Timing of finger opening and ball release in fast and accurate overarm throws

1995 ◽  
Vol 103 (2) ◽  
Author(s):  
J. Hore ◽  
S. Watts ◽  
J. Martin ◽  
B. Miller
Keyword(s):  
Ball Release ◽  
Overarm Throws

Prediction and Compensation by an Internal Model for Back Forces During Finger Opening in an Overarm Throw

1999 ◽  
Vol 82 (3) ◽  
pp. 1187-1197 ◽  
Author(s):  
J. Hore ◽  
S. Watts ◽  
D. Tweed
Keyword(s):  
Internal Model ◽  
Middle Finger ◽  
Proximal Interphalangeal Joint ◽  
Force Transducers ◽  
Ball Release ◽  
Overarm Throw ◽  
Finger Motion ◽  
The Moment ◽  
Finger Control ◽  
Overarm Throws

Previous studies have indicated that timing of finger opening in an overarm throw is likely controlled centrally, possibly by means of an internal model of hand trajectory. The present objective was to extend the study of throwing to an examination of the dynamics of finger opening. Throwing a heavy ball and throwing a light ball presumably require different neural commands, because the weight of the ball affects the mechanics of the arm, and particularly, the mechanics of the finger. Yet finger control is critical to the accuracy of an overarm throw. We hypothesized that finger opening in an overarm throw is controlled by a central mechanism that uses an internal model to predict and compensate for movement-dependent back forces on the fingers. To test this idea we determined whether finger motion is affected by back forces, i.e., whether larger back forces cause larger finger extensions. Back forces were varied by having subjects throw, at the same fast speed, tennis-sized balls of different weights (14, 55, and 196 g). Arm- and finger-joint rotations were recorded with the search-coil technique; forces on the middle finger were measured with force transducers. Recordings showed that during ball release, the middle finger experienced larger back forces in throws with heavier balls. Nevertheless, most subjects showed proximal interphalangeal joint extensions that were unchanged or actually smaller with the heavier balls. This was the case for the first throw and for all subsequent throws with a ball of a new weight. This suggests that the finger flexors compensated for the larger back forces by exerting larger torques during finger extension. Supporting this view, at the moment of ball release, all finger joints flexed abruptly due to the now unopposed torques of the finger flexors, and the amplitude of this flexion was proportional to ball weight. We conclude that in overarm throws made with balls of different weights, the CNS predicts the different back forces from the balls and adjusts finger flexor torques accordingly. This is consistent with the view that finger opening in overarm throws is controlled by means of an internal model of the motor apparatus and the external load.

Timing of ball release in overarm throws affects ball speed in unskilled but not skilled individuals

2005 ◽  
Vol 23 (8) ◽  
pp. 805-816 ◽  
Author(s):  
E Jegede ◽  
S Watts ◽  
L Stitt ◽  
J Hore
Keyword(s):  
Ball Speed ◽  
Ball Release ◽  
Overarm Throws

Failure of Cerebellar Patients to Time Finger Opening Precisely Causes Ball High-Low Inaccuracy in Overarm Throws

1999 ◽  
Vol 82 (1) ◽  
pp. 103-114 ◽  
Author(s):  
D. Timmann ◽  
S. Watts ◽  
J. Hore
Keyword(s):  
Arm Movement ◽  
Three Dimensions ◽  
Central Command ◽  
Hand Trajectory ◽  
Release Times ◽  
Ball Release ◽  
Timing Variability ◽  
Medium Speed ◽  
Release Timing ◽  
Overarm Throws

