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OBJECTIVES: To determine whether the proprioceptive ability of advanced and expert snowsport participants increased with time on-snow, and whether gender, age, snowsport discipline and/or previous ankle injury were factors in proprioceptive ability at the start of the winter snow season (T1, n=80) compared to mid- season (T2, n=39). DESIGN: Observational study METHOD: Participants completed a questionnaire at T1, and proprioception was measured at T1 and T2 by the Active Movement Extent Discrimination Apparatus (AMEDA), which tests lower limb proprioception. RESULTS: At T1 there was no significant difference between the proprioception scores of the two cohorts of advanced and expert snowsport participants, between females and males, younger and older age groups, nor between alpine skiers and snowboarders. At T2, after a minimum of 5 weeks on-snow, the whole group had improved their proprioception by 0.04 (p<.0001) as measured by the AMEDA. Groups undertaking different snowsport disciplines achieved different gains across the season, with minimal change of 0.02 in skiers (p=.056), while snowboarders and mixed ski/snowboard participants gained 0.05 (p=.034) and 0.06 (p=.005) (η2 0.63 and 0.47 respectively). Males, females, instructors and elite youth participants all improved their proprioception by mid-season (η2 0.29-0.46). CONCLUSIONS: Amongst an established group of snowsports participants, lower limb proprioception is a consistent skill that is equally well developed in all cohorts. Several weeks of regular snowsport exposure improves this proprioceptive acuity amongst snowboarders, and those who mix snowboarding with skiing. Exposure to a prolonged period of snowsport improves proprioception, with benefits to neuromuscular control mechanisms.

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PURPOSE: This study aimed to examine the link between stress (measured via salivary cortisol and testosterone), cognition (measured via pupillometry, with greater pupil constriction and reduced pupil constriction latency associated with increased attention and improved information processing), and motor skill capacity (measured via somatosensory processing). METHODS: Twenty-five professional rugby players participated in this study. Saliva samples were collected upon waking, before pupillometry and somatosensory processing testing, and after testing. Testing times varied for participants; however, it was always in the morning, and the order of testing was randomized. RESULTS: Very small differences in hormone concentrations were seen across the morning (effect size = 0.01). Moderate to large differences in left eye pupil constriction for direct (left eye) versus consensual (right eye) stimulus were also seen (P < 0.01; effect size = 0.51 to 1.04). No differences for pupil constriction latency were seen for direct versus consensual stimulus. Some positive weak to moderate relationships were seen for testosterone and pupil constriction latency (r = 0.37 to 0.39, P < 0.05). Moderate to strong inverse relationships were seen for hormones with left eye pupil constriction difference between direct and consensual stimulus, and for pre- to posttest testosterone-to-cortisol ratio decline with left eye pupil constriction for direct and consensual stimulus (r = 0.41 to 0.52, P < 0.05). Weak to moderate inverse relationships for testosterone-to-cortisol ratio decline and somatosensory processing were seen (r = 0.36 to 0.47, P < 0.05). CONCLUSION: Stress may affect ability to receive information and ability to execute motor tasks. Thus, stress may compromise ability to make appropriate objective decisions and consequently execute skill/task behavior. Strategies to help mitigate negative stress responses are noted.

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Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance. Second, we review a strategy for mitigating imbalance associated with vestibular pathology and fostering readaptation. In discussing the first strategy (for imbalance assessment), we review a pilot study wherein imbalance was elicited (among healthy subjects) via an adaptive challenge that caused a temporary/reversible disruption. The surrogate vestibular deficit was caused by a brief period of movement-induced adaptation to an altered (rotating) gravitoinertial frame of reference. This elicited adaptation and caused imbalance when head movements were made after reentry into the normal (non-rotating) frame of reference. We also review a strategy for fall mitigation, viz., a prototype tactile sway feedback device for aiding balance/recovery after disruptions caused by vestibular pathology. We introduce the device and review a preliminary exploration of its effectiveness in aiding clinical balance rehabilitation (discussing the implications for healthy astronauts). Both strategies reviewed in this article represent cross-disciplinary research spin-offs: the ground-based vestibular challenge and tactile cueing display were derived from aeromedical research to benefit military aviators suffering from flight simulator-relevant aftereffects or inflight spatial disorientation, respectively. These strategies merit further evaluation using clinical and astronaut populations.