Effect of rider experience on the jumping kinematics of riding horses

2005 ◽  
Vol 2 (4) ◽  
pp. 263-267 ◽  
Author(s):  
Pippa NR Powers ◽  
Anna M Kavanagh
Keyword(s):  
Repeated Measures ◽  
Stride Length ◽  
Body Position ◽  
Body Movement ◽  
Experimental Conditions ◽  
Repeated Measures Anova ◽  
Video Recordings ◽  
Current Belief

AbstractThe aim of this study was to examine the influence of an experienced rider and a novice rider on the stride kinematics of experienced riding horses. SVHS video recordings (50 Hz) were made of ten experienced riding horses jumping a 1.05 m-high vertical fence. The horses were randomly assigned to jump the fence under two experimental conditions: ridden by an experienced rider and ridden by a novice rider. Three trials for each ridden condition were analysed, and the effects of the rider type on four kinematic variables were examined using a repeated measures ANOVA. No significant differences were found between the riders for velocity and stride length during the approach, or for the take-off and landing distances from the fence. The results suggest that the rider's body position and body movement had no effect on the horse's jumping kinematics as measured in this study, and that each horse jumped the fence in its own manner, regardless of what the rider was doing. This is contrary to the current belief that a horse's jumping technique is strongly influenced by the rider. These findings have relevance for both horses and riders, in that if an experienced horse does not respond to a rider's instructions as expected, then the implications for training of the horse and the rider are considerable.

scholarly journals The effects of a sled push at different loads on 20 metre sprint time in well-trained soccer players

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Nick Grimes ◽  
Jorge Arede ◽  
Benjamin Drury ◽  
Steve Thompson ◽  
John Fernandes
Keyword(s):  
Body Mass ◽  
Repeated Measures ◽  
Soccer Players ◽  
Control Group ◽  
Control Groups ◽  
Experimental Conditions ◽  
Repeated Measures Anova ◽  
Sprint Time ◽  
And Control ◽  
Experimental Group

This study determined the effects of a single sled push at different loads on sprint performance in competitive male soccer players. Twenty male competitive outfield soccer players (age 19.6±1.3y, body mass 73.6±8.2kg) were split into experimental (n=10) and control groups. In the experimental group, 20m linear sprint time was measured immediately before and 5, 6 and 7minutes after the sled push with either 50 or 100% body mass. The control group performed the 20m sprints only. A repeated measures ANOVA comparing control and experimental groups revealed no effects of time, group or time by group interaction for either experimental condition (all P>0.05). The repeated measures ANOVA compared the experimental conditions revealed effects of time (P=0.034) and group (P=0.002), but not time by group (P>0.05). The effects sizes demonstrated within group effects on sprint time that were small to moderate (-0.26 to 0.71) and trivial to small (-0.31 to 0.09) for the 50% and 100% body mass condition, respectively. These findings demonstrate that a sled push has no significant effect on 20 m sprint time in competitive footballers. If coaches continue to prescribed a sled push before sprinting, a single 15 m push with 50% body mass could have positive benefits.

Influences of a rider on the rotation of the horse–rider system during jumping

2004 ◽  
Vol 1 (1) ◽  
pp. 33-40 ◽  
Author(s):  
PNR Powers ◽  
AJ Harrison
Keyword(s):  
Angular Momentum ◽  
Angular Velocity ◽  
Repeated Measures ◽  
Total Angular Momentum ◽  
Sagittal Plane ◽  
Repeated Measures Anova ◽  
Flight Phase ◽  
Video Recordings

AbstractThis study examined the effects of a rider on the angular momentum and angular velocity of the jumping horse, particularly during the flight phase. Sagittal plane video recordings were digitized of eight horses jumping a vertical fence (1 m high) under two conditions: Loose and Ridden. An experienced rider rode the horses during the Ridden condition. Using appropriate segmental inertial data for the horse and rider, angular momentum and angular velocity were calculated for the Loose and Ridden conditions. Estimates of the various rider effects on angular momentum and angular velocity were obtained by comparison of Loose and Ridden conditions and examination of the contributions of the horse and rider segments to the total angular momentum. The results showed that the rider's effect on angular momentum was significant but that the rider's segmental contribution to the angular momentum of the horse–rider system was minimal. Repeated-measures ANOVA revealed that the rider had a significant effect on the angular momentum and angular velocity of the horse during the flight phase (P<0.01). However, the rider did not have a significant effect on the transfer of angular momentum during the flight. We concluded that the rider's instruction has a greater influence on the horse's motion than the mechanical transfer between rider and horse.