We investigated the idea that the cerebellum is required for precise timing of fast skilled arm movements by studying one situation where timing precision is required, namely finger opening in overarm throwing. Specifically, we tested the hypothesis that in overarm throws made by cerebellar patients, ball high-low inaccuracy is due to disordered timing of finger opening. Six cerebellar patients and six matched control subjects were instructed to throw tennis balls at three different speeds from a seated position while angular positions in three dimensions of five arm segments were recorded at 1,000 Hz with the search-coil technique. Cerebellar patients threw more slowly than controls, were markedly less accurate, had more variable hand trajectories, and showed increased variability in the timing, amplitude, and velocity of finger opening. Ball high-low inaccuracy was not related to variability in the height or direction of the hand trajectory or to variability in finger amplitude or velocity. Instead, the cause was variable timing of finger opening and thereby ball release occurring on a flattened arc hand trajectory. The ranges of finger opening times and ball release times (timing windows) for 95% of the throws were on average four to five times longer for cerebellar patients; e.g., across subjects mean ball release timing windows for throws made under the medium-speed instruction were 11 ms for controls and 55 ms for cerebellar patients. This increased timing variability could not be explained by disorder in control of force at the fingers. Because finger opening in throwing is likely controlled by a central command, the results implicate the cerebellum in timing the central command that initiates finger opening in this fast skilled multijoint arm movement.

Overarm throws with the nondominant arm: kinematics of accuracy

1996 ◽  
Vol 76 (6) ◽  
pp. 3693-3704 ◽  
Author(s):  
J. Hore ◽  
S. Watts ◽  
D. Tweed ◽  
B. Miller
Keyword(s):  
Right Hemisphere ◽  
Angular Position ◽  
Ball Impact ◽  
Hand Trajectory ◽  
Finger Extension ◽  
Ball Release ◽  
Left And Right ◽  
The Right ◽  
Timing Of Onset ◽  
Overarm Throws

1. Overarm throws made with the nondominant arm are usually less accurate than those made with the dominant arm. The objective was to determine the errors in the joint rotations associated with this inaccuracy, and thereby to gain insight into the neural mechanisms that contribute to skill in overarm throwing. 2. Overarm throws from both left and right arms were recorded on different occasions as six right-handed subjects sat with a fixed trunk and threw 150 tennis balls at about the same speed at a 6-cm square on a target grid 3 m away. Joint rotations at the shoulder, elbow, wrist, and finger, and arm translations, were computed from recordings of arm segment orientations made with the magnetic-field search-coil technique. 3. All subjects threw less accurately in this task with the left (nondominant) arm. For throws made with the left arm, the height of ball impact on the target grid was related to hand trajectory length and to hand orientation in space at ball release, but not to hand trajectory height. 4. Two hypotheses were proposed to explain the decreased ball accuracy in the high-low direction during throwing with the nondominant arm: that it was caused by increased variability in the velocity or timing of onset of rotations at proximal joints (which determine the path of the hand through space) or increased variability in the velocity or timing of onset of finger extension (which determine the moment of ball release). 5. A prediction of the first hypothesis was that proximal joint rotations should be more variable in throws with the left arm. This was the case for the majority of proximal joint rotations in the six subjects when variability was examined in joint space. However, some proximal joint rotations were more variable in the right arm. 6. The first hypothesis was directly tested by determining whether hand angular position in space (which represents the sum of all proximal joint rotations) was related to ball impact height on the target grid at a fixed translational position in the throw. No relation was found between these variables for throws with the left arm in four subjects, whereas a weak relation was found for two subjects. It was concluded that, considering all subjects, the first hypothesis could not explain the results. 7. In contrast, in agreement with the second hypothesis, a strong relation (P < 0.001) was found in all subjects between ball impact height on the target grid and time of ball release for throws with the left arm, and with time of onset of finger extension. 8. Across all six subjects the timing precision (windows) for 95% of the throws was (for ball release) right arm, 9.3 ms; left arm, 22.5 ms; (for onset of finger extension) right arm, 13.7 ms; left arm, 26.7 ms. 9. Timing of onset of finger extension was no less accurate than timing of onset of other joint rotations for both left and right arms. However, simulations of throws showed that, for the same error in timing, finger extension had twice as large an effect on ball direction as any other joint rotation. Timing errors at the fingers have a greater effect than errors at other joints because finger errors are scaled by the higher angular velocity of the hand in space rather than by the smaller angular velocities of the individual joints. 10. It is concluded that although rotations were in general more variable at both proximal and distal joints of the nondominant (left) arm, the major cause of its decreased throwing accuracy was increased variability at the distal joints, i.e., in the timing of onset of finger extension. This may be due to a lack of precision in the commands from the right hemisphere to the left fingers in right-handed throwers.

