scholarly journals A Kinematic and Kinetic Comparison of Mound and Rocker Throws

2020 ◽  
Author(s):  
Anthony Brady ◽  
Sam Briend ◽  
Alex Caravan ◽  
Kyle Lindley ◽  
Michael E O'Connell ◽  
...  
Keyword(s):  
Doppler Radar ◽  
Rotation Angle ◽  
External Rotation ◽  
A Priori ◽  
P Value ◽  
Lower Body ◽  
Ball Release ◽  
Wide Range ◽  
Ball Velocity ◽  
Throwing Motion

The stride phase of the baseball throwing motion is an influential aspect in throwing performance as described in previously published literature. The Rocker drill is a constraint that is often used to change or improve baseball throwing performance throughout a wide range of settings, coaches, and training programs. Due to the lack of quantified and documented effects of the Rocker drill on throwing mechanics, this study aims to identify the resulting changes in performance, kinematics, kinematic velocities, and kinetics from the Rocker drill and a variation of the Rocker drill to determine which constraint may promote more effective mechanical changes. We hypothesize that the normal Rocker drill will have significantly different throwing arm, trunk, and lower body kinematic positions at front Foot Plant, maximum throwing shoulder external rotation, and Ball Release, as well as significantly different ball velocity, maximum kinematic velocities, and throwing elbow kinetics when compared to the “Foot-up” variation of the Rocker drill. A total of 30 healthy baseball pitchers with collegiate or professional competition experience threw three to five regulation baseballs out of the “stretch” pitching position, the Rocker drill, and a less constrained, Foot-up variation of the Rocker drill as close to maximal intent as possible. Subjects wore retroreflective markers for use in kinematic measurements and ball velocity was measured with a Doppler radar device. Eleven statistically significant differences were found among the a priori tests conducted between the normal Rocker drill and the Foot-up Rocker drill. Ball velocity in the Foot-up Rocker was significantly greater than the normal Rocker (82.03 vs 79.53, p-value < 0.0001).Within the trunk kinematics category, the normal Rocker drill showed significantly greater trunk rotation angle at both Ball Release (BR) (111.90 vs 108.43, p-value = 0.0008) and Maximum External Rotation (MER) (98.76 vs 95.85, p-value = 0.0220) while the Foot-up Rocker showed significantly greater trunk lateral tilt at both Ball Release (33.86 vs 31.66, p-value = 0.0021) and Foot Plant (FP) (5.55 vs -0.13, p-value = 0.0222) as well as trunk forward tilt at BR (21.25 vs 16.85, p-value < 0.0001). Within the lower body kinematics category, the normal Rocker showed significantly greater front knee flexion at BR (41.71 vs 36.17, p-value = 0.0010), MER (49.51 vs 44.80, p-value = 0.0220) and FP (62.92 vs 51.04, p-value < 0.0001) while the Foot-up Rocker had significantly greater pelvis rotation angle at FP (38.25 vs 26.51, p-value = 0.0432). Within the kinematic velocity category, the Foot-up Rocker had significantly greater shoulder internal rotation angular velocity (4295.33 vs 4143.25, p-value = 0.0006). This study aims to identify various mechanical and performance differences in the throwing motion between the Rocker drill and a less constrained, Foot-up variation of the Rocker drill. Ball velocity, trunk and lower body kinematics as well as kinematic velocities showed significant differences between the Rocker and the Foot-up variation of the drill. These results can be used by coaches and trainers to determine in which setting these drills may provide desired throwing motion adjustments.

The Association Among Trunk Rotation, Ball Velocity, and the Elbow Varus Moment in Collegiate-Level Baseball Pitchers

2019 ◽  
Vol 47 (12) ◽  
pp. 2816-2820 ◽  
Author(s):  
Andrew D. Cohen ◽  
Erin J. Garibay ◽  
Matthew J. Solomito
Keyword(s):  
Elbow Joint ◽  
Rotation Angle ◽  
Rotational Velocity ◽  
Trunk Rotation ◽  
Joint Stress ◽  
Trunk Motion ◽  
Ball Release ◽  
Average Maximum ◽  
Ball Velocity ◽  
Baseball Pitchers

