Contextual influences on baseball ball-strike decisions in umpires, players, and controls

Baseball umpires, players, and control participants with no baseball experience were asked to call balls and strikes for video clips. In a basic judgement task, umpires and players were significantly better at calling pitches than controls. In a direct information task, borderline pitches were presented following clips of definite balls and definite strikes. Participants called target pitches closer to the strike end of the scale when viewed after definite balls than when they followed definite strikes. Similarly, when borderline pitches were shown in different pitch counts, participants called pitches more towards the strike end of the scale when there were three balls in the count (3-0, 3-2). These findings indicate that the standard for evaluation changes based on the context in which stimuli are processed. Moreover, the strength of the contextual factors is illustrated in that the effects were shown in observers with and without experience in the task. Overall, however, umpires had a greater tendency to call strikes, indicating that they may use a norm of "hastening the game".     

Time-out! How psychological momentum builds up and breaks down in table tennis

ABSTRACT

The current study examined the development of psychological momentum (PM) in table tennis and the effect of a time-out. Eighty table tennis players were exposed to an audiovisual scenario, in which they either came back from 1–7 to 7–7 in an all-decisive game (positive momentum), or in which the opponent came back from 7–1 to 7–7 (negative momentum). Furthermore, at the score of 7–7 a time-out was called. One group of participants received no specific instructions during the time-out, whereas the other group received task (mastery-approach – MAp) instructions. Overall, PM perceptions increased for participants in the positive momentum condition, but decreased rapidly for participants in the negative momentum condition. In addition, the time-out led to a loss of PM in the positive momentum condition, but to a recovery of PM in the negative momentum condition. The instructions during the time-out did not make a significant difference. Together, these results suggest that scoring patterns in a table tennis game significantly affect the PM of players. Furthermore, a player or coach could benefit from calling a time-out in a negative momentum situation, as this provides an opportunity to psychologically recover.     

Bat speed,trajectory, and timing for collegiate baseball batters hitting a stationary ball

The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time–speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory     

Strike type variation among Tarahumara Indians in minimal sandals versus conventional running shoes

PurposeThis study examined variation in foot strike types, lower extremity kinematics, and arch height and stiffness among Tarahumara Indians from the Sierra Tarahumara, Mexico.MethodsHigh speed video was used to study the kinematics of 23 individuals, 13 who habitually wear traditional minimal running sandals (huaraches), and 10 who habitually wear modern, conventional running shoes with elevated, cushioned heels and arch support. Measurements of foot shape and arch stiffness were taken on these individuals plus an additional sample of 12 individuals.ResultsMinimally shod Tarahumara exhibit much variation with 40% primarily using midfoot strikes, 30% primarily using forefoot strikes, and 30% primarily using rearfoot strikes. In contrast, 75% of the conventionally shod Tarahumara primarily used rearfoot strikes, and 25% primarily used midfoot strikes. Individuals who used forefoot or midfoot strikes landed with significantly more plantarflexed ankles, flexed knees, and flexed hips than runners who used rearfoot strikes. Foot measurements indicate that conventionally shod Tarahumara also have significantly less stiff arches than those wearing minimal shoes.ConclusionThese data reinforce earlier studies that there is variation among foot strike patterns among minimally shod runners, but also support the hypothesis that foot stiffness and important aspects of running form, including foot strike, differ between runners who grow up using minimal versus modern, conventional footwear.     

The influence of pitch dimensions on performance during small-sided and conditioned soccer games

Abstract

This study examined the influence of pitch dimensions in small-sided soccer games in shaping opportunities for performers to maintain ball possession, pass to teammates and shoot at goal. Fifteen amateur standard male participants (M = 21.87, σ = 1.96 years) played 5 v 5 small-sided soccer games in three varying pitch conditions (28 m × 14 m, 40 m × 20 m and 52 m × 26 m). Thirty sequences of play in each condition were selected for digitisation using TACTO software, allowing the capture of bi-dimensional displacement coordinate data of all players and the ball. The values of interpersonal distance between all attackers and immediate defenders and the relative distances of defenders to intercept a shot and a pass were computed as dependent variables. Results showed existence of fewer opportunities to maintain ball possession on smaller pitches, compared to medium and larger pitches. Conversely, the different dimensions set to the pitch did not influence opportunities for players to shoot at goal, or to perform passes to other teammates. By examining the specific spatial–temporal relationships of players and key-task constraints, the data from this study explain how effects of manipulating pitch dimensions of small-sided games might enhance opportunities for acquiring specific movement and decision-making skills.     

