Relationship between pelvic tilt control, horse-rider synchronisation, and rider position in sitting trot

2020 ◽  
Vol 16 (5) ◽  
pp. 423-432
Author(s):  
V.A. Walker ◽  
I. Pettit ◽  
C.A. Tranquille ◽  
J. Spear ◽  
S.J. Dyson ◽  
...  
Keyword(s):  
High Speed ◽  
Pelvic Tilt ◽  
Body Position ◽  
Performance Outcomes ◽  
Significance Level ◽  
Angular Measurements ◽  
Artificial Surface ◽  
Pelvic Movement ◽  
Control Horse ◽  
Left And Right

Investigation of dressage riders suggests that the performance outcomes of riding can be enhanced by a rider correctly adapting the motion of their pelvis. The pelvis has been identified as an important component of the physical connection of the horse and the rider. This preliminary study aimed to assess whether riders with better control of their pelvic movement, had increased postural stability and horse-rider synchronicity. Twenty-six amateur riders competing in Novice to Grand Prix level dressage rode 35 mixed breed horses in active dressage training which they were used to riding. Riders were divided into two groups according to their ability to perform posterior pelvic tilt whilst sat on a Swiss ball. High-speed motion-capture was captured from the left and right sides and used to assess rider body position, angular measurements and horse-rider synchronicity whilst riding a pre-defined test at collected trot on an artificial surface. Appropriate statistical analyses were used to compare variables between groups. Differences between groups were compared using one-way ANOVA or independent samples t-tests; the significance level was set at P<0.05. No riders in the study were able to perform anterior or posterior pelvic tilt whilst seated on a ball without demonstrating mild or major compensations; the most common of these were inclusion of the lumbar spine or leaning forwards or backwards. The results suggest that riders who could not perform pelvic tilt without major compensations had a more leaning forward posture, were more asymmetrical between the left and right sides and more phase shifted during the swing and stance phases than riders who could perform pelvic tilt with mild compensations.

scholarly journals The Relationship between Foot Status and Motor Status in Preschool Children: A Simple, Comparative Observational Study

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 936
Author(s):  
Milan Kojić ◽  
Branka Protić Gava ◽  
Milan Bajin ◽  
Marko Vasiljević ◽  
Jasmina Bašić ◽  
...  
Keyword(s):  
Preschool Children ◽  
Observational Study ◽  
Total Sample ◽  
Nonparametric Tests ◽  
Significance Level ◽  
Flat Feet ◽  
Significant Difference ◽  
Left And Right ◽  
The Relationship

Background: The research objective of the study is to determine the differences in the manifestation of the motor status of normally fed preschool test subjects, classified into groups according to foot status. Methods: This is a simple, comparative observational study. Preschool children included in this study have been subjected to anthropometric measurements in order to determine BMI, tests for motor skills assessment (running at 20 m from a high start, standing broad jump, backwards polygon, rectangular seated forward bend, plate tapping, sit-ups for 60 s, and bent arm hang), and a determination of foot status. The total sample was comprised of 202 test subjects who attended a regular sports program, aged 3.9 to 6.5 years of decimal age (M = 141; Age = 5.3 ± 0.74; Height = 117.3 ± 7.1; Weight = 22 ± 3.7; F = 61; Age = 5.1 ± 0.73; Height = 114.9 ± 7.4; Weight = 21.2 ± 3.8), of which 153 (75.7%) were normally fed, 6 (3%) were undernourished, 30 were overweight (14.9%), and 13 were obese (6.4%). Results: In the total sample, 30 (14.9%) subjects had normal arch feet, 90 (44.6%) high arched feet, and 41 (20.3%) flat feet. We found 41 (20.3%) subjects who had different left and right foot statuses within this sample. The data were processed by means of nonparametric tests (the Kruskal–Wallis and Mann–Whitney U tests) at a significance level p ≤ 0.05. Conclusion: The results show that there is a statistically significant difference between groups of subjects with different foot statuses in the manifestation of motor status in most tests, with a significance level of p ≤ 0.01, and in tests of sit-ups for 60 s and the bent arm hang, there is a statistically significant difference, the level of which is p ≤ 0.05. It is only in the inclination test of rectangular seated forward bend that no statistically significant difference was displayed.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

scholarly journals Dynamic of Friction Coupling Independently Rotating Wheels for High Speed

