scholarly journals Rotace horní části těla při golfovém švihu u elitních hráčů

2013 ◽  
Vol 7 (1) ◽  
pp. 35-42
Author(s):  
Tomáš Gryc ◽  
František Zahálka ◽  
Tomáš Malý
Keyword(s):  
Upper Body ◽  
Body Segment ◽  
Kinematic Parameters ◽  
Segment Model ◽  
Motion System ◽  
Ball Contact ◽  
Club Head ◽  
The Relationship ◽  
Hip Rotation ◽  
Contact Parameters

When the golf swing is involving all body segments and is thus considered as one of the most complex of sports motions. The aim of this study was to determine the selected kinematic parameters of movement of pelvic and segments of the upper body (shoulder rotation, hip rotation, X-Factor, stretch X-Factor) that affect the club head speed at ball contact in elite golfers. To build the upper body segment model were used spots and their position during the measurement was scanned by 3D kinematic analyzer CODA Motion System. To determine the interindividual stability of performance the coefficient of variation was used and for statistical analysis of the relationship between kinematic and temporal parameters and the club head speed at ball contact the Pearson's correlation coefficient was used. We found a high interindividual stability in maximized shoulders rotation and club head speed at ball contact parameters. When analyzing relationship between the club head speed at ball contact and the observed kinematic parameters of the movement of the upper body only a high relationship with the stretch X-factor parameter was found.

Effects of Bat Grip on Baseball Hitting Kinematics

2009 ◽  
Vol 25 (3) ◽  
pp. 203-209 ◽  
Author(s):  
Rafael F. Escamilla ◽  
Glenn S. Fleisig ◽  
Coop DeRenne ◽  
Marcus K. Taylor ◽  
Claude T. Moorman ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Range Of Motion ◽  
Elbow Flexion ◽  
Linear Velocity ◽  
Elbow Extension ◽  
Kinematic Parameters ◽  
Time Duration ◽  
Motion System ◽  
Ball Contact ◽  
Pelvis Rotation

A motion system collected 120-Hz data from 14 baseball adult hitters using normal and choke-up bat grips. Six swings were digitized for each hitter, and temporal and kinematic parameters were calculated. Compared with a normal grip, the choke-up grip resulted in 1) less time during stride phase and swing; 2) the upper torso more opened at lead foot contact; 3) the pelvis more closed and less bat linear velocity at bat-ball contact; 4) less range of motion of the upper torso and pelvis during swing; 5) greater elbow flexion at lead foot contact; and 6) greater peak right elbow extension angular velocity. The decreased time during the stride phase when using a choke-up grip implies that hitters quicken their stride when they choke up. Less swing time duration and less upper torso and pelvis rotation range of motion using the choke-up grip supports the belief of many coaches and players that using a choke-up grip results in a “quicker” swing. However, the belief that using a choke-up grip leads to a faster moving bat was not supported by the results of this study.

The Relationship Between Isometric Force-Time Curve Characteristics and Club Head Speed in Recreational Golfers

2012 ◽  
Vol 26 (10) ◽  
pp. 2685-2697 ◽  
Author(s):  
Brian K. Leary ◽  
Jason Statler ◽  
Britton Hopkins ◽  
Rachael Fitzwater ◽  
Tucker Kesling ◽  
...  
Keyword(s):  
Isometric Force ◽  
Time Curve ◽  
Club Head ◽  
Force Time ◽  
The Relationship ◽  
Recreational Golfers

6-DOF Motion System of Amphibious Vehicle Driving Simulator Motion Parameter Design Research

2011 ◽  
Vol 460-461 ◽  
pp. 704-709
Author(s):  
Shu Tao Zheng ◽  
Zheng Mao Ye ◽  
Jun Jin ◽  
Jun Wei Han
Keyword(s):  
Design Research ◽  
Driving Simulator ◽  
Motion Parameter ◽  
Driving Simulators ◽  
Motion System ◽  
Vehicle Acceleration ◽  
Vehicle Driving Simulator ◽  
Simulator Motion ◽  
Result Analysis ◽  
The Relationship

