How about running on Mars? Influence of sensorimotor coherence on running and spatial perception in simulated reduced gravity.

Motor control, including locomotion, strongly depends on the gravitational field. Recent developments such as lower-body positive pressure treadmills (LBPPT) have enabled studies on Earth about the effects of reduced body weight (BW) on walking and running, up to 60% BW. The present experiment was set up to further investigate adaptations to a more naturalistic simulated hypogravity, mimicking a Martian environment with additional visual information during running sessions on LBPPT. Twenty-nine participants performed three sessions of four successive five-min runs at preferred speed, alternating Earth- or simulated Mars-like gravity (100% vs. 38% BW). They were displayed visual scenes using a virtual reality headset to assess the effects of coherent visual flow while running. Running performance was characterized by normal ground reaction force and pelvic accelerations. The perceived upright and vection (visually-induced self-motion sensation)in dynamic visual environments were also investigated at the end of the different sessions. We found that BW reduction induced biomechanical adaptations independently of the visual context. Active peak force and stance time decreased, while flight time increased. Strong inter-individual differences in braking and push-off times appeared at 38% BW, which were not systematically observed in our previous studies at 80% and 60% BW. Additionally, the importance given to dynamic visual cues in the perceived upright diminished at 38% BW, suggesting an increased reliance on the egocentric body axis as a reference for verticality when the visual context is fully coherent with the previous locomotor activity. Also, while vection was found to decrease in case of a coherent visuomotor coupling at 100% BW (i.e., post-exposure influence), it remained unaffected by the visual context at 38% BW. Overall, our findings suggested that locomotor and perceptual adaptations were not similarly impacted, depending on the -simulated- gravity condition and visual context.

Neuromuscular adjustments to unweighted running: the increase in hamstring activity is sensitive to trait anxiety.

Introduction: Originally developed for astronauts, lower body positive pressure treadmills (LBPPTs) are increasingly being used in sports and clinical settings because they allow for unweighted running. However, the neuromuscular adjustments to unweighted running remain understudied. They would be limited for certain lower limb muscles and interindividually variable. This study investigated whether this might be related to familiarization and/or trait anxiety. Methods: Forty healthy male runners were divided into two equal groups with contrasting levels of trait anxiety (high, ANX+, n = 20 vs. low, ANX-, n = 20). They completed two 9-min runs on a LBPPT. Each included three consecutive 3-min conditions performed at 100%, 60% (unweighted running), and 100% body weight. Normal ground reaction force and electromyographic activity of 11 ipsilateral lower limb muscles were analyzed for the last 30 s of each condition in both runs. Results: Unweighted running showed muscle- and stretch-shortening cycle phase-dependent neuromuscular adjustments that were repeatable across both runs. Importantly, hamstring (BF, biceps femoris; STSM, semitendinosus/semimembranosus) muscle activity increased during the braking (BF: +44 ± 18%, p < 0.001) and push-off (BF: +49 ± 12% and STSM: +123 ± 14%, p < 0.001 for both) phases, and even more so for ANX+ than for ANX-. During the braking phase, only ANX+ showed significant increases in BF (+41 ± 15%, p < 0.001) and STSM (+53 ± 27%, p < 0.001) activities. During the push-off phase, ANX+ showed a more than twofold increase in STSM activity compared to ANX- (+119 ± 10% vs. +48 ± 27, p < 0.001 for both). Conclusion: The increase in hamstring activity during the braking and push-off phases may have accelerated the subsequent swing of the free-leg, likely counteracting the unweighting-induced slowing of stride frequency. This was even more pronounced in ANX+ than in ANX-, in an increased attempt not to deviate from their preferred running pattern. These results highlight the importance of individualizing LBPPT training and rehabilitation protocols, with particular attention to individuals with weak or injured hamstrings.

Epidemiology of sport climbing injuries caused by a climbing fall among climbers of the French Federation of Mountain and Climbing.

BACKGROUND: Fall-related injuries (FRIs) are the most severe sport climbing injuries. The main objective of this study was to measure FRI prevalence and risk factors in a representative sample of climbers of the French Federation of Mountain and Climbing. The second objective was to explore FRI mechanisms. METHODS: The study included 3919 climbers aged 16+. They were invited to fill out an online questionnaire where they reported sociodemographics, sport-related characteristics and whether they had sustained an FRI in the past 12 months (12-FRI), and over their entire career (ALL-FRI). The mechanisms of 12-FRI were asked for. Multivariable logistic regression analyses were performed to evaluate the association between sport-related characteristics and FRI. RESULTS: Nine per cent of the participants reported a 12-FRI and 29% an ALL-FRI. No statistically significant effect of sex, context of climbing, or onsight level was observed on 12-FRI. Climbers with 0-3 years of experience (YE) were 1.7 (95% CI: 1.2-2.6) and 3.6 (95% CI: 2.2-6.3) times more likely to have sustained a 12-FRI compared with those with 5-8 YE and 14-23 YE, respectively. An interaction effect was found between YE and onsight level. Among climbers with 0-8 YE, those with a higher onsight level had a higher risk of 12-FRI. Natural falls, unexpected falls and static belaying were the most commonly reported 12-FRI mechanisms. CONCLUSIONS: These results highlight that future FRI prevention programs should target priority-inexperienced climbers who have progressed rapidly. Climbers should be taught as a priority to stay focused while belaying even in the least difficult passage, and to belay dynamically.

Sex and Age Differences in the Endorsement of Sex Stereotypes Associated with Driving.

