Browsing by Autor "Buchheit, Martin"

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Predicting sickness during a 2-week soccer camp at 3600 m (ISA 3600)
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 2013) Buchheit, Martin
Abstract. Objectives. To examine the time course of changes in wellness and health status markers before and after episodes of sickness in young soccer players during a high-altitude training camp (La Paz, 3600 m). Methods Wellness and fatigue were assessed daily on awakening using specifically-designed questionnaires and resting measures of heart rate and heart rate variability. The rating of perceived exertion and heart rate responses to a submaximal run (9 km/h) were also collected during each training session. Players who missed the morning screening for at least two consecutive days were considered as sick. Results Four players met the inclusion criteria. With the exception of submaximal exercise heart rate, which showed an almost certain and large increase before the day of sickness (4%; 90% confidence interval 3 to 6), there was no clear change in any of the other psychometric or physiological variables. There was a very likely moderate increase (79%, 22 to 64) in self-reported training load the day before the heart rate increase in sick players (4 of the 4 players, 100%). In contrast, training load was likely and slightly decreased (−24%, −78 to −11) in players who also showed an increased heart rate but remained healthy. Conclusions A >4% increased heart rate during submaximal exercise in response to a moderate increase in perceived training load the previous day may be an indicator of sickness the next day. All other variables, that is, resting heart rate, heart rate variability and psychometric questionnaires may be less powerful at predicting sickness.
Wellness, fatigue and physical performance acclimatisation to a 2-week soccer camp at 3600 m (ISA3600)
(Facultad de Medicina, Enfermería, Nutrición y Tecnología Médica, 2013) Buchheit, Martin
Abstract. Objectives: To examine the time course of wellness, fatigue and performance during an altitude training camp (La Paz, 3600 m) in two groups of either sea-level (Australian) or altitude (Bolivian) native young soccer players. Methods Wellness and fatigue were assessed using questionnaires and resting heart rate (HR) and HR variability. Physical performance was assessed using HR responses to a submaximal run, a Yo-Yo Intermittent recovery test level 1 (Yo-YoIR1) and a 20 m sprint. Most measures were performed daily, with the exception of Yo-YoIR1 and 20 m sprints, which were performed near sea level and on days 3 and 10 at altitude. Results Compared with near sea level, Australians had moderate-to-large impairments in wellness and Yo-YoIR1 relative to the Bolivians on arrival at altitude. The acclimatisation of most measures to altitude was substantially slower in Australians than Bolivians, with only Bolivians reaching near sea-level baseline highintensity running by the end of the camp. Both teams had moderately impaired 20 m sprinting at the end of the camp. Exercise HR had large associations (r>0.5–0.7) with changes in Yo-YoIR1 in both groups. Conclusions Despite partial physiological and perceptual acclimatisation, 2 weeks is insufficient for restoration of physical performance in young sea-level native soccer players. Because of the possible decrement in 20 m sprint time, a greater emphasis on speed training may be required during and after altitude training. The specific time course of restoration for each variable suggests that they measure different aspects of acclimatisation to 3600 m; they should therefore be used in combination to assess adaptation to altitude.