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yan Shi ◽  
Miao Li ◽  
Weihua Ma ◽  
Kang Chen
Keyword(s):  
High Speed ◽  
Rotation Speed ◽  
Friction Pair ◽  
Large Radius ◽  
Coupling Structure ◽  
Lateral Coupling ◽  
Creep Force ◽  
Left And Right ◽  
Curved Track ◽  
Dynamics Models

A new lateral coupling structure with independently rotating wheels (IRW) is proposed, and longitudinal creepage is obtained by replacing the gear pair with the friction pair to synchronize the rotation speed of left and right wheels. The auxiliary wheelset made up of two friction wheels can be placed either under the primary suspension or on the frame. Vehicles dynamics models with three different kinds of bogies are developed, including friction coupling bogie with independently rotating wheels (FCIRW-bogie), bogie with independently rotating wheels (IRW-bogie), and bogie with rigid wheelsets, and their guiding and resetting capability when negotiating large-radius curves are compared and analyzed. Results show that FCIRW has the advantages of both IRW and rigid wheelset. On the straight track, FCIRW has sufficient wheel-rail longitudinal creep force to assist the reset; its critical speed is much higher than that of the rigid wheelset. On the curved track, the whole vehicle wear power of FCIRW-bogie vehicle is about 2/3 of the rigid axle level.

Analysis on Vehicle-Bridge Coupled Vibration of a Rigid-Frame Arch Bridge Based on Measured Road Roughness

2011 ◽  
Vol 255-260 ◽  
pp. 1775-1780
Author(s):  
Wan Shui Han ◽  
Su Jing Yuan ◽  
Bing Wang
Keyword(s):  
High Speed ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Coupled Vibration ◽  
Arch Bridge ◽  
Rigid Frame ◽  
Road Roughness ◽  
Left And Right ◽  
Spectrum Characteristics ◽  
Bridge System

Firstly, synchronous field measurements were carried out for the road roughness of the left and right wheels to obtain the roughness profile using a high speed laser roadway testing vehicle. Secondly, programming idea of multi-girder vehicle-bridge coupled vibration analysis module was presented briefly. Finally, a three-axle heavy truck crossing a rigid-frame arch bridge was taken as an example, detailed comparing and analyzing was carried out for the influence on the dynamic responses and spectrum characteristics of the vehicle-bridge system from three excitation cases which include using measured road roughness corresponding respectively to left and right wheels, using measured road roughness of left wheels and right wheels simultaneously. The analysis shows that when the differences in road roughness between left and right wheels are significant, the responses computed with inconsistent excitation is smaller than that with both of the latter two excitation cases, and there are some differences between the vertical contact forces of wheels and the spectrum characteristics of the vehicle-bridge system.

scholarly journals Will the Foot Strike Pattern Change at Different Running Speeds with or without Wearing Shoes?

2020 ◽  
Vol 17 (17) ◽  
pp. 6044
Author(s):  
Ying-Jen Lai ◽  
Willy Chou ◽  
I-Hua Chu ◽  
Yu-Lin Wang ◽  
Yi-Jing Lin ◽  
...  
Keyword(s):  
High Speed ◽  
Physical Therapist ◽  
Random Order ◽  
Heel Strike ◽  
Running Speed ◽  
Chi Square ◽  
Significance Level ◽  
Limb Injuries ◽  
Foot Strike ◽  
Chi Square Analysis

