Movement velocity as a measure of exercise intensity in three lower limb exercises     

Filipe Conceição  Juvenal Fernandes  Martin Lewis  Juan José Gonzaléz-Badillo  Pedro Jimenéz-Reyes 《Journal of sports sciences》2016,34(12):1099-1106

The purpose of this study was to investigate the relationship between movement velocity and relative load in three lower limbs exercises commonly used to develop strength: leg press, full squat and half squat. The percentage of one repetition maximum (%1RM) has typically been used as the main parameter to control resistance training; however, more recent research has proposed movement velocity as an alternative. Fifteen participants performed a load progression with a range of loads until they reached their 1RM. Maximum instantaneous velocity (V_max) and mean propulsive velocity (MPV) of the knee extension phase of each exercise were assessed. For all exercises, a strong relationship between V_max and the %1RM was found: leg press (r²_adj = 0.96; 95% CI for slope is [?0.0244, ?0.0258], P < 0.0001), full squat (r²_adj = 0.94; 95% CI for slope is [?0.0144, ?0.0139], P < 0.0001) and half squat (r²_adj = 0.97; 95% CI for slope is [?0.0135, ?0.00143], P < 0.0001); for MPV, leg press (r²_adj = 0.96; 95% CI for slope is [?0.0169, ?0.0175], P < 0.0001, full squat (r²_adj = 0.95; 95% CI for slope is [?0.0136, ?0.0128], P < 0.0001) and half squat (r²_adj = 0.96; 95% CI for slope is [?0.0116, 0.0124], P < 0.0001). The 1RM was attained with a MPV and V_max of 0.21 ± 0.06 m s^?1 and 0.63 ± 0.15 m s^?1, 0.29 ± 0.05 m s^?1 and 0.89 ± 0.17 m s^?1, 0.33 ± 0.05 m s^?1 and 0.95 ± 0.13 m s^?1 for leg press, full squat and half squat, respectively. Results indicate that it is possible to determine an exercise-specific %1RM by measuring movement velocity for that exercise.  相似文献   

Towards the reform of science teaching in Spain: the social and personal relevance of junior secondary school science projects for a socially responsible understanding of science     

Pedro Membiela 《International Journal of Science Education》2013,35(7):721-730

This article describes aspects of more than a decade of research and implementation of cross-curriculum themes as part of the curriculum for secondary school students in Spain. The educational reform described is an attempt to develop a more socially responsible education, using what, for Spain, has been a highly novel breaking down of subject barriers as a way of preparing young adults for life as citizens. It provides other investigators in the field with a commentary on some of the theoretical and practical issues encountered in developing similar projects.  相似文献   

La comprensión por el niño de la intención del mensaje publicitario     

Pedro Vidal 《Infancia y Aprendizaje》2013,36(35-36):123-138

Resumen

El propósito central de este artículo es mostrar cómo un modelo integrado, multidisciplinar, puede dar cuenta de la comprensión del mensaje publicitario por el niño. El modelo parte de la consideración del mensaje como acto-de-habla-global y su representación cognitiva por el receptor, como esquema de acción e interacción. Este doble abordamiento permite trascender el marco de las teorías de la competencia, hasta ahora dominantes, y explicar, en cierto modo, la actuación concreta de los sujetos en la comprensión de los mensajes.  相似文献   

How the use of the International Classification of Functioning,Disability and Health for Children and Youth changed the Individualized Education Programs in Portugal     

Mónica Silveira-Maia  Pedro Lopes-dos-Santos  Manuela Sanches-Ferreira 《International Journal of Inclusive Education》2017,21(5):573-583

  相似文献   

Serial position effects in social transmission of food preference     

Juárez-Maldonado CE  Ortega-Saavedra G  Huichan-Olivares F  Gómez-Romero J  Cruz-Morales SE  Arriaga-Ramírez JC 《Learning & behavior》2006,34(4):374-378

