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Search Results: 1 - 10 of 7764 matches for " running efficiency "
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Comparison of base running in baseball players and track-and-field athletes  [PDF]
Kazuyoshi Miyaguchi, Shinich Demura, Kazuya Nagai, Yu Uchida
Health (Health) , 2011, DOI: 10.4236/health.2011.31005
Abstract: This study aimed to examine the relationship be-tween sprint ability and base running of baseball players and track-and- field (T&F) athletes, and to identify the association between sprint ability and running skill on base running. The subjects were 25 male university baseball players and 15 male T&F athletes without baseball experience. The straight sprint time of 54.8 m and 109.6 m (corresponding to the distance to second and home) was measured. In the home run test, the times to reach each base were measured. In the second base run test, the actual running distance and 3 m section time around the first base were measured. Base running efficiency was obtained by dividing the base running time by the straight sprint time. T&F athletes showed higher values than baseball players only in the 109.6 m straight sprint time (P < 0.05, ES=1.35). Baseball players were significantly superior to T&F athletes in terms of base running efficiency. As for 3 m section times, baseball players showed significant and higher values. The straight sprint time showed significant and high correlations (r = 0.87, 0.90) between the 109.6 m run and the run home and be-tween the 54.8 m run and the second base run in baseball players, but not in T&F athletes. It was found that superior sprint ability does not always lead to good base running. In base running, it is important to run outward to some extent. In particular, the skill acquisition of base running in 3 m sections around the base will contribute to shortening base running time.
Comparison of Barefoot vs. Shod Gait on Spinal Dynamics Using DIERS Formetric 4D and DIERS Pedoscan Systems  [PDF]
Carolyn Draus, David Moravec, Adam Kopiec, Patrick Knott
Open Journal of Therapy and Rehabilitation (OJTR) , 2015, DOI: 10.4236/ojtr.2015.33010
Abstract: Barefoot running is increasing in popularity within the running community, yet the biomechanical differences compared to traditional shod running are not well understood. This study investigates the changes in spinal dynamics during the gait cycle of runners wearing traditional running shoes (shod) compared to those wearing no shoes (barefoot). Pedal force distribution, kyphotic angle, lordotic angle, and trunk inclination were measured during shod and barefoot gait at three different speeds on a treadmill. Subjects were examined using the DIERS Formetric 4D system and DIERS Pedoscan system. While running barefoot, pedal force distribution analysis showed that 21.0% more force load goes through the forefoot vs. a 10.2% increase in forefoot force with shod (p = 0.0006). At 8.0 km·h-1 the average kyphotic angle was 1.6 degrees greater under barefoot conditions vs. shod conditions (p = 0.008). At 8.0 km·h-1 the average lordotic angle was 0.8 degrees greater under barefoot conditions vs. shod conditions (p = 0.05). Trunk inclination was 0.6 degrees and 0.8 degrees greater under barefoot conditions compared to shod conditions at natural speeds (p = 0.005) and 8.0 km·h-1 (p = 0.015), respectively. Barefoot runners show an increased force load in the forefoot, eliciting a forefoot strike pattern while running barefoot compared to shod running, and it was also found that barefoot runners have reduced trunk inclination. These dynamic changes allow for a more spring-like effect for barefoot runners creating a less transient and slower rise in force. In contrast, a heel strike pattern yields a rapid and high impact collision between heel and ground. As a result, barefoot running translates into less stress on the joints of the lower extremity and back and therefore less risk of injury.
Epidemiology of exercise-related injuries among children  [PDF]
Ches Jones, Bart Hammig
Health (Health) , 2012, DOI: 10.4236/health.2012.49098
Abstract: The objective of this study was to describe the epidemiology of injuries from exercise not involving equipment among children 18 and under. Methods included a retrospective review of data for children birth to 18 years old from the National Electronic Injury Surveillance (NEISS) system of the US consumer Product Safety Commission for the years 2005-2009. A total of 5093 cases were identified and would result in an estimated 175,000 injuries in the US. The most common type of injury was a sprain/strain to the ankle (20%). Four out of five injuries were among children between 10 and 18. Injuries occurring at school accounted for 40% of the injuries. Exercise-related injuries are common among older children and often occur in schools or recreational environments but are usually minor. School officials and athletic personnel should make efforts to provide proper instruction on exercise activities and have resources to provide emergency care for injuries.