Evaluation of Acoustic Analyses of Voice in Nonoptimized Conditions

2020 ◽  
Vol 63 (12) ◽  
pp. 3991-3999
Author(s):  
Benjamin van der Woerd ◽  
Min Wu ◽  
Vijay Parsa ◽  
Philip C. Doyle ◽  
Kevin Fung
Keyword(s):  
Repeated Measures ◽  
Voice Quality ◽  
Data Sets ◽  
Acoustic Measurements ◽  
Sample Collection ◽  
Experimental Conditions ◽  
Environment Analysis ◽  
Acoustic Measures ◽  
Recording Conditions ◽  
Cepstral Peak Prominence

Objectives This study aimed to evaluate the fidelity and accuracy of a smartphone microphone and recording environment on acoustic measurements of voice. Method A prospective cohort proof-of-concept study. Two sets of prerecorded samples (a) sustained vowels (/a/) and (b) Rainbow Passage sentence were played for recording via the internal iPhone microphone and the Blue Yeti USB microphone in two recording environments: a sound-treated booth and quiet office setting. Recordings were presented using a calibrated mannequin speaker with a fixed signal intensity (69 dBA), at a fixed distance (15 in.). Each set of recordings (iPhone—audio booth, Blue Yeti—audio booth, iPhone—office, and Blue Yeti—office), was time-windowed to ensure the same signal was evaluated for each condition. Acoustic measures of voice including fundamental frequency ( f o ), jitter, shimmer, harmonic-to-noise ratio (HNR), and cepstral peak prominence (CPP), were generated using a widely used analysis program (Praat Version 6.0.50). The data gathered were compared using a repeated measures analysis of variance. Two separate data sets were used. The set of vowel samples included both pathologic ( n = 10) and normal ( n = 10), male ( n = 5) and female ( n = 15) speakers. The set of sentence stimuli ranged in perceived voice quality from normal to severely disordered with an equal number of male ( n = 12) and female ( n = 12) speakers evaluated. Results The vowel analyses indicated that the jitter, shimmer, HNR, and CPP were significantly different based on microphone choice and shimmer, HNR, and CPP were significantly different based on the recording environment. Analysis of sentences revealed a statistically significant impact of recording environment and microphone type on HNR and CPP. While statistically significant, the differences across the experimental conditions for a subset of the acoustic measures (viz., jitter and CPP) have shown differences that fell within their respective normative ranges. Conclusions Both microphone and recording setting resulted in significant differences across several acoustic measurements. However, a subset of the acoustic measures that were statistically significant across the recording conditions showed small overall differences that are unlikely to have clinical significance in interpretation. For these acoustic measures, the present data suggest that, although a sound-treated setting is ideal for voice sample collection, a smartphone microphone can capture acceptable recordings for acoustic signal analysis.

One Size Fits All?

Methodology ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 23-38 ◽  
Author(s):  
Manuel C. Voelkle ◽  
Patrick E. McKnight
Keyword(s):  
Repeated Measures ◽  
Structural Equation ◽  
Type I Error ◽  
Equation Modeling ◽  
Type I ◽  
Finite Sample ◽  
Traditional Methods ◽  
Repeated Measures Anova ◽  
Special Cases ◽  
Latent Curve

The use of latent curve models (LCMs) has increased almost exponentially during the last decade. Oftentimes, researchers regard LCM as a “new” method to analyze change with little attention paid to the fact that the technique was originally introduced as an “alternative to standard repeated measures ANOVA and first-order auto-regressive methods” (Meredith & Tisak, 1990, p. 107). In the first part of the paper, this close relationship is reviewed, and it is demonstrated how “traditional” methods, such as the repeated measures ANOVA, and MANOVA, can be formulated as LCMs. Given that latent curve modeling is essentially a large-sample technique, compared to “traditional” finite-sample approaches, the second part of the paper addresses the question to what degree the more flexible LCMs can actually replace some of the older tests by means of a Monte-Carlo simulation. In addition, a structural equation modeling alternative to Mauchly’s (1940) test of sphericity is explored. Although “traditional” methods may be expressed as special cases of more general LCMs, we found the equivalence holds only asymptotically. For practical purposes, however, no approach always outperformed the other alternatives in terms of power and type I error, so the best method to be used depends on the situation. We provide detailed recommendations of when to use which method.

