Do Mound Height and Pitching Distance Affect Youth Baseball Pitching Biomechanics?

2018 ◽  
Vol 46 (12) ◽  
pp. 2996-3001 ◽  
Author(s):  
Glenn S. Fleisig ◽  
Alek Z. Diffendaffer ◽  
Brett Ivey ◽  
Takanori Oi
Keyword(s):  
Analysis Of Variance ◽  
Repeated Measures ◽  
Injury Risk ◽  
Random Order ◽  
Kinematic Parameters ◽  
Joint Stress ◽  
Repeated Measures Analysis ◽  
Youth Baseball ◽  
Ball Velocity ◽  
Post Hoc

Background: Pitching injuries continue to be a serious problem, with adolescents now representing the group with the most injuries. Some have proposed that lowering or eliminating the pitching mound in youth baseball may reduce joint stress and subsequent injuries. Another potential risk factor is advancing from youth to adult pitching distance without an intermediate distance. Hypotheses: It was hypothesized that for a group of young pitchers, pitching kinetics and kinematics would change with mound height. It was also hypothesized that pitching kinetics and kinematics would change with pitching distance. Study Design: Controlled laboratory study. Methods: Twenty-one young (12.6 ± 0.5 years) baseball pitchers pitched 5 full-effort fastballs each from 5 different conditions, in random order: 14.02-, 16.46-, and 18.44-m distances from a 25 cm–high mound, 16.46-m distance from a 15 cm–high mound, and 16.46-m distance from flat ground. Pitching biomechanical values were collected with a 12-camera automated motion capture system. Ball velocity and 31 other parameters were computed for each pitch. Data were compared between the 3 mound heights at 16.46 m by use of repeated-measures analysis of variance and paired post hoc t tests ( P < .05). Similarly, data were compared between the 3 distances from the 25-cm mound via repeated-measures analysis of variance and paired post hoc t tests ( P < .05). Results: No differences were found in ball velocity, shoulder kinetics, or elbow kinetics associated with mound height. Ten kinematic parameters differed with mound height, including 8 parameters at lead foot contact. Maximum shoulder horizontal adduction torque and maximum shoulder anterior force increased with pitching distance. Only 3 kinematic parameters showed significant differences with pitching distance. Conclusion: The hypothesis that shoulder and elbow kinetics would change with mound height was not supported by the data. Several kinematic differences were found, but the majority were at lead foot contact before the rapid, dynamic phases of pitching. Change in pitching distance was associated with slight increase in shoulder kinetics as well as a few kinematic differences. Clinical Relevance: Lowering or eliminating pitching mounds in youth baseball would not significantly decrease joint stress and injury risk to young pitchers. However, when available, transition from 14.02-m to 16.46-m to 18.44-m pitching distance may reduce stress on the young throwing shoulder.

Effects of Pretest Stimulative and Sedative Music on Grip Strength

1996 ◽  
Vol 83 (3_suppl) ◽  
pp. 1347-1352 ◽  
Author(s):  
Costas I. Karageorghis ◽  
Kevin M. Drew ◽  
Peter C. Terry
Keyword(s):  
White Noise ◽  
Grip Strength ◽  
Analysis Of Variance ◽  
Repeated Measures ◽  
Noise Control ◽  
Sensitive Measure ◽  
Repeated Measures Analysis ◽  
Post Hoc

The purpose of the present study was to investigate the effects of stimulative (energizing) and sedative (relaxing) music on grip strength. A 2 × 3 (gender × condition) repeated-measures analysis of variance and post hoc tests showed that participants ( N = 50) evidenced higher grip strength after listening to stimulative music ( M = 43.94 kg. force) than after sedative music or a white noise control condition. Sedative music yielded lower scores than white noise. Men evidenced higher grip strength than women, but there was no interaction between gender and music condition. It was concluded that a simple motoric task such as grip strength provides a sensitive measure of psychophysical responses to music.

