might be the global navigation satellite system (GNSS), a collective term used to encompass all satellite navigation systems providing geospatial positioning with global coverage. Currently, this includes both the United States–based GPS (n = 24) and the Russian-based GLONASS (GLObal NAvigation
Benjamin M. Jackson, Ted Polglaze, Brian Dawson, Trish King and Peter Peeling
Giovanna Ghiani, Sara Magnani, Azzurra Doneddu, Gianmarco Sainas, Virginia Pinna, Marco Caboi, Girolamo Palazzolo, Filippo Tocco and Antonio Crisafulli
of the race on certain physiological parameters related to the racer’s cardiovascular functions and physical capacity. We hypothesized that a proper dietetic approach would reduce body mass (BM) changes due to the solitary navigation. The Athlete On October 15, 2016, the Italian ocean racer Gaetano
David W. Eccles, Susanne E. Walsh and David K. Ingledew
The objective of this study was to gain an understanding of expert cognition in orienteering. The British orienteering squad was interviewed (N = 17) and grounded theory was used to develop a theory of expert cognition in orienteering. A task constraint identified as central to orienteering is the requirement to manage attention to three sources of information: the map, the environment, and travel. Optimal management is constrained by limited processing resources. However, consistent with the research literature, the results reveal considerable adaptations by experts to task constraints, characterized primarily by various cognitive skills including anticipation and simplification. By anticipating the environment from the map, and by simplifying the information required to navigate, expert orienteers can circumvent processing limitations. Implications of this theory for other domains involving navigation, and for the coaching process within the sport, are discussed.
Pål Haugnes, Jan Kocbach, Harri Luchsinger, Gertjan Ettema and Øyvind Sandbakk
navigation satellite system device with integrated barometry and accompanying HR monitor. The work rate was estimated from the combined contribution of work against gravity, gliding friction, and air resistance. The snow friction and weather conditions were stable throughout the whole test day with light
Lenny D. Wiersma
Extreme sport athletes perform in environments that are characterized by danger, unpredictability, and fear, and the consequences of a mistake include severe injury or death. Maverick’s is a big-wave surfing location in northern California that is known for its cold water temperatures, dangerous ocean wildlife, deep reef, and other navigational hazards. The purpose of this study was to use a phenomenological framework to understand the psychology of big-wave surfing at Maverick’s. Seven elite big-wave surfers completed in-depth phenomenological interviews and discussed the psychology related to various stages of big-wave surfing, including presurf, in the lineup, catching the wave, riding the wave, wiping out, and postsurf. Big-wave surfers described a variety of experiences associated with surfing at Maverick’s and discussed several ways that they coped with its challenges. The results provide a greater understanding of the psychology of participating in an extreme environment.
Martin Gérin-Lajoie, Carol L. Richards and Bradford J. McFadyen
This article introduces a novel, ecological, obstructed walking paradigm. Gait adaptations to circumvent obstacles undergoing uncertain displacements, and the effect of revealing the obstacle’s action beforehand, were investigated in young adults. The personal space (PS) maintained during walking was quantified for the first time under different environmental factors including auditory distractions. Obstacle movement and its uncertainty resulted in gait adjustments aimed at gaining time to assess the situation. Early gait adaptations and constant clearances around the obstacle suggest that anticipation and preplanning are involved in such navigational tasks. Participants systematically maintained an elliptical PS during circumvention, but they adjusted its size according to different environmental factors. There was a relationship between the size of PS and level of attention, which suggests that the regulation of PS is used to control locomotion. This novel paradigm has important implications for the assessment and training of locomotor ability within real world environments.
Øyvind Sandbakk, Silvana Bucher Sandbakk, Matej Supej and Hans-Christer Holmberg
This study examined the influence of turn radius on velocity and energy profiles when skidding and step turning during more and less effective downhill turns while cross-country skiing. Thirteen elite female cross-country skiers performed single turns with a 9- or 12-m radius using the skidding technique and a 12- or 15-m radius with step turning. Mechanical parameters were monitored using a real-time kinematic Global Navigation Satellite System and video analysis. Step turning was more effective during all phases of a turn, leading to higher velocities than skidding (P < .05). With both techniques, a greater radius was associated with higher velocity (P < .05), but the quality of turning, as assessed on the basis of energy characteristics, was the same. More effective skidding turns involved more pronounced deceleration early in the turn and maintenance of higher velocity thereafter, while more effective step turning involved lower energy dissipation during the latter half of the turn. In conclusion, the single-turn analysis employed here reveals differences in the various techniques chosen by elite cross-country skiers when executing downhill turns of varying radii and can be used to assess the quality of such turns.
Nathan Millikan, Dustin R. Grooms, Brett Hoffman and Janet E. Simon
Context: Functional tests are limited primarily by measuring only physical performance. However, athletes often multitask, and deal with complex visual-spatial processing while being engaged in physical activity. Objective: To present the development and reliability of 4 new neurocognitive single-leg hop tests that provide more ecological validity to test sport activity demands than previous functional return to sport testing. Design: Cross-sectional. Setting: Gymnasium. Participants: Twenty-two healthy participants (9 males and 13 females; 20.9 [2.5] y, 171.2 [11.7] cm, 70.3 [11.0] kg) were recruited. Interventions: Maximum distance (physical performance) and reaction time (cognitive performance) were measured for 3 of the neurocognitive hop tests all testing a different aspect of neurocognition (single-leg central-reaction hop—reaction time to 1 central stimulus, single-leg peripheral-reaction crossover hop—reaction time between 2 peripheral stimuli, and single-leg memory triple hop—reaction to memorized stimulus with distractor stimuli). Fastest time (physical performance) and reaction time (cognitive performance) were measured for the fourth neurocognitive hop test (single-leg pursuit 6m hop—requiring visual field tracking [pursuit] and spatial navigation). Main Outcome Measures: Intraclass correlation coefficients were calculated to assess reliability of the 4 new hop tests. Additionally, Bland–Altman plots and 1-sample t tests were conducted for each single-leg neurocognitive hop to evaluate any systematic changes. Results: Intraclass correlation coefficients based on day 1 and day 2 scores ranged from .87 to .98 for both legs for physical and cognitive performance. The Bland–Altman plots and 1-sample t tests (P > .05) indicated that all 4 single-leg neurocognitive hop tests did not change systematically. Conclusions: These data provide evidence that a neurocognitive component can be added to the traditional single-leg hop tests to provide a more ecologically valid test that incorporates the integration of physical and cognitive function for return to sport. The test–retest reliability of the 4 new neurocognitive hop tests is highly reliable and does not change systematically.
Aaron Manzanares, Ruperto Menayo and Francisco Segado
passage of the windward mark or downwind sailing, among other situations. This is because the task changes; thus, the navigation mode and behavior of the sailors must be adapted to the target at each moment of the race. A factor that highly influences the performance is the relationship between perception
’accessibilité du site, déterminent une diffusion des pratiques nautiques principalement centrée sur la navigation en rivière. L’aviron est une activité très en vogue sur les bords de Marne. Des régates sont organisées, des règlements sont mis en place et le record est recherché par les rameurs. L’aviron devient