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.
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http://dx.doi.org/10.1152/jn.2001.86.6.2678 | DOI Listing |
BMC Oral Health
January 2025
Department of Prosthetic Dentistry, Biomaterials Division, Faculty of Dentistry, King Salman International University, El Tur, South Sinai, Egypt.
Purpose: Investigating high performance thermoplastic polymers as substitutes to titanium alloy, in fabrication of implants and attachments to support mandibular overdenture, aiming to overcome stress shielding effect of titanium alloy implants. AIM OF STUDY: Assessment of stress distribution in polymeric prosthetic components and bone around polymeric implants, in case of implant-supported mandibular overdenture.
Materials And Methods: 3D finite element model was established for mandibular overdenture, supported bilaterally by two implants at canine region, and retained by two ball attachments.
J Sport Rehabil
January 2025
Exercise Science and Neuroscience Unit, Department of Exercise & Health, Paderborn University, Paderborn, Germany.
Context: Traditional assessments of high-order neurocognitive functions are conducted using pen and paper or computer-based tests; this neglects the complex motor actions athletes have to make in team ball sports. Previous research has not explored the combination of neurocognitive functions and motor demands through complex tasks for team ball sport athletes. The primary aim of the present study was to determine the construct validity of agility-based neurocognitive tests of working memory (WM) and inhibition.
View Article and Find Full Text PDFNeural Netw
January 2025
School of Mathematics and Statistics, Minnan Normal University, Zhangzhou, Fujian 363000, China. Electronic address:
As an effective data preprocessing method, feature subset selection has been widely explored in recent years. However, the feature subset selection for the Wu-Leung model and its extended model involves high time complexity. Therefore, we combine the granular ball neighborhood rough set with the Wu-Leung model.
View Article and Find Full Text PDFJBJS Case Connect
January 2025
Olympia Hospital & Research Centre, Trichy, Tamilnadu, India.
Case: Dorsal dislocations of the distal interphalangeal joint with associated volar base fractures of the distal phalanx are complex injuries that pose challenges for achieving stable reduction and restoring optimal joint function. This case report describes the successful management of a 40-year-old male cardiologist who sustained such an injury after a cricket ball trauma. The treatment involved a combined approach of closed reduction, dorsal extension block pinning, and intrafocal pinning of the volar base fracture.
View Article and Find Full Text PDFClin Exp Dermatol
January 2025
Department of Dermatology, Venereology and Leprosy, Sri Manakula Vinayagar Medical College and Hospital, Pondicherry, India.
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