Effects of Hue, Value, and Chroma on College Students' Preferences for Apparel and Upholstery Fabrics

1989 ◽  
Vol 69 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Deanna J. Radeloff
Keyword(s):  
College Students ◽  
Analysis Of Variance ◽  
Repeated Measures ◽  
Experimental Conditions ◽  
Color Preferences ◽  
Repeated Measures Analysis ◽  
Post Hoc

To investigate the effects of hue, value, and chroma on college students' color preferences for apparel and upholstery fabrics, experimental conditions were established for evaluation of coded fabric swatches by 118 college students. On a repeated-measures analysis of variance, significant differences were noted among all variables for both conditions. From post hoc tests summer and winter hue categories did not differ for apparel but did for upholstery. Conversely, spring and autumn hue categories did not differ for upholstery but did for apparel. Cool hues were preferred over warm hues for apparel and upholstery. There was no consistent preference for value for apparel and upholstery. For chroma, dull colors were preferred significantly for both apparel and upholstery. Of 20 sets of matched fabrics, only five color preferences for apparel and upholstery fabrics were not significantly different. Overall, color preferences were not equivalent for apparel and for upholstery.

Effects of a Combination of Stances and Points of Aim on Putting Accuracy

1988 ◽  
Vol 66 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Erich Gott ◽  
Carl Mc Gown
Keyword(s):  
Analysis Of Variance ◽  
Repeated Measures ◽  
Traditional Method ◽  
Constant Error ◽  
Popular Opinion ◽  
Variable Error ◽  
Repeated Measures Analysis ◽  
Better Than

The purpose of this study was to determine the effects of two putting stances (conventional versus side-saddle) and two points of aim (ball versus hole) on putting accuracy. Subjects (12 men, 4 women) were taught to putt using four methods: (a) conventional stance, eyes on the ball; (b) conventional stance, eyes on the hole; (c) side-saddle stance, eyes on the ball; and (d) side-saddle stance, eyes on the hole. Each subject practiced each method for 2 wk., after which they were tested for purring accuracy by counting putts made, determining constant error, and by calculating variable error. Accuracy was assessed at 5 and 15 ft. A 2 by 2 repeated-measures analysis of variance showed that there was no single combination of stance and point of aim that was significantly better than another at either distance. This suggests that, contrary to popular opinion, the traditional method of putting is not the best method for putting; other methods are equally as good and could be used if individually desired.

scholarly journals Estimating Bayes factors from minimal summary statistics in repeated measures analysis of variance designs

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Thomas Faulkenberry
Keyword(s):  
Analysis Of Variance ◽  
Repeated Measures ◽  
Bayes Factor ◽  
Linear Models ◽  
Repeated Measurements ◽  
Bayes Factors ◽  
Complex Method ◽  
Summary Statistics ◽  
Minimal Set ◽  
Repeated Measures Analysis

In this paper, I develop a formula for estimating Bayes factors directly from minimal summary statistics produced in repeated measures analysis of variance designs. The formula, which requires knowing only the F-statistic, the number of subjects, and the number of repeated measurements per subject, is based on the BIC approximation of the Bayes factor, a common default method for Bayesian computation with linear models. In addition to providing computational examples, I report a simulation study in which I demonstrate that the formula compares favorably to a recently developed, more complex method that accounts for correlation between repeated measurements. The minimal BIC method provides a simple way for researchers to estimate Bayes factors from a minimal set of summary statistics, giving users a powerful index for estimating the evidential value of not only their own data, but also the data reported in published studies.

scholarly journals Effect of Educational Workshops on Disaster Risk Perception in Nurses

2020 ◽  
pp. 270-278
Keyword(s):  
Risk Perception ◽  
Repeated Measures ◽  
Intervention Group ◽  
Round Table ◽  
Disaster Risk ◽  
National Standards ◽  
Control Group ◽  
Repeated Measures Analysis ◽  
Post Hoc ◽  
And Control

INTRODUCTION: The enhancement of nurses’ risk perception plays a significant role in their preparedness during disasters and emergencies. Therefore, this study aimed to investigate the effect of educational workshops on disaster risk perception in nurses METHODS: This randomized controlled field trial study included 62 nurses working at Razi Hospital, Birjand, Iran. The participants were divided into intervention and control groups. The intervention group was then requested to participate in a one-day intensive educational workshop based on the current national standards. The workshop content included a combination of lecturing methods, round-table exercises, and film display. The data were collected using the demographic characteristic form and researcher-made questionnaires measuring the nurses’ risk perception during disasters and emergencies. Subsequently, the data were analyzed using independent t-test, repeated measures analysis, and Bonferroni post hoc tests. FINDINGS: The mean total score of risk perception were significantly higher in the intervention group before, immediately, and two months after the workshop session, compared to those in the control group (P˂0.001). CONCLUSION: The implementation of nurses’ national preparation program during disasters and emergencies can result in an increase in the nurses’ risk perception during these events. Therefore, regarding the importance of nurses’ preparedness in confrontation with disasters and emergencies, it seems necessary to integrate the National Preparedness Program into the educational programs immediately after recruitment and in the form of in-service courses.