Runners strike their feet with three different patterns during running: forefoot, midfoot, and rearfoot. This study aimed to investigate whether runners maintain consistent patterns while running speed and foot condition change. The foot strike patterns of runners when running on a treadmill at paces ranging from slow to fast were recorded from twenty healthy male regular runners, with and without shoes, in random order. A high-speed camera was used to observe the strike patterns, which were then categorized by an experienced physical therapist. Linear-log and Pearson chi-square analysis with a significance level of α = 0.05 was performed to examine the correlation between foot strike pattern, running speed, and shoe conditions. The results suggest that runners strike with different patterns when running with and without shoes (χ2 = 99.07, p < 0.01); runners preferred to adopt heel strike regardless of running speeds when running with shoes. While running barefoot, only 23.8% of landing strikes were rearfoot, and the strike pattern distribution did not change significantly with the running speed (χ2 = 2.26, p = 0.89). In summary, the foot strike preference of runners is correlated with the foot condition (barefoot or shod) rather than running speed. For runners who intend to change their strike patterns for any reason, we recommend that they consider adjusting their footwear, which may naturally help with the foot strike adjustment. Future studies should attempt to use advanced techniques to observe further foot biomechanics in order to discover if changing strike pattern is directly correlated with lower limb injuries.

Effects of Load Cycling on the Microleakage of Beveled and Nonbeveled Margins in Class V Resin-Based Composite Restorations

2010 ◽  
Vol 11 (5) ◽  
pp. 25-32 ◽  
Author(s):  
Hamideh Ameri ◽  
Marjaneh Ghavamnasiri ◽  
Ehsan Abdoli
Keyword(s):  
High Speed ◽  
Class V ◽  
Significance Level ◽  
Gingival Margin ◽  
Composite Restorations ◽  
Nail Polish ◽  
Significant Difference ◽  
Load Cycling ◽  
Composite Restoration

Abstract Aim This study evaluated the influence of mechanical loading and thermocycling on microleakage of class V resin-based composite restorations with and without enamel bevel. Methods and Materials Sixty class V cavity preparations measuring 3.0 mm wide (mesiogingivally) x 2.0 mm high (occluso-gingivally) x 1.5 mm deep with the occlusal margin in enamel and the gingival margin in cementum were prepared on the buccal surfaces of human premolars using a #12 diamond round bur (Drendel & Zweiling Diamant GmbH, Lemgo, Germany) in a high-speed, water-cooled handpiece. The specimens were then divided into two groups of 30 specimens each, based on the type of enamel cavosurface margin configuration as beveled or nonbeveled (butt joint). After restoring the preparations with a flowable resin-based composite (Tetric Flow, Ivoclar Vivadent-AG, Schaan, Liechtenstein) and finishing and polishing with sequential discs (Sof-Lex Pop-on, 3M-ESPE, St. Paul, MN, USA), the teeth were stored at 37°C and 100 percent humidity. Twenty-four hours later, half of the specimens in each group (nonbeveled “N” or beveled “B”) were exposed to a cycling loading for 250,000 cycles to simulate occlusal loading and assigned to two subgroups (NL+ or BL+), while the remainder of the specimens in each group were only maintained in a 100-percent-humidity environment, without any cyclical loading, until tested (NL– or BL–). The specimens were sealed with sticky wax (Kemdent, Associated Dental Products, Swindon, UK) and nail polish. The apical foramen of each tooth was sealed with sticky wax and the rest of the tooth was covered with nail varnish, except for an area within 1.0 mm around the composite restoration. To detect marginal leakage, all of the samples were stored in a 0.5 percent basic fuchsine solution for 24 hours. The specimens were then sectioned longitudinally using a low-speed diamond blade (IsoMet, Buehler Ltd., Lake Bluff, IL, USA), machined, and evaluated under 25X magnification using a stereomicroscope (M9, Wild Heerbrugg, Switzerland). The specimens were scored on a scale from 1 to 4 on the degree of dye penetration. The qualitative data were analyzed by the Mann- Whitney U test at a 5 percent significance level (p<0.05). The null hypothesis of this study was that there is no difference in microleakage between beveled and nonbeveled class V buccal preparations in premolar teeth restored with resinbased composite and subjected to simulated occlusal loading and thermocycling. Results In each group the gingival margin showed significantly more microleakage than the enamel margin (p<0.05). Load cycling did not result in an increase in microleakage in nonbeveled (p=0.259) or in beveled (p=0.053) occlusal margins. However, the gingival margins showed a statistically significant difference in microleakage after load cycling whether in cavities with enamel occlusal bevel (p=0.004) or in groups without a bevel. This means the enamel margin configuration of the enamel occlusal margin had no effect on decreasing microleakage in the gingival aspect of class V composite restorations. In general, the nonbeveled preparations in this study had significantly less microleakage than the bevel specimens whether they were loaded occlusally or not (p=0.001). Clinical Significance Within the limitations of this in vitro study, no benefit was derived from placing an enamel cavosurface bevel on the occlusal margin of a standardized class V composite restoration located at the cementoenamel junction. The most important consideration is to prevent microleakage along the gingival margin regardless of whether the occlusal enamel margin is beveled. Citation Ameri H, Ghavamnasiri M, Abdoli E. Effects of load cycling on the microleakage of beveled and nonbeveled occlusal margins in class V resin-based composite restorations. J Contemp Dent Pract [Internet]. 2010 October; 11(5):025- 032. Available from: http://www.thejcdp.com/ journal/view/volume11-issue5-ghavamnasiri