The dynamic impact characteristics of tennis balls with tennis rackets

Abstract

The dynamic properties of six types of tennis balls were measured using a force platform and high-speed digital video images of ball impacts on rigidly clamped tennis rackets. It was found that the coefficient of restitution reduced with velocity for impacts on a rigid surface or with a rigidly clamped tennis racket. Pressurized balls had the highest coefficient of restitution, which decreased by 20% when punctured. Pressureless balls had a coefficient of restitution approaching that of a punctured ball at high speeds. The dynamic stiffness of the ball or the ball-racket system increased with velocity and pressurized balls had the highest stiffness, which decreased by 35% when punctured. The characteristics of pressureless balls were shown to be similar to those of punctured balls at high velocity and it was found that lowering the string tension produced a smaller range of stiffness or coefficient of restitution. It was hypothesized that players might consider high ball stiffness to imply a high coefficient of restitution. Plots of coefficient of restitution versus stiffness confirmed the relationship and it was found that, generally, pressurized balls had a higher coefficient of restitution and stiffness than pressureless balls. The players might perceive these parameters through a combination of sound, vibration and perception of ball speed off the racket.     

Martial arts striking hand peak acceleration,accuracy and consistency

Abstract

The goal of this paper was to investigate the possible trade-off between peak hand acceleration and accuracy and consistency of hand strikes performed by martial artists of different training experiences. Ten male martial artists with training experience ranging from one to nine years volunteered to participate in the experiment. Each participant performed 12 maximum effort goal-directed strikes. Hand acceleration during the strikes was obtained using a tri-axial accelerometer block. A pressure sensor matrix was used to determine the accuracy and consistency of the strikes. Accuracy was estimated by the radial distance between the centroid of each subject's 12 strikes and the target, whereas consistency was estimated by the square root of the 12 strikes mean squared distance from their centroid. We found that training experience was significantly correlated to hand peak acceleration prior to impact (r ²=0.456, p =0.032) and accuracy (r ²=0. 621, p=0.012). These correlations suggest that more experienced participants exhibited higher hand peak accelerations and at the same time were more accurate. Training experience, however, was not correlated to consistency (r ²=0.085, p=0.413). Overall, our results suggest that martial arts training may lead practitioners to achieve higher striking hand accelerations with better accuracy and no change in striking consistency.     

Perceptual Decision Making for Baseball Pitch Recognition: Using P300 Latency and Amplitude to Index Attentional Processing

Abstract

This study was designed to examine the perceptual and attentional processes associated with the effects of administering a cost-benefit precuing paradigm to intermediate and advance-level baseball batters. Psychophysiological and performance data obtained from 10 advanced and 10 intermediate-level players were compared. A total of 400 pitches (200 fastballs, 200 curveballs) was randomly presented via a large projection screen, and participants pressed one of two buttons to indicate the type of pitch thrown. Verbal precues were given for 300 of the pitches. Of those, 75% were valid, and 25% were invalid. Electroencephalographic data collected from the P_z location was used to assess the latency and amplitude of P300. Analysis of variance (Skill Level x Precue x Pitch) for P300 and reaction time (RT) indicated that intermediate batters produced shorter P300 latencies, larger P300 amplitudes, longer RTs, and less correct responses than the advanced batters; the effects were more pronounced for the curveballs. These results suggest that intermediate batters are less efficient in their perceptual decision-making processes due to greater limitations in attentional capacity when compared with advanced batters.     

