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At least 109 records · Page 6Linked to original sources

PubMed2003

Evolution of the human hand: the role of throwing and clubbing.

It has been proposed that the hominid lineage began when a group of chimpanzee-like apes began to throw rocks and swing clubs at adversaries, and that this behaviour yielded reproductive advantages for millions of years, driving natural selection for improved throwing and clubbing prowess. This assertion leads to the prediction that the human hand should be adapted for throwing and clubbing, a topic that is explored in the following report. It is shown that the two fundamental human handgrips, first identified by J. R. Napier, and named by him the 'precision grip' and 'power grip', represent a throwing grip and a clubbing grip, thereby providing an evolutionary explanation for the two unique grips, and the extensive anatomical remodelling of the hand that made them possible. These results are supported by palaeoanthropological evidence.

Adaptation, Physiological↗

PubMed2000

Improvement strategies in free-throw shooting and grip-strength tasks.

Participants performed a free-throw shooting task and a grip-strength task before and after imagery, nonspecific arousal, or no instructions. Imagery improved performance in the free-throw shooting task, which is assumed to have more cognitive components than the grip-strength task. Imagery did not improve performance in the grip-strength task, which is assumed to have fewer cognitive components than the free-throw task. Nonspecific arousal, on the other hand, improved performance in the grip-strength task but not in the free-throw shooting task. Athletic experience, confidence levels, and gender were correlated with actual performance levels in both tasks, but not with improvement. Results are discussed within the transfer-appropriate processing framework.

Adult↗

PubMed2000

The regulation of release parameters in underarm precision throwing.

The aim of this study was to determine if adults spontaneously exploit the laws of physics to achieve better accuracy when throwing at various distances. Eight adults performed 25 underarm throws at five horizontal circular targets located 4, 5, 6, 7 and 8 m away with a constant 5% relative accuracy requirement. Angle and speed of the ball at release were found to increase with throwing distance, while the coordinates of the release point did not change significantly. These results support the idea that people minimize the variability in impact distance by adapting both the angle and the speed at ball release following a mechanical optimum predicted by the laws of physics. Moreover, variability in distance was found to be less than expected because of independent variations in the angle and speed at ball release. Hence, the control of precision throwing seems to imply compensatory variability, as frequently reported in the control of skilled actions.

Adult↗

PubMed1995

Critical characteristics of technique in throwing the discus.

The purpose of this study was to identify those characteristics of the techniques used by elite discus throwers that are most closely related to the distances they record. The subjects were the competitors in the discus throw events at two major meetings. Two S-VHS video cameras were used to record the performances of the subjects; the direct linear transformation (DLT) procedure was used to obtain three-dimensional data from these records. For the males, the change in speed of the discus during the second double support phase was more influential than the change in speed during any other phase in accounting for differences in the distances of the throws recorded. For the females, the changes in speed during the flight phase and during the second double support phase were about equally influential in accounting for differences in the distance thrown. The findings suggest that emphasis placed on achieving a large change in the speed of the discus during the second double support phase is well founded; that the speed of release is the most influential determinant of the distance of the throw; and that, in most cases, the aerodynamic forces exerted on the discus during the flight increase the distance of the throw.

Acceleration↗

PubMed1996

Finger flexion does not contribute to ball speed in overarm throws.

The aim of this study was to determine whether, in overarm throws made by recreational ball players, the fingers undergo flexion movement before ball release and thereby contribute to the generation of ball speed. To obtain the high resolution needed to answer this question, the magnetic-field search-coil technique was used and the data were sampled at 1000 Hz. The subjects, who were either seated or were standing, threw tennis balls at different speeds at a target 3 m away. Angular positions in three dimensions were simultaneously recorded of the distal phalanx of the middle finger and hand and, in additional experiments to determine the mechanism of ball release in more detail, three middle finger phalanges and the hand. Different phases of ball release were determined by pressure-sensitive microswitches on the proximal and distal phalanges of the middle finger. Irrespective of whether the subjects were seated or were standing, for all throws at all speeds, finger flexion did not occur before ball release. That is, up until final release of the ball, the fingers only underwent extension associated with hand opening. For fast throws, at the instant of final ball release the fingers began to flex, presumably as a result of reactive forces associated with release of the ball. Thus, in overarm throws made by recreational ball players, finger flexion movement does not appear to contribute to the generation of ball speed.

