EFFICIENCY INDEX USED TO ASSESS SHOULDER STRESS IN COLLEGE SOFTBALL PITCHERS THROUGHOUT A SIMULATED GAME

Shoulder distraction forces in softball pitching are known to have a positive impact on performance yet a negative impact on musculoskeletal health. The purpose of this study was to assess changes in shoulder stress across innings pitched using Efficiency Arm-Stress Index (EASI) scores. Motion capture was used on collegiate softball pitchers pitching a simulated game. Peak shoulder distraction force was obtained using inverse dynamics procedures and used to calculate an EASI score (fastball velocity divided by peak shoulder distraction force in percent body weight). A RM·ANOVA revealed inning had no effect on EASI score (F[6,7]=1.28, p=0.286). Understanding a pitcher’s efficiency score may help shape individual pitching loads. Future work should investigate clinically meaningful changes in efficiency scores and mechanisms behind low efficiencies

THE RELATIONSHIP BETWEEN TRUNK ENERGY FLOW AND COLLEGIATE SOFTBALL HITTING PERFORMANCE

The purpose of this study was to determine the relationship between trunk energy flow and performance (exit velocity) during collegiate softball hitting. Nineteen collegiate softball athletes (age: 19.6 ± 1.0yrs) performed three maximal effort swings off a pitching machine. Kinematic data were collected using an electromagnetic tracking system. A segmental power analysis was performed to quantify peak rates of trunk energy flow (proximal inflow (IF) and distal outflow (OF) on front and back sides). Regression analyses determined exit velocity was best predicted by peak rate of distal trunk energy OF on the front side. On average, the model showed exit velocity increased by .9 mph for every 100 W increase in distal trunk energy OF on the front side while holding body mass constant

Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond

Enhanced Growth and Osteogenic Differentiation of Human Osteoblast-Like Cells on Boron-Doped Nanocrystalline Diamond Thin Films

Intrinsic nanocrystalline diamond (NCD) films have been proven to be promising substrates for the adhesion, growth and osteogenic differentiation of bone-derived cells. To understand the role of various degrees of doping (semiconducting to metallic-like), the NCD films were deposited on silicon substrates by a microwave plasma-enhanced CVD process and their boron doping was achieved by adding trimethylboron to the CH4:H2 gas mixture, the B∶C ratio was 133, 1000 and 6700 ppm. The room temperature electrical resistivity of the films decreased from >10 MΩ (undoped films) to 55 kΩ, 0.6 kΩ, and 0.3 kΩ (doped films with 133, 1000 and 6700 ppm of B, respectively). The increase in the number of human osteoblast-like MG 63 cells in 7-day-old cultures on NCD films was most apparent on the NCD films doped with 133 and 1000 ppm of B (153,000±14,000 and 152,000±10,000 cells/cm2, respectively, compared to 113,000±10,000 cells/cm2 on undoped NCD films). As measured by ELISA per mg of total protein, the cells on NCD with 133 and 1000 ppm of B also contained the highest concentrations of collagen I and alkaline phosphatase, respectively. On the NCD films with 6700 ppm of B, the cells contained the highest concentration of focal adhesion protein vinculin, and the highest amount of collagen I was adsorbed. The concentration of osteocalcin also increased with increasing level of B doping. The cell viability on all tested NCD films was almost 100%. Measurements of the concentration of ICAM-1, i.e. an immunoglobuline adhesion molecule binding inflammatory cells, suggested that the cells on the NCD films did not undergo significant immune activation. Thus, the potential of NCD films for bone tissue regeneration can be further enhanced and tailored by B doping and that B doping up to metallic-like levels is not detrimental for cells