Sex and age differences are particularly pronounced in car accidents. Current psychological research is exploring the relationship between risky driving and compliance with sex stereotypes, notably conformity with social expectations concerning masculinity. Some studies have already shown that sex stereotypes associated with driving (SSAD) may influence driving behaviors. The aim of this research was to explore the participants' sex and age differences in SSAD endorsement. A questionnaire was developed and validated on four dimensions of SSAD: male's driving skills and female's compliance with traffic rules, courtesy behind the wheel, and risk avoidance in driving. SSAD endorsement was measured for 291 licensed drivers from 18 to 64 years of age. Results revealed that females endorsed the female's risk avoidance stereotype more (p < .05), whereas males endorsed the male drivers (driving skills) stereotype more (p < .05). Results also revealed that the endorsement of male's driving skills decreases with age (p < .01) and the endorsement of female's courtesy increases with age among all participants (p = .01), while the endorsement of female's compliance with traffic rules increases with age only among female participants (p < .05). The results are discussed in terms of in-group/out-group relations and sex and age differences.

Pilot evaluation of physical and psychological effects of a physical trek programme including a dog sledding expedition in children and teenagers with cancer.

AIM OF THE STUDY: To evaluate the feasibility and to measure the effects of a six-week-long adapted physical activity programme (APAP), including 5 days of intense dog sledding, on the physical and psychological health of children and adolescents treated for cancer. METHODS: Eleven children and teenagers (4 girls, 7 boys; mean age 14.3 ± 2.9 years) participated in this monocentric pilot programme of adapted physical activities from February 2013 to March 2013. Seven were still on treatment. The programme lasted 6 weeks. A series of physical tests and psychological questionnaires were carried out before and after the programme. RESULTS: All children and teenagers completed the full programme. An improvement in all physical and psychological parameters was observed. Statistically significant differences were observed for global self-esteem (6.2 ± 2.1 to 7.7 ± 1.8; p = 0.02), perceived sport competence (5.3 ± 3.2 to 7.4 ± 2; p = 0.02) and perceived physical strength (5.6 ± 2.5 to 7.1 ± 1.8; p = 0.001). Regarding physical tests, the physical training led to statistically significant improvement for sit-ups (13.8 ± 2.6 to 21.75 ± 5.4; p = 0.01), muscle tone (76 ± 23.7 to 100 ± 22.9; p = 0.01), and resting heart rate (96.1 ± 3.2 to 91.6 ± 4.5; p = 0.03). CONCLUSION: This programme is feasible in children and adolescents even during their oncologic treatment. During the 6-week programme, children and adolescents improved their physical and psychological health, and the putative benefits of the APAP are discussed. A larger randomised trial started in 2014.

Are drivers' comparative risk judgments about speeding realistic?

INTRODUCTION: This study focused on comparative judgments about speeding risks among young drivers who have a high risk of being involved in a traffic accident. METHOD: We examined (a) how these drivers assess their risk of sanctions and their risk of causing an automobile crash because of speeding in comparison to the estimated risks of other drivers, and (b) how realistic their comparative risk judgments are. We measured the relationship between the drivers' comparative risk judgments, self-reported speeding, and driving-related sensation-seeking. We hypothesized that (a) they would think they have less risk of sanctions and of causing a car accident than others, and (b) their comparative judgments of speeding risks would be linked to self-reported speeding and driving-related sensation-seeking. The study was based on a computerized questionnaire survey conducted with 3,002 young drivers (mean age=22.3) administered by professional investigators. RESULTS: The results confirmed our hypotheses. IMPACT ON INDUSTRY: In order to improve the effectiveness of prevention measures and to evaluate the effect of them, road-safety interventions should take into account comparative risk judgments about the targeted risk behavior.

Risk taking and risk perception in road safety: comparative study of young sportsmen and nonsportsmen in southeastern France.

The relationship between participation in sporting activity and both risk taking and risk perception when traveling on a two-wheeled vehicle were evaluated among 614 adolescents between the ages of 14 and 17 years. The sex of the respondents (252 girls, 362 boys) and their experience with road accidents were taken into account. Three-way analyses of variance indicated a significant main effect for sex, with girls reporting both fewer risky behaviors and higher risk perception than boys when traveling on a two-wheeled vehicle. Effect for sporting activity was also significant, with sports practitioners reporting lower risk taking and higher risk perception than nonsportsmen. There was also a significant interaction between sex and sporting activity. For boys, risk taking was higher and risk perception lower among the nonsportsmen than among the sports practitioners. Experience with road accidents had no significant relationship with risk taking or risk perception when traveling on a two-wheeled vehicle.

Brief report: how do adolescents perceive the risks related to cell-phone use?

Besides the social risks of incivility and impoliteness (I-incivility), cell-phone use is classically associated with two types of physical risk: microwave radiation (LIMRadiation) and decreased attention while driving (CPUWDriving). As the literature has showed that adolescents' risky behavior was consistent with their risk perception, we ran a self-report survey to evaluate 1/how French adolescents (n=1129) perceived physical risks related to CPUWDriving, exposure to LIMRadiation, and social risks related to I-incivility; and 2/the factors underlying these risk perceptions. Results showed that adolescents have an acute perception of the risks associated with CPUWDriving and appeared to be concerned, as a whole, with social risks related to I-Incivility. They do not appear particularly concerned by the risks related to LIMRadiation, which may reflect societal confusion about risks still considered as hypothetical and/or based on equivocal evidence. Gender, ethnicity, and age were not predictive for perceived risks. Level of schooling had a positive influence on perceived risks related to CPUWDriving and I-Incivility, and cell-phone ownership had an inverse relationship with perceived risks related to I-Incivility.