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2010 Winter Games Themed Issue

This special issue of Experimental Physiology contains a series of articles that provide an insight into elite human performance in the unique, and often spectacular, environments associated with the Winter Olympics. When most people think about these Games they conjure up glorious images of snow and high mountains, but when physiologists think of cold and altitude most of us immediately think of environmental challenges, including hypothermia and hypoxia. We have encouraged review authors to try to resist stereotypical thought progression and avoid the standard, and perhaps dated, tactic of examining each of the major physiological systems in turn with the aim of identifying limiting factors to performance. Our intention, therefore, was to invite submissions from those with a novel, insightful and, most importantly, integrative view of the limitations to performance in Winter Olympic sport. We are delighted with this unique collection of articles, clearly demonstrating that the physiology underlying a medal-winning performance in many winter sports is still far from fully understood. If one examines skiing and skating, a fall is always possible, but the important question is whether or not the fall was preventable. If it resulted from muscle fatigue or failure to execute a motor programme correctly, the probable answer to this question is yes, and these are preventable circumstances. Richard Ferguson (2010) points out that a well-rehearsed motor programme assumes a certain force output at a specific time from activated