scholarly journals Some metric characteristics of tests to assess ball speed during overarm throw performance

sportlogia ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 59-66
Author(s):  
Nikola Foretić ◽  
Ognjen Uljević ◽  
Ante Prižmić
Keyword(s):  
Ball Speed ◽  
Overarm Throw

Control of Finger Grip Forces in Overarm Throws Made by Skilled Throwers

2001 ◽  
Vol 86 (6) ◽  
pp. 2678-2689 ◽  
Author(s):  
J. Hore ◽  
S. Watts ◽  
M. Leschuk ◽  
A. MacDougall
Keyword(s):  
Grip Force ◽  
Mean Amplitude ◽  
Middle Finger ◽  
Standing Position ◽  
Ball Speed ◽  
Force Transducers ◽  
Finger Extension ◽  
Ball Release ◽  
Overarm Throw ◽  
The Mean

In an overarm throw, as the hand opens and the ball rolls along the fingers, the ball exerts a back force on the fingers. Previous studies suggested that skilled throwers compensate for this back force by producing an appropriate finger flexor torque to oppose the back force, but it was unclear how this is controlled by the CNS. We investigated whether the increase in finger flexor torque is timed precisely to occur late in the throw as the fingers open or whether the increase occurs throughout the throw to anticipate the increase in hand acceleration. Recreational ball players threw balls of different weights and diameters at different speeds from both a sitting and standing position while arm joint rotations were recorded with the search-coil technique. Force transducers were taped to the distal and middle phalanges of the middle finger and subjects released the ball from this finger. Passive forces on the finger were also recorded in “fake” throws in which the ball was taped to the finger and subjects did not grip the ball. These skilled throwers correctly anticipated the magnitude of the back force from the ball on the finger because the mean amplitude of finger extension did not increase in throws made with a large range of increasing back forces. This was achieved by subjects gripping the ball during the backswing with a force proportional to ball weight and intended ball speed (acceleration) and progressively increasing the grip force throughout the backswing and forward throw. The magnitude of this grip force during the forward throw was not affected by ball texture. After ball release from the fingertip, the finger flexed in proportion to the peak force on the finger before ball release. It is concluded, in a skilled fast overarm throw where large, fast-changing forces on the fingers result from the sum of motions at all arm joints, that finger flexor torque is progressively increased throughout the throw in an anticipatory (predictive) fashion to counteract the progressively increasing back force from the ball.

Effects of Ball Speed and Distance on Roll and Skid Distance During Putting in Golf

2018 ◽  
Vol 12 (2) ◽  
pp. 31-40
Author(s):  
Jeong-Dug Sul ◽  
◽  
Young-Ho Lee ◽  
Byung-Hoon Woo
Keyword(s):  
Ball Speed

Age-Related Differences in Throwing Techniques Used by the Catcher in Baseball

1994 ◽  
Vol 6 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Shinji Sakurai ◽  
Bruce Elliott ◽  
J. Robert Grove
Keyword(s):  
High Speed ◽  
High Performance ◽  
Age Groups ◽  
Three Dimensional ◽  
Transformation Method ◽  
High Speed Photography ◽  
Two Phase ◽  
Ball Speed ◽  
Age Related ◽  
Release Speed

Three-dimensional (3-D) high speed photography was used to record the overarm throwing actions of five open-age, four 18-year-old, six 16-year- old, and six 14-year-old high-performance baseball catchers. The direct linear transformation method was used for 3-D space reconstruction from 2-D images of the catchers throwing from home plate to second base recorded using two phase-locked cameras operating at a nominal rate of 200 Hz. Selected physical capacity measures were also recorded and correlated with ball release speed. In general, anthropometric and strength measures significantly increased through the 14-year-old to open-age classifications, while a range of correlation coefficients from .50 to .84 was recorded between these physical capacities and ball speed at release. While many aspects of the kinematic data at release were similar, the key factors of release angle and release speed varied for the different age groups.

