Physical size associations to offensive performance among major league leaders.

Minimal work has studied physical size effects on statistical performance among Major League players. In this study, longitudinal, bivariate, and regression analyses studied the impact of physical size on offensive baseball statistics within a homogeneous talent sample of Major League batting leaders. Body mass index (BMI) was calculated from heights and weights that were publicly available to form a statistical database of 4,360 offense leaders from 1950 to 2010. Repeated-measures analysis of variances examined differences in anthropometrics and baseball statistics between each decade from 1950 to 2010. Bivariate correlation and linear regression analyses evaluated BMI as an independent variable of influence, where all tests applied an a priori significance level (p ≤ 0.05). After 1980, offensive performance increased (p ≤ 0.05) concurrent to body mass and BMI growth (p < 0.001). During the 1960s, only batting average and on-base plus slugging percentages were found statistically decreased (p ≤ 0.05). All baseball statistics were positively correlated and predicted by BMI (p < 0.001). Consideration to covariant factors is required in data interpretation, yet nonetheless, our results showed physical size (BMI) to positively influence Major League offensive statistics. Over the 60-year period, greater body weight-to-height proportions owed to improved competitive performance, which suggests greater emphasis on hypertrophic stimuli in training and nutrition, as well as selection of larger professional baseball prospects.

Changes in physical size among major league baseball players and its attribution to elite offensive performance.

Major League Baseball (MLB) players have not been longitudinally examined for changes in physical size. Height, weight, and body mass indices (BMIs) were examined among offensive league leaders (OLL) and MLB reference cohorts at 1970, 1990, and 2010. Anthropometric values were expected to increase successively, where OLL were expected to be larger at each respective time point. A Mixed Model analysis of variance (p ≤ 0.05) examined anthropometric differences over time within and between groups. Mass and BMI increased over successive years with the largest effect seen between 1990 and 2010 (p < 0.001). A significant height reduction was shown for OLL from 1970 to 1990 (p ≤ 0.05), being the only significant decrease in physical size; yet, leaders were heavier and taller compared with the MLB reference population (p < 0.014). Results show that physical size has evolved in MLB, with the OLL being the largest players shown at each year in succession. Professional baseball scouts may have been influenced by greater offensive prowess shown by larger athletes; yet, increased secular anthropometrics must also be factored in greater heights, weights, BMIs shown over time in MLB. It is possible that greater participation in strength and conditioning programs at an earlier age, advances in sport nutrition, and potential abuse of anabolic drugs are factors perpetuating growth rates at present.

An inferential and descriptive statistical examination of the relationship between cumulative work metrics and injury in Major League Baseball pitchers.

In Major League Baseball (MLB), games pitched, total innings pitched, total pitches thrown, innings pitched per game, and pitches thrown per game are used to measure cumulative work. Often, pitchers are allocated limits, based on pitches thrown per game and total innings pitched in a season, in an attempt to prevent future injuries. To date, the efficacy in predicting injuries from these cumulative work metrics remains in question. It was hypothesized that the cumulative work metrics would be a significant predictor for future injury in MLB pitchers. Correlations between cumulative work for pitchers during 2002-07 and injury days in the following seasons were examined using regression analyses to test this hypothesis. Each metric was then "binned" into smaller cohorts to examine trends in the associated risk of injury for each cohort. During the study time period, 27% of pitchers were injured after a season in which they pitched. Although some interesting trends were noticed during the binning process, based on the regression analyses, it was found that no cumulative work metric was a significant predictor for future injury. It was concluded that management of a pitcher's playing schedule based on these cumulative work metrics alone could not be an effective means of preventing injury. These findings indicate that an integrated approach to injury prevention is required. This approach will likely involve advanced cumulative work metrics and biomechanical assessment.

Fastball velocity trends in short-season minor league baseball.