Load,stress, and recovery in adolescent rugby union players during a competitive season

Abstract

Despite increased professionalization of adolescent sport and improved articulation to elite adult participation, the impact of sports such as rugby union among adolescents is under-explored. This study describes psychological stress–recovery responses relative to training loads in 106 male adolescent rugby union players. The results showed that players with the highest training and physical activity volumes during the season demonstrated more favourable recovery–stress states than moderate- and low-volume groups. Stress and under-recovery did not increase with increases in weekly volume when assessed across a season. When assessed more acutely during intensive competition phases, stress and under-recovery increased with increases in participation demands. Despite better psychological stress and recovery profiles of more elite, higher-load players, not all participants demonstrated favourable capacities to deal with stress and recovery processes. Seven participants were in at least two of three categories of highest volume, highest stress, and poorest recovery. Even in the absence of a full understanding of the impact of high-volume, high-stress, poor-recovery participation among adolescent athletes, these markers may be precursors for more deleterious outcomes such as injury, performance decrements, and overtraining. Findings support the efficacy of serially monitoring young athletes.     

Bat speed, trajectory, and timing for collegiate baseball batters hitting a stationary ball

The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time-speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory.     

Physical,physiological, and technical demands of national netball umpires at different competition levels

ABSTRACT

To compare demands of national netball umpires between levels of competition, 22 Netball New Zealand high-performance umpires participated in this investigation. These included from highest to lowest standard: 9 × semi-professional ANZ Championships (ANZC); 6 × National A Squad (NZA); and 7 × National Development Squad (DEV). Physical (global positioning system tri-axial accelerometry), physiological (heart rate) and technical (video analysis) demands were determined for 48 (16 per group) umpire match performances. Level of competition had no significant effect on physical or mean physiological demands. However, ANZC umpires spent a lower proportion of time at low heart rates compared to DEV, and a greater proportion of time at high, rather than moderate, heart rates compared to NZA. Compared to lower standard umpires, ANZC spent lesser proportions of time standing but greater proportions of time walking backwards and sideways, and turning to change direction. Furthermore, ANZC umpires spent lower proportions of time jogging, but greater proportions of time sprinting compared to DEV. Finally, ANZC umpires spent longer mean durations than DEV on the goal third side line. As such, the difference in demands experienced by national netball umpires between levels of competition is more technical than physical or physiological.     

A shorter cricket pitch improves decision-making by junior batters

ABSTRACT

This study sought to determine whether playing on a shorter cricket pitch would lead batters to make more appropriate decisions about whether to play front foot or back foot shots. Based on an analysis of the shots played by top order batters against seam bowling in county under-10 matches, an age-specific “good length” region between 5.0 yards and 6.5 yards (4.57 to 5.94 m) from the batters’ stumps was derived. This was where batters were uncertain whether to play on the front or back foot. It was then possible to define deliveries as “short” or “full” depending upon whether they bounced further from or nearer to the batter than the good length region. Club under-11 and county under-10 match data revealed that when playing on a 16-yard pitch batters played more back foot shots to short balls, and county batters also played more front foot shots to full balls compared with matches on the currently recommended 20- or 19-yard pitches. For batters, a shorter pitch should strengthen the coupling between the perception of delivery length and appropriate shot selection, and the increased task demand should lead to improved anticipation, both key features of skilled batting.     

The effect of ball compression on the match-play characteristics of elite junior tennis players

The purpose of this article was to examine the effect of equipment scaling, through the modification of tennis ball compression, on elite junior tennis players (aged 10 years) within a match-play context. The two types of ball compressions that were compared were the standard compression (the normal ball) and 75% compression (termed the modified ball). Ten boys and 10 girls participated in the study. Participants were stratified into pairs based on their Australian Age Ranking and gender. Each pair played two two-set matches: one match with standard compression balls and one match with modified balls. The characteristics of each match were analysed and compared. The results showed that the use of the modified ball increased rally speed, allowed players to strike the ball at a lower (more comfortable) height on their groundstrokes and increased the number of balls played at the net. Ball compression had no effect on the relative number of winners, forehands, backhands, first serves in and double faults. The results are discussed in relation to skill acquisition for skilled junior tennis players.     