scholarly journals ARTIFICIAL NEURAL NETWORKS BASED SLEEP MOTION RECOGNITION USING NIGHT VISION CAMERAS

2004 ◽  
Vol 16 (02) ◽  
pp. 79-86 ◽  
Author(s):  
CHUNG-HSIEN KUO ◽  
FANG-CHUNG YANG ◽  
MING-YUAN TSAI ◽  
MING-YIH LEE
Keyword(s):  
Neural Networks ◽  
High Speed ◽  
Body Position ◽  
Body Movement ◽  
The Body ◽  
Night Vision ◽  
Ann Model ◽  
Motion Recognition ◽  
Video Frames ◽  
Artificial Neural

The body movement is one of the most important factors to evaluate the sleep quality. In general, the sleep motion is hardly investigated, and it must take a long time to observe the motion of the patient in terms of a pre-recoded video storage media with high speed playing. This paper proposes an image-based solution to recognize the sleep motions. We use the contact free and IR-based night vision camera to capture the video frames during the sleep of the patient. The video frames are used to recognize the body positions and the body directions such as the “body up”, “body down”, “body right”, and “body left”. In addition to the image processing, the proposed artificial neural network (ANN) sleep motion recognition solution is composed of two neural networks. These two neural networks are organized as in a cascade configuration. The first ANN model is used to identify the body position features from the images; and the follower ANN model is constructed based on the features that are identified by the first ANN model to recognize the body direction. Finally, the implementations and the practical results of this work are all illustrated in this paper.

scholarly journals Modulation of the ultradian human nasal cycle by sleep stage and body position

2017 ◽  
Vol 75 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Richard E. Frye ◽  
Deborah F. Rosin ◽  
Adrian R. Morrison ◽  
Fidias E. Leon-Sarmiento ◽  
Richard L. Doty
Keyword(s):  
Rem Sleep ◽  
Sleep Stage ◽  
Body Position ◽  
Video Camera ◽  
Sleep Stages ◽  
Nasal Airflow ◽  
Somatosensory Stimulation ◽  
Nasal Cycle ◽  
Left And Right ◽  
The Right

ABSTRACT Objective: The nasal cycle, which is present in a significant number of people, is an ultradian side-to-side rhythm of nasal engorgement associated with cyclic autonomic activity. We studied the nasal cycle during REM/non-REM sleep stages and examined the potentially confounding influence of body position on lateralized nasal airflow. Methods: Left- and right-side nasal airflow was measured in six subjects during an eight-hour sleep period using nasal thermistors. Polysomnography was performed. Simultaneously, body positions were monitored using a video camera in conjunction with infrared lighting. Results: Significantly greater airflow occurred through the right nasal chamber (relative to the left) during periods of REM sleep than during periods of non-REM sleep (p<0.001). Both body position (p < 0.001) and sleep stage (p < 0.001) influenced nasal airflow lateralization. Conclusions: This study demonstrates that the lateralization of nasal airflow and sleep stage are related. Some types of asymmetrical somatosensory stimulation can alter this relationship.

