Long-term Tai Chi exercise increases body stability of the elderly during stair ascent under high and low illumination*     

Qipeng Song  Shen Wang  Del P. Wong  Jingyi Zhou  Wei Sun  Cui Zhang 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(3):402-413

The effects of long-term Tai Chi exercise on body stability of the elderly during stair ascent under high and low illumination were investigated. Forty-five healthy elderly women were divided into three groups, namely, Tai Chi exercise group, brisk walking group and no-exercise control group. All the participants ascended a staircase, during which force platforms and a motion capture system collected the data. Under the high illumination, Tai Chi exercise participants exhibited higher loading rate and anteroposterior centre of pressure (COP_ap) displacement as well as a lower braking impulse than no-exercise group. Under the low illumination, Tai Chi exercise participants demonstrated higher COP_ap and mediolateral centre of pressure (COP_ml) displacements as well as lower braking and lateral impulses compared with no-exercise participants. The centre of mass (COM)_ml sway in Tai Chi and no exercise participants were higher, the loading rates in Tai Chi and walking participants were higher, and the lateral impulse in no exercise participants was higher under low illumination than under high illumination. Thus, low illumination increases the risk of falling. Tai Chi participants increased their foot clearance, head inclination angle and COP_ap displacement under low illumination to increase their stability during stair ascent.  相似文献   

Post-activation potentiation (PAP) in endurance sports: A review     

Daniel Boullosa  Sebastian Del Rosso  David G. Behm  Carl Foster 《European Journal of Sport Science》2018,18(5):595-610

While there is strong support of the usefulness of post-activation potentiation (PAP) phenomenon in power demanding sports, the role that PAP could play in endurance sports has received less attention. The aim of this review is to present evidence for a better understanding of PAP in endurance athletes; and to discuss the physiological basis and methodological aspects necessary for better practices and designing further studies. A search for relevant articles on PAP and endurance trained athletes was carried out using Medline and ISI Web of Knowledge databases. Twenty-two studies were included in the review. The current evidence suggests the possible influence of PAP for performance enhancement after appropriate conditioning activities during warm up. Evaluation of PAP responses during testing, training and competition may be also important for athletes monitoring. There are many unresolved questions about the optimum load parameters for benefiting from PAP in both training and competition; and the role that PAP may exert for optimal performance while interacting with central and peripheral factors associated with muscle fatigue. Further studies should elucidate the association between PAP responses and long-term adaptations in endurance athletes.  相似文献   

Caffeine ingestion changes time-motion and technical-tactical aspects in simulated boxing matches: A randomized double-blind PLA-controlled crossover study     

Victor Silveira Coswig  Paulo Gentil  Francine Irigon  Fabrício Boscolo Del Vecchio 《European Journal of Sport Science》2018,18(7):975-983

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二次投票与区块链治理     

赖特  姚远 《科学．经济．社会》2022,40(1):48-65

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Developing game-like simulations to formalize tacit procedural knowledge: the ONT experience     

Blanca Borro-Escribano  Ángel Del Blanco  Javier Torrente  Itziar Martínez Alpuente  Baltasar Fernández-Manjón 《Educational technology research and development : ETR & D》2014,62(2):227-243

The exceptional success achieved by the Spanish National Transplant Organization (ONT) in recent years has made other countries highly interested in following this organization’s methodologies. A good training program is one of the key elements of the ONT. Until 2012, the ONT training program was a paper-based case teaching method, and the small number of ONT experts limited the audience. In an attempt to improve and increase the attendees in this program, a game-like simulation was developed to represent transplant management procedural knowledge. To maximize the educational value, this game-like simulation was based on representative teaching cases to help students practice with different real situations and different levels of complexity in a risk-free environment. This study presents how an iterative game development methodology has been applied to evolve from a paper-based case teaching method to a game-like simulation, with a special focus on the efforts made to include the ONT experts’ tacit procedural knowledge in the simulation. Apart from increasing the number of students who can access the ONT training, this game-like simulation also helped to achieve a more detailed formalization of transplant management as well as a more comprehensive systematization of a set of relevant teaching cases.  相似文献   

Description of the finger mechanical load of climbers of different levels during different hand grips in sport climbing     

Jesús Morenas Martín  Vicente Luis Del Campo  Marta Leyton Román  Juan Miguel Gómez-Valadés Horrillo  Juan Santiago Gómez Navarrete 《Journal of sports sciences》2013,31(15):1713-1721

Abstract

Currently, direct empirical evidence exists about the amount of mechanical load that climbers apply to each finger during several hand grips specific to sport climbing, but not yet in a specific hanging position.