Sagittal Plane Kinematics of Passive Dorsiflexion of the Foot in Adolescent Athletes

2013 ◽  
Vol 103 (5) ◽  
pp. 394-399 ◽  
Author(s):  
Alfred Gatt ◽  
Nachiappan Chockalingam ◽  
Owen Falzon
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Random Order ◽  
Adolescent Athletes ◽  
Range Of Movement ◽  
Kinematic Data ◽  
Repeated Measures Analysis ◽  
Foot Posture ◽  
Foot Model ◽  
Oxford Foot Model

Background: Although assessment of passive maximum foot dorsiflexion angle is performed routinely, there is a paucity of information regarding adolescents’ foot and foot segment motion during this procedure. There are currently no trials investigating the kinematics of the adolescent foot during passive foot dorsiflexion. Methods: A six-camera optoelectronic motion capture system was used to collect kinematic data using the Oxford Foot Model. Eight female amateur gymnasts 11 to 16 years old (mean age, 13.2 years; mean height, 1.5 m) participated in the study. A dorsiflexing force was applied to the forefoot until reaching maximum resistance with the foot placed in the neutral, pronated, and supinated positions in random order. The maximum foot dorsiflexion angle and the range of movement of the forefoot to hindfoot, tibia to forefoot, and tibia to hindfoot angles were computed. Results: Mean ± SD maximum foot dorsiflexion angles were 36.3° ± 7.2° for pronated, 36.9° ± 4.0° for neutral, and 33.0° ± 4.9° for supinated postures. One-way repeated-measures analysis of variance results were nonsignificant among the 3 groups (P = .70), as were the forefoot to tibia angle and hindfoot to tibia angle variations (P = .091 and P = .188, respectively). Forefoot to hindfoot angle increased with the application of force, indicating that in adolescents, the forefoot does not lock at any particular posture as portrayed by the traditional Rootian paradigm. Conclusions: Participants had very flexible foot dorsiflexion, unlike those in another study assessing adolescent athletes. This finding, together with nonsignificant statistical results, implies that foot dorsiflexion measurement may be performed at any foot posture without notably affecting results. (J Am Podiatr Med Assoc 103(5): 394–399, 2013)

The Effect of Register, Direction, and Magnitude on Musicians’ Evaluations of Chamber Ensemble Intonation: A Within-Study Comparison for Analysis of Repeated Measures

2021 ◽  
pp. 002242942110604
Author(s):  
David S. Miller
Keyword(s):  
Music Education ◽  
String Quartet ◽  
Repeated Measures ◽  
Teaching And Learning ◽  
Chamber Ensemble ◽  
Random Order ◽  
Item Order ◽  
Evaluation Task ◽  
Repeated Measures Analysis ◽  
Methodological Considerations

This study had two primary purposes: (1) to investigate the effect of register, direction, and magnitude on musicians’ evaluation of chamber ensemble intonation, and (2) determine whether a novel nonparametric technique, ordinal pattern analysis (OPA), was a viable alternative to repeated-measures analysis of variance (rANOVA). I digitally mastered a recording of a string quartet performing a phrase from Capriol Suite by altering the intonation of the violin or cello voice ±20 and 30 cents sharp and flat. Participants ( N = 72) completed a discrimination task and an evaluation task with the recordings, with task order, and within-task item order presented in a random order. Analysis using rANOVA revealed significant differences due to register, direction, and magnitude: Excerpts with cello errors were rated as more in tune than excerpts with violin errors; excerpts with flat errors were rated as more in tune than excerpts with sharp errors, and excerpts with 20-cent magnitude errors were rated as more in tune than excerpts with 30-cent magnitude errors. OPA results were consistent with rANOVA results. Substantive implications for music teaching and learning are discussed alongside methodological considerations and implications for music education research using repeated-measures designs.

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