Background: The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decade, research has attempted to elucidate the cause of these injuries, focusing mainly on pitching arm mechanics with little examination of other important segments, such as the trunk. This is surprising, as trunk motion has been shown to have significant effects on pitching mechanics. Purpose: To determine the associations between trunk rotation, ball velocity, and the moments about the elbow joint. Study Design: Descriptive laboratory study. Methods: Data collected using 3-dimensional motion analysis techniques from 99 collegiate pitchers (18.0-24.8 years) were analyzed. A random intercept mixed-effects regression model was used to determine if significant associations existed between trunk rotation and ball velocity or elbow varus moment. Results: Significant associations were found between trunk rotation angle at ball release and elbow varus moment ( P = .019, β = 0.254) as well as ball velocity ( P = .016, β = 0.060). For every 10° increase over the average trunk rotation angle at ball release, the elbow varus moment increased by 2.54 N·m and the ball velocity increased by 0.60 m/s. Additionally, the maximum rotational velocity of the trunk was positively associated with elbow varus moment ( P < .001, β = 0.029) and ball velocity ( P < .001, β = 0.007). For every 100 deg/s increase over the average maximum rotational velocity of the trunk, the elbow varus moment increased by 2.90 N·m and the ball velocity increased by 0.70 m/s. Conclusion: In collegiate pitchers, trunk rotation angle at ball release was significantly associated with ball velocity and elbow varus moment. Also, an increase in maximum rotational velocity of the trunk was significantly associated with an increase in the ball velocity and elbow varus moment. This work demonstrates the importance of trunk mechanics in the kinetic chain of the pitch cycle. Clinical Relevance: Pitching coaches and trainers can use the results to stress the importance of trunk mechanics in pitching, specifically, combining adequate core function with increased trunk rotational velocity in an effort to increase pitching velocity without increasing elbow joint stress.

scholarly journals The effects of a four weeks combined resistance training programme on cricket bowling velocity

2021 ◽  
Vol 33 (1) ◽  
pp. 1-6
Author(s):  
Mogammad Sharhidd Taliep ◽  
Rifqah Maker
Keyword(s):  
Resistance Training ◽  
Training Programme ◽  
Upper Body ◽  
Lower Body ◽  
Neuromuscular Performance ◽  
Resistance Training Programme ◽  
Ball Release ◽  
Significant Difference ◽  
Ball Velocity ◽  
Cricket Bowling

Background: Despite the importance of resistance training for cricket pace bowlers, there is limited research displaying meaningful improvements in ball release velocity following resistance training. Objectives: The study aimed at investigating the effects of a four weeks combined resistance training programme on ball release velocity in club cricket pace bowlers. Methods: Eighteen adult male club level pace bowlers were allocated into a combined resistance training (CRT) group or a traditional cricket training (TR) group. The CRT group (n=9) performed two training sessions a week for four weeks, consisting of a combination of core and lower body strength exercises, plyometric exercises, and weighted implement training. The TR group (n=9) did no resistance training and only bowled with regular weighted cricket balls. Pre- testing/post-testing variables were ball release velocity, bowling accuracy, and upper and lower body neuromuscular performance. Results: The CRT group significantly increased their ball release velocity by six percent (5.1 km·h-1), effect size (ES) =0.65, p<0.001) after four weeks of training, while there was no significant difference in the TR group (0.00 km·h-1, ES=0.0, p=0.674). There was no statistically significant difference in the bowling accuracy and lower body neuromuscular performance for both groups and the upper body neuromuscular performance for the CRT group. Conclusion: This study provides evidence of a combined resistance training programme that can be used to improve bowling velocity in cricket pace bowlers. This increase in ball velocity was not related to any of the neuromuscular performance variables measured.

Overarm Throwing Variability as a Function of Trunk Action

2013 ◽  
Vol 1 (4) ◽  
pp. 89-95 ◽  
Author(s):  
M. A. Urbin ◽  
David Stodden ◽  
Glenn Fleisig
Keyword(s):  
External Rotation ◽  
Movement Pattern ◽  
Linear Velocity ◽  
Body Segment ◽  
Ball Release ◽  
Angular Velocities ◽  
Overarm Throwing ◽  
Trunk Tilt ◽  
Throwing Motion ◽  
Individual Body

