Quiet eye gaze behavior of expert, and near-expert, baseball plate umpires.

The quiet eye gaze behavior of 4 near-expert and 4 expert baseball umpires who called balls and strikes in simulated pitch-hit situations was assessed with a mobile eye cornea tracker system. Statistical analyses of the umpires' gaze behavior (fixation/pursuit tracking, saccades, and blinks)--onset, duration, offset, and frequency--were performed between and within 4 stages (pitcher's preparation, pitcher's delivery, ball in flight, and umpire call) by umpire's skill level. The results indicated that the quiet eye of expert umpires at onset of the pitcher's release point occurred earlier and was longer in duration than near-expert umpires. Expert expert umpires. The area outside the pitcher's ball release point may be the key environment cue for the behind-the-plate umpire.

Visual gaze behavior of near-expert and expert fast pitch softball umpires calling a pitch.

The purpose of this study was to examine the difference in visual gaze behavior between near expert (NE) and expert (E) umpires in a simulated pitch-hit situation in fast pitch softball. An Applied Science Laboratory mobile eye tracker was worn by 4 NE and 4 E fast pitch umpires and recorded their visual gaze behavior while following pitches (internal view). A digital camera located behind the pitcher recorded the external view of the pitcher, hitter, catcher, and umpire actions for each pitch. The internal and external video clips of 10 representative pitches--5 balls and 5 strikes--were synchronized and displayed in a split screen and were then coded for statistical analyses using Quiet eye solution software. Analysis of variance and multivariate analysis of variance statistical analyses of the umpires' gaze behavior during onset, duration, offset, and frequency (fixation/pursuit tracking, saccades, and blinks) were conducted between and within the 5 stages (pitcher's preparation, delivery and release, ball in flight, and umpire call) by umpire's skill level. Significant differences (p < 0.05) observed for combined gaze behavior frequency, type of gaze by phase, quiet eye duration and onset, and ball duration tracking indicated that E umpires' visual control was more stable and economical than NE umpires. Quiet eye significant results indicated that E umpires had an earlier onset (mean = 50.0 ± 13.9% vs. 56 ± 9.5%) and longer duration (mean = 15.1 ± 11.3% vs. 9.3 ± 6.5%) of the pitcher's release area than NE umpires. These findings suggest that gaze behavior of expert fast pitch umpires was more economical, fixated earlier and for a longer period of time on the area where the ball would be released, and was able to track the ball earlier and for a longer period of time.

Effects of increasing and decreasing intratrial stimulus speed on coincidence-anticipation timing.

The effects of intratrial stimulus speeds on coincidence-anticipation timing was investigated. The Bassin Anticipation Timer was used to test 82 participants' response times when the intratrial stimulus speed decreased, was constant, or increased. Analysis showed a significant temporal directional bias with increased and decreased intratrial speed. Decreasing intratrial stimulus speed produced the greatest magnitude of error compared to constant and increasing speeds. Differences in response times associated with intratrial stimulus-speed changes may depend on participants' identifying stimulus speeds and preprogramming a coincident response.

Use of an occlusion paradigm to examine anticipation of accelerating and decelerating stimuli.

An occlusion paradigm was used to study the effects of intratrial accelerating, decelerating, and constant stimulus velocity on coincidence-anticipation timing. The Bassin anticipation timer was used to occlude the beginning, middle, and end locations of the stimulus traveling to a designated target area. The coincident anticipation responses of 64 college-age participants (32 men; 32 women) were measured for each intratrial stimulus velocity. Analysis of variance indicated a significant main and interaction effect of occluded location by type of intratrial stimulus velocity. Decreasing intratrial stimulus velocity with the beginning and middle of the runway occluded and increasing intratrial velocity with the middle occluded produced the highest error in the participants' coincidence-anticipation accuracy. The contention that more viewing time of the stimulus would result in the lowest coincidence error was not supported for decelerating and accelerating stimulus speeds but was supported for the constant velocity condition. A temporal directional bias was found in both nonoccluded and occluded location conditions which may be due to an assimilation effect.

Kinematic assessment of treadmill running using different body-weight support harnesses.

10 male collegiate runners (M age = 21.4, SD = 1.5 yr.) ran on a treadmill with no body-weight support (BWS), 20% BWS, and 40% BWS conditions. In addition, they wore three different commercially available harnesses at the 20% and 40% BWS conditions. The aim was to run on the treadmill at a fast speed while maintaining an adequate step length. The purpose was to investigate how each harness changed running gait, and the differences in running gait between the harnesses with various body-weight support. Analysis of variance indicated significant restriction of upper body torso rotation between the harnesses at the 40% BWS conditions. Body-weight support resulted in a longer stride, decreased cadence, less vertical displacement of the center of mass, and diminished hip and ankle joint excursions. These changes indicated that increased body-weight support results in longer steps with the foot contacting the belt for a shorter period of time with less leg angular changes throughout the running cycling.

