Measuring Block Reaction Time in Volleyball Players Using a Novel and Accurate Reaction Time Measurement System

Athletes who spend more time planning and executing plays can anticipate the outcome of their reactions more quickly and accurately, thus increasing the likelihood of effective plays. Video stimuli that replicate real sports have been used to study players’ reactions toward stimuli in various sports. However, the low frame rates of the video stimuli used in previous studies have resulted in errors when measuring reaction time. Further, a video display delay occurs in experiments where computers are used. The purpose of this study was to develop a novel and accurate reaction time measurement system to solve these problems. A video taken with a high-speed camera was used as the stimulus video to enable measurement of the time from the keyframe to the response. A marker was displayed on the computer screen during the keyframe in the stimulus video and was detected by a photosensor attached to the computer to compensate for video display delay. Using the new measurement system, the time required for a block maneuver reaction by volleyball players, known as the block reaction time (BRT), was measured in 15 male collegiate volleyball players. The BRTs were 0.214 ± 0.051, 0.616 ± 0.150, and 0.233 ± 0.065 s against the left, center, and right attacks, respectively. The measured BRTs were shorter than those measured using light stimuli in previous studies, probably because participants in this study were able to predict the direction of the ball toss using cues gleaned from the setter’s preliminary movements.