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

INFLUENCE OF IN-GAME SITUATION ON BALL RELEASE PARAMETERS IN DIVISION 1 COLLEGE BASEBALL PITCHERS

BACKGROUND: Success at high competition levels often hinges on performing well during high pressure (leverage) situations. Advanced baseball analytics enable teams to quantify the pressure of in-game situations, and markerless motion capture makes it possible to capture in-game biomechanical data. Research suggests consistent pitch release parameters improve performance across a season. Therefore, this study aimed to compare fastball release parameters and pitch velocity in college baseball pitchers between in-game high and low Leverage Index (LI) situations. METHODS: In-game markerless motion capture data (300Hz) for fifty-six NCAA Division 1 baseball pitchers (1.89±0.1m; 92.7±8.9kg) were analyzed. Pitch velocity and hand position (relative to the middle of the pitching rubber) in the anterior/posterior, superior/inferior, and medial/lateral directions at ball release were analyzed. Play-by-play data were scraped for LI components (score, innings, outs, and baserunners) and matched to the appropriate pitch. LI is an estimate of in-game pressure that measures the potential change in win expectancy and is calculated as the sum of the weighted change in win probability divided by the average win probability added per swing. Each pitcher’s highest and lowest LI fastball pitches were used for within-pitcher comparison. A one-way repeated measures multivariate analysis of variance (RM·MANOVA) determined if release parameters and pitch velocity differed between high and low LI situations (α = .05). RESULTS: Descriptive statistics (high LI mean ± SD vs. low LI mean ± SD) for the parameters analyzed are as follows: LI (2.8±1.6 vs. 0.4±0.5), pitch velocity (40.45±3.2 vs. 40.54±1.4 m/s), anterior/posterior hand position (1.72±0.1 vs. 1.73±0.1 m), medial/lateral hand position (0.52±0.2 vs. 0.47±0.2 m), and superior/inferior hand position (1.79±0.2 vs. 1.82±0.2 m). The RM·MANOVA revealed no significant differences in release parameters between high and low LI pitches (F4,52 =.322, p=.862). CONCLUSION: While prior research identified a relationship between consistency in the release position and season long performance, these release parameters are not influenced by high or low pressure (leverage) situations. Additional comparisons of high and low leverage situations, as determined by LI, should include analysis of additional kinematics, ball flight metrics, and ball/strike outcomes

KINEMATIC PREDICTORS OF INGAME FASTBALL VELOCITY IN NCAA DIVISION I BASEBALL PITCHERS

BACKGROUND: Pitch velocity is a key measure of fastball performance in baseball pitchers. The kinematics related to ball velocity are traditionally examined in laboratory settings with marker-based motion capture systems. However, limited research exists investigating their influence on in-game performance. The purpose of this study was to identify the kinematic predictors of in-game fastball velocity in collegiate baseball pitchers. METHODS: Kinematic data from 57 NCAA Division I pitchers (height: 1.89 ± 0.06m, mass: 93.1 ± 1.18kg) were collected at 300hz using an eight-camera markerless motion capture system (KinaTrax, Boca Raton, FL). Data were processed and filtered using propriety KinaTrax software. Kinematics were measured at foot contact (FC) (stride length, shoulder rotation, shoulder horizontal abduction, and shoulder abduction), maximum shoulder external rotation (MER) (shoulder rotation and elbow flexion), ball release (BR) (elbow flexion, shoulder abduction, trunk flexion, trunk lateral flexion, and lead knee flexion). Maximum knee extension velocity as well as trunk and pelvis rotation velocity were also included for analysis. Fastball velocity was recorded using a TrackMan (Scottsdale, AZ) V3 Game Tracking unit. The average of each subject’s first five fastballs thrown in a game was used for analysis. A backward multiple linear regression (α = .05) was used to identify the kinematic predictors of in-game fastball velocity. RESULTS: The average fastball velocity from the cohort was 40.9 ± 1.22m/s (91.4 ± 2.73mph). After the backward elimination (cutoff of p ≥ 0.05), three predictors explained 17.7% of the variance in fastball velocity (F(3,54)=3.81, R2 =.177, p=.014). As fastball velocity increases by 1 m/s (2.2 mph), max lead knee angle velocity increases by 0.003°/s (β=0.003, t=2.46, p=.017), max trunk rotational velocity increases by 0.005°/s (β=0.005, t=2.40, p=.020), or lead knee flexion at BR decreases by 0.027° (β=-0.027, t=-2.33, p=.024), while all other variables are held constant. CONCLUSION: The findings show greater stride knee extension at BR, maximum stride knee extension velocity, and maximum trunk rotational velocity are predictors of in-game fastball velocity. Investigating in-game data provided similar results to those of prior laboratory studies, while a higher pitch velocity, fewer significant variables, and lower coefficient of determination were noted