Vehicle driving simulators are widely employed in training and entertainment utilities because of its safe, economic and efficient. Amphibious vehicle driving simulator was used to simulate amphibious vehicle on land and in water. Because of the motion difference between aircraft and amphibious vehicle, it is necessary to design a reasonable 6-DOF motion system according to the flight simulator motion system standard and vehicle motion parameter. FFT of DSP and PSD were used to analysis the relationship between them. Finally according to the result analysis, a set of reasonable 6-DOF motion system motion parameter was given to realize the driving simulator motion cueing used to reproduce vehicle acceleration.

scholarly journals The relationship between second-to-fourth digit ratio (2D:4D), muscle strength and body composition to bone mineral density in young women

Kinesiology ◽  
2019 ◽  
Vol 51 (2) ◽  
pp. 238-245
Author(s):  
Hamid Arazi ◽  
Ehsan Eghbali
Keyword(s):  
Body Composition ◽  
Muscle Strength ◽  
Young Women ◽  
Upper Body ◽  
Lower Body ◽  
Fat Percentage ◽  
Mineral Density ◽  
Body Strength ◽  
Lower Body Strength ◽  
The Relationship

2D:4D ratio is determined by balance between androgens and estrogens. Low level estrogen reduces bone mineral density (BMD) and incurs negative changes to bone microarchitecture, increasing the risk of osteoporosis and, as a consequence, fracture risk in women. The purpose of this study was to investigate the relationship between 2D:4D, muscle strength and body composition to BMD in young women. One hundred twenty-seven young women (age range 24-36 years) voluntarily participated in this study. Lengths of the second (index) and fourth (ring) fingers, upper and lower body strength and body composition (body mass index, BMI; waist to hip ratio, WHR) and body fat percentage were estimated. Also, blood levels of calcium and 25-hydroxyvitamin D (25OHD) were evaluated and dual-energy X-ray absorptiometry device was used to measure BMD in the lumbar spine (LS) and femoral neck (FN). The results showed that digit ratios, upper body and lower body muscle strength, BMI and fat percentage had a positive relationship with LS and FN BMD (LS BMD: r=.47, r=.56, r=.46, r=.34, r=.28, p≤.001, respectively; FN BMD: r=.34, r=.49, r=.51, r=.45, r=.27, p≤.001, respectively). In addition, there was no significant relationship between WHR and BMD of LS and FN (p˃.05). Multiple linear regression analysis showed the upper body strength was a stronger determinant of LS BMD and the lower body strength was a stronger determinant of FN BMD. Based on the results, the researchers concluded that upper and lower body strength, 2D:4D ratios and BMI were important determinants of young women’s BMD. Also, it seemed that some of these factors may be able to help predicting the osteoporosis potential in young women

scholarly journals KINEMATIC PARAMETERS OF JUMP SHOT IN ELITE MALE BASKETBALL PLAYERS

2019 ◽  
pp. 237
Author(s):  
Emilija Stojanović ◽  
Marko Radenković ◽  
Saša Bubanj ◽  
Ratko Stanković
Keyword(s):  
Body Height ◽  
The Body ◽  
Release Time ◽  
Kinematic Parameters ◽  
Basketball Players ◽  
The Relationship ◽  
Lower Angle

The primary aim of this study was to determine kinematic parameters of jump shot in elite male basketball players, by analyzing the release time for shooting, the angle of entry, and ball spin and. The secondary aim of this study was to examine possible differences in these kinematic parameters among the players associated with their playing position. Eighteen male basketball players (7 guards, 8 forwards, 3 centers) from six Serbian senior teams were tested. 94Fifty basketball sensor was used to obtain the following kinematic parameters of jump shot). The highest average measured values of shot release time were found in centres (1.23±0.23 s) and the lowest in guards (1.07±0.28 s), although these differences were not statistically significant. Further, centres had a lower angle of entry (36.6±2.08°) than guards (40.54±4.76°) and forwards (42.05±3.77°). The highest value of backspin was obtained by forwards (130±11.91 rotations / min). There were no significant differences between guards, forwards and centers in any kinematic variables (p>.01). The relationship between the body height and angle of entry was not significant (p>0.05). In conclusion, compared to centers, guards and forwards showed similar results for the examined variables. This evidence seems to support the theory that compared to guards and forwards centres have the weaker shooting techniques. Coaches should encourage all players, especially centers, to shoot from all positions.

