Effects of different percentages of body weight support on spatiotemporal step characteristics during running     

Luis E. Roche-Seruendo  Isabel Auria-Martin  Ana V. Bataller-Cervero  Pedro A. Latorre Román  Victor M. Soto -Hermoso 《Journal of sports sciences》2018,36(13):1441-1446

This study aimed to determine the effect of different percentages of body weight support (BWS) on spatiotemporal step characteristics during running. 26 endurance runners (age: 37 ± 9 years) completed a running treadmill protocol consisting of 6 different conditions (BWS combinations: 0–50%), with velocity maintained at 12 km/h. Each condition lasted 1 minute. Step angle, ground contact time (CT), flight time (FT), step length (SL) and frequency (SF), and duration of phases during stance time (phase1: initial contact; phase2: midstance; phase3: propulsion) were measured for every step during the test using a photoelectric cell system. Compared with the baseline condition (100% BW), FT was longer, CT was shorter, SL was longer, SF was lower, and the step angle was higher with each increase in BWS (p < 0.05). Also, some changes were observed in the duration of phases during stance time: phase1 did not experience changes across experimental conditions (p = 0.096), phase2 decreased and phase3 increased as BW was supported (p < 0.05). These results indicate that as BW was supported, runners showed longer FT and SL, shorter CT, lower SF, and greater step angle as well as some changes in the phases during the ground contact. Therefore, this study highlights the effect of different percentages of BWS on spatiotemporal parameters.  相似文献   

Fatigue does not conjointly alter postural and cognitive performance when standing in a shooting position under dual-task conditions     

José Luis Bermejo  Xavier García-Massó  Thierry Paillard 《Journal of sports sciences》2018,36(4):429-435

This study investigated the effects of fatigue on balance control and cognitive performance in a standing shooting position. Nineteen soldiers were asked to stand while holding a rifle (single task – ST). They also had to perform this postural task while simultaneously completing a cognitive task (dual task – DT). Both the ST and DT were performed in pre- and post-fatigue conditions. In pre-fatigue, participants achieved better balance control in the DT than in the ST, thus suggesting that the increased cognitive activity associated with the DT improves balance control by shifting the attentional focus away from a highly automatised activity. In post-fatigue, balance control was degraded in both the ST and DT, while reaction time was enhanced in the first minutes following the fatiguing exercise without affecting the accuracy of response in the cognitive task, which highlights the relative independent effects of fatigue on balance control and cognitive performance.  相似文献   

Effect of a pilot multi-component intervention on motor performance and metabolic risks in overweight/obese youth     

Dominique Silva Silveira  Luis Filipe Gomes Barbosa Ferreira Lemos  Rafael Miranda Tassitano  Maria Teresa Cattuzzo  Anderson Henry Pereira Feitoza  Luisa Maria Seara Moreira Carneiro Aires 《Journal of sports sciences》2018,36(20):2317-2326

This study evaluated the effect of a multi-component intervention on motor performance (MP) and metabolic risk markers (MRM) in overweight/obese youth. A secondary aim was to examine whether changes in MP are associated to changes in MRM. A 3-month multi-component intervention was performed, consisting of physical exercise sessions (twice/week;1h), nutritional education sessions (once/month), and parental support (twice/week). The sample included 35 volunteers (7–13 y.o), allocated to intervention (INT, n = 17) and control (CONT, n = 18) group. Variables were measured pre (T0) and post intervention (T1). Fasting blood samples were analyzed for MRM. MP tests included the measurement of health related physical fitness components and motor coordination performance (KTK battery). To assess food intake, a 24-hour recall diary was used. GLM-ANCOVA was performed. Standardized scores were calculated for the outcome variables, and multilinear regressions were applied to analyze associations between the key variables. INT group showed improvements in MP, glycolytic and hepatic profiles. After adjustments for MVPA, SB, total intake and maturational stage, negative associations between %ΔMP and %Δglycolytic (β = -.424; 95%CI:-0.343:-0.022), and %Δhepatic scores (β = -.382 95%CI:-0.001:-0.009) were observed. The intervention produced a moderate-to-high effect on the MP and some MRM. Changes in MP were inversely associated with changes in glycolytic and hepatic markers.  相似文献   

DESIGNING AND EVALUATING RESEARCH-BASED INSTRUCTIONAL SEQUENCES FOR INTRODUCING MAGNETIC FIELDS     

Jenaro Guisasola  Jose Manuel Almudi  Mikel Ceberio  Jose Luis Zubimendi 《International Journal of Science and Mathematics Education》2009,7(4):699-722

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Determinants for the commitment relationship maintenance between the alumni and the alma mater     