COMPARISON OF IN-GAME TRUNK AND UPPER EXTREMITY KINEMATICS BETWEEN PITCH TYPES IN COLLEGIATE BASEBALL PITCHERS

BACKGROUND: Baseball pitchers commonly experience shoulder and elbow injuries. Pitch type has been identified as a possible risk factor, but previous biomechanical studies were limited to laboratory analysis. The purpose of this study was to compare in-game trunk and upper extremity kinematics between fastballs, breaking balls, and changeups in collegiate baseball pitchers. METHODS: Twenty-four NCAA Division I collegiate baseball pitchers (1.9±0.1m; 94.5±10.5kg) who threw at least five in-game fastballs, breaking balls, and changeups were included in this study. Trunk and throwing-arm kinematics were recorded during games using a markerless motion capture system (300Hz). A TrackMan V3 Game Tracking unit defined pitch type. Kinematics of each pitcher’s first five pitches of each pitch type were averaged for analysis. A repeated measures multivariate analysis of variance (MANOVA) was used to assess within-subject differences between each pitch type (α = .05). The variables of interest were shoulder abduction at foot contact (FC), shoulder horizontal abduction at FC, shoulder external rotation at FC, shoulder maximum external rotation (MER), elbow flexion at MER, maximum shoulder rotational velocity, lateral trunk tilt at ball release (BR), shoulder abduction at BR, and elbow flexion at BR. RESULTS: The MANOVA revealed differences in kinematics between pitch types (F18,78 = 3.49, p\u3c.001). Follow-up univariate testing revealed significant differences across pitch types for MER (F2 = 3.77, p=.03) along with shoulder abduction (F2 = 6.27, p=.004), lateral trunk tilt (F2 = 11.63, p\u3c.001), and elbow flexion (F2 = 5.06, p =.01), all at BR. Pairwise comparisons revealed that fastballs had greater MER than breaking balls (mean within-subjects difference: 1.5±2.6°, p=.03). At BR, changeups resulted in greater shoulder abduction than fastballs (1.2±2.0°, p=.03) and breaking balls (1.5±2.3°, p=.01). Changeups produced less lateral trunk tilt at BR than fastballs (-3.6±4.8°, p=.003) and breaking balls (-2.9±4.2°, p=.008) and greater elbow flexion at BR than breaking balls (1.2±1.7°, p=.006). All other variables were not significantly different (p \u3e.10). CONCLUSION: Collegiate pitchers had in-game kinematic differences between pitch types, especially at BR. It is unknown if these differences alter injury risk, but they may impact performance by showing the batter which pitch type will be thrown

DIFFERENCES IN THROWING PHASE DURATIONS BETWEEN FAST AND SLOW TRANSFER TIMES IN YOUTH BASEBALL CATCHERS

BACKGROUND: Transfer time in baseball catching is the duration of time from receiving a pitch until the ball is released for a throw to second base. While transfer time is vital to a catcher’s success, research in baseball catching has mainly focused on the kinematics influencing throw velocity, rather than the duration of transfer time. Therefore, the purpose of this study was to compare the duration of throwing phases between fast and slow transfer times in youth baseball catchers. METHODS: Kinematics of twenty-one youth catchers (12±3yrs, 52.7±14.8kg, 1.57±0.15m) were recorded and analyzed using an electromagnetic motion capture system (100Hz). Transfer time for the throwdown consisted of three phases: start phase (movement initiation to stride foot contact), arm-cocking phase (stride foot contact to maximum shoulder external rotation), and acceleration phase (maximum shoulder external rotation to ball release). Two repeated measures MANOVAs were used for within-subjection comparison for the fastest and slowest trials for each participant. The first analysis (TT) compared the total time (sec) spent in each phase of the event, while the second analysis (PT) examined the percentage of time spent in each phase of the event. RESULTS: Significant within-subjects differences were observed for the fast and slow trials in the TT analysis (F3,18= 6.20, p =.004). Follow-up univariate analysis for TT showed the start phase being significantly quicker (F1=15.33, p \u3c.001) for fast trials (0.77 ± 0.24 s) compared to slow trials (1.17 ± 0.49 s). Remaining phases presented no differences in the TT analysis (p\u3e.514). The PT analysis also revealed significant differences between the fast and slow trials (F2,19 =9.80, p=.001). Follow-up univariate analysis for the PT test revealed that in the fast trials the start phase was significantly shorter (75.9 ± 7.7 vs 81.9 ± 6.9%; F1=12.23, p=.002), whereas the arm-cocking (18.63 ± 6.4 vs 14.35 ± 5.5%; F1=8.95, p =.007) and acceleration phases (5.5 ± 2.2 vs 4.2 ± 2.0%; F1=19.82, p \u3c.001) were longer. CONCLUSION: Fast trials resulted in less time spent in the start phase compared to slow trials. The percentage of total throw also varied between fast and slow trials with cocking and acceleration phases taking up larger percentages of time for fast trials. Considering these findings, catchers should focus on decreasing the time of their start phase to optimize their performance