scholarly journals Impacts of high-speed rail development on urban land expansion and utilization intensity in China

2021 ◽  
Vol 14 (1) ◽  
pp. 583-601
Author(s):  
Xin Li ◽  
Xiaodong Ma
Keyword(s):  
High Speed ◽  
Joint Effect ◽  
Urban Land ◽  
Urban Land Use ◽  
Policy Implications ◽  
Eastern Region ◽  
Significance Level ◽  
Positive Effects ◽  
Urban Land Expansion ◽  
The Impact

Urban land expansion (ULE) is a crucial factor for socioeconomic and environmentally sustainable development. However, nowadays, the unprecedented scale of high-speed railway (HSR) construction in China could exert an important influence on ULE. This manuscript first reveals the influence mechanism of HSR on ULE and then employs difference-in-difference (DID) models to investigate this effect based on the data of 280 prefectures and above level cities of 2001-2016. We analyze that HSR exerts a joint effect on ULE from the territorial and local levels and then affects urban land-use intensity (ULUI). HSR opening and HSR station distance both have notably positive effects on ULE, with elastic coefficients of 4.1% and 0.5%, respectively. HSR opening and HSR station distance also both exert positive effects on ULE of the central, eastern region cities and large cities of China, while for the western region and small to medium cities, they are not significant. The impact of HSR station distance on ULUI is negative with a significance level of 0.073, while the impact of HSR opening on ULUI is not significant. Lastly, relevant policy implications are proposed to alleviate urban land waste and spatial disequilibrium under the context of HSR building. This study can provide an important basis for sustainable urban land allocation.

Evaluation of Changes in Temperature of Zirconia Frameworks During Grinding Under Different Chair-Side Conditions: An In Vitro Study

2020 ◽  
pp. 232020682095394
Author(s):  
Özgecan S¸ivet ◽  
Özlem Malkondu ◽  
Sercan Küçükkurt ◽  
Ender Kazazoglu
Keyword(s):  
High Speed ◽  
In Vitro Study ◽  
Water Cooling ◽  
Significance Level ◽  
Mean Temperature ◽  
Significant Difference ◽  
Clinical Conditions ◽  
Rotary Instrument ◽  
Difference Test

Aim: To evaluate the changes in the temperature of zirconia during grinding under different clinical conditions. Materials and Methods: A total of 60 zirconia framework specimens were fabricated and divided into groups of 10 specimens each. Two different handpieces, namely, a high-speed handpiece (HSH) and a low-speed handpiece (LSH), were used for grinding with and without water cooling. Fine- and coarse-grit diamond burrs were used with the HSH, separately. The following six groups were created: (a) HSH fine-grit with water cooling, (b) HSH coarse grit with water cooling, (c) HSH fine grit without water cooling, (d) HSH coarse grit without water cooling, (e) LSH with water cooling, and (f) LSH without water cooling. Each zirconia framework was ground until 1 mm3 of the material was removed. Temperature values corresponding to the grinding techniques were compared and statistically analyzed. One-way analysis of variance was used to compare the group parameters, while the Tukey honest significant difference test was used to detect significant differences between the groups. The significance level was set at P <.05. Results: The highest mean temperature was measured in the case of grinding with the LSH without water cooling (54.7 °C ± 11.6 °C), while the lowest mean temperature was observed in the case of grinding with the HSH using the coarse-grit diamond rotary instrument under water cooling (22.6 °C ± 0.6 °C). Conclusions: The grinding of zirconia must be performed with an HSH under water cooling. Further, when water cooling is used, neither the type of handpiece nor the grain type of the rotary instrument used as it has a significant effect on the temperature.

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