Effect of environmental feedbacks on pacing strategy and affective load during a self-paced 30 min cycling time trial.

The purpose of this study was to analyze the pacing strategy and its affective consequences during self-paced cycling time trials (TT) performed at different severity of hypoxia. Eight competitive cyclists performed five 30 min self-paced TTs at their best performance in the following conditions: 1) normobaric normoxia (NNSL); 2) normobaric hypoxia under two simulated altitudes: 2000 m (NH2000) and 3500 m (NH3500) and 3) normobaric hypoxia but the cyclists were deceived and thought to be at sea level for 2000 m (DecNH2000) and 3500 m (DecNH3500). Power Output (PO), oxygen uptake (VO2), and blood lactate concentration ([La]) were recorded to assess exercise intensity and physiological adaptations. The rate of perceived exertion (RPE) and pleasure were measured with a CR10 Borg scale to evaluate the affective load (AL). PO and VO2 decreased with the severity of hypoxia but no significantly difference on performance was measured between deceived and real conditions, except for pacing strategy. The started intensity depends on the exercise expectations, but PO was rapidly adjusted with the physiological constraints and the rate of increase of RPE. Finally, AL did not reach maximal values so that the athletes sustained a physiological and emotional reserve to perform a final spurt.

Emotional responses during repeated sprint intervals performed on level, downhill and uphill surfaces.

The purpose of this study was to test emotional responses during sprint intervals performed on a level, down and up surface. Fifty trained participants performed a maximal effort during a 60-m sprint and 10 repetitions of 60 m running sprints on a level, down and up surface on a 5.9% slope. Running speeds, emotional responses and heart rate were measured. Self-selected speeds were correlated with the rating of perceived exertion, the affective balance, the desire to stop and the resources needed for the task in all conditions whereas the pleasure, the desire to continue and the capacity to realise the task were correlated with speeds only during level and uphill running. Mean values of emotional parameters were significantly different (P < 0.05) during running on a flat surface, downhill and uphill. When the gradient of running surface is changed, the pattern of emotional responses was just translated, i.e. most of the slope between the evolution of emotional parameters and the repetitions were not significantly different whereas Y-intercepts were different. Consented effort is highly correlated with the resources needed for the task (P < 0.001, r(2) = 0.72). We propose that the difference in the resources needed for the task between level, downhill and uphill running (F 2, 1499 = 166.5, P < 0.001, Eta(2) = 0.18) is the most important key that explains our results.

Vitamin C: is supplementation necessary for optimal health?

BACKGROUND: Consumption of vitamin C is essential for life in humans because the body does not synthesize it. Numerous studies have demonstrated that supplementation with vitamin C enhances the immune system, avoids DNA damage, and significantly decreases the risk of a wide range of pathologies, such as cancers, and degenerative and chronic diseases. Moreover, it has been demonstrated that modern crop production, transport, and food storage severely impair the quality of food and provoke a loss in micronutrients, such as vitamin C. OBJECTIVES: In this paper, we report that the Recommended Daily Allowance (RDA) in vitamin C is lower than the bodily needs. In fact, it does not seem to ensure true health protection and it appears difficult to reach an effective dose of vitamin C only through food consumption. Furthermore, the literature shows that vitamin C intake higher than the RDA is safe. Therefore, in order to achieve optimal health and avoid a number of diseases, we suggest that, in the present situation, vitamin C supplementation is required. CONCLUSIONS: According to the current literature, we would like to emphasize that to ensure an optimal allowance of vitamin C, we advise 1 g daily intake of vitamin C supplementation, accompanied by a diet rich in fruits and vegetables.

Effect of incremental and submaximal constant load tests: protocol on perceived exertion (CR10) values.

The purpose of the present investigation was to determine to what extent the protocol (incremental and constant load exercises) affects the ratings of perceived exertion for a given submaximal intensity on a cycle ergometer. 10 healthy and well-trained male students (M age=23 yr., SD=2.9) performed an incremental exercise to determine maximal oxygen uptake (VO2 max), maximal aerobic power, and the ratings of perceived exertion (CR10) corresponding to 70% and 75% VO2 max (CR10(70i) and CR10(75i)). Two 30-min. constant load exercises set at these intensities were performed to establish the corresponding CR10 values. CR10(70i) (5.6 +/- 1.9) and CR10(75i) (6.2 +/- 1.9) were significantly higher than all CR10 values collected at Minutes 5, 10, 15, 20, 25, and 30 of the constant load exercises. These results indicate that, for a given exercise intensity (70% and 75% VO2 max), subjects are rated higher during an incremental exercise than during a 30-min. submaximal constant load test. Therefore, when coaches and physiotherapists want to use CR10 values reported during an incremental standard exercise to set training loads, they have to be prudent since the same relative exercise intensity does not seem to be perceived identically during a submaximal constant exercise as during an incremental one.