This study examined how the central nervous system organizes mediolateral (ML) “anticipatory postural adjustments” (APAs) for stepping initiation (SI) to take into account the postural perturbation induced by voluntary lateral arm raising. Subjects purposely stepped in isolation (“isolated stepping”) or in combination with lateral raising of dominant arm (“motor sequence”). SI was carried out with the leg ipsilateral or controlateral to raising arm. Results showed that APA amplitude increased from “ipsilateral isolated stepping” to “ipsilateral sequence”, but did not change in conditions involving controlateral leg; ML instability increased from “ipsilateral isolated stepping” to “ipsilateral sequence”, but decreased from “controlateral isolated stepping” to “controlateral sequence”. These changes were exacerbated when inertia was added at the hand during raising. These results suggest that APAs for SI are globally scaled as a function of the biomechanical consequences of forthcoming arm movement on ML postural stability.
E.V. Biryukova and B. Bril
We analyzed the relationship between goal achievement and execution variability in craftsmen who have acquired the highest “ultimate” skills of stone knapping. The goal of a knapping movement is defined as the vector of the final velocity of a hammer, crucial for detaching a flake and, consequently, for the shape of the final product. The execution of the movement is defined by the kinematic pattern of the arm (i.e., by the coordination between the joint angles corresponding to the seven arm degrees of freedom). The results show that (a) the direction of final velocity is very stable for all craftsmen, whereas the amount of kinetic energy transmitted to the stone was craftsman specific and (b) the kinematic pattern of the arm was strongly individual and was a reliable sign of the level of skill—the highest level was characterized by the highest flexibility of movement kinematics. We stress the importance of conducting the experiment in natural conditions for better understanding of the relationship among the purpose (the final shape of the stone), the goal, and the execution of the movement.
Yeshayahu Hutzler, Colin Higgs and David Legg
Nancy A. Ecclestone, Canada and C. Jessie Jones
Joanne G. Mirtschin, Sara F. Forbes, Louise E. Cato, Ida A. Heikura, Nicki Strobel, Rebecca Hall and Louise M. Burke
The authors describe the implementation of a 3-week dietary intervention in elite race walkers at the Australian Institute of Sport, with a focus on the resources and strategies needed to accomplish a complex study of this scale. Interventions involved: traditional guidelines of high carbohydrate (CHO) availability for all training sessions; a periodized CHO diet which integrated sessions with low and high CHO availability within the same total CHO intake; and a ketogenic low-CHO high-fat diet. Seven-day menus and recipes were constructed for a communal eating setting to meet nutritional goals as well as individualized food preferences and special needs. Menus also included nutrition support before, during, and after exercise. Daily monitoring, via observation and food checklists, showed that energy and macronutrient targets were achieved. Diets were matched for energy (∼14.8 MJ/d) and protein (∼2.1 g·kg−1·day−1) and achieved desired differences for fat and CHO, with high CHO availability and periodized CHO availability: CHO = 8.5 g·kg−1·day−1, 60% energy, fat = 20% of energy and low-CHO high-fat diet: 0.5 g·kg−1·day−1 CHO, fat = 78% energy. There were no differences in micronutrient intake or density between the high CHO availability and periodized CHO availability diets; however, the micronutrient density of the low-CHO high-fat diet was significantly lower. Daily food costs per athlete were similar for each diet (∼AU$ 27 ± 10). Successful implementation and monitoring of dietary interventions in sports nutrition research of the scale of the present study require meticulous planning and the expertise of chefs and sports dietitians. Different approaches to sports nutrition support raise practical challenges around cost, micronutrient density, accommodation of special needs, and sustainability.
Rebecca Reynolds, Santhya and David Menzies
organizational alignment, the provision of input from members, and the inclusion of members from the built environment and education sectors. 4 This largely qualitative study surveyed members of the NPAA about agenda, commitment, and vision for the alliance to contribute to the currently sparse evidence base and
Edgard Melo Keene von Koenig Soares, Guilherme E. Molina, Daniel Saint Martin, João Luís A. E. Sadat P. Leitão, Keila E. Fontana, Luiz F. Junqueira Jr., Timóteo Leandro de Araújo, Sandra Mahecha Matsudo, Victor K. Matsudo and Luiz Guilherme Grossi Porto
, one of the most influential documents was published by the World Health Organization (WHO) in 2010. 10 All of them recommend at least 150 minutes of moderate to vigorous physical activity (MVPA) per week. Albeit this agreement, there are many differences as regard to PA intensity, frequency, and how
Mark S. Tremblay
developmental origins of health and disease hypothesis posits that noncommunicable disease processes originate prenatally and/or early in life 10 , 11 with the first 1000 days of life being particularly important. 12 In the specific context of obesity, the World Health Organization (WHO) formed a Commission
Alex J. Benson and Mark Eys
Based on theoretical and empirical accounts from organizational contexts, the timeframe within which initial interactions between newcomers and existing group members occur may be a key leverage point for managing team dynamics in sport ( Fang, Duffy, & Shaw, 2011 ; Hackman, 2012 ; Saks
Claire R. Jenkin, Rochelle M. Eime, Hans Westerbeek and Jannique G.Z. van Uffelen
Worldwide populations are aging ( World Health Organization, 2015 ) and it often correlates with a decline in health. Being physically active is important for good health. Therefore, it is prudent to support older adults (referring to people aged 50 years and older) to continue being physically