Individual body segment actions evolve during throwing skill development. Maximal trunk involvement is typically the last feature of the movement pattern to fully develop. The current study examined developmental levels of trunk action and the associated variability in the throwing motion. The throwing motions of children and adolescents were analyzed via motion capture and trunk actions were classified as exhibiting no rotation (n = 7), blocked rotation (n = 6), or differentiated rotation (n = 11). Results indicated nonrotators exhibited greater variability than blocked-rotators in maximum humeral external rotation and humeral horizontal adduction angles at ball release; nonrotators also demonstrated greater variability than differentiated-rotators on these parameters, in addition to forward trunk tilt and elbow extension angle at ball release. Nonrotators produced more variable peak upper torso and humeral horizontal adduction angular velocities, as well as peak upper torso linear velocity, relative to differentiated-rotators. Blocked-rotators produced more variable peak pelvis, upper torso, and humeral horizontal adduction angular velocities, as well peak pelvis linear velocity, relative to differentiated-rotators. Nonrotators were less consistent relative to blocked- and differentiated-rotators in the time that elapsed from peak pelvis angular velocity to ball release. These results indicate that greater trunk involvement is associated with more consistent movement production.

scholarly journals Motion Analysis Focusing on Rotational Movements of Professional Female Baseball Pitchers: Comparison with Male University Baseball Pitchers

2021 ◽  
Vol 18 (24) ◽  
pp. 13342
Author(s):  
Yoshikazu Azuma ◽  
Tomoyuki Matsui ◽  
Machiko Hiramoto ◽  
Ruo Hashimoto ◽  
Kanta Matsuzawa ◽  
...  
Keyword(s):  
Motion Analysis ◽  
External Rotation ◽  
Three Dimensional ◽  
Lateral Side ◽  
Kinematic Data ◽  
Ball Release ◽  
Rotation Phase ◽  
Baseball Pitchers ◽  
Analysis System ◽  
Throwing Motion

Purpose: The purpose of this study was to compare pitching motion of the professional female baseball pitchers with the male university baseball pitchers focused on the pelvic and thoracic movements. Subjects and methods: The participants were 15 healthy professional female baseball pitchers (11 right-handers and 4 left-handers; age, 21.7 ± 3.2 years; height, 162.5 ± 5.1 cm; weight, 59.0 ± 6.6 kg) and 14 healthy male university baseball pitchers (12 right-handers and 2 left-handers; age, 19.9 ± 0.8 years; height, 176.4 ± 3.0 cm; body mass, 73.1 ± 3.0 kg). Throwing motion was captured by three-dimensional motion analysis system. Kinematic data of the lead hip, pelvis, thorax, and dominant shoulder were collected and the joint angle at maximum external rotation phase and ball release phase were compared. Results: The female baseball pitchers rotated pelvis and thorax more than the male at the maximum external rotation phase and ball release phase (p < 0.05). At the same, the pelvis and thorax of the female baseball pitchers were tilted significantly closer to horizontal plane than the male (p < 0.05). The pelvis and thorax of the male baseball pitchers was tilted to non-dominant lateral side. Conclusions: The results of this study indicate that the pelvic and thoracic movements of the professional female baseball pitchers was different from male university pitchers.

The influence of shoulder abduction and external rotation on throwing arm kinetics in professional baseball pitchers

2021 ◽  
pp. 175857322110103
Author(s):  
Joseph E Manzi ◽  
Brittany Dowling ◽  
Nicolas Trauger ◽  
Michael C Fu ◽  
Benjamin R Hansen ◽  
...  
Keyword(s):  
Body Weight ◽  
External Rotation ◽  
Professional Baseball ◽  
Shoulder Abduction ◽  
3D Motion Analysis ◽  
Ball Release ◽  
Ball Velocity ◽  
Shoulder External Rotation ◽  
Baseball Pitchers ◽  
Distraction Force

Background The relationships between shoulder abduction and external rotation with peak kinetic values at the shoulder and elbow in professional baseball pitchers are not well established. Methods Professional pitchers ( n = 322) threw 8–12 fastballs under 3D motion analysis (480 Hz). Pitchers were stratified into quartiles by shoulder abduction and external rotation at distinct timepoints. Regression analyses were performed to quantify associations between shoulder position and kinetics. Results Shoulder abduction remained relatively consistent throughout the pitch (foot contact–ball release: 85.5 ± 11.1–90.7 ± 8.4°); shoulder external rotation increased dramatically (foot contact–ball release: 30.8 ± 24.6–165.2 ± 9.7°). For every 10° increase in maximum shoulder rotation, shoulder superior force increased by 2.3% body weight ( p < 0.01), shoulder distraction force increased by 5.9% body weight ( p < 0.01), and ball velocity increased by 0.60 m/s ( p < 0.01). Shoulder abduction was significantly associated with shoulder superior force at all timepoints but not with ball velocity ( p > 0.05). For every 10° increase in shoulder abduction at ball release, shoulder superior force increased by 3.7% body weight ( p < 0.01) and shoulder distraction force increased by 11.7% body weight ( p < 0.01). Conclusion Increased shoulder abduction at ball release and increased maximum shoulder external rotation were associated with greater superior and distraction forces in the shoulder. Pitchers can consider decreasing shoulder abduction at later stages of the pitch to around 80° in order to minimize shoulder superior force, with no impact on ball velocity.

