Visual abilities distinguish pitchers from hitters in professional baseball

Visual Performance and Sports: A Scoping Review

Vision is central to success in nearly all sports, and there is an emerging body of research investigating the links between visual abilities and athletic performance. This preregistered scoping review seeks to clarify the topics of study, methodologies used, populations under investigation, researchers, and disciplines driving this field. Systematic searches of English-language articles were conducted in PubMed and Web of Science, with additional literature identified through bibliographic searches. Six hundred sixty-seven articles published between 1976 and 2023 were identified with 547 empirical studies, 58 review articles, 20 commentaries, and 4 meta-analyses, among others. Among the empirical papers, 411 reported on visual assessments and 98 on vision training interventions. The most represented sports included baseball, soccer, basketball, and cricket, with over 150 articles reporting on professional, elite, or Olympic athletes. This scoping review describes the breadth of this emerging field, identifies its strengths and weaknesses, and provides recommendations for future improvement.

Strength, speed, and anthropometric predictors of in-game batting performance in baseball

A key focus of sports science research is the identification of quantitative assessments that can predict players' on-field performance and developmental potential. Despite efforts to establish predictive models, there are few validated measures that show reliable associations and large gaps in understanding. Here, we test a multidimensional battery of assessments developed through the USA Baseball, Prospect Development Pipeline that capture strength and functional movement abilities, and anthropometric characteristics, in a two-year cohort of collegiate baseball players from the Appalachian League. Swing propensity metrics for Zone Contact Percentage (ZCP: proportion pitches in strike zone swung at and hit) and Hard-Hit Percentage (HHP: proportion in-play balls with exit velocity ≥ 95 mph) were calculated on 189 players. Models testing hierarchical combinations of anthropometric and anthropometric plus assessment data were implemented using nested cross-validation with random forest and elastic net regression. Results indicate that anthropometric features account for 29% of variance in ZCP and 50-55% of HHP, while the addition of assessment contributed an additional 1-3% to ZCP and 5-12% to HHP, with top predictors coming from PDP strength and power assessments. These findings delineate contributions of andromorphic and physical abilities to in-game baseball performance using a validated assessment battery and advanced game statistics.

Predictors of batting and pitching performance in the USA baseball prospect development pipeline

This study examined the relationship between psychomotor abilities and baseball performance by analysing data from 379 athletes who participated in the USA Baseball, Prospect Development Pipeline (PDP). Hit and pitch metrics were generated during practice sessions using the RapsodoTM System. Data were compared through exploratory factor analysis and hierarchical regression. Factor analysis grouped batter's PDP evaluations into four latent variables accounting for 63% of variance. Pitcher performance grouped into three factors accounting for 51% of variance. Regression on batter data revealed a significant demographic/anthropometric base model with height, weight, and age that accounted for 58% of the batted ball speed (R2 = 0.581). Player position explained 2% of the variance (R2 = 0.604), and PDP evaluation scores contributed an additional 3% (R2 = 0.631). Regression of pitcher data showed a significant base demographic/anthropometric model accounting for 36% of fastball pitch speeds (R2 = 0.363), with the PDP evaluation scores adding 6% additional variance (R2 = 0.424). Uniformly, assessments of lower body strength added the greatest predictive information. Hand grip strength did not correlate with pitch metrics. While demographics/anthropometrics are major contributors to batted and pitched ball speed, position and psychomotor variables add statistically significant contributions and may be of practical value for player selection.

Opposite effects of Covid-19 infection on pitchers and batters: a retrospective study on Chinese Professional Baseball League players

BACKGROUND

The influence of COVID-19 infection on elite athletes remains largely unknown, especially on baseball players. The goal of this study is to examine the actual performance of infected elite baseball players from the Chinese Professional Baseball League (CPBL) from a sabermetric point of view.

METHODS

This was a retrospective observational cohort study. CPBL players who were infected with COVID-19 from April 27th to May 31st, 2022, were eligible for this study. The performance of study participants before and after COVID-19 infection was compared, and statistics from the batters and pitchers were analyzed separately.