scholarly journals Accuracy of emergency physicians’ self-estimates of CT scan utilization and its potential effect on an audit and feedback intervention: a randomized trial

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Celine Larkin ◽  
Alexandra M. Sanseverino ◽  
James Joseph ◽  
Lauren Eisenhauer ◽  
Martin A. Reznek
Keyword(s):  
Randomized Trial ◽  
Repeated Measures ◽  
Intervention Group ◽  
Potential Effect ◽  
Audit And Feedback ◽  
Emergency Physicians ◽  
Feedback Intervention ◽  
Experimental Conditions ◽  
Actual Performance ◽  
Ct Utilization

Abstract Background Audit and feedback (A&F) has been used as a strategy to modify clinician behavior with moderate success. Although A&F is theorized to work by improving the accuracy of clinicians’ estimates of their own behavior, few interventions have included assessment of clinicians’ estimates at baseline to examine whether they account for intervention success or failure. We tested an A&F intervention to reduce computed tomography (CT) ordering by emergency physicians, while also examining the physicians’ baseline estimates of their own behavior compared to peers. Methods Our study was a prospective, multi-site, 20-month, randomized trial to examine the effect of an A&F intervention on CT ordering rates, overall and by test subtype. From the electronic health record, we obtained 12 months of baseline CT ordering per 100 patients treated for every physician from four emergency departments. Those who were randomized to receive A&F were shown a de-identified graph of the group’s baseline CT utilization, asked to estimate wherein the distribution of their own CT order practices fell, and then shown their actual performance. All participants also received a brief educational intervention. CT ordering rates were collected for all physicians for 6 months after the intervention. Pre-post ordering rates were compared using independent and repeated measures t tests. Results Fifty-one of 52 eligible physicians participated. The mean CT ordering rate increased significantly in both experimental conditions after the intervention (intervention pre = 35.7, post = 40.3, t = 4.13, p < 0.001; control pre = 33.9, post = 38.9, t = 3.94, p = 0.001), with no significant between-group difference observed at follow-up (t = 0.43, p = 0.67). Within the intervention group, physicians had poor accuracy in estimating their own ordering behavior at baseline: most overestimated and all guessed that they were in the upper half of the distribution of their peers. CT ordering increased regardless of self-estimate accuracy. Conclusions Our A&F intervention failed to reduce physician CT ordering: our feedback to the physicians showed most of them that they had overestimated their CT ordering behavior, and they were therefore unlikely to reduce it as a result. After “audit,” it may be prudent to assess baseline clinician awareness of behavior before moving toward a feedback intervention.

Time of imagery’s effect on performance and self-efficacy in college baseball players

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Colton Haight ◽  
Sandra Moritz ◽  
Tanis Walch
Keyword(s):  
Self Efficacy ◽  
Repeated Measures ◽  
Group Interaction ◽  
Physical Effect ◽  
Baseball Players ◽  
Repeated Measures Anova ◽  
Significant Time ◽  
Imagery Group ◽  
College Baseball ◽  
Group 2

AbstractThe relationships among the time of imagery use on performance and self-efficacy in college baseball players during a hitting task was examined. Participants (n=24) were randomly assigned to one of three imagery conditions: (a) before practice, (b) during practice, (c) after practice. A one-shot MG-M imagery intervention was used. Results from a 3 (imagery group) ×2 (pretest and posttest) repeated measures ANOVA showed only a significant time by imagery group interaction for self-efficacy (F (2, 21)=4.67, p<0.05). These findings suggest that imagery had a stronger psychological effect than physical effect.

scholarly journals Differences in Graphomotor Skills by the Writing Medium and Children’s Gender

2021 ◽  
Vol 11 (4) ◽  
pp. 162
Author(s):  
Boram No ◽  
Naya Choi
Keyword(s):  
Preschool Children ◽  
Repeated Measures ◽  
Repeated Measures Anova ◽  
Surface Textures ◽  
Young Learners ◽  
And Gender ◽  
Print Size ◽  
Writing Practice ◽  
Pressure Analysis