scholarly journals A Systematic Review and Qualitative Synthesis Resulting in a Typology of Elementary Classroom Movement Integration Interventions

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Spyridoula Vazou ◽  
Collin A. Webster ◽  
Gregory Stewart ◽  
Priscila Candal ◽  
Cate A. Egan ◽  
...  
Keyword(s):  
Physical Activity ◽  
Teacher Collaboration ◽  
A Priori ◽  
Real Life ◽  
Dose Intensity ◽  
Routine Practice ◽  
Qualitative Synthesis ◽  
Wide Range ◽  
Meta Analyses ◽  
Movement Integration

Abstract Background/Objective Movement integration (MI) involves infusing physical activity into normal classroom time. A wide range of MI interventions have succeeded in increasing children’s participation in physical activity. However, no previous research has attempted to unpack the various MI intervention approaches. Therefore, this study aimed to systematically review, qualitatively analyze, and develop a typology of MI interventions conducted in primary/elementary school settings. Subjects/Methods Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to identify published MI interventions. Irrelevant records were removed first by title, then by abstract, and finally by full texts of articles, resulting in 72 studies being retained for qualitative analysis. A deductive approach, using previous MI research as an a priori analytic framework, alongside inductive techniques were used to analyze the data. Results Four types of MI interventions were identified and labeled based on their design: student-driven, teacher-driven, researcher-teacher collaboration, and researcher-driven. Each type was further refined based on the MI strategies (movement breaks, active lessons, other: opening activity, transitions, reward, awareness), the level of intrapersonal and institutional support (training, resources), and the delivery (dose, intensity, type, fidelity). Nearly half of the interventions were researcher-driven, which may undermine the sustainability of MI as a routine practice by teachers in schools. An imbalance is evident on the MI strategies, with transitions, opening and awareness activities, and rewards being limitedly studied. Delivery should be further examined with a strong focus on reporting fidelity. Conclusions There are distinct approaches that are most often employed to promote the use of MI and these approaches may often lack a minimum standard for reporting MI intervention details. This typology may be useful to effectively translate the evidence into practice in real-life settings to better understand and study MI interventions.

scholarly journals Natural Experiment on Trade and Investment Liberalization and Soft Drink Consumption

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
Y Tcholakov
Keyword(s):  
Public Health ◽  
International Trade ◽  
Natural Experiment ◽  
Soft Drink ◽  
Trade Agreement ◽  
P Value ◽  
Soft Drink Consumption ◽  
Obesity And Diabetes ◽  
Wide Range ◽  
The Impact

Abstract Background Globalization is recognized to as a contributing factor to a health harming environment through a variety of mechanisms including through changes in food systems and food availability. Sugar-sweetened beverage (SSB) consumption is linked to obesity and diabetes and its regulation is a key priority for public health. The Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) is an international trade agreement between 11 countries. Methods This project uses of natural experiment methods to predict the impact of the entry into force of the CPTPP on SSB consumption. These methods allow quantitative inferences to be drawn in the situations where the exposure is not randomly assigned. Soft drink consumption data was collected from the Euromonitor database for 80 countries from all regions. This data was used to estimate the effect of agreements similar to the TPP. Results Eleven country trade agreement pairs were identified. In 5 cases out of the 11, the exposed country had a higher soft drink consumption at five years after the trade agreement. The effect of the trade agreement exposure for an average country in the sample in a trade agreement was found to be 1.10 (95% CI: 1.01-1.18; p-value: 0.03) after adjusting for GDP and the involvement of the US. In 7 of the 11 member-countries soft drink consumption is expected to increase yielding an average increase of 9.0% in those countries; the changes did not yield statistically significant differences in others. Conclusions This projected extended the use of synthetic methods to the projection of future effects of policy implementation. While it showed that there may be increasing trend of SSB consumption in certain scenarios, this could not be generalized to all cases. This illustrates the wide range of effects of international trade liberalization and highlights that national policy probably plays a strong modulating role on the impact that it has on local food environments. Key messages Globalization can lead to health harming environments and its impacts should further be studied by public health professionals and researchers. Many global policies have the potential to lead to significant health impacts but are negotiated without involving public health experts.