Diminishing baseball velocities are objective measures to delineate pitching fatigue. Yet, velocity changes over the course of a competitive season vs. a single game remain unknown. This study examined fastball velocity (FBV) trends of minor league pitchers over an 8-game span. We assumed that accumulation of pitches would cause similar velocity decreases within games to produce velocity decreases between games pitched. Retrospective analysis of major league-affiliated pitching charts indicated mean FBVs, game pitches thrown, game innings pitched, rest days, and pitching work to rest ratios (PWRRs) for 12 pitchers over 8 games. Regression analyses (p < 0.05) were performed using the ordinary least squares method. The FBV was the dependent variable, where the explanatory variable was the game number (representing cumulative workload). Further analyses were performed on ball velocity differences predicted by days rest and PWRRs. The FBV increased linearly for the first 8 games of the season (R = 0.91, F(1,7) = 64.67, p < 0.001). Over the 8 - game period, mean FBVs increased 0.25 m/s (0.56 mph) with the greatest velocity increase occurring between the first and eighth game at 1.97 m/s (4.4 mph). Days rest and PWRRs did not impact FBV differences. When compared with previous research, minor league pitchers at the Class A Short Season level did not show similar exertion responses to cumulative workloads (pitches and innings pitched). Recovery factors (rest days, PWRRs, and training) also did not impact FBVs. Velocity increases may be attributable to biomechanical compensations, skill development, strength and conditioning regimens, multistarter rotations, and other performance-related factors. Strength and conditioning professionals should be aware of ball velocity trends, as apparent changes may infer neuromuscular fatigue and increased injury susceptibility, which require in-season training modifications.

The influence of body mass index and gender on the impact attenuation properties of flooring systems.

The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.

Examining the influence of physical size among major league pitchers.

BACKGROUND: Among professional pitchers, anthropometric changes and their effect on statistics are relatively unknown. Bivariate analyses and repeated one-way ANOVA evaluated the impact of physical size on baseball pitching statistics and attributes within an elite talent sample of Major League pitching leaders. METHODS: Body Mass Index (BMI) was calculated from publicly available players' heights and weights to form a statistical database of 1028 pitching leaders from 1950-2010. Repeated measures ANOVAs examined differences in anthropometrics and baseball statistics between decades 1950-2010. Bivariate correlation evaluated BMI as an independent variable of influence on statistics, where all tests applied an a-priori significance level (P<0.05). RESULTS: BMI increased throughout the sixty year period with weight growth greater than height (P<0.001). Increased BMI reported earlier signing age, and age of debut (P<0.05), where larger pitchers showed small positive correlation seen among saves (P<0.001) concurrent to negative correlation with innings pitched and complete games (P≤0.001), as well as shutouts (P<0.05). A contrast between saves and complete games pitched was found where saves increased over time (P<0.001) while complete games pitched declined (P<0.001). CONCLUSIONS: Over time, throwing workloads showed better management for larger starting pitchers with less innings pitched and complete games thrown added to an extra rest day in the pitching rotation. In contrast, paralleled increases in physical size with recorded saves at present requires greater medical and training attention to protecting the throwing arm of the larger relief pitchers, as increased body size can increase force properties and ball velocity owing to greater injury risks.

Injuries to young professional baseball pitchers cannot be prevented solely by restricting number of innings pitched.

BACKGROUND: The Major League Baseball schedule is longer and more intensive than minor and amateur leagues. As a result, major league pitchers endure a considerably higher cumulative workload throughout the season. Ligament, tendon, muscle, and bone tissues in young pitchers need time to adapt to the workload a major league pitcher must endure. To mitigate the risk of overuse injury, and allow time for tissue adaptation to occur, most teams limit the number of innings a young pitcher may throw. This study examined the relationship between innings pitched and future injury in young professional baseball pitchers. METHODS: All pitchers under 25 years of age that pitched at least one third of an inning in Major League Baseball during the 2002-2007 seasons were included in this study. Total innings pitched were accumulated for each season across three levels of professional baseball (Major League Baseball, and two levels of Minor Leagues). Regression analyses were preformed comparing innings pitched during a single season and difference in innings pitched over consecutive seasons to future injury, as measured by time spent on the disabled list. RESULTS: No significant correlation was found between innings pitched and future injury or consecutive season innings pitched difference and future injury. No significant differences were found when pitchers were split into groups based upon consecutive season innings pitched difference cutoffs. CONCLUSIONS: Based upon the evidence presented, strength and conditioning coaches, sports medicine specialists, and team trainers cannot rely solely on inning counts to accurately measure the tissue demands of professional baseball pitching. Therefore, inning limits alone cannot be used to protect young professional pitchers against the threat of injury.