Tactical proficiency among table tennis players with and without intellectual disabilities

Abstract

The effect of intellectual impairment on sports performance has received limited attention by researchers. As a contribution to closing this gap, the purpose of the present investigation was to examine the differences in tactical proficiency between table tennis players with and without intellectual disabilities (ID). These groups were matched for training-volume and experience and consisted of 41 male (age = 27±8) and 30 female (age= 28±8) elite players with ID and a reference group of 12 male (age= 24±12) and 5 female (age= 20±9) players without ID. In two different test settings – one a World Championship and the other a training camp – the players in each group performed 60 semi-standardised rallies against the same opponent. Players were told that 12 sets of five identical services would be delivered, and their goal was to return the service with the intention of ‘winning the point’. The test results were validated for this study, to compute tactical proficiency scores (maximal score of eight points) for each player. A two-way Analysis of Variance (ANOVA) revealed significantly lower proficiency scores for players with ID than for those without ID. Repeated-measures ANOVA revealed that within each series of five rallies, starting with identical services, all participants were able to significantly improve their tactical proficiency gradually, but players without ID scored 4.3±0.5 from the first ball on, and while athletes with ID only 3.3±0.7 after five balls. The results of this study indicate that ID is associated with decreased tactical proficiency in table tennis.     

Evaluation of pre-game hydration status,heat stress,and fluid balance during professional soccer competition in the heat

Abstract

In this study, we assessed initial hydration status (stadium arrival urine specific gravity), fluid balance (pre- and post-game nude body weight, fluid intake, urine collection), and core temperature changes (pre-game, half-time, post-game) during a professional soccer game. We monitored 17 male players (including goalkeepers) between arrival at the stadium and the end of the game (3 h), playing at 34.9°C and 35.4% relative humidity, for an average wet bulb globe temperature (WBGT) heat stress index of 31.9°C. Data are reported as mean±standard deviation (range). Initial urine specific gravity was 1.018±0.008 (1.003–1.036); seven players showed urine specific gravity ≥ 1.020. Over the 3 h, body mass loss was 2.58±0.88 kg (1.08–4.17 kg), a dehydration of 3.38±1.11% body mass (1.68–5.34% body mass). Sweat loss was 4448±1216 ml (2950–6224 ml) versus a fluid intake of 1948±954 ml (655–4288 ml). Despite methodological problems with many players, core temperatures ≥ 39.0°C were registered in four players by half-time, and in nine players by the end of the game. Many of these players incurred significant dehydration during the game, compounded by initial hypohydration; thermoregulation may have been impaired to an extent we were unable to measure accurately. We suggest some new recommendations for soccer players training and competing in the heat to help them avoid substantial dehydration.     

Coordination of hitting movement revealed in baseball tee-batting

Baseball batters must react to pitches delivered to different locations within the strike zone by modulating their movements. In tee-batting practice, such batters place a ball on a tee stand at a location, where they intend to hit the ball, assuming a particular pitch’s trajectory. In the present study, we analysed three-dimensional movements in tee-batting to identify characteristics of the batters’ intended impact locations across the strike zone, thereby investigating spatiotemporal features of movement modulation. More specifically, 10 experienced baseball batters performed tee-batting at their preferred impact locations at nine different heights and courses within the strike zone. The distribution of impact locations showed regularity, i.e., the location shifted forward for balls placed high and inside, while it shifted backward for balls placed low and outside. Furthermore, trunk and arm movements showed systematic modulation as the impact locations changed. The duration of bat movement was also location dependent, i.e., hitting the inside ball took more time than hitting the outside ball. Our results indicate that even though movements among body segments were properly coordinated to adjust the bat swing for different impact locations, fine timing adjustments were also required to hit the ball at those preferred impact locations and therefore properly react to differences in flight paths.     

Differences in ball speed and accuracy of tennis groundstrokes between elite and high-performance players

