Search results for "Running"
showing 10 items of 407 documents
Analyzing dynamical gluon mass generation
2007
We study the necessary conditions for obtaining infrared finite solutions from the Schwinger-Dyson equation governing the dynamics of the gluon propagator. The equation in question is set up in the Feynman gauge of the background field method, thus capturing a number of desirable features. Most notably, and in contradistinction to the standard formulation, the gluon self-energy is transverse order-by-order in the dressed loop expansion, and separately for gluonic and ghost contributions. Various subtle field-theoretic issues, such as renormalization group invariance and regularization of quadratic divergences, are briefly addressed. The infrared and ultraviolet properties of the obtained so…
Mechanical energy states during running.
1978
Changes in total mechanical work and its partitioning into different energy states (kinetic, potential and rotational) during a step cycle of running were investigated on six well trained athletes who ran at the test speeds of 40, 60, 80, and 100% (9.3 +/- 0.3 m/s) of maximum. Cinematographic techniques were utilized to calculate the mechanical energy states as described by Norman et al. (1976), using a 13 segment mechanical model of a runner as the basis for the computations. The data showed that both the kinetic and rotational energy increased parabolically but the potential energy decreased linearly with increases in running velocity. The calculated power of the positive work phase incre…
Force-Time Characteristics and Running Velocity of Male Sprinters during the Acceleration Phase of Sprinting
1988
Abstract In an effort to investigate the force-time characteristics during the acceleration phase of the sprint start, eight male sprinters were used as subjects. Runs up to 3 m were analyzed from film, and force-time parameters were measured on a force platform. In a starting stance the reaction time of the group was .118 ± .016 s and the force production lasted .342 ± .022 s. The maximal resultant force at the moment of maximal horizontal force was 19.3 ± 2.2 N x kg1, and the direction of the force was 32 ± 7°. In the very last instant before leaving the blocks the velocity of the center of gravity was 3.46 ± .32 m x s−1. In the first contact after leaving the blocks there was a braking p…
Force-, power-, and elasticity-velocity relationships in walking, running, and jumping
1980
Ground reaction forces and mechanical power were investigated when the subjects walked normally, while they were racing or running at four speeds, and when they performed the running long jump take-off. In addition, the apparent spring constants of the support leg in eccentric and concentric phases were investigated at the four running speeds, during the running long jump take-off, and in the triple jump. Six club level track and field athletes, four national level long jumpers, and six national level triple jumpers took part in the study. Cinematographic technique and a mathematical model of hopping (Alexander and Vernon 1975) were employed in the analysis. Force and power values were foun…
Swimrun: An emerging new endurance sport
2018
International audience; The swimrun is a new endurance team-sport based on two persons swimming and running alternatively through open water and mostly trails. The aim of this study was to analyse participation and performance trends for males, females and mixed duo team at the ÖTILLÖ Swimrun race (10 km open-water swimming and 65 km trail running). During the 2012–2016 period, the mean total time performance of the best athletes at the ÖTILLÖ Swimrun decreased significantly by 17 min/year for males, 40 min/year for mixed and 59 min/year for females duo, respectively. The difference in performance between the best males and females duo (26 ± 15%) was significantly greater compared to the di…
Bronchial epithelial damage after a half-marathon in nonasthmatic amateur runners.
2010
Am J Physiol Lung Cell Mol Physiol. 2010 Jun;298(6):L857-62. Epub 2010 Apr 2. Bronchial epithelial damage after a half-marathon in nonasthmatic amateur runners. Chimenti L, Morici G, Paternò A, Santagata R, Bonanno A, Profita M, Riccobono L, Bellia V, Bonsignore MR. SourceDept. Biomedico Di Medicina Interna & Specialistica, Section of Pneumology, Univ. of Palermo, Via Trabucco 180, 90146 Palermo, Italy. laurachimenti@yahoo.it Abstract High neutrophil counts in induced sputum have been found in nonasthmatic amateur runners at rest and after a marathon, but the pathogenesis of airway neutrophilia in athletes is still poorly understood. Bronchial epithelial damage may occur during intense exer…
Markerless 2D kinematic analysis of underwater running : A deep learning approach
2018
Kinematic analysis is often performed with a camera system combined with reflective markers placed over bony landmarks. This method is restrictive (and often expensive), and limits the ability to perform analyses outside of the lab. In the present study, we used a markerless deep learning-based method to perform 2D kinematic analysis of deep water running, a task that poses several challenges to image processing methods. A single GoPro camera recorded sagittal plane lower limb motion. A deep neural network was trained using data from 17 individuals, and then used to predict the locations of markers that approximated joint centres. We found that 300–400 labelled images were sufficient to tra…
Regulation of Endurance Performance: New Frontiers
2017
Successful endurance performance requires the integration of multiple physiological and psychological systems, working together to regulate exercise intensity in a way that will reduce time taken or increase work done. The systems that ultimately limit performance of the task are hotly contested, and may depend on a variety of factors including the type of task, the environment, external influences, training status of the individual and a host of psychological constructs. These factors can be studied in isolation, or inclusively as a whole-body or integrative system. A reductionist approach has traditionally been favoured, leading to a greater understanding and emphasis on muscle and cardio…
A neural network approach to movement pattern analysis.
2004
Movements are time-dependent processes and so can be modelled by time-series of coordinates: E.g., each articulation has geometric coordinates; the set of the coordinates of the relevant articulations build a high-dimensional configuration. These configurations--or "patterns"--give reason for analysing movements by means of neural networks: The Kohonen Feature Map (KFM) is a special type of neural network, which (after having been coined by training with appropriate pattern samples) is able to recognize single patterns as members of pattern clusters. This way, for example, the particular configurations of a given movement can be identified as belonging to respective configuration clusters, …
Influence of custom-made and prefabricated insoles before and after an intense run
2017
[EN] Each time the foot contacts the ground during running there is a rapid deceleration that results in a shock wave that is transmitted from the foot to the head. The fatigue of the musculoskeletal system during running may decrease the ability of the body to absorb those shock waves and increase the risk of injury. Insoles are commonly prescribed to prevent injuries, and both custom-made and prefabricated insoles have been observed to reduce shock accelerations during running. However, no study to date has included a direct comparison of their behaviour measured over the same group of athletes, and therefore great controversy still exists regarding their effectiveness in reducing impact …