Applications of 3D printing in critical care medicine: A scoping review

2021 ◽  
pp. 0310057X2097665
Author(s):  
Natasha Abeysekera ◽  
Kirsty A Whitmore ◽  
Ashvini Abeysekera ◽  
George Pang ◽  
Kevin B Laupland
Keyword(s):  
Critical Care ◽  
Scoping Review ◽  
A Priori ◽  
Three Dimensional ◽  
Critical Care Medicine ◽  
Future Research ◽  
Care Practice ◽  
Three Dimensional Printing ◽  
Wide Range ◽  
Dimensional Printing

Although a wide range of medical applications for three-dimensional printing technology have been recognised, little has been described about its utility in critical care medicine. The aim of this review was to identify three-dimensional printing applications related to critical care practice. A scoping review of the literature was conducted via a systematic search of three databases. A priori specified themes included airway management, procedural support, and simulation and medical education. The search identified 1544 articles, of which 65 were included. Ranging across many applications, most were published since 2016 in non – critical care discipline-specific journals. Most studies related to the application of three-dimensional printed models of simulation and reported good fidelity; however, several studies reported that the models poorly represented human tissue characteristics. Randomised controlled trials found some models were equivalent to commercial airway-related skills trainers. Several studies relating to the use of three-dimensional printing model simulations for spinal and neuraxial procedures reported a high degree of realism, including ultrasonography applications three-dimensional printing technologies. This scoping review identified several novel applications for three-dimensional printing in critical care medicine. Three-dimensional printing technologies have been under-utilised in critical care and provide opportunities for future research.

scholarly journals Hierarchical Matching and Regression with Application to Photometric Redshift Estimation

2016 ◽  
Vol 12 (S325) ◽  
pp. 145-155
Author(s):  
Fionn Murtagh
Keyword(s):  
Information Structure ◽  
Data Analytics ◽  
A Priori ◽  
Sloan Digital Sky Survey ◽  
Photometric Redshifts ◽  
Merging Galaxies ◽  
Photometric Redshift ◽  
Sky Survey ◽  
Wide Range ◽  
Regression Problems

AbstractThis work emphasizes that heterogeneity, diversity, discontinuity, and discreteness in data is to be exploited in classification and regression problems. A global a priori model may not be desirable. For data analytics in cosmology, this is motivated by the variety of cosmological objects such as elliptical, spiral, active, and merging galaxies at a wide range of redshifts. Our aim is matching and similarity-based analytics that takes account of discrete relationships in the data. The information structure of the data is represented by a hierarchy or tree where the branch structure, rather than just the proximity, is important. The representation is related to p-adic number theory. The clustering or binning of the data values, related to the precision of the measurements, has a central role in this methodology. If used for regression, our approach is a method of cluster-wise regression, generalizing nearest neighbour regression. Both to exemplify this analytics approach, and to demonstrate computational benefits, we address the well-known photometric redshift or ‘photo-z’ problem, seeking to match Sloan Digital Sky Survey (SDSS) spectroscopic and photometric redshifts.

scholarly journals A Consistent Track-to-Track Fusion Method Based on Copula Theory

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kelin Lu ◽  
K. C. Chang ◽  
Rui Zhou
Keyword(s):  
Probability Distributions ◽  
A Priori ◽  
Joint Probability ◽  
Network Connectivity ◽  
Consistent Estimate ◽  
Fusion Algorithm ◽  
Copula Theory ◽  
Wide Range ◽  
Primary Advantage ◽  
Joint Probability Distributions

This paper addresses the problem of distributed fusion when the conditional independence assumptions on sensor measurements or local estimates are not met. A new data fusion algorithm called Copula fusion is presented. The proposed method is grounded on Copula statistical modeling and Bayesian analysis. The primary advantage of the Copula-based methodology is that it could reveal the unknown correlation that allows one to build joint probability distributions with potentially arbitrary underlying marginals and a desired intermodal dependence. The proposed fusion algorithm requires no a priori knowledge of communications patterns or network connectivity. The simulation results show that the Copula fusion brings a consistent estimate for a wide range of process noises.

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