The objectives of this study are a) to draw and build a solid and rigid support that simulates the real action of a hand grip in a hanging position in sport climbing, to enable the measurement of the mechanical load endured by the fingers in a hanging position and in addition, b) to describe the distribution of mechanical load among fingers as a function of the level of climbing during different hand grips in a hanging position.

Thirty young male participants took part in the initial phase of reliability of the measurements, while another 64 male climbers participated in the subsequent study phase to check the relations between independent and dependent variables. The level of on sight climbing and the total practice experience were used to define the groups. The research task consisted of performing hanging positions on the created support in order to measure the mechanical load endured by the fingers in the three most characteristic hand grips in climbing (crimp, half crimp and slope). It has been concluded that the performance level of the climbers had no influence on the production of a pattern of differentiated finger mechanical load during the research task.  相似文献   

The Effects of Contextual Interference on Females With Varied Experience in Open Sport Skills     

Patricia Del Rey  Emily H. Wughalter  Michael Whitehurst 《Research quarterly for exercise and sport》2013,84(2):108-115

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Training and Contextual Interference Effects on Memory and Transfer     

Patricia Del Rey 《Research quarterly for exercise and sport》2013,84(4):342-347

Abstract

An experimental intervention program to train subjects on coincidence anticipation and prediction skills was administered to novice females. An attempt was undertaken to study the effects of this sports training and training on laboratory tasks. According to Battig' s predictions on the structure of practice sessions, both random and blocked contexts were presented. These acquisition contexts were viewed as orienting tasks that preceded sports training. The effects of high-contextual interference and sports training on acquisition, retention, and transfer were investigated. Practice conditions in the intervention were selected because of processing demands similar to random acquisition. Other research has shown that acquisition in random is influenced by sport-skill expertise and further indicates that processing of events occurring outside the laboratory influences performance of laboratory tasks. Observed results supported prior theoretical predictions and empirical findings on contextual interference. Predicted hypotheses were supported, and the effects of sports training were most profound during retention and transfer if the acquisition context for the trained subjects was random. Supported by prior research, activities performed outside the laboratory influenced performance on laboratory tasks. These results shift more emphasis on the learner as an active processor of information, which relates to Lee's (1988) views on transfer-appropriate processing.  相似文献   

The ingestion of a caffeinated energy drink improves jump performance and activity patterns in elite badminton players     

Pablo Abian  Juan Del Coso  Juan José Salinero  Cesar Gallo-Salazar  Francisco Areces  Diana Ruiz-Vicente 《Journal of sports sciences》2015,33(10):1042-1050

The aim of this study was to investigate the effectiveness of a caffeine-containing energy drink to enhance physical and match performance in elite badminton players. Sixteen male and elite badminton players (25.4 ± 7.3 year; 71.8 ± 7.9 kg) participated in a double-blind, placebo-controlled and randomised experiment. On two different sessions, badminton players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed the following tests: handgrip maximal force production, smash jump without and with shuttlecock, squat jump, countermovement jump and the agility T-test. Later, a 45-min simulated badminton match was played. Players’ number of impacts and heart rate was measured during the match. The ingestion of the caffeinated energy drink increased squat jump height (34.5 ± 4.7 vs. 36.4 ± 4.3 cm; P < 0.05), squat jump peak power (P < 0.05), countermovement jump height (37.7 ± 4.5 vs. 39.5 ± 5.1 cm; P < 0.05) and countermovement jump peak power (P < 0.05). In addition, an increased number of total impacts was found during the badminton match (7395 ± 1594 vs. 7707 ± 2033 impacts; P < 0.05). In conclusion, the results show that the use of caffeine-containing energy drink may be an effective nutritional aid to increase jump performance and activity patterns during game in elite badminton players.  相似文献   

Does Bradford's Law of Scattering predict the size of the literature in Cochrane Reviews?     

Nash-Stewart CE  Kruesi LM  Del Mar CB 《Journal of the Medical Library Association : JMLA》2012,100(2):135-138

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