The serial position effect in Long-Evans rats was evaluated in two experiments. In Experiment 1, the effect in a group for which an interstimulus interval (ISI) was introduced between items in a list of demonstrators was compared with that in a group without an ISI. With an ISI, a recency effect was produced. In Experiment 2, a serial position effect group was compared with four groups in which either the distinctiveness or the context of the middle item was changed, relative to the items on either side of it. A von Restorff effect was produced when a rat from a different strain was used as a demonstrator in Position 2. The results for Experiment 1 are discussed in relation to interstimulus effects in monkeys and those for Experiment 2 with respect to changes in the physical properties of middle items.  相似文献   

High-throughput study of alpha-synuclein expression in yeast using microfluidics for control of local cellular microenvironment   总被引：1，自引：0，他引：1  

Rosa P  Tenreiro S  Chu V  Outeiro TF  Conde JP 《Biomicrofluidics》2012,6(1):14109-141099

Microfluidics is an emerging technology which allows the miniaturization, integration, and automation of fluid handling processes. Microfluidic systems offer low sample consumption, significantly reduced processing time, and the prospect of massive parallelization. A microfluidic platform was developed for the control of the soluble cellular microenvironment of Saccharomyces cerevisiae cells, which enabled high-throughput monitoring of the controlled expression of alpha-synuclein (aSyn), a protein involved in Parkinson's disease. Y-shaped structures were fabricated using particle desorption mass spectrometry-based soft-lithography techniques to generate biomolecular gradients along a microchannel. Cell traps integrated along the microchannel allowed the positioning and monitoring of cells in precise locations, where different, well-controlled chemical environments were established. S. cerevisiae cells genetically engineered to encode the fusion protein aSyn-GFP (green fluorescent protein) under the control of GAL1, a galactose inducible promoter, were loaded in the microfluidic structure. A galactose concentration gradient was established in the channel and a time-dependent aSyn-GFP expression was obtained as a function of the positioning of cells along the galactose gradient. Our results demonstrate the applicability of this microfluidic platform to the spatiotemporal control of cellular microenvironment and open a range of possibilities for the study of cellular processes based on single-cell analysis.  相似文献   

Proximity-to-goal as a constraint on patterns of behaviour in attacker-defender dyads in team games     

Headrick J  Davids K  Renshaw I  Araújo D  Passos P  Fernandes O 《Journal of sports sciences》2012,30(3):247-253

The aim of this study was to determine whether spatiotemporal interactions between footballers and the ball in 1 vs. 1 sub-phases are influenced by their proximity to the goal area. Twelve participants (age 15.3 ± 0.5 years) performed as attackers and defenders in 1 vs. 1 dyads across three field positions: (a) attacking the goal, (b) in midfield, and (c) advancing away from the goal area. In each position, the dribbler was required to move beyond an immediate defender with the ball towards the opposition goal. Interactions of attacker-defender dyads were filmed with player and ball displacement trajectories digitized using manual tracking software. One-way repeated measures analysis of variance was used to examine differences in mean defender-to-ball distance after this value had stabilized. Maximum attacker-to-ball distance was also compared as a function of proximity-to-goal. Significant differences were observed for defender-to-ball distance between locations (a) and (c) at the moment when the defender-to-ball distance had stabilized (a: 1.69 ± 0.64 m; c: 1.15 ± 0.59 m; P < 0.05). Findings indicate that proximity-to-goal influenced the performance of players, particularly when attacking or advancing away from goal areas, providing implications for training design in football. In this study, the task constraints of football revealed subtly different player interactions than observed in previous studies of dyadic systems in basketball and rugby union.  相似文献   

Interpersonal dynamics and relative positioning to scoring target of performers in 1 vs. 1 sub-phases of team sports     

PT Esteves  D Araújo  K Davids  L Vilar  B Travassos  C Esteves 《Journal of sports sciences》2012,30(12):1285-1293