Strength Training Using Elastic Bands: Improvement of Muscle Power and Throwing Performance in Young Female Handball Players

2017 ◽  
Vol 26 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Naryana Cristina Mascarin ◽  
Claudio Andre Barbosa de Lira ◽  
Rodrigo Luiz Vancini ◽  
Alberto de Castro Pochini ◽  
Antonio Carlos da Silva ◽  
...  
Keyword(s):  
Strength Training ◽  
Outcome Measures ◽  
Interaction Effect ◽  
Muscle Power ◽  
Young Female ◽  
Muscle Performance ◽  
Significant Group ◽  
Ball Speed ◽  
Time Interaction ◽  
Elastic Bands

Context:Imbalance in shoulder-rotator muscles has been considered a risk factor for injuries in handball. Strength training programs (STPs) may play an important preventive role.Objective:To verify the effects of an STP using elastic bands on shoulder muscles and ball-throwing speed.Design:Randomized and prospective controlled trial.Setting:Exercise physiology laboratory.Participants:Thirty-nine female handball players were randomly assigned to an experimental (EG, n = 21, 15.3 ± 1.1 y) or a control (CG, n = 18, 15.0 ± 0.8 y) group.Intervention:The EG performed the STP with elastic-band progressive exercises for 6 wk before regular handball training, and the CG underwent only their regular training.Main Outcome Measures:Before and after the STP, both groups underwent a ball-throwing-speed test and isokinetic test to assess shoulder internal- (IR) and external-rotator muscle performance.Results:Average power values for IR muscles presented a significant group-vs-time interaction effect (F = 3.9, P = .05); EG presented significantly higher values after the STP (P = .03). Ball speed presented higher values in EG after the STP in standing (P = .04) and jumping (P = .03) throws. IR peak-torque values and balance in shoulder-rotator muscles presented no group-vs-time interaction effect.Conclusions:STP using elastic bands performed for 6 wk was effective to improve muscle power and ball speed for young female handball players.

scholarly journals Qualitative and quantitative change in the kinematics of learning a non-dominant overarm throw

2018 ◽  
Vol 62 ◽  
pp. 134-142
Author(s):  
Hannah A. Palmer ◽  
Karl M. Newell ◽  
Dan Gordon ◽  
Lee Smith ◽  
Genevieve K.R. Williams
Keyword(s):  
Quantitative Change ◽  
Qualitative And Quantitative ◽  
Overarm Throw

scholarly journals Modeling and Optimization of an Indirect Coil Gun for Launching Non-Magnetic Projectiles

Actuators ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 39 ◽  
Author(s):  
Valentin Gies ◽  
Thierry Soriano
Keyword(s):  
Initial Position ◽  
Fine Tuning ◽  
Model Coupling ◽  
Ball Speed ◽  
Limited Size ◽  
Modeling And Optimization ◽  
Electromagnetic Models

This article focuses on indirect coil guns used for launching non-magnetic objects. A mechatronic model, coupling electrical, mechanical, and electromagnetic models, is proposed. This model is applied to the optimization of a kicking system used on limited size robots for propelling real soccer balls at the RoboCup. Working with an existing coil gun, we show that fine tuning its setup, especially the initial position and the length of the non-magnetic plunger extension, leads to an increase in the ball speed of 30 % compared to previous results.

The Measurement and Analysis of Ball Motion in High Speed Deep Groove Ball Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 341-348 ◽  
Author(s):  
R. J. Boness ◽  
J. J. Chapman
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Complete Analysis ◽  
Ball Speed ◽  
Rolling Axis ◽  
High Speeds ◽  
Deep Groove ◽  
Wide Range ◽  
Ring Mode ◽  
Ball Motion

This paper reports on a study of ball motion, including the measurement of ball rolling axis, in deep groove bearings operating at high speeds under thrust load conditions. The technique employed relies on viewing the test bearing, operating in the conventional fixed outer ring mode, through a rotating prism which eliminates optically the gross rotation of the separator. Videotape recordings of a selected ball, distinctively marked and illuminated stroboscopically, allows a complete analysis of ball bearing kinematics. Experimental results of separator speed, ball speed and rolling axis together with separator slip, ball slip and spin velocities at both the inner and outer raceway contacts are presented for a wide range of loads and shaft speeds up to 12,000 rev/min. These results are compared with the existing theory of Jones. Discrepancies between predicted and actual ball motion are due to the assumption made by Jones in neglecting bearing element slip. A further analysis of the experimental results including both gyroscopic torques and slip based on elastohydrodynamic traction values for the test lubricant explains actual ball motion more fully.

scholarly journals Movement form of the overarm throw for children at 6, 10 and 14 years of age

2020 ◽  
pp. 1-9
Author(s):  
Hannah A. Palmer ◽  
Karl M. Newell ◽  
Franky Mulloy ◽  
Dan Gordon ◽  
Lee Smith ◽  
...  
Keyword(s):  
Overarm Throw
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