Adult↗

PubMed2002

Change in throwing pattern: critical values for control parameter of velocity.

The purpose of this study was to determine the critical values at which throwing patterns change when scaling up on the control parameter of velocity. Thirty-six participants (ages: 6-12 years) were categorized into four throwing levels according to patterns represented by temporal joint lag. Each participant was required to complete 5 overhand throws at each of 10 relative velocities for a total of 50 trials per participant. The lowest velocity was 10% of maximum, with increases in increments of 10% up to a maximum effort. Quantitative and qualitative analyses indicated that critical values varied according to throwing category and joint. Generally, lower skilled throwers (Levels 1 and 2) had less stable joint lag and changed patterns at lower velocities than higher skilled (Levels 3 and 4) throwers.

Analysis of Variance↗

PubMed2006

Changing throwing pattern: instruction and control parameter.

The purpose of this study was to determine the effects of instruction and scaling up a control parameter (velocity of throw) on changes in throwing pattern. Sixty adult female throwers (ages 20-26 years) were randomly placed into one offour practice conditions: (a) scale up on velocity with no instruction, (b) maintain constant velocity with no instruction, (c) maintain constant velocity with instruction, and (d) scale up on velocity with instruction. Participants in each condition were required to practice throwing with the nondominant arm twice per week for 5 weeks (10 sessions). Practice consisted of 20 throws per session. Participants in conditions including instruction were encouraged to rotate the trunk in an attempt to take advantage of the order parameter. Analysis indicated that each condition improved relative to use of the open kinetic chain. However, participants who increased velocity were more likely to attain maximum use of the order parameter with less practice. Additionally, throwers who increased velocity without instruction attained an optimal pattern of complete distal lag one session earlier than those who increased velocity with instruction. Data indicated that for those conditions without instruction, hand to forearm lag (H-F lag) occurred before humeral lag. It was concluded that emphasizing proximal movement (trunk rotation) without increasing velocity does not result in a final pattern that uses H-F lag.

Adult↗

PubMed2006

Release angle for attaining maximum distance in the soccer throw-in.

We investigated the release angle that maximizes the distance attained in a long soccer throw-in. One male soccer player performed maximum-effort throws using release angles of between 10 and 60 degrees, and the throws were analyzed using two-dimensional videography. The player's optimum release angle was calculated by substituting mathematical expressions for the measured relationships between release speed, release height and release angle into the equations for the flight of a spherical projectile. We found that the musculoskeletal structure of the player's body had a strong influence on the optimum release angle. When using low release angles the player released the ball with a greater release speed and, because the range of a projectile is strongly dependent on the release speed, this bias toward low release angles reduced the optimum release angle to about 30 degrees. Calculations showed that the distance of a throw may be increased by a few metres by launching the ball with a fast backspin, but the ball must be launched at a slightly lower release angle.

Adult↗

PubMed2005

Stress distribution in the superior labrum during throwing motion.

BACKGROUND: Superior labrum anterior posterior lesions are common among athletes participating in overhead throwing sports. One described mechanism of injury is application of high local stress via repetitive loading of the long head of the biceps tendon attached to the superior labrum; however, the stress environment within the labrum has not been investigated to date. HYPOTHESIS: Biceps origin locations and throwing phases determine the stress distributions causing lesions of the superior labrum within the labrum itself. STUDY DESIGN: Descriptive laboratory study. METHODS: Three-dimensional finite element models of the labrum glenoid complex with anterior, central, and posterior biceps origins were developed at 4 orientations to simulate the phases of pitching: early cocking, late cocking, acceleration, and deceleration. RESULTS: The stress magnitudes at the labrum glenoid interface for the deceleration phase were highest for all biceps origins. Anatomical variations of the biceps insertion affected the stress only during the deceleration phase. Both the biceps origin and throwing phase influenced the location of high stress. CONCLUSION: Deceleration could be the throwing phase that causes tearing at the superior labrum. This finding provides further understanding for localizing the possible initiation of superior labrum anterior posterior lesions.