Increased Variability in Finger Position Occurs Throughout Overarm Throws Made by Cerebellar and Unskilled Subjects

2001 ◽  
Vol 86 (6) ◽  
pp. 2690-2702 ◽  
Author(s):  
D. Timmann ◽  
R. Citron ◽  
S. Watts ◽  
J. Hore
Keyword(s):  
Rate Of Change ◽  
Three Dimension ◽  
Finger Force ◽  
Large Variability ◽  
Ball Release ◽  
Finger Position ◽  
Overarm Throw ◽  
Tennis Balls ◽  
Finger Control ◽  
Overarm Throws

We investigated the ability of cerebellar patients and unskilled subjects to control finger grip position and the amplitude of finger opening during a multijoint overarm throw. This situation is of interest because the appropriate finger control requires predicting the magnitude of back forces from the ball on the finger throughout the throw and generating the appropriate level and rate of change of finger flexor torque to oppose the back force. Cerebellar patients, matched controls, and unskilled subjects threw tennis balls and tennis-sized balls of different weights. In all cases angular positions of five arm segments in three dimension were recorded at 1,000 Hz with the search-coil technique as subjects threw from a seated position. When the hand was stationary, cerebellar patients showed a normal ability to grip the ball and open the fingers and drop the ball. In contrast, in overarm throws where a back force occurred on the fingers, cerebellar patients showed an abnormally large variability in amplitude of the change in finger position when gripping, in amplitude of finger opening, and in amplitude of the change in finger position 10 ms after ball release. This was not due to more trial-to-trial variation in throwing speed. When throwing balls of increasing weights, both controls and cerebellar patients had increasing finger flexions after ball release that indicated that, on average, both scaled finger force in proportion to ball weight during the throw. Unlike skilled controls, cerebellar patients showed a small (<20°) increase in the amplitude of finger opening with balls of increasing weight. However, neither the increase in variability of finger position nor the increase in finger amplitude with balls of increasing weight were unique cerebellar signs because both were observed to various degrees in unskilled throwers. It is concluded that in the absence of either normal cerebellar function or skill, the central neural activity that controls finger opening in throwing can increase finger flexor force to oppose an increase in back force from heavier balls and can open the fingers but cannot control finger force or finger opening precisely and consistently from throw to throw. These results fit with the idea that cerebellar disorders are greater in multijoint than single-joint movements because control of force is more complicated. They are also consistent with the hypothesis that the cerebellum produces skill in movement by reducing variability in the timing and force of muscle contractions.

3–Dimensional Kinematics of Overarm Throwing Action of Children Age 15 to 30 Months

1997 ◽  
Vol 84 (3_suppl) ◽  
pp. 1267-1283 ◽  
Author(s):  
Pascual Marques-Bruna ◽  
Paul N. Grimshaw
Keyword(s):  
Qualitative Analysis ◽  
Motor Development ◽  
Developmental Stages ◽  
Elbow Extension ◽  
3 Dimensional ◽  
Video Recordings ◽  
Ball Release ◽  
Different Ages ◽  
Overarm Throwing ◽  
Older Subjects

7 children 15 to 30 mo. old participated in a study of 3–dimensional kinematics of overarm throwing. Children of different ages were considered to be at different developmental stages of motor development. Video recordings were digitised and 3-dimensional coordinates established using the DLT algorithm. Qualitative analysis indicated that the children executed either a ‘static’ or ‘dynamic’ throwing action. Either could further be classified as ‘arm dominated’ or ‘sequentially linked.’ Maximum elbow extension was no more than 163° for any child; release velocity was higher for older subjects; and the angle of ball release was large in ‘arm-dominated throws’ ( M = 49°) and comparatively smaller in ‘sequentially linked’ throws ( M = 15°).

