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Sara M. Scharoun, David A. Gonzalez, Eric A. Roy, and Pamela J. Bryden

Young adults plan actions in advance to minimize the cost of movement. This is exemplified by the end-state comfort (ESC) effect. A pattern of improvement in ESC in children is linked to the development of cognitive control processes, and decline in older adults is attributed to cognitive decline. This study used a cross-sectional design to examine how movement context (pantomime, demonstration with image/glass as a guide, actual grasping) influences between-hand differences in ESC planning. Children (5- to 12-year-olds), young adults, and two groups of older adults (aged 60–70, and aged 71 and older) were assessed. Findings provide evidence for adult-like patterns of ESC in 8-year-olds. Results are attributed to improvements in proprioceptive acuity and proficiency in generating and implementing internal representations of action. For older adults early in the aging process, sensitivity to ESC did not differ from young adults. However, with increasing age, differences reflect challenges in motor planning with increases in cognitive demand, similar to previous work. Findings have implications for understanding lifespan motor behavior.

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Sara M. Scharoun, Pamela J. Bryden, Michael E. Cinelli, David A. Gonzalez, and Eric A. Roy

This study investigated whether 5- to 11-year-old children perceive affordances in the same way as adults (M age = 22.93, SD = 2.16) when presented with a task and four tools (nail in a block of wood and a hammer, rock, wrench, and comb; bucket of sand and a shovel, wooden block, rake, and tweezers; and a screw in a block of wood and a screwdriver, knife, dime, and crayon). Participants were asked to select the best tool and act on an object until all four assigned tools had been selected. No explicit instructions were provided because we were interested in how task perception would influence tool selection and action. Results support the notion that the capacity to perceive affordances increases with age. Furthermore, differences in the way in which 5-year-olds acted on the screw in a block of wood demonstrated that the ability to detect some affordances takes longer to refine. Findings help to further the understanding of the development of perception-action coupling.

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Luis A. Marco-Contreras, Beatriz Bachero-Mena, David Rodríguez-Rosell, and Juan J. González-Badillo

Purpose: To analyze the relationships between the evolution of training-load values and countermovement jump (CMJ) as an indicator of stress and fatigue in a high-level 800-m runner during a whole season, including indoor (ID) and outdoor season (OD). Methods: Over 42 weeks, daily training load was quantified as the result of the product of the intensity and volume, and it was termed load index (LI). CMJ was measured in every running session after warm-up and immediately after the last effort of the session. Other jump-related variables such as CMJ height loss, average weekly CMJ, initial CMJ of the next consecutive session, and initial CMJ of the following week were studied. Results: A significant negative relationship was observed between LI and weekly CMJ (ID: r = −.68, P < .001, common variance [CV] = 46%; OD: r = −.73, P < .001, CV = 53%), initial CMJ of the following week (OD: r = −.71, P < .01, CV = 50%), and CMJ height loss (ID: r = −.58, P < .01, CV = 34%; OD: r = −.52, P < .01, CV = 27%). A significant positive relationship was observed between LI and initial CMJ of the next consecutive session when LI values were <8 (OD: r = .72; P < .01, CV = 52%). However, from values ≥8, the relationship turned into a significant negative one (ID: r = −.74; P < .01, CV = 55%; OD: r = −64, P < .01, CV = 41%). Conclusions: CMJ may be a valid indicator of the degree of stress or fatigue generated by specific training sessions of a competitive athlete within a single session, a week, or even the following week. There could be an individual limit LI value from which the training volume does not allow a positive effect on high-speed actions such as a CMJ in the next consecutive session.

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Palma ChiMón, Francisco B. Ortega, Jonatan R. Ruiz, Ilse De Bourdeaudhuij, David Martínez-Gómez, Germán Vicente-Rodriguez, Kurt Widhalm, Dénes Molnar, Frédéric Gottrand, Marcela González-Gross, Dianne S. Ward, Luis A. Moreno, Manuel J. Castillo, and Michael Sjöström

