Sports teams as complex adaptive systems: manipulating player numbers shapes behaviours during football small-sided games

Small-sided and conditioned games (SSCGs) in sport have been modelled as complex adaptive systems. Research has shown that the relative space per player (RSP) formulated in SSCGs can impact on emergent tactical behaviours. In this study we adopted a systems orientation to analyse how different RSP values, obtained through manipulations of player numbers, influenced four measures of interpersonal coordination observed during performance in SSCGs. For this purpose we calculated positional data (GPS 15 Hz) from ten U-15 football players performing in three SSCGs varying in player numbers (3v3, 4v4 and 5v5). Key measures of SSCG system behaviours included values of (1) players’ dispersion, (2) teams’ separateness, (3) coupling strength and time delays between participants’ emerging movements, respectively. Results showed that values of participants’ dispersion increased, but the teams’ separateness remained identical across treatments. Coupling strength and time delay also showed consistent values across SSCGs. These results exemplified how complex adaptive systems, like football teams, can harness inherent degeneracy to maintain similar team spatial–temporal relations with opponents through changes in inter-individual coordination modes (i.e., players’ dispersion). The results imply that different team behaviours might emerge at different ratios of field dimension/player numbers. Therefore, sport pedagogists should carefully evaluate the effects of changing RSP in SSCGs as a way of promoting increased or decreased pressure on players

Numerical relations and skill level constrain co-adaptive behaviors of agents in sports teams

Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national - NLP and regional-level - RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed emergence of co-adaptive behaviors between interacting neurobiological social system agents in the context of sport performance. Such observations have broader implications for training design involving manipulations of numerical relations between interacting members of social collectives

Pacing and Decision Making in Sport and Exercise: The Roles of Perception and Action in the Regulation of Exercise Intensity

In pursuit of optimal performance, athletes and physical exercisers alike have to make decisions about how and when to invest their energy. The process of pacing has been associated with the goal-directed regulation of exercise intensity across an exercise bout. The current review explores divergent views on understanding underlying mechanisms of decision making in pacing. Current pacing literature provides a wide range of aspects that might be involved in the determination of an athlete's pacing strategy, but lacks in explaining how perception and action are coupled in establishing behaviour. In contrast, decision-making literature rooted in the understanding that perception and action are coupled provides refreshing perspectives on explaining the mechanisms that underlie natural interactive behaviour. Contrary to the assumption of behaviour that is managed by a higher-order governor that passively constructs internal representations of the world, an ecological approach is considered. According to this approach, knowledge is rooted in the direct experience of meaningful environmental objects and events in individual environmental processes. To assist a neuropsychological explanation of decision making in exercise regulation, the relevance of the affordance competition hypothesis is explored. By considering pacing as a behavioural expression of continuous decision making, new insights on underlying mechanisms in pacing and optimal performance can be developed. © 2014 Springer International Publishing Switzerland

Milieubeleid verbetert technische efficiëntie in glastuinbouw

Milieubeleid heeft een positief effect op technische efficiëntie in de Nederlandse glastuinbouw. De overheersende mening in kringen van ondernemers, beleidsmakers en politici dat milieubeleid alleen maar tot hogere kosten leidt behoeft nuancering

Effect of fluvastatin on ischaemia following acute myocardial infarction:a randomized trial

Alms Residual ischaemia following acute myocardial infarction (AMI) is related to an adverse outcome, although the effect of early initiation of statin therapy is unknown. Methods A randomized, placebo-controlled, double-blind, parallel study was performed, which compared fluvastatin 80 mg daily with placebo in patients with an AMI and total cholesterol of <6(.)5 mmol . 1(-1). Ischaemia was measured by ambulatory electrocardiographic (AECG) monitoring over 48-h at baseline, after 6 weeks and at 12 months. Results Five hundred and forty patients were included (83% male, age 61 +/- 11 years); 43% had an anterior AMI and 50% were treated with fibrinolytics in the acute phase. After 12 months, the total cholesterol (TC) level was reduced by 13% and LDL-C (low-density-lipoprotein cholesterol) by 21% (from 3(.)5 mmol . 1(-1) to 2-7 mmol . 1(-1)) in the fluvastatin treatment group. Both TC and LDL increased by 9% in the placebo group (P Conclusion Residual ischaemia after AMI is observed less frequently in the present study, than in earlier studies, although it is predictive for future cardiovascular events. As a result, the present study was underpowered, and no effect of fluvastatin on AECG ischaemia, or major clinical events in the first year after AMI, could be detected. The present data do not confirm other reports which support widespread use of statin treatment early after AMI. (C) 2002 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved

Old Main - 13

Buildings: Old Mainphotograph date: Unknow

Gut estimates: Pregnant women adapt to changing possibilities for squeezing through doorways

Possibilities for action depend on the fit between the body and the environment. Perceiving what actions are possible is challenging because the body and the environment are always changing. How do people adapt to changes in body size and compression? In Experiment 1, we tested pregnant women monthly over the course of pregnancy to determine whether they adapted to changing possibilities for squeezing through doorways. As women gained belly girth and weight, previously passable doorways were no longer passable, but women’s decisions to attempt passage tracked their changing abilities. Moreover, their accuracy was equivalent to that of non-pregnant adults. In Experiment 2, non-pregnant adults wore a “pregnancy pack” that instantly increased the size of their bellies and judged whether doorways were passable. Accuracy in “pregnant” participants was only marginally worse than that of actual pregnant women, suggesting that participants adapted to the prosthesis during the test session. In Experiment 3, participants wore the pregnancy pack and gauged passability before and after attempting passage. Judgments were grossly inaccurate prior to receiving feedback. Findings indicate that experience facilitates perceptual-motor recalibration for certain types of actions