Effects of Carnosine and Beta-Alanine Ingestion on Anaerobic Sprint Performance and Peripheral Blood Mononuclear Cell Interleukin-6 and -10 Gene Expression  [PDF]
Pietro Luigi Invernizzi, Bruno Venerando, Francesco Di Pierro, Sandro Saronni, Nadia Papini
Advances in Physical Education (APE) , 2013, DOI: 10.4236/ape.2013.34032
Abstract: Chronic administration of β-alanine has been shown to increase muscle carnosine content and improve anaerobic performance. It is not clear whether acute ingestion of carnosine and beta alanine may have the same effects. With a view to investigating acute effects of carnosine and β-alanine ingestion on anaerobic intermittent running performance and on the responses of Interleukin-6 and -10 to exercise, twelve healthy, young, active participants (age: 21 ± 4 years) underwent the running-based anaerobic test (RAST) twice (with 30 min recovery in between) on two separate occasions (randomized, crossover design). The test consisted of 6 × 35-m sprints interspersed with 10 s rests after acute ingestion (4 hours before the test) of either 2 g L-carnosine + 2 g β-alanine or placebo. The overall performance decreased (RAST1 vs RAST2, carnosine + β-alanine: 32.8 ± 1.3 s, 33.4 ± 1.2 s; Placebo: 32.9 ± 1.0 s, 33.6 ± 1.2 s), pain after RASTs increased (RAST1 vs RAST2, carnosine + β-alanine: 3.0 ± 2.1 a.u., 4.2 ± 1.9 a.u.; Placebo: 3.0 ± 1.8 a.u., 3.4 ± 1.2 a.u.) almost in the same way in both groups, and RPE did not show any difference. IL6 and IL10 gene expression increased and decreased respectively in response to exercise in the same fashion in both conditions. During RAST 2 we found a potentially increased performance in the carnosine + β-alanine group (main effect of condition, p < 0.05). In conclusion these findings suggest that acute administration of carnosine + β-alanine does not influence the cytokine response to exercise but might have a very small enhancing effect on anaerobic sprint performance.
Multi-Objective Optimization Problems with Arena Principle and NSGA-II
Wang Dong-Feng,Xu Feng
Information Technology Journal , 2010,
Abstract: Existing test problems for multi-objective optimization are mainly criticized for high computational complexity. In this study, we introduce a new non- dominated sorting algorithm based on Pareto optimal solutions which alleviates the problem of high computational complexity in NSGA-II. We use the Arena Principle in NSGA-II to retain the non-dominated solutions found during the evolutionary process. The main goal of this work is to keep the fast convergence exhibited by Arena Principle in global optimization when extending this heuristic to multi-objective optimization. The algorithm’s computational complexity is O(rmN). We adopt two standard test functions and simulation results show that the Arena Principle is able to find more useful and better spread of solutions.
An Explorative Study of Possible Demographic Variables, Sports-Related Sit-uational Variables, and Social Variables as Predictors of Athlete Burnout and Its Core Dimensions among German Non-Elite Endurance Athletes  [PDF]
Heiko Ziemainz, Amely Drescher, Melanie Schipfer, Oliver Stoll
Advances in Physical Education (APE) , 2015, DOI: 10.4236/ape.2015.51008
Abstract: Sport science has focused more and more on burnout in sports. Up to now, however, there are some studies that deal with burnout among coaches, but there are very few that deal with burnout among athletes. This article provides an overview on the topic and presents data from a cross-sectional study of 785 non-elite endurance athletes regarding possible predictors of athlete burnout. Burnout was assessed with a German version of the Athlete Burnout Questionnaire (ABQ; Raedeke & Smith, 2001), and multiple regressions were performed using burnout and its sub-dimensions as outcomes. 1.3% of the sample reported high levels of athlete burnout; various situational and demographic variables (e.g. training hours per week, gender, main sports) could be identified as determinants of the phenomenon. These results support the conditional theory (e.g. Coakley, 1992), which links burnout to environmental factors and sees stress as a symptom rather than a causal factor of burnout.
Disordered Eating and Exercise Dependence in Endurance Athletes  [PDF]
Bernd Zeulner, Heiko Ziemainz, Christian Beyer, Matthias Hammon, Rolf Janka
Advances in Physical Education (APE) , 2016, DOI: 10.4236/ape.2016.62009
Abstract: Background: The goal of this study was to assess the prevalence of disordered eating and exercise dependence among elite and amateur endurance athletes, both male and female, and to find out whether there was an association between disordered eating and exercise addiction in these athletes. Methods: 1031 participants of major German endurance events (745 male, 286 female, 528 elite athletes and 503 hobby athletes) with a mean age of 41.6 ± 10.7 years old completed a set of questionnaires, including the SCOFF questionnaire and the Exercise Addiction Inventory (EAI). Results: A rate of 18.9% of the athletes surveyed were at risk for developing an eating disorder, slightly higher than that in the normal population, and 2.7% had the potential to develop an exercise addiction. There was a significant correlation between exercise addiction and eating disorders. No gender difference related to the probability of developing an eating disorder or an exercise addiction, nor a difference between elite or amateur athletes was found. Exercise addiction and eating disorders showed a significant correlation.