An inferential investigation into how stride length influences temporal parameters within the baseball pitching delivery.

Motion analyses of lower body mechanics offer new schemas to address injury prevention strategies among baseball pitchers, where the influence of stride length remains unknown. This study examined the temporal effect of stride length at constituent pitching events and phases. Nineteen competitive pitchers (15 collegiate, 4 high school) were randomly assigned to pitch two simulated, 80-pitch games at ±25% of their desired stride length. An integrated, three-dimensional motion capture system recorded each pitch. Paired t-tests were used to determine whether differences between stride conditions at respective events and within phases were significantly different. The results demonstrate the shorter strides mediated earlier onset of stride foot contact, reduced time in single support whereas double support intervals increased (p<.001). The opposite was observed with the longer strides. However, the acceleration phase, which comprises the highest throwing arm kinematics and kinetics, remained unchanged. The interaction between stride length, stride foot contact onsets, and time in single support is inferentially evidenced. The equivalent acceleration phases suggest stride length alone influenced time in single and double support by altering the onset of stride foot contact, which perhaps affects the mechanics in preparing the throwing arm for maximal external shoulder rotation.

Energy absorption during impact on the proximal femur is affected by body mass index and flooring surface.

Impact mechanics theory suggests that peak loads should decrease with increase in system energy absorption. In light of the reduced hip fracture risk for persons with high body mass index (BMI) and for falls on soft surfaces, the purpose of this study was to characterize the effects of participant BMI, gender, and flooring surface on system energy absorption during lateral falls on the hip with human volunteers. Twenty university-aged participants completed the study with five men and five women in both low BMI (<22.5 kg/m(2)) and high BMI (>27.5 kg/m(2)) groups. Participants underwent lateral pelvis release experiments from a height of 5 cm onto two common floors and four safety floors mounted on a force plate. A motion-capture system measured pelvic deflection. The energy absorbed during the initial compressive phase of impact was calculated as the area under the force-deflection curve. System energy absorption was (on average) 3-fold greater for high compared to low BMI participants, but no effects of gender were observed. Even after normalizing for body mass, high BMI participants absorbed 1.8-fold more energy per unit mass. Additionally, three of four safety floors demonstrated significantly increased energy absorption compared to a baseline resilient-rolled-sheeting system (% increases ranging from 20.7 to 28.3). Peak system deflection was larger for high BMI persons and for impacts on several safety floors. This study indicates that energy absorption may be a common mechanism underlying the reduced risk of hip fracture for persons with high BMI and for those who fall on soft surfaces.

The effects of body mass index and sex on impact force and effective pelvic stiffness during simulated lateral falls.

BACKGROUND: The incidence of hip fractures is highest for underweight females with low body mass index (BMI). However, it is unknown how these factors influence impact dynamics during in-vivo lateral hip impacts.We used a pelvis release paradigm to compare: (1) absolute and normalized forces applied to the femur-pelvis system across sex and BMI groups; (2) the force-prediction accuracy of vibration-based versus force-deflection-based estimates of effective pelvic stiffness; and (3) effective pelvic stiffness between BMI and sex groups. METHODS: Twenty-eight persons participated (7 low-BMI females, 7 low-BMI males, 7 high-BMI females, 7 high-BMI males,with BMI criteria of <22.5 and >28 for low- and high-BMI groups respectively). The participant's pelvis was released from heights of 0 to 5 cm. A force plate measured impact loads, while a motion capture system measured pelvic deflection. FINDINGS: Peak impact forces were 22.6% higher, while normalized peak forces were 31.2% lower, for high- compared to low-BMI participants. Accuracy of peak force predictions improved by 25% for the force-deflection versus the vibration-based stiffness estimation method. Effective pelvic stiffness was greater for males than females, but no significant differences were observed between BMI groups. INTERPRETATION: This study adds to clinical understanding of the effects of sex and BMI on impact dynamics during falls on the hip, and raises questions about the biomechanical mechanisms underlying the protective role of high BMI on hip fracture risk. Understanding the relationship between impact mechanics and faller characteristics should lead to more effective prevention of hip fractures.