RESULTS

During the study interval, 56 players were infected with COVID-19, including 35 batters and 21 pitchers. After excluding injured players and players with inadequate playing opportunities, 23 batters and 12 pitchers were enrolled. For batters, there were no significant differences before and after COVID-19 infection. However, batters older than 28 years of age showed a decline in slugging percentage (0.372 vs. 0.292, P=0.049). Analysis of pitchers revealed significantly boosted fastball velocity after COVID-19 infection (142.10 km/h vs. 142.82 km/h, P=0.028) and improved strikeouts per nine innings (6.89 vs. 8.56, P=0.021).

CONCLUSIONS

COVID-19 might have a potential influence on professional baseball players. For batters, veteran players more than 28 years of age were more likely to be negatively affected by COVID-19, whereas the effect of COVID-19 on pitchers was generally positive, with significantly improved fastball velocity and K/9 numbers.

Topical Review: Optometric Considerations in Sports vs. E-Sports

Electronic sports (e-sports) have recently emerged to become a rapidly growing form of videogame competition, requiring gamers to spend many hours in front of a visual display. The nature of this new modality raises important considerations for ocular health, and visual and perceptual functioning, compared to traditional sports. In general, sports performance has been associated with open spaces, gross motor movement, and balance, while electronic sports require visual and attentional stamina at near distances with fine motor control. From an optometric viewpoint, visual perception is specific to both the sports modality and the environment where sports take place. In this topical review, we consider e-sport optometric factors such as screen time and digital eyestrain, visual skill demands, and perceptual cognitive skills such as visual attention. We compare training considerations for traditional sports and training in gaming platforms, with recommendations for future research in this growing modality. The goal of this review is to raise awareness of the various elements to consider when providing vision care to e-sport participants.

Stereopsis in Sports: Visual Skills and Visuomotor Integration Models in Professional and Non-Professional Athletes

Visual skills in sport are considered relevant variables of athletic performance. However, data on the specific contribution of stereopsis-as the ability to perceive depth-in sport performance are still scarce and scattered in the literature. The aim of this review is therefore to take stock of the effects of stereopsis on the athletic performance, also looking at the training tools to improve visual abilities and potential differences in the visuomotor integration processes of professional and non-professional athletes. Dynamic stereopsis is mainly involved in catching or interceptive actions of ball sports, whereas strategic sports use different visual skills (peripheral and spatial vision) due to the sport-specific requirements. As expected, professional athletes show better visual skills as compared to non-professionals. However, both non-professional and professional athletes should train their visual skills by using sensory stations and light boards systems. Non-professional athletes use the visual inputs as the main method for programming motor gestures. In contrast, professional athletes integrate visual information with sport expertise, thus, they encode the match (or the athletic performance) through a more complex visuomotor integration system. Although studies on visual skills and stereopsis in sports still appear to be in their early stages, they show a large potential for both scientific knowledge and technical development.

Efficacy of a Digital Sports Vision Training Program for Improving Visual Abilities in Collegiate Baseball and Softball Athletes

SIGNIFICANCE

Dynamic reactive sports involve visual abilities such as visual acuity, depth perception, contrast sensitivity, and visual-motor reaction speed. This randomized, double-blinded control design showed no significant improvement in the visual parameters among athletes after training on a digital sports vision training program.

PURPOSE

There is a need for evidence supporting the efficacy of recently developed digital training programs.

METHODS

Thirty-two athletes from National Collegiate Athletic Association Division III softball and baseball teams were randomly divided into experimental and placebo training groups, undergoing three 20-minute training sessions per week for 3 weeks. The experimental group trained on procedures designed to improve dynamic visual acuity and depth perception, and the placebo group trained on procedures designed to have no direct impact on those same parameters. All measures were recorded at baseline, post-training, and after a month of no training. The athletes also completed a questionnaire to determine the efficacy of the placebo effect.

RESULTS

There was no significant effect of evaluation type (post-training and follow-up) and condition (experimental and placebo) on any of the visual parameters. However, stereoacuity, contrast sensitivity, depth perception, and dynamic visual acuity showed minimum effect sizes of 0.5. Fifteen of 16 athletes in the placebo group thought they trained on experimental procedures.

CONCLUSIONS

No significant improvement differences were seen between experimental and placebo training groups. However, stereoacuity, contrast sensitivity, and depth perception achieved minimum clinical relevance.