How should we assess the mechanical properties of lower-limb prosthesis technology used in elite sport?—An initial investigation  [PDF]
Bryce Dyer, Philip Sewell, Siamak Noroozi
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.62015
Abstract:

Despite recent controversy, it is not yet formally recognised how lower-limb prosthesis should be assessed for their performance. To assist in this process, experiments are undertaken to investigate the linearity, stiffness and assessment of feet based energy return prosthesis technology typically used for elite level high speed running. Through initial investigations, it is concluded that static load testing would not be recommended to specify or regulate energy return prostheses for athletes with a lower-limb amputation. Furthermore, an assessment of energy return technology when loaded under dynamic conditions demonstrates changes in mechanical stiffness due to bending and effective blade length variation during motion. Such radical changes of boundary conditions due to loading suggest that any assessment of lower-limb prosthesis technology in the future should use methods that do not assume linear mechanical stiffness. The research into such effects warrants further investigation in the future.


The Acute Administration of Carnosine and Beta-Alanine Does Not Improve Running Anaerobic Performance and has No Effect on the Metabolic Response to Exercise  [PDF]
Pietro Luigi Invernizzi, Stefano Benedini, Sandro Saronni, Giampiero Merati, Andrea Bosio
Advances in Physical Education (APE) , 2013, DOI: 10.4236/ape.2013.34028
Abstract:

An increase in muscle carnosine content, following its chronic supplementation, has been shown to im- prove anaerobic performance. In addition, carnosine can affect plasma glucose concentration and insulin response. However, it is not clear whether the acute ingestion of carnosine can have the same effects. Aim of this study was to investigate the acute effects of carnosine ingestion on anaerobic intermittent per- formance and the responses of blood insulin, glucose, bicarbonate and lactate concentrations to exercise. Twelve healthy, young, active participants (BMI 23.5 ± .6, age: 22 ± 2 years) underwent in two separate occasions (double-blind, randomized, crossover design) the running-based anaerobic test (RAST), con- sisting of 6 × 35-m sprints interspersed with 10 s rest after acute (4 hours before the test) ingestion of ei- ther 1 g of L-carnosine and 1 g of β-alanine or placebo. None significant difference was found between the acute ingestion of carnosine and the placebo conditions in terms of running performance (30.0 ± .8 and 29.8 ± .8, p = .302), perceptual response to exercise (RPE), blood lactate, insulin (23.8 ± 13.0 and 19.5 ± 9.0 μU·ml-1, p = .329), blood glucose (109 ± 23 and 104 ± 12 mg·dl-1, p = .969), and blood bicarbonates (16 ± 2 and 16 ± 2 mEq·l-1, p = .277). In conclusion, the acute ingestion of carnosine had no effect on performance, perceptual response to exercise, blood lactate concentration, insulin, glucose, and bicarbonates responses to exercise compared to a placebo treatment. It is not clear whether these results may be attributed to an insufficient dose of carnosine or to a lack of acute effect per sé.

Patterns of Interpersonal Coordination in Rugby Union: Analysis of Collective Behaviours in a Match Situation  [PDF]
Marta Rodrigues, Pedro Passos
Advances in Physical Education (APE) , 2013, DOI: 10.4236/ape.2013.34034
Abstract: This study aims to analyze how intra-team coordination patterns in the team sport of rugby union influenced successful performance. We hypothesized that high interpersonal coordination patterns are a crucial issue to cross (or not) the gain line. Video record and digitizing procedures were used as a method to collect data for further analysis of interpersonal coordination patterns that took place during the formation of subunits of attack. The results showed the existence of three types of outputs, which differ depending on the correlations between attackers and defenders. Therefore, for high and positive values of interpersonal coordination (r values between 0.8 < r < 1), there are possibilities of action that lead to success when the opponents have inverse or lower values of correlation. The conclusion was that interpersonal coordination within subunits becomes a relevant factor in analyzing the success in each game situation.
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