Chillón and Ruiz are with the Department of Physical Education and Sport, University of Granada, Spain. Chillón and Ward are with the Center for Health Promotion and Disease Prevention, University of North Carolina at Chapel Hill, NC, USA. Ortega, Ruiz and Sjöström are with the Unit for Preventive Nutrition, Department of Biosciences and Nutrition, Karolinska Institutet, Sweden. Ortega and Castillo are with the Department of Medical Physiology, University of Granada, Spain. De Bourdeaudhuij is with the Department of Movement and Sport Sciences, Ghent University, Belgium. Martínez-Gómez is with the Immunonutrition Research Group, Department of Metabolism and Nutrition, ICTAN, Spanish National Research Council (CSIC), Spain. Vicente-Rodríguez and Moreno are with Growth, Exercise, Nutrition and Development (GENUD) Research Group, Universidad de Zaragoza, Spain. Widhalm is with the Department of Paediatrics, Division of Clinical Nutrition, Medical University of Vienna, Austria. Molnar is with the Deprtment of Paediatrics, Clinical Center, University of Pécs, Hungary. Gottrand is with Inserm U995, University Lille2 and CIC-9301-CH&U-Inserm, University Hospital of Lille, France. González-Gross is with the Department of Health and Human Performance, Universidad Politécnica de Madrid, Spain.

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James A. Betts, Javier T. Gonzalez, Louise M. Burke, Graeme L. Close, Ina Garthe, Lewis J. James, Asker E. Jeukendrup, James P. Morton, David C. Nieman, Peter Peeling, Stuart M. Phillips, Trent Stellingwerff, Luc J.C. van Loon, Clyde Williams, Kathleen Woolf, Ron Maughan, and Greg Atkinson

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Salomé Aubert, Joel D. Barnes, Chalchisa Abdeta, Patrick Abi Nader, Ade F. Adeniyi, Nicolas Aguilar-Farias, Dolores S. Andrade Tenesaca, Jasmin Bhawra, Javier Brazo-Sayavera, Greet Cardon, Chen-Kang Chang, Christine Delisle Nyström, Yolanda Demetriou, Catherine E. Draper, Lowri Edwards, Arunas Emeljanovas, Aleš Gába, Karla I. Galaviz, Silvia A. González, Marianella Herrera-Cuenca, Wendy Y. Huang, Izzeldin A.E. Ibrahim, Jaak Jürimäe, Katariina Kämppi, Tarun R. Katapally, Piyawat Katewongsa, Peter T. Katzmarzyk, Asaduzzaman Khan, Agata Korcz, Yeon Soo Kim, Estelle Lambert, Eun-Young Lee, Marie Löf, Tom Loney, Juan López-Taylor, Yang Liu, Daga Makaza, Taru Manyanga, Bilyana Mileva, Shawnda A. Morrison, Jorge Mota, Vida K. Nyawornota, Reginald Ocansey, John J. Reilly, Blanca Roman-Viñas, Diego Augusto Santos Silva, Pairoj Saonuam, John Scriven, Jan Seghers, Natasha Schranz, Thomas Skovgaard, Melody Smith, Martyn Standage, Gregor Starc, Gareth Stratton, Narayan Subedi, Tim Takken, Tuija Tammelin, Chiaki Tanaka, David Thivel, Dawn Tladi, Richard Tyler, Riaz Uddin, Alun Williams, Stephen H.S. Wong, Ching-Lin Wu, Paweł Zembura, and Mark S. Tremblay

Background: Accumulating sufficient moderate to vigorous physical activity is recognized as a key determinant of physical, physiological, developmental, mental, cognitive, and social health among children and youth (aged 5–17 y). The Global Matrix 3.0 of Report Card grades on physical activity was developed to achieve a better understanding of the global variation in child and youth physical activity and associated supports. Methods: Work groups from 49 countries followed harmonized procedures to develop their Report Cards by grading 10 common indicators using the best available data. The participating countries were divided into 3 categories using the United Nations’ human development index (HDI) classification (low or medium, high, and very high HDI). Results: A total of 490 grades, including 369 letter grades and 121 incomplete grades, were assigned by the 49 work groups. Overall, an average grade of “C-,” “D+,” and “C-” was obtained for the low and medium HDI countries, high HDI countries, and very high HDI countries, respectively. Conclusions: The present study provides rich new evidence showing that the situation regarding the physical activity of children and youth is a concern worldwide. Strategic public investments to implement effective interventions to increase physical activity opportunities are needed.