scholarly journals The Relationship between Physical Fitness and Simulated Firefighting Task Performance

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Goris Nazari ◽  
Joy C. MacDermid ◽  
Kathryn E. Sinden ◽  
Tom J. Overend
Keyword(s):  
Heart Rate ◽  
Physical Fitness ◽  
Grip Strength ◽  
Upper Body ◽  
Task Completion ◽  
Body Strength ◽  
Fitness Parameters ◽  
Lower Body Strength ◽  
The Relationship ◽  
Completion Times

The overall aim of this study was to measure the physiological responses of firefighters from a single fire service during simulated functional firefighting tasks and to establish the relationship between physical fitness parameters and task performance. 46 males and 3 females firefighters were recruited. Firefighters’ aerobic capacity levels were estimated using the Modified Canadian Aerobic Fitness Test (mCAFT). Grip strength levels, as a measure of upper body strength levels, were assessed using a calibrated J-Tech dynamometer. The National Institute for Occupational Safety and Health (NIOSH) protocol for the static floor lifting test was used to quantify lower body strength levels. Firefighters then performed two simulated tasks: a hose drag task and a stair climb with a high-rise pack tasks. Pearson’s correlation coefficients (r) were calculated between firefighters’ physical fitness parameters and task completion times. Two separate multivariable enter regression analyses were carried out to determine the predictive abilities of age, sex, muscle strength, and resting heart rate on task completion times. Our results displayed that near maximal heart rates of ≥88% of heart rate maximum were recorded during the two tasks. Correlation (r) ranged from −0.30 to 0.20. For the hose drag task, cardiorespiratory fitness and right grip strength (kg) demonstrated the highest correlations of −0.30 and −0.25, respectively. In predicting hose drag completion times, age and right grip strength scores were shown to be the statistically significant (p<0.05) independent variables in our regression model. In predicting stair climb completion times, age and NIOSH scores were shown to be the statistically significant (p<0.05) independent variables in our regression model. In conclusion, the hose drag and stair climb tasks were identified as physiological demanding tasks. Age, sex, resting heart rate, and upper body/lower body strength levels had similar predictive values on hose drag and stair climb completion times.

scholarly journals Voluntary Upper-Extremity Movements in Patients With Unilateral Peripheral Vestibular Hypofunction

2002 ◽  
Vol 82 (3) ◽  
pp. 216-227
Author(s):  
Diane F Borello-France ◽  
Jere D Gallagher ◽  
Joseph M Furman ◽  
Mark S Redfern ◽  
George E Carvell
Keyword(s):  
Reaction Time ◽  
Choice Reaction Time ◽  
Arm Movements ◽  
Arm Movement ◽  
Upper Body ◽  
Body Segment ◽  
Motor Impairments ◽  
Vestibular Loss ◽  
Head Velocity ◽  
Vestibular Hypofunction

Abstract Background and Purpose. People with peripheral vestibular pathology demonstrate motor impairments when responding and adapting to postural platform perturbations and during performance of sit-to-stand and locomotor tasks. This study investigated the influence of unilateral peripheral vestibular hypofunction on voluntary arm movement. Subjects and Methods. Subjects without known neurological impairments and subjects with vestibular impairments performed 3 voluntary arm movements: an overhead reach to a target, a sideward reach to a target, and a forward flexion movement through 90 degrees. Subjects performed these tasks under precued and choice reaction time conditions. During all tasks, body segment motion was measured. Head velocity measurements were calculated for the side task only. Results. Subjects with vestibular loss restricted upper body segment motion within the frontal and transverse planes for the 90-degree and overhead tasks. Average angular head velocity was lower for the group with vestibular hypofunction. Task uncertainty (the introduction of a choice reaction time paradigm) differentially influenced the groups regarding head velocity at target acquisition. Discussion and Conclusion. Individuals with vestibular loss altered their performance of voluntary arm movements. Such alterations may have served to minimize the functional consequences of gaze instability.

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