The aim of this study was to examine the influence of exercise intensity and session duration on rating of perceived exertion (RPE) in adolescent Taekwondo (TKD) athletes. Twelve male youth competitive TKD athletes, aged between 13 and 18 years took part in this study. Training data (368 individual sessions) were collected during the 12 weeks of the pre‐competitive TKD season. Daily training load was calculated using the heart rate and the session‐RPE. Exercise intensity was also classified in five zones [i.e. 50–60%, 61–70%, 71–80%, 81–90% and 91–100% of maximal heart rate (HRmax)] and the time spent in each zone was expressed as percentage of total session time. The analysis of variance showed a significant main effect for zone (p<0.001) with most of the time (69%) spent at intensities between 61 and 90% of HRmax, and only 10% spent above 91% (mean differences compared to the other zones ranging from –6.6% versus zone 1 to –14.8% versus zone 3; p<0.0001). The individual correlation between session‐RPE and HR‐based methods were moderate to large. The stepwise multiple regression showed that RPE was influenced mainly by the time spent in the high intensity zone that explained 22.1% of the variance in RPE. Session duration accounted for only an additional 3.2%. The results suggest the time spent at high‐intensity (i.e. between 91 and 100% HRmax) and only marginally the session duration influences the RPE referred to the whole training session. This seems to confirm that the determination of the TL multiplying the RPE and session duration is acceptable.

Physical performance in a tropical environment, combining high heat and humidity, is a difficult physiological challenge that requires specific preparation. The elevated humidity of a tropical climate impairs the thermoregulatory mechanisms by limiting the rate of sweat evaporation. Hence, a proper management of whole-body temperature is required to complete an ultra-endurance event in such an environment. In these long-duration events, which can last from 8 to 20 h, held in hot and humid settings, performance is tightly linked to the ability in maintaining an optimal hydration status. Indeed, the rate of withdrawal in these longer races was associated with lower water intake, and the majority of finishers exhibited alterations in electrolyte balance (e.g., sodium). Hence, this work reviews the effects on performance of high heat and humidity in two representative ultra-endurance sports, ultramarathons and long-distance triathlons, and several countermeasures to counteract the impact of these harsh environmental stresses and maintain a high level of performance, such as hydration, cooling strategies and heat acclimation.

The thermal discomfort caused by a hot or hot-wet climate can have negative effects on human performance. The 2020 Summer Olympic and Paralympic Games will take place in Tokyo’s hot and humid summer period, possibly exposing athletes to severe environmental stressors. In addition to technical, tactical, physical and nutritional preparation, Olympians and Paralympians need an optimal psychological state to turn in their best performances, especially in terms of emotional control, concentration and motivation. Yet, the tropical climate can have many negative effects on these factors. Better understanding of the negative effects of this climate and the strategies to manage them might be crucial for competitors, coaches and their teams in Japan. At the psychological level, cooling interventions before, during and/or immediately after exercise were mainly studied on perceptual responses. However, the effects of these interventions on other psychological components such as cognitive abilities or psychological states and the use of psychological techniques have been little explored, especially in hot-wet climate. Thus, this article proposes to take stock of the knowledge on the conventional and alternative strategies that help athletes to psychologically cope with the subtropical climate of Tokyo.

Endurance and prolonged exercise are altered by hot climate. In hot and dry climate, thermoregulation processes, including evapotranspiration, normally maintain a relatively constant body core temperature. In hot and wet climate (usually called “tropical”), the decrease in evapotranspiration efficacy increases the sweating rate, which can rapidly induce severe hypohydration without efficiently reducing core temperature. The negative effects of tropical environment on long-duration exercise have been well documented, with clear demonstrations that they exceed the acclimation possibilities: both acclimated athletes and natives to tropical climate show impaired performances compared with that in neutral climate. New countermeasures, applicable during competitive events, are therefore needed to limit these negative effects. We studied the effects of several countermeasures in outdoor or natural tropical climates and noted that the easiest method to apply is cooling with cold (−1 to 3°C) beverage. Moreover, adding menthol increased the cold sensation induced by the beverage temperature, optimizing the positive effects on performance. We also demonstrated that efficient pre-cooling with cold menthol beverage requires drinking for 1 h instead of 30 min before the exercise. The optimal cooling method seems to be 1 h of cold + menthol pre-cooling ingestion followed by menthol + ice-slurry per-cooling. However, limitations should be noted: (1) the menthol concentration seems to be crucial, with positive effects for a 0.05% solution, whereas higher concentrations need to be explored; and (2) because it acts as a cold adjuvant without decreasing core temperature, menthol can lead to decreased thermoregulatory processes, thus inducing hyperthermia. Last, if menthol is added to cooling processes, athletes should first test them in training conditions for the maximal cooling effect to ensure optimal performance in competition in tropical climate.

L’étude des représentations de la drépanocytose dans une population scolarisée de l’île de Marie-Galante (N=267), en Guadeloupe, est ici réalisée à partir du traitement des réponses à une question d’association libre qui s’inscrivait dans un questionnaire plus large. L’analyse des occurrences et des co-occurrences spontanément associées à la drépanocytose montre le flou qui entoure cette maladie dans la population étudiée, attestant d’une faible maîtrise des représentations biomédicales. Ce sont finalement le statut et la signification du sang, ainsi que la notion même de maladie génétique, qui paraissent mal assurés, car réinscrits dans l’univers des représentations culturelles et sociales liées à l’identité/altérité et à la filiation.

To determine the relationships between limiting factors and neuromuscular activity during a self-paced 20-km cycling time trial and evaluate the effect of environmental conditions on fatigue indices. Methods: Ten endurance-trained and heat-acclimated athletes performed in three conditions (ambient temperature, relative humidity): HUMID (30 °C, 90%), DRY (35 °C, 46%) and NEUTRAL (22 °C, 55%). Voluntary muscular contractions and electromagnetic stimulations were recorded before and after the time trials to assess fatigue. The data on performance, temperature, heat storage, electromyogram, heart rate and rating of perceived exertion data were analyzed. Results: Performance was impaired in DRY and HUMID compared with NEUTRAL environment (p < 0.05). The force developed by the vastus lateral muscle during stimulation of the femoral nerve remained unchanged across conditions. The percentage of integrated electromyogram activity, normalized by the value attained during the pre-trial maximal voluntary contraction, decreased significantly throughout the trial only in HUMID condition (p < 0.01). Neuromuscular activity in peripheral skeletal muscle started to fall from the 11th km in HUMID and the 15th km in DRY condition, although core temperature did not reach critical values. Conclusions: These alterations suggest that afferences from core/skin temperature regulate the central neural motor drive, reducing the active muscle recruited during prolonged exercise in the heat in order to prevent the system from hyperthermia.