Association between Clinical Vision Measures and Visual Perception and Soccer Referees' On-field Performance

SIGNIFICANCE

The decisions taken by soccer officials are critically important to game management. Understanding the underlying processes that mediate expert performance in soccer refereeing may lead to a better standard of officiating. Vision is the dominant source of incoming information upon which officials rely to make their on-field decisions.

PURPOSE

We tested the hypothesis that performance on generic tests of vision and visual perception predicts domain-specific performance in elite-level soccer referees (R) and assistant referees (AR).

METHODS

We assessed the vision of R and AR who officiate at the highest level in Portugal. To be eligible for inclusion, R and AR had to have officiated for at least two consecutive seasons across the 2014/2015, 2015/2016, and 2016/2017 seasons. A single, rank-order list of the performance of eligible officials was created based on the rank-order list for each season that was made by the Portuguese Soccer Federation. Clinical vision measures included visual acuity and stereoacuity, and visual perception measures were gathered using the Test of Visual Perceptual Skills, Third Edition.

RESULTS

A total of 59 officials participated (21 R, 38 AR), 17 of whom officiated at the international level. The R and AR groups did not differ in vision or visual perception measures. We found that better stereoacuity (P < .001) and visual memory (P = .001) are associated with a higher rank order of on-field performance after adjusting for the age, experience, the national/international status, and the regional affiliation of the officials. Together, these two measures explain 22% of the variance in rank-order performance.

CONCLUSIONS

This is the first study to show a link between the vision of officials and their on-field performance. The origin and significance of these findings remain to be established, and further work is required to establish whether they are component skills in the domain of soccer refereeing.

Topical Review: Visual Performance Assessments for Sport

SIGNIFICANCE

Eye care professionals seek to provide effective vision care for a variety of patient needs, including performance in sports and recreational pursuits. This review provides an analysis of common visual performance assessments, including summaries of recent clinical research from a diverse array of professional literature.Vision is recognized as an important element of sports performance. Elite athletes frequently demonstrate exceptional abilities to see and respond effectively in sports competition. Which visual factors are important and how to most effectively assess visual performance are the sources of much debate. This topical review presents an evidence-based review of the common visual performance factors assessed in athletes, beginning with guidance for conducting a visual task analysis for the variety of sports that athlete patients may compete in. An information processing model is used to provide a framework for understanding the contributions of the many visual performance factors used during sports.

Topical Review: Perceptual-cognitive Skills, Methods, and Skill-based Comparisons in Interceptive Sports

SIGNIFICANCE

We give a comprehensive picture of perceptual-cognitive (PC) skills that could contribute to performance in interceptive sports. Both visual skills that are low level and unlikely influenced by experience and higher-level cognitive-attentional skills are considered, informing practitioners for identification and training and alerting researchers to gaps in the literature.Perceptual-cognitive skills and abilities are keys to success in interceptive sports. The interest in identifying which skills and abilities underpin success and hence should be selected and developed is likely going to grow as technologies for skill testing and training continue to advance. Many different methods and measures have been applied to the study of PC skills in the research laboratory and in the field, and research findings across studies have often been inconsistent. In this article, we provide definitional clarity regarding whether a skill is primarily visual attentional (ranging from fundamental/low-level skills to high-level skills) or cognitive. We review those skills that have been studied using sport-specific stimuli or tests, such as postural cue anticipation in baseball, as well as those that are mostly devoid of sport context, considered general skills, such as dynamic visual acuity. In addition to detailing the PC skills and associated methods, we provide an accompanying table of published research since 1995, highlighting studies (for various skills and sports) that have and have not differentiated across skill groups.

Soccer goalkeeper expertise identification based on eye movements

By focusing on high experimental control and realistic presentation, the latest research in expertise assessment of soccer players demonstrates the importance of perceptual skills, especially in decision making. Our work captured omnidirectional in-field scenes displayed through virtual reality glasses to 12 expert players (picked by DFB), 10 regional league intermediate players, and13 novice soccer goalkeepers in order to assess the perceptual skills of athletes in an optimized manner. All scenes were shown from the perspective of the same natural goalkeeper and ended after the return pass to that goalkeeper. Based on the gaze behavior of each player, we classified their expertise with common machine learning techniques. Our results show that eye movements contain highly informative features and thus enable a classification of goalkeepers between three stages of expertise, namely elite youth player, regional league player, and novice, at a high accuracy of 78.2%. This research underscores the importance of eye tracking and machine learning in perceptual expertise research and paves the way for perceptual-cognitive diagnosis as well as future training systems.