Incremental exercise in dynamic visual acuity.

As research is limited the purpose of this study was to investigate dynamic visual acuity while cycling at different exercise loads. Accuracy of dynamic visual acuity scores of 20 college-age participants was analyzed by a repeated-measures analysis of variance which indicated improved dynamic visual acuity during cycling as the intensity of exercise increased. A retention test conducted two days after testing yielded evidence of trainability of dynamic visual acuity. In the discussion findings were compared to other visual functions associated with exercise.

Comparative Kinematic Measures of Treadmill Running with or without Body Weight Support in Runners.

Treadmill walking and running using a supportive harness has been used as a training method to rehabilitate injured patients' walking or running gait. Comparison of full weight support (FWS) and body weight support (BWS) kinematic measures in competitive runners has received little attention. The purpose of this study was to compare selected FWS to BWS kinematic measures in healthy competitive runners. Ten male runners (age = 21.4 ± 1.5 years) with a training regimen averaging 64 km per week at 3.8 m·s(-1) participated. All participants ran three 3-minute trials. The randomized trial conditions were: FWS, 20% BWS, and 40% BWS. All conditions were videotaped with 2 cameras and a 21-point, 3-D model was generated for analysis. From the position-time data, cycle length (CL), cycle frequency (CF), time of contact (TC), hip-, knee-, ankle- range of motion in degrees (H-ROM, K-ROM, and A-ROM, respectively), and vertical displacement of the center of mass (COM) were derived and compared. With increasing support conditions, cycle length increased. Cycle frequency, hip and ankle angle ranges, and COM vertical displacement decreased (p < 0.05). However, the ankle angle range of motion varied little between 20% and 40 % BWS (p > 0.05). BWS running produced significant changes in selected kinematic measures. These changes may provide insight into runners' behavior when using BWS in training or recovery from competition. Additional investigation of BWS training affect with competitive runners would be recommended. Key PointsRunning kinematics change gradually with increasing levels of body weight support.At constant speed, center of mass vertical displacement, lower leg angular displacement, foot contact time and cycle frequency decrease significantly from FWS to 40S.Harness running can have beneficial effects in healthy runners recovering from intense bouts of exercise.

Effects of foot-pedal positions by inexperienced cyclists at the highest aerobic level.

The purpose of this study was to assess whether the platform foot-pedal position affected maximal oxygen intake (VO2 max) at the highest aerobic demand in cycling. 21 inexperienced cyclists completed two exercise tests, one in the "normal" platform foot-pedal position and the other in the Biopedal forefoot varus foot-pedal position, cycling on an exercise ergometer. The time between tests ranged from 1 to 3 days depending on the subject's reported fatigue and muscle soreness. The highest aerobic demand was the subject's VO2 max at the point just below the subject's anaerobic threshold. A one-way analysis of variance indicated that the subject's VO2 max performance was similar between the foot-pedal positions. These results did not support the assumption that the Biopedal forefoot varus foot-pedal position would enable the cyclist to be more efficient at the highest aerobic demand when compared to a standard platform foot-pedal position.

Coincidence anticipation and dynamic visual acuity in young adolescents.

Research involving college-age students and women fast pitch softball players indicated that coincidence anticipation and dynamic visual acuity are different visual abilities. This study used an alternative procedure to measure dynamic visual acuity to re-examine their relationship. Coincidence anticipation and dynamic visual acuity were measured in 24 young adolescents (12 boys, 12 girls) 11 to 14 years of age. During the dynamic visual acuity procedure, the subject tracked an object of a constant size while the researcher manipulated the object's velocity. Analysis indicated that they are different visual abilities. Findings indicated that the dynamic visual acuity of boys was significantly better than that of girls, and coincidence anticipation between boys and girls did not differ.

Recognition accuracy by experienced men and women players of basketball.

This study examined 30 experienced basketball players' recognition accuracy by sex, playing position (guard, forward, and center), and situations in the game of basketball. The study used a perceptual cognitive paradigm in which subjects viewed slides of structured and unstructured game situations and accurately recognized the presence or absence of the basketball. A significant difference in recognition accuracy by sex, players' position, and structure of the game situation was found. Male players' recognition accuracy was better than the female players'. The recognition accuracy of subjects who played guard was better than that of subjects who played forward or center. The players' recognition accuracy was more accurate when observing structured plays versus unstructured plays. The conclusion of this study suggested that experienced basketball players differ in their cognitive and visual searching processes by sex and player position within the sport of basketball.