Arm↗

PubMed2004

Effect of different training programs on the velocity of overarm throwing: a brief review.

Throwing velocity in overarm throwing is of major importance in sports like baseball, team handball, javelin, and water polo. The purpose of this literature review was to give an overview of the effect of different training programs on the throwing velocity in overarm throwing, provide a theoretical framework that explains findings, and give some practical applications based on these findings. The training studies were divided into 4 categories: (a) specific resistance training with an overload of velocity, (b) specific resistance training with an overload of force, (c) specific resistance training with a combination of overload of force and velocity, and (d) general resistance training according to the overload of force. Each category is presented and discussed.

Adolescent↗

PubMed1996

Biomechanics of overhand throwing with implications for injuries.

Proper throwing mechanics may enable an athlete to achieve maximum performance with minimum chance of injury. While quantifiable differences do exist in proper mechanics for various sports, certain similarities are found in all overhand throws. One essential property is the utilisation of a kinetic chain to generate and transfer energy from the larger body parts to the smaller, more injury-prone upper extremity. This kinetic chain in throwing includes the following sequence of motions: stride, pelvis rotation, upper torso rotation, elbow extension, shoulder internal rotation and wrist flexion. As each joint rotates forward, the subsequent joint completes its rotation back into a cocked position, allowing the connecting segments and musculature to be stretched and eccentrically loaded. Most notable is the external rotation of the shoulder, which reaches a maximum value of approximately 180 degrees. This biomechanical measurement is a combination of true glenohumeral rotation, trunk hyperextension and scapulothoracic motion. Near the time of maximum shoulder external rotation (ERmax), shoulder and elbow musculature eccentrically contract to produce shoulder internal rotation torque and elbow varus torque. Both the shoulder and the elbow are susceptible to injury at this position. At ball release, significant energy and momentum have been transferred to the ball and throwing arm. After ball release, a kinetic chain is used to decelerate the rapidly moving arm with the entire body. Shoulder and elbow muscles produce large compressive forces to resist joint distraction. Both joints are susceptible to injury during arm deceleration.

Arm↗

PubMed1996

Biomechanical factors critical for performance in the men's javelin throw.

In the men's javelin event the athlete throws an 800g implement into a 40 degrees sector. The objective is to throw as far as possible. Compared with most other throwing implements, the javelin is relatively aerodynamic. Even so, the most important release parameter is still the release speed. Maximising this parameter gives the athlete the best chance of attaining success in the event. For an elite thrower, as much as 70% of the release speed of the javelin is developed in the last 0.1 second. As such, the movements of throwers during this period and immediately preceding it have received attention from researchers. It would appear that a thrower's body position at the instant of final foot strike, his ability to transfer momentum between the lower body and the upper body during the delivery, and coordination of the working body segments in the most effective manner are linked to his success in the event. This paper reviews the most important biomechanical research on the men's javelin throw and highlights findings such as these which may improve the understanding of how elite javelin throwers achieve success.

Biomechanical Phenomena↗

PubMed2006

Transfer of training for two ball-throwing tasks.

The effects of training overhand ball throws to enhance underhand ball-throwing accuracy were studied with 921 Italian high school pupils (575 girls, M age = 16.5 yr., SD = 1.3; 346 boys, M = 16.5 yr., SD = 1.2) ages 14 to 18 years. A standardized test (10 underhand tennis-ball throws into the floor area delimited by an 80-cm radius wooden hoop lying on the floor 9 m from the standing pupil) was performed and scored. An Experimental group (435 girls, M age = 16.5 yr., SD = 1.3; 204 boys, M age = 16.5 yr., SD = 1.2) was randomly selected to participate in 10 weekly training periods. The set included 10 overhand throws of a rubber bouncing ball (14.5 cm diameter, weight 240 g) into a basketball hoop from 5 standardized positions (in front of the basketball hoop; at 45 degrees, 90 degrees on the right and on the left of the basketball hoop) at a distance of 4.40 m. The underhand test was repeated for both groups. On the average, boys obtained higher test scores than girls of the same age. Older adolescents had higher mean scores than younger adolescents. After 10 weeks, boys and girls of all ages improved. Mean differences between sessions were significant for the Experimental group (Student t test, p < .01). In Session 2, consistent differences between Experimental and Control groups were also found (Student t test, p < .05).

