Analysis of performance in orienteering with treadmill tests and physiological field tests using a differential global positioning system     

Larsson P  Burlin L  Jakobsson E  Henriksson-Larsén K 《Journal of sports sciences》2002,20(7):529-535

The aim of this study was to determine the physiological responses to orienteering by examining the interrelationships between the information provided by a differential global positioning system (dGPS) about an orienteer's route, speed and orienteering mistakes, portable metabolic gas analyser data during orienteering and data from incremental treadmill tests. Ten male orienteers completed a treadmill threshold test and a field test; the latter was performed on a 4.3 km course on mixed terrain with nine checkpoints. The anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio, onset of blood lactate accumulation and peak oxygen uptake (VO2peak) were determined from the treadmill test. Time to complete the course, total distance covered, mean speed, distance and timing of orienteering mistakes, mean oxygen uptake, mean relative heart rate, mean respiratory exchange ratio and mean running economy were computed from the dGPS data and metabolic gas analyser data. Correlation analyses showed a relationship between a high anaerobic threshold and few orienteering mistakes (r = - 0.64, P < 0.05). A high threshold of decompensated metabolic acidosis and VO2peak were related to a fast overall time (r = -0.70 to -0.72, P < 0.05) and high running speed (r = 0.64 to 0.79, P < 0.05 and P < 0.01, respectively), and were thus the best predictors of performance.  相似文献   

Impact absorption of tennis shoe-surface combinations     

S.?J.?DixonEmail author  V.?H.?Stiles 《Sports Engineering》2003,6(1):1-9

The aim of this study was to investigate, for typical shoes and surfaces used in tennis, the relative role of the shoe and surface in providing cushioning during running. Five test surfaces ranging from concrete to artificial turf were selected, together with two shoe models. Impact absorbing ability was assessed mechanically using drop test procedures and biomechanically using peak magnitude and rate of loading of impact force and peak in-shoe pressure data at the lateral heel. Differences in biomechanical variables between shoe-surface combinations were identified using a two-way ANOVA (p < 0.05). Mechanical test results were found to rank the surfaces in the same order regardless of the shoe model, suggesting that the surface is influential in providing cushioning. However, for all mechanical and biomechanical (p < 0.05) variables representing impact absorbing ability, it was found that the difference between shoes was markedly greater than the differences between surfaces. The peak heel pressure data were found to rank the surfaces in the same order as the mechanical tests, while impact force data were not as sensitive to the changes in surface. Correlations between mechanical and biomechanical impact absorption highlighted the importance of testing the shoe-surface combination in mechanical tests, rather than the surface alone. In conclusion, mechanical testing of the shoe-surface combination was found to provide a strong predictor of the impact absorbing ability during running if pressure data were used. In addition, for typical shoe-surface combinations in tennis, the shoe was found to have more potential than the surface to influence impact loading during running. Finally, in-shoe pressure data were found to be more sensitive than force plate data to changes in material cushioning.  相似文献   

University-Industry-Government Relations on the Periphery: The University of Campinas,Brazil     

Dagnino  Renato  Velho  Léa 《Minerva》1998,36(3):229-251

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Un inventaire des notions impliquées dans un enseignement général de mathématique à l'école secondaire     

Théo Bernet  André Delessert 《Educational Studies in Mathematics》1972,4(4):450-465

Sans résumé  相似文献   

Education in Africa—form dependency to self-sufficiency     

Ben Mady Cissé 《Prospects》1976,6(2):181-195

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Stress sensitivity and reading performance in Spanish: A study with children     

Nicols Gutirrez‐Palma  Alfonso Palma Reyes 《Journal of Research in Reading》2007,30(2):157-168

This paper investigates the relationship between ability to detect changes in prosody and reading performance in Spanish. Participants were children aged 7–8 years. Their tasks consisted of reading words, reading non‐words, stressing non‐words and reproducing sequences of two, three or four non‐words by pressing the corresponding keys on the computer keyboard. Non‐word sequences were constructed with minimal non‐word pairs differing in a single phoneme (/kúpi/ ‐ /kúti/) or in the stress pattern (/mípa/ ‐ /mipá/). Results showed that performance on phoneme contrast sequences (e.g. /kúpi/ ‐ /kúti/) predicted word reading. In contrast, performance on stress contrast sequences (e.g. /mípa/ ‐ /mipá/) predicted non‐word reading, but only when two‐non‐word sequences were analysed. This suggests that stress sensitivity may be one of the factors related to reading fluency as most errors at reading non‐words consisted of false starts and pauses between syllables. Results also showed that stress sensitivity (scored in two non‐word sequences) predicted stress assignment, and that knowledge of stress rules predicted both word and non‐word reading. This suggests that stress sensitivity may help in learning stress rules, and that knowledge of stress rules is relevant for reading.  相似文献   

Impact of question-answering tasks on search processes and reading comprehension     

Raquel Cerdán  Eduardo Vidal-Abarca  Tomás Martínez  Ramiro Gilabert  Laura Gil 《Learning and Instruction》2009,19(1):13-27

This study examined the effect of (a) high- and low-level questions and (b) reading the text before the questions asked on performance, delayed text recall, and deep text comprehension, as well as on specific text-inspection patterns. Participants were 37 undergraduate students who answered either high- or low-level questions using the software Read&Answer to read and answer questions on the computer screen. Additionally, half of the sample read first a text and then answered the questions (reading-first condition), whereas the other half answered the questions without having read the text in advance (no-reading-first condition). All participants had the text available to search for the answer. Results indicated that high-level questions facilitated deep comprehension but not immediate performance or delayed recall of text, independently of the reading condition, and that high- and low-level questions differentially affected text-inspection patterns.  相似文献   

Life and Death Decision Making     

r. s.  downie 《Philosophical Books》1989,30(4):234-235

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The influence of live- vs. video-model presentation on the early acquisition of a new complex coordination     

Léna Lhuisset  Eric Margnes 《Physical Education & Sport Pedagogy》2015,20(5):490-502

Background: Demonstration is a widely used method in sports teaching and coaching, based on the assumption that it is more beneficial than verbal instructions or trial-and-error methods for skill acquisition. Although in teaching/coaching situations, the demonstration is usually carried out in front of the learners, in a research context, it is most often presented via a video. However, a direct comparison between these two types of model has rarely been undertaken in a motor context.

Purpose: In this study, we aimed to compare the effectiveness of the observation of a live and a videomodel for the early acquisition of a complex judo movement.

Research Design: Participants observed either a live or a videomodel executing the task. After observation, they practised for three minutes taking five trials and then performed it for analysis. This procedure was repeated three times. The form and technique of each participant's execution were evaluated using a technical score.

Main results: The results indicated a significant improvement in the task execution by the end of the practice session. However, this improvement occurred only for the video-model group between the second and third blocks of practice.

Conclusions: The video demonstration seems more effective than the live one for the early acquisition of a completely new complex coordination. This may be due to the simplification of the visual information in the former condition because of its two-dimensionality. This simplification may allow the observer to identify the more key elements that would guide him/her for the subsequent performance of the task.  相似文献   

Degradation of Anthocyanin Content in Sour Cherry Juice During Heat Treatment     

Lilla Szalóki-Dorkó  Gy?rgy Végvári  Márta Ladányi  Gitta Ficzek  Mónika Stéger-Máté 《Food Technology and Biotechnology》2015,53(3):354-360

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