Ilda Maria Pedro  Luis Nobre Pereira  Hélder Brito Carrasqueira 《Journal of Marketing for HIGHER EDUCATION》2018,28(1):128-152

This study aims to find determinants for the commitment relationship between alumni and alma mater. Based on the literature, satisfaction and image are proposed as drivers of commitment. A survey applied to 2544 alumni in a Portuguese university provides data analyzed through a structural equation modeling technique. The results present ‘image of education’, ‘image of communication’ and ‘satisfaction with social and academic environment’ as determinants of the commitment relationship, which provide important clues for the marketers’ decision-making process when developing activities geared towards alumni. This process should emphasize aspects relating to their willingness to give back, academic and relationship quality, and institutional values. Within the Higher Education market, this study underscores the need to maintain and reinforce the relationship with alumni, and contributes to the scarce Portuguese literature on alumni matters.  相似文献   

Cardiorespiratory fitness and arm bone mineral health in young males with spinal cord injury: the mediator role of lean mass     

Irene Rodríguez-Gómez  Soraya Martín-Manjarrés  María Martín-García  Sara Vila-Maldonado  Ángel Gil-Agudo  Luis M. Alegre 《Journal of sports sciences》2019,37(7):717-725

Spinal cord injury (SCI) derives in loss of bone mineral content (BMC) and bone mineral density (BMD). However, physical activity is an important determinant in bone mass acquisition, which is partially mediated through the lean mass (LM). The aim was to examine the effect of cardiorespiratory fitness (CRF) on BMD and BMC arms of adult males with SCI and able-bodied controls using the arm LM as a mediator variable. Thirty able-bodied men and thirty men with SCI participated. BMC and BMD were analysed by DXA, and indirect calorimetry was used to calculate VO_2peak during a progressive arm-cranking test. When groups were divided by the amount of LM, the subgroup with highest LM had significantly higher arm BMC compared to the lowest LM subgroup (p ≤ 0.05) in both SCI and able-bodied groups. Moreover, same differences were found when confidence intervals were analysed. Only in the SCI group, arm LM mediated the relationship between bone mass and CRF at 30.9%, as indicated by the Sobel test (z = 2.17 and z = 2.04 for BMC and BMD, respectively). In conclusion, LM mediates the indirect association between CRF and bone health, specifically in the arms. This finding highlights the importance of having an adequate CRF for the maintenance of good bone health in SCI men.  相似文献   

Architectures of the information age     

Luis F. Alvarez León 《Journal of Cultural Economy》2017,10(2):217-222

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The Last and Most Developed Naṣrid Palace in the Alhambra: The Alijares and Its Country Estate (Fourteenth Century)     

Luis José García-Pulido 《Al-Masaq: Islam & the Medieval Mediterranean》2017,29(1):60-83

The country estate (al-munya, almunia in Spanish) of the Alijares occupied grounds near the Alhambra and the Generalife, although it was higher up. It was constructed at the peak of the Na?rid dynasty's splendour, during the last stage of the reign of Mu?ammad V (r.1354–1359 / 1362–1391), after he had finished the Palace of the Lions.

The Alijares formed the last link in the chain in the stylistic development of the palaces of al-Andalus. When its founder decided on the features of the Alijares, he was in search of something that was completely innovative, as he had already undertaken work in the medinas of Granada and in the Alhambra that turned out to be a transformation of the architectural forms so far developed.

Life in the palace and the al-munya was cut short by sizeable earthquake in 1431, which coincided with a hard Castilian military campaign against the Kingdom of Granada. The consequences of the allegiance formed after the Na?rid defeat hindered the reconstruction of the Alijares, and so the royal buildings above the Royal Water Channel (Acequia Real) of the Alhambra were abandoned. Although time has erased many of the traces of the palace and its al-munya, we have extensive knowledge of its main architectural features, thanks to an analysis of all the available sources.  相似文献   

Scientific collaboration for a better,more sustainable tomorrow     

H N Cheng  Angela K Wilson  Luis Echegoyen 《国家科学评论(英文版)》2021,8(5)

Collaboration among scientists and the chemistry community is as much a feature of the research process as the desire to discover.At the American Chemical Socie...  相似文献   

Information-governing dynamics of attacker-defender interactions in youth rugby union   总被引：1，自引：1，他引：0  

Passos P  Araújo D  Davids K  Gouveia L  Milho J  Serpa S 《Journal of sports sciences》2008,26(13):1421-1429

Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker-defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker-defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m x s(-1), a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker-defender dyads in rugby union over time as spatial proximity to the try line increased.  相似文献