Abstract

The main aim of this study was to identify and compare ball speed and hitting accuracy of forehand and backhand groundstrokes between ATP professionals (elite) and high-performance youth players when shots were played cross-court and down the line to a target square. Six elite and seven high-performance tennis players volunteered to participate in the study. A Doppler-radar device and a digital video camera, operating at 120 frames per second, were used to measure ball speed and accuracy of forehand and backhand groundstrokes in the respective situation (cross-court and down the line). The results of 1040 measured groundstrokes indicate that the ball speed of the forehand and the backhand ground stroke was higher in the elite group when analysing (1) all valid shots, (2) the six fastest shots, and (3) the six most accurate shots (all P < 0.05). In addition, all players achieved a higher forehand speed compared with their backhand when balls were directed cross-court (P < 0.01). The participants demonstrated similar ability when considering accuracy of their groundstrokes (P > 0.05). However, a group difference for accuracy was identified when considering the six fastest forehand shots (P<0.05), and the forehand cross-court stroke was played more accurately than the backhand cross-court stroke by both groups (valid shots and six most accurate shots, P<0.05). Moreover, there was no evidence that players who impacted the ball faster were any less accurate than those who impacted the ball more slowly. Analyses for participants actually revealed a negative correlation between ball speed and mean radial error (accuracy) for the backhand down the line (r= ? 0.77, P<0.01). According to the results of this study, ball speed seems to be the determining factor that separates elite from sub-elite tennis players.     

An examination of slo-pitch pitching trajectories

Many slo-pitch coaches and players believe that generating spin on a ball can affect its trajectory. The influence of air resistance on a ball that is thrown at a moderate speed and spin is unclear. The aim of this study was to examine the influence of spin on the ball's trajectory in slo-pitch pitching using both experimental results and ball flight simulations. Fourteen pitchers participated in the study, each of whom threw five backspin and topspin pitches each. Data were collected using standard three-dimensional videography. The horizontal velocity, vertical velocity, angular velocity, release height, and horizontal displacement of the backspin pitches were significantly higher than those of the topspin pitches. The ball flight simulations were developed to examine the influence of the ball spin, and it was concluded that the spin of the ball had a significant effect on the ball's vertical and horizontal displacements. Furthermore, our results suggest that a backspin pitch that reaches the maximum height allowable and lands in the front edge of the strike zone has the steepest slope. The present results add to our understanding of projectile motion and aerodynamics.     

Foot strike patterns of recreational and sub-elite runners in a long-distance road race

Abstract

Although the biomechanical properties of the various types of running foot strike (rearfoot, midfoot, and forefoot) have been studied extensively in the laboratory, only a few studies have attempted to quantify the frequency of running foot strike variants among runners in competitive road races. We classified the left and right foot strike patterns of 936 distance runners, most of whom would be considered of recreational or sub-elite ability, at the 10 km point of a half-marathon/marathon road race. We classified 88.9% of runners at the 10 km point as rearfoot strikers, 3.4% as midfoot strikers, 1.8% as forefoot strikers, and 5.9% of runners exhibited discrete foot strike asymmetry. Rearfoot striking was more common among our sample of mostly recreational distance runners than has been previously reported for samples of faster runners. We also compared foot strike patterns of 286 individual marathon runners between the 10 km and 32 km race locations and observed increased frequency of rearfoot striking at 32 km. A large percentage of runners switched from midfoot and forefoot foot strikes at 10 km to rearfoot strikes at 32 km. The frequency of discrete foot strike asymmetry declined from the 10 km to the 32 km location. Among marathon runners, we found no significant relationship between foot strike patterns and race times.     

Information recall of younger and older skilled athletes: The role of display complexity,attentional resources and visual exposure duration

This study was concerned with the interactive role of experience of athletic skill with other relevant environmental variables (display complexity, attentional resources, exposure time of stimuli) on perception (recall) of structured handball game situations. Nineteen experienced (older) and 19 less experienced (younger) handball players were assigned randomly either to ball‐bouncing (diverted attention) or to calm seated (focused attention) conditions. In each of the two conditions, the subjects were exposed to a total of 36 slides containing 2–3, 5–6 and 8–10 players. Eighteen slides were exposed for 0.5 s and 18 for 1.0 s. All the slides contained structured defence and offence situations. Recall scores were subjected to repeated‐measures ANOVA using attention condition and age as between‐subject factors and task complexity and exposure duration as within‐subject factors. The results showed that the recall of less experienced players deteriorated more than the recall of more experienced players following exposure to complex displays (≥ 8 players) while engaging in a secondary task (bouncing). The findings suggest that research paradigms should be applied in the field of sport which share both ecological validity and a potential to discover the cognitive substrates underlying experience and age in skilled motor performance.