3M electrode tape and a ball, painted with silver electroconductive printed circuit board paint. The other microswitches used in this study were a floor mat and a switch in the catcher's glove. Two portable camera delay mechanisms were designed to trigger on the floor mat signal press the shutter release button of two 35 mm cameras at the moment of release of the pitched baseball. A regulating delay potentiometer permitted adjustments for the varying delays required for each subject's pitch type. From the nine subjects studied, sequential release patterns, time from foot plant to release, flight time, stride length and stride position were calculated on 104 fastballs and 88 curveballs. The moment of release was captured on 48 fastballs and 38 curveballs and, from photographs from the side and the front, the following calculations were made for each subject: release height above the head; body height at release; forward and lateral trunk lean and forward and lateral arm angle. The following statements can be made at the .05 level of significance: the release of the fastball was thumb first followed by middle or index finger; the release of the curveball was either the thumb or middle finger first or second with the index finger last; the time from foot plant to release was shorter for fastballs than curveballs; the stride for the fastball was longer and more open than for the curveball; the sideways lean, forward lean and release height for curveballs was greater than for fastballs; the body height, forward arm angle and sideways arm angle were greater for the fastball than the curveball.