Peripheral Vision Tests in Sports: Training Effects and Reliability of Peripheral Perception Test

Various studies suggest the importance of peripheral vision (PV) in sports. Computer-based test systems provide objective methods to measure PV. Nevertheless, the reliability and training effects are not clarified in detail. The purpose of this investigation was to present a short narrative non-systematic review on computer-based PV tests and to determine the reliability and the training effects of peripheral perception sub-test (PP) of the Vienna test system (VTS) in a test–retest design. N = 21 male athletes aged between 20 and 30 years (M = 26.15; SD = 3.1) were included. The main outcome parameters were peripheral reaction (PR), PR left (PRL), PR right (PRR), field of vision (FOV), visual angle left (VAL), and visual angle right (VAR). Reliability was assessed using intraclass correlation coefficient (ICC) and Bland–Altman plots. Training effects were determined by students t-test. Good reliability was observed in PR, PRL, and PRR. Moderate reliability was found in FOV, VAL, and VAR. Significant improvements between T₀ and T₁ were found in PRL with a mean difference of 0.04 s (95% CI [0.00–0.07]) and in PR with a mean difference of 0.02 s (95% CI [0.00–0.05]). For PRR, FOV, VAL, VAR, no significant differences were detected. These results indicate that PP can be applied to asses PV abilities in sports. Future research is needed to clarify the influence of test repetitions on visuomotor learning in PP. Moreover, PV tests should be cross-validated with sport-specific measurements (e.g., on-field and/or ‘virtual reality’ approaches).

The Effect of Visual Function on the Batting Performance of Professional Baseball Players

This report evaluates the role of the combined visual abilities of acuity, contrast sensitivity and presentation time on plate discipline and baseball batting performance. A visual function test (EVTS) was performed on 585 professional baseball players. The results were compared to several common plate-discipline measures. The EVTS test provides a single measure combining target size, contrast and presentation time. Correlations (statistically significant) were found between this measure and several plate discipline metrics (InzoneSwingPct, inzoneFbSwingPct, ChasePct, FbChasePct, BBperPa). Years of major league service did not appear to be related to visual ability. When comparing the best and worst 20% groups based on visual ability, statistically significant improvements ranging from 11.6% in BBperPa to 3.5% in inzoneSwingPct were noted in the better visual function group. Effect sizes ranged from 0.278 to 0.387. These results demonstrate the relationship between basic visual function and batting performance. These are the first results, on a large group at the professional level, to demonstrate this relationship statistically. These results may aid player selection, indicating that batters with better visual function are more likely to be successful when batting and more productive for their team.

Team sport expertise shows superior stimulus-driven visual attention and motor inhibition

Previous studies on athletes' cognitive functions have reported superior performance on tasks measuring attention and sensorimotor abilities. However, how types of sports training shapes cognitive profile remains to be further explored. In this study, we recruited elite athletes specialized in badminton (N = 35, female = 12) and volleyball (N = 29, female = 13), as well as healthy adult controls (N = 27, female = 17) who had not receive any regular sports training. All participants completed cognitive assessments on spatial attention, sensory memory, cognitive flexibility, motor inhibition, and the attention networks. The results showed that athletes generally showed superior performance on selective cognitive domains compared to healthy controls. Specifically, compared to the healthy control, volleyball players showed superior on iconic memory, inhibitory control of action, and attentional alerting, whereas badminton players showed advantages on iconic memory and basic processing speed. Overall, volleyball players outperformed badminton players on those tasks require stimulus-driven visual attention and motor inhibition, likely due to different training modalities and characteristics of specialty that involves even more complex cognitive processes. To conclude, our findings suggest cognitive plasticity may drive by sports training in team/individual sports expertise, manifesting cognitive profile in sport expertise with distinct training modalities.

Functional significance of stereopsis in professional table-tennis players

BACKGROUND

Stereopsis is the most important part of depth perception, especially in athletic population. At present, there are few studies on how to comprehensively evaluate athletes' stereoscopic function and how the impairment of stereoscopic function affects sports performance.