Abstract In this study, we examined the effects of relative positioning of attacker-defender dyads to the basket on interpersonal coordination tendencies in basketball. To achieve this aim, four right-hand dominant basketball players performed in a 1 vs. 1 sub-phase, at nine different playing locations relative to the basket (from 0° to 180°, in 20° increments). Performers' movement displacement trajectories were video-recorded and digitized in 162 trials. Results showed that interpersonal coordination tendencies changed according to the scaling of the relative position of performers to the basket. Stable in-phase modes of coordination were observed between performers' longitudinal and lateral displacements (50.47% and 43.02%) on the left side of the court. On the right side of the court, a shift in the dominant mode of coordination was observed to a defender lead-lag of -30°, both for longitudinal and lateral displacements (30.51% and 32.65%). These results suggest how information about dribbler hand dominance and relative position to the basket may have constrained attacker-defender coordination tendencies in 1 vs. 1 sub-phases of basketball.  相似文献   

Analysis of foot strike pattern,rearfoot dynamic and foot rotation over childhood. A cross-sectional study     

Pedro Ángel Latorre Román  Fernando Redondo Balboa  Juan Párraga Montilla  Víctor Manuel Soto Hermoso  Pedro José Consuegra González  Felipe García Pinillos 《Journal of sports sciences》2019,37(5):477-483

The purpose of this study was to determine the foot strike patterns (FSP), rearfoot position at initial contact (RPic, i.e., No INV/EVE) and foot rotation in children in relation to age. A total of 932 children aged 3 to 16 years participated in this study. A sagittal and frontal-plane video was recorded using a high-speed camcorder to analyse these variables. There is a significant increase (p < 0.001) of rearfoot strike patterns (RFS) prevalence in relation to age; e.g. preschool children (3–6 years old) displayed an RFS prevalence 46.65% and the adolescent population(15–16 years old) an RFS prevalence 92.20%. The total RFS prevalence in all samples was 69.25%. There was a significant reduction (p < 0.001) of prevalence of RPic in relation to age groups; preschool children displayed a prevalence of RPic 60.37% and the adolescent population 10%. There was a significant reduction (p < 0.001) of prevalence of no foot rotation in relation to age groups; preschool children displayed a prevalence of no foot rotation 48.95% and the adolescent population 13.55%. In conclusion, FSP in children are influenced by age. It is noteworthy that the RFS prevalence of children is lower in comparison to the adult population.  相似文献   

Accelerometer and self-reported measures of sedentary behaviour and associations with adiposity in UK youth     

Robert J. Noonan  Danielle Christian  Lynne M. Boddy  Pedro F. Saint-Maurice  Gregory J. Welk  Paul R. Hibbing 《Journal of sports sciences》2019,37(16):1919-1925

This study used accelerometer and self-report measures of overall sedentary time (ST) and screen time behaviours to examine their respective associations with adiposity among UK youth. Participants (Year groups 5, 8, and 10; n=292, 148 girls) wore the SenseWear Armband Mini accelerometer for eight days and completed the Youth Activity Profile, an online report tool designed to estimate physical activity and ST.Stature, body mass and waist circumference were measured to classify adiposity outcomes (overweight/obese and central obesity). One-way between groups ANOVA and adjusted linear, logistic and multinomial logistic regression analyses were conducted. There was a significant main effect of age on total ST across the whole week (F(2, 289)=41.64, p≤0.001). ST increased monotonically across Year 5 (581.09±107.81 min·dˉ¹), 8 (671.96±112.59 min·dˉ¹) and 10 (725.80±115.20 min·dˉ¹), and all pairwise comparisons were significant at p≤0.001. A steep age-related gradient to mobile phone use was present (p≤0.001). ST was positively associated with adiposity outcomes independent of moderate-to-vigorous intensity physical activity (MVPA; p≤0.001). Engaging in >3 hours of video gaming daily was positively associated with central obesity (OR=2.12, p≤0.05) but not after adjustment for MVPA. Results further demonstrate the importance of reducing overall ST to maintain healthy weight status among UK youth.  相似文献