Training in altitude: Analysis of practical examples
Altitude affects performance in a range of endurance activities, including intermittent exercise. The effects are attributed to a fall in aerobic power (V&O2 max), and an increased aerobic metabolism at fixed exercise intensity. The decrease in V&O2 max is about 15% at 2.3 km but displays large individual variability. The initial impairment is reduced with acclimatisation but does not attain sea-level values when the altitude exceeds 2 km. Strategies for preparing to compete at altitude include acclimatisation during sojourns to altitude training camps, exposure to altitude chambers, use of hypoxic tents and intermittent hypoxic training. These strategies are also employed in facilitating aerobic performance at sea level. The experiences of athletes utilising altitude training are generally positive. Negative experiences have been associated with the timing of the return to sea level. Exposures to altitudes of about 2.2 km have been more effective than at 1.8 km in inducing physiological adaptations. An aggressive rehydration strategy can counteract the reduced plasma volume commonly experienced at altitude. Difficulties in sleeping are also experienced and attention can be directed towards daytime rests (Pedlar et al., 2005). Altitude has been of particular interest in football in view of the restrictions placed recently on matches in FIFA competitions. Little scientific evidence has been gathered from the two World Cups at Mexico, or in advance of the 2010 World Cup. Most concerns have been raised in the context of South America. There is evidence that altitude provides an advantage, independent of home bias and ability level (McSharry, 2007). The order in which matches are staged within the qualifying period also implicates an influence of altitude. Altitude training has not been used systematically in soccer, with a few exceptions. Use of altitude simulators is more common, including normobaric hypoxic chambers. Training programmes have been reported to be effective in endurance athletes (Dufour et al., 2006) but not in lower-level performers (Morton et al., 2005). In professional soccer, these simulations are utilised more during rehabilitation than in training non-injured players. Their benefits in this context are not yet fully validated.
Dufour, S.P., Ponsot, E., Zoll, J., Doutreleau, S. et al. (2006). Exercise training in normobaric hypoxia in endurance runners. I. Improvement in aerobic performance capacity. Journal of Applied Physiology, 100, 1238-1248. Pedlar, C., Whyte, G., Emegbo, S. et al. (2005). Acute sleep responses in a normobaric hypoxic tent. Medicine and Science in Sports and Exercise, 37, 1075-1079.
McSharry, P.E. (2007). Effect of altitude on physiological performance: a statistical analysis using results of international football games. British Medical Journal, 335, 1278-1281.
Morton, J.P. and Cable, N.T. (2005). The effects of intermittent hypoxic training on aerobic and anaerobic performance. Ergonomics, 48, 1535-1546.