The aim of this study was to identify and explain the optimum projection angle that maximises the distance achieved in a standing long jump. Five physically active males performed maximum-effort jumps over a wide range of take-off angles, and the jumps were recorded and analysed using a 2-D video analysis procedure. The total jump distance achieved was considered as the sum of three component distances (take-off, flight, and landing), and the dependence of each component distance on the take-off angle was systematically investigated. The flight distance was strongly affected by a decrease in the jumper's take-off speed with increasing take-off angle, and the take-off distance and landing distance steadily decreased with increasing take-off angle due to changes in the jumper's body configuration. The optimum take-off angle for the jumper was the angle at which the three component distances combined to produce the greatest jump distance. Although the calculated optimum take-off angles (19-27 degrees) were lower than the jumpers' preferred take-off angles (31-39 degrees), the loss in jump distance through using a sub-optimum take-off angle was relatively small.
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http://dx.doi.org/10.1016/j.humov.2004.12.001 | DOI Listing |
Bioinspir Biomim
January 2025
School of Mechatronical Engineering, Beijing Institute of Technology, 5 South Zhonghuancun, Haidian District, Beijing 100081, Beijing, 100081, CHINA.
The wings of birds contain complex morphing mechanisms that enable them to perform remarkable aerial maneuvers. Wing morphing is often described using five wingbeat motion parameters: flapping, bending, folding, sweeping, and twisting. However, owing to a lack of real bird flight data, in-depth studies on the aerodynamic properties of these coupled motions remain scarce.
View Article and Find Full Text PDFNeurospine
December 2024
Balgrist University Hospital, Zurich, Switzerland.
This video aims to describe an endoscopic surgical approach for accessing difficult to reach pathology such as disc herniations after previous surgery. The relatively small size of endoscopic instruments facilitates significant freedom of movement inside the spinal canal. The authors have experience with interlaminar approaches for contralateral pathology such as disc herniations, recurrent disc herniations, spinal stenosis, and facet cysts.
View Article and Find Full Text PDFLife (Basel)
November 2024
Heart and Vascular Center, Semmelweis University, 1122 Budapest, Hungary.
Purpose: to investigate the effects of vessel geometry on steno-occlusive and dilatative common iliac artery (CIA) pathologies.
Methods: this single-center, retrospective study included 100 participants, namely 60 participants with a unilateral, isolated CIA pathology who were divided into three pathology-based groups (a stenosis group, = 20, an occlusion group, = 20, and an aneurysm group, = 20) and 40 participants without a CIA pathology (control group). All participants underwent abdominal and pelvic computed tomography angiography.
Children (Basel)
November 2024
Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Rome Open University, 00166 Rome, Italy.
Motor skill development is crucial in human growth, evolving with the maturation of the nervous and musculoskeletal systems. Quantifying these skills, especially coordinative abilities, remains challenging. This study aimed to assess the performance of five motor tasks in children and adolescents using high-speed video analysis, providing data for movement and health professionals.
View Article and Find Full Text PDFJ Bodyw Mov Ther
October 2024
Department of Biomedical Engineering, Sahand University of Technology, Tabriz, 53318-17634, Iran.
Previous research has used primarily linear regression models to predict jump height and establish contributors of performance. The purpose of this study was to compare the performance of artificial neural network (ANN) and multi-linear regression (MLR) in prediction of countermovement jump (CMJ) height and investigating the contribution of kinematic variables to CMJ performance. Thirty-four healthy young male athletes performed a total of 204 CMJ while eight kinematic variables (the hip, knee, and ankle angles at the begging of the concentric phase of CMJ, the hip and knee take-off angles, and the shoulder, hip, and knee maximum angular velocities) were used as inputs to ANN and MLR to predict CMJ height.
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