Adolescent↗

PubMed1989

Effects of preshot routine on free-throw shooting.

The effect of prohibiting the use of a preshot routine on free-throw shooting in competitive situations was investigated. 25 male high school basketball players were instructed to attempt 50 free throws alternating in blocks of 10 between the use of their preshot routine and shooting without it. To make the situation competitive, subjects were run in groups of five and their performance was recorded on a large easel placed to the side of the free-throw line. A significantly larger number of baskets were made in the preshot routine condition than without the routine. A competitive situation led to a greater decrement in baskets than had been reported in 1986 by Lobmeyer and Wassermen during noncompetitive free-throw shooting.

Adolescent↗

PubMed1991

Immediate effect of weight training as compared to aerobic exercise on free-throw shooting in collegiate basketball players.

This study empirically assessed the effect weight training has on the accuracy of free-throw shots immediately following a weight-training session. On On alternating days of the week for eight weeks, 14 members of a women's varsity intercollegiate basketball team engaged in a weight-training program and an aerobics exercise program. Each day immediately following the conditioning, the players shot two sets of 10 free throws. Analysis indicated no significant difference in free-throw shooting accuracy as a function of weight training when compared to the aerobic exercise, suggesting that the immediate effects of weight training are no more detrimental or beneficial for free-throw shooting than aerobic exercise.

Achievement↗

PubMed1992

Effects of a cognitive intervention package on the free-throw performance of varsity basketball players during practice and competition.

To examine the effects of a cognitive intervention package on the free-throw shooting performance of basketball players, with 3 Canadian male university caliber basketball players ages 20, 22, and 24 years, during practice and in competition single-subject multiple-baseline design was implemented. Each subject was introduced to the imagery-rehearsal intervention at different times during the 14-week competitive basketball season. Free-throw data were collected during 50 practice sessions and 32 games. Data from both practice and competitive situations were examined using a comparison of graphed means. In the practice condition an increase in free-throw performance for all three subjects occurred during the posttreatment intervention. In the game condition, Subjects A and B showed posttreatment improvement. The cognitive intervention package consisting of visualization and relaxation can be an effective strategy for improving free-throw performance of some basketball players. Further research should involve control-group examination using a larger sample across a variety of tasks.

Adult↗

PubMed1997

3-dimensional kinematics of overarm throwing action of children age 15 to 30 months.

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 degrees for any child; release velocity was higher for older subjects; and the angle of ball release was large in 'arm-dominated throws' (M = 49 degrees) and comparatively smaller in 'sequentially linked' throws (M = 15 degrees).

Age Factors↗

PubMed1998

Accuracy characteristics of throwing as a result of maximum force effort.

Fitts' law predicts the accuracy of movement to a target decreases as the velocity of the movement increases. This speed-accuracy tradeoff has been examined under numerous conditions. During some tasks, however, increased force to nearly maximal level decreases the variability of the movement (Sherwood & Schmidt, 1980). This condition apparently produced results different from what would be predicted by Fitts' law. The purpose of the present study was to examine the effects of maximal force on dart throwing accuracy and variability. 54 subject were categorized into groups based upon their experience with dart throwing: Advanced, Intermediate, or Beginners. Each subject performed two sessions of 15 trials. Subjects were instructed to "throw normally" for one session and "throw as hard as you can" for the other session Distances from the target (triple-20 area) on the regulation dart board were measured and recorded after each of three darts was thrown. Average Error and Variable Error were calculated for each condition for each subject. The Average Error and Variable Error were greatest for the Beginner group and least for the Advanced group. For all three experience categories both Average Error and Variable Error were significantly greater when subjects performed with maximal force. The greater average error for the maximal force for all subjects suggested that the speed-accuracy tradeoff applied to this aiming task. The greater variability in accuracy with maximal force suggested a ceiling effect, which reduced variability in previous studies, was not achieved.

Adult↗