METHODS

Twenty-two professional table-tennis players from Sichuan Province Team were recruited as player group and 23 age-matched students were recruited as the controls. All subjects were measured the habitual visual acuity, best corrected visual acuity, dominant eye, retinoscopy and three stereo acuity tests. Both groups completed two motor skills tasks: Purdue Pegboard and beads threading with habitual binocular viewing and monocular viewing by covering dominant eye. In addition, the player group was asked to complete a brief questionnaire and catch balls served by the auto table-tennis machine under two viewing conditions.

RESULTS

The player group had better stereo acuity with median values of 60, 25 and 40 arc sec in TNO, Butterfly, and Frisby tests, respectively. There had statistically correlations between stereo acuity and two motor skills tasks. Both the two tasks were statistically significant different between binocular and monocular viewings in both groups. The player group had better performance on Purdue Pegboard task with binocular viewing (16±1.1, P=0.006) compared to the control group, while no statistical difference was found under monocular condition in beads threading task. In player group, the brief questionnaire demonstrated very negative feeling of players under monocular viewing and the number of catching balls had statistically significant difference between binocular (9.9±0.3) and monocular (6.9±1.6) viewings (P<0.001).

CONCLUSIONS

Stereopsis plays an important role in sports performance, the stereo tests combined with Purdue pegboard can be used to evaluate athletes' stereoscopic function comprehensively.

Sensorimotor abilities predict on-field performance in professional baseball

Baseball players must be able to see and react in an instant, yet it is hotly debated whether superior performance is associated with superior sensorimotor abilities. In this study, we compare sensorimotor abilities, measured through 8 psychomotor tasks comprising the Nike Sensory Station assessment battery, and game statistics in a sample of 252 professional baseball players to evaluate the links between sensorimotor skills and on-field performance. For this purpose, we develop a series of Bayesian hierarchical latent variable models enabling us to compare statistics across professional baseball leagues. Within this framework, we find that sensorimotor abilities are significant predictors of on-base percentage, walk rate and strikeout rate, accounting for age, position, and league. We find no such relationship for either slugging percentage or fielder-independent pitching. The pattern of results suggests performance contributions from both visual-sensory and visual-motor abilities and indicates that sensorimotor screenings may be useful for player scouting.

Vision and Visual History in Elite/Near-Elite-Level Cricketers and Rugby-League Players

BACKGROUND

The importance of optimal and/or superior vision for participation in high-level sports remains the subject of considerable clinical research interest. Here, we examine the vision and visual history of elite/near-elite cricketers and rugby-league players.

METHODS

Stereoacuity (TNO), colour vision, and distance (with/without pinhole) and near visual acuity (VA) were measured in two cricket squads (elite/international-level, female, n = 16; near-elite, male, n = 23) and one professional rugby-league squad (male, n = 20). Refractive error was determined, and details of any correction worn and visual history were recorded.

RESULTS

Overall, 63% had their last eye examination within 2 years. However, some had not had an eye examination for 5 years or had never had one (near-elite cricketers 30%; rugby-league players 15%; elite cricketers 6%). Comparing our results for all participants to published data for young, optimally corrected, non-sporting adults, distance VA was ~ 1 line of letters worse than expected. Adopting α = 0.01, the deficit in distance VA was significant, but only for elite cricketers (p < 0.001) (near-elite cricketers, p = 0.02; rugby-league players, p = 0.03). Near VA did not differ between subgroups or relative to published norms for young adults (p > 0.02 for all comparisons). On average, near stereoacuity was better than in young adults, but only in elite cricketers (p < 0.001; p = 0.03, near-elite cricketers; p = 0.47, rugby-league players). On-field visual issues were present in 27% of participants and mostly (in 75% of cases) comprised uncorrected ametropia. Some cricketers (near-elite 17.4%; elite 38%) wore refractive correction during play, but no rugby-league player did. Some individuals with prescribed correction choose not to wear it when playing.

CONCLUSIONS

Aside from near stereoacuity in elite cricketers, the basic visual abilities we measured were not better than equivalent, published data for optimally corrected adults; 20-25% exhibited sub-optimal vision, suggesting that the clearest possible vision might not be critical for participation at the highest levels in the sports of cricket or rugby league. Although vision could be improved in a sizeable proportion of our sample, the impact of correcting these, mostly subtle, refractive anomalies on playing performance is unknown.