Factors of graphomotor skills may serve as indicators to determine a writer’s handwriting proficiency or acclimation to different writing surface textures. This study examines differences in children’s graphomotor skills based on types of writing medium and gender. Participants were 97 six-year-old Korean preschool children who had not received formal writing training prior to the study. Writing tasks were completed on a tablet screen and paper. Writing samples were analyzed using the Eye and Pen software to investigate spatial, temporal, and pressure exertion exhibited during the writing tasks. A repeated measures ANOVA revealed differences in graphomotor skills such as print size, writing speed, and writing pressure. Writing on a tablet screen decreased clarity of writing; print size and speed increased as the stylus slides across the tablet surface with relatively less friction, thereby decreasing the exertion of writing pressure. Analysis of writing differences according to gender indicated that boys generated larger print sizes than girls. Results suggest that while simple writing tasks may be feasible on the tablet screen, providing children with a larger writing medium and encouraging larger print sizes for writing practice, especially for boys, may be beneficial in the development of graphomotor skills among young learners.

scholarly journals Microhardness evaluation of root dentin after using resin sealer solvents

2021 ◽  
Vol 15 (4) ◽  
pp. 256-261
Author(s):  
Gamze Nalci ◽  
Tayfun Alaçam ◽  
Bülent Altukaynak
Keyword(s):  
Repeated Measures ◽  
Saline Solution ◽  
Prolonged Exposure ◽  
Repeated Measures Anova ◽  
Ultrasonic Agitation ◽  
Gutta Percha ◽  
Before And After ◽  
Root Dentin ◽  
Substantial Decline ◽  
Hardness Values

Background. This study aimed to assess the effects of methyl ethyl ketone (MEK) and ethyl acetate (EA) on dentin microhardness, used as resin sealer solvents. Methods. Eighty halves of single-rooted teeth were randomly divided into four groups to apply MEK, EA, chloroform, or saline solution. Vickers hardness values were measured for three root levels before and after the direct application of solvents for 5 and 15 minutes or a 1-minute application with ultrasonic agitation. The results were analyzed using repeated-measures ANOVA, and adjustments were made for comparisons with Bonferroni tests. Results. The dentin microhardness decreased in all the solvent groups (P<0.05). The changes in microhardness increased with prolonged exposure times, except for the saline solution group. Chloroform exhibited the most significant decrease in value. Furthermore, ultrasonic agitation elicited a more substantial decline in values. Conclusion. MEK and EA might be preferred over chloroform as a solvent for resin sealers because they offer an attenuated decrease in dentin microhardness and do not have gutta-percha-dissolving properties.

scholarly journals Mechanisms behind the portion size effect-visibility and bite size

2017 ◽  
Author(s):  
Kyle Stanley Burger ◽  
Susan L. Johnson
Keyword(s):  
Size Effect ◽  
Energy Intake ◽  
Repeated Measures ◽  
Visual Cues ◽  
Normal Weight ◽  
Portion Size ◽  
Experimental Conditions ◽  
Bite Size ◽  
Subject Design ◽  
Participant Characteristics

Increases in portion size lead to increases in energy intake, yet the mechanisms behind this ‘portion size effect’ are unclear. This study tested possible mechanisms of the portion size effect i.e., bite size and visual cues in 30 over- and normal-weight individuals (15 men, 15 women). A 2x2 repeated measures, within-subject design was used to test the effects of portion size (410g vs. 820g of a pasta dish) and visual cues (blindfolded vs. visible) on energy intake. At each meal participants were exposed to one of four experimental conditions (small portion/visible; small portion/blindfold; large portion/visible; large portion/blindfold). Participant characteristics, food intake, number of bites, meal duration, palatability measures and hunger and fullness were assessed. In response to a doubling of the portion presented, entrée energy intake increased 26% (220kcal P &lt; 0.001) and mean bite size increased 2.4g/bite (P &lt; 0.05). Overweight individuals consumed 40% (334kcal) more of the entrée in response to the large portion condition (P &lt; 0.05), while lean individuals’ intakes did not differ (P &lt; 0.56). A 12% (122kcal) decrease in entrée intake was observed in the blindfolded condition (P &lt; 0.01), but no portion by visual cue interaction was found; indicating that blindfolding did not attenuate the portion size effect. These data suggest that the portion size effect is greater in overweight individuals and occurs via changes in bite size.

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