The Relationship Between Prescribed, Perceived, and Actual Delivery Intensity in Cricket Pace Bowling

2020 ◽  
pp. 1-4
Author(s):  
Simon A. Feros ◽  
Damon A. Bednarski ◽  
Peter J. Kremer
Keyword(s):  
Warm Up ◽  
Training Adaptation ◽  
Ball Release ◽  
Release Speed ◽  
The Relationship

Purpose: To investigate the relationship between prescribed (preDI), perceived (perDI), and actual delivery intensity (actDI) in cricket pace bowling. Methods: Fourteen male club-standard pace bowlers (mean [SD]: age 24.2 [3.2] y) completed 1 bowling session comprising 45 deliveries. The first 15 deliveries composed the warm-up, where participants bowled 3 deliveries each at a preDI of 60%, 70%, 80%, 90%, and 95%. Bowlers reported the perDI after each delivery. The fastest delivery in the session was used as a reference to calculate relative ball-release speed for the warm-up deliveries, with this measure representing the actDI. Ball-release speed was captured by a radar gun. Results: For perDI, there was a very large relationship with preDI (rs = .90, P < .001). Similarly, for actDI, there was a large relationship with preDI (rs = .52, P < .001). Higher concordance was observed between perDI and preDI from 60% to 80% preDI. A plateau was observed for actDI from 70% to 95% preDI. Conclusions: The relationship between perDI and actDI was very large and large with respect to preDI, indicating that both variables can be used to monitor delivery intensity against the planned intensity and thus ensure healthy training adaptation. The optimal preDI that allowed pace bowlers to operate at submaximal perDI but still achieve close to maximal ball-release speeds was 70%. Bowling at the optimal preDI may significantly reduce the psychophysiological load per delivery in exchange for a trivial loss in ball-release speed.

The Association Among Trunk Rotation, Ball Velocity, and the Elbow Varus Moment in Collegiate-Level Baseball Pitchers

2019 ◽  
Vol 47 (12) ◽  
pp. 2816-2820 ◽  
Author(s):  
Andrew D. Cohen ◽  
Erin J. Garibay ◽  
Matthew J. Solomito
Keyword(s):  
Elbow Joint ◽  
Rotation Angle ◽  
Rotational Velocity ◽  
Trunk Rotation ◽  
Joint Stress ◽  
Trunk Motion ◽  
Ball Release ◽  
Average Maximum ◽  
Ball Velocity ◽  
Baseball Pitchers

Background: The incidence of upper extremity injuries in baseball pitchers is increasing. Over the past decade, research has attempted to elucidate the cause of these injuries, focusing mainly on pitching arm mechanics with little examination of other important segments, such as the trunk. This is surprising, as trunk motion has been shown to have significant effects on pitching mechanics. Purpose: To determine the associations between trunk rotation, ball velocity, and the moments about the elbow joint. Study Design: Descriptive laboratory study. Methods: Data collected using 3-dimensional motion analysis techniques from 99 collegiate pitchers (18.0-24.8 years) were analyzed. A random intercept mixed-effects regression model was used to determine if significant associations existed between trunk rotation and ball velocity or elbow varus moment. Results: Significant associations were found between trunk rotation angle at ball release and elbow varus moment ( P = .019, β = 0.254) as well as ball velocity ( P = .016, β = 0.060). For every 10° increase over the average trunk rotation angle at ball release, the elbow varus moment increased by 2.54 N·m and the ball velocity increased by 0.60 m/s. Additionally, the maximum rotational velocity of the trunk was positively associated with elbow varus moment ( P < .001, β = 0.029) and ball velocity ( P < .001, β = 0.007). For every 100 deg/s increase over the average maximum rotational velocity of the trunk, the elbow varus moment increased by 2.90 N·m and the ball velocity increased by 0.70 m/s. Conclusion: In collegiate pitchers, trunk rotation angle at ball release was significantly associated with ball velocity and elbow varus moment. Also, an increase in maximum rotational velocity of the trunk was significantly associated with an increase in the ball velocity and elbow varus moment. This work demonstrates the importance of trunk mechanics in the kinetic chain of the pitch cycle. Clinical Relevance: Pitching coaches and trainers can use the results to stress the importance of trunk mechanics in pitching, specifically, combining adequate core function with increased trunk rotational velocity in an effort to increase pitching velocity without increasing elbow joint stress.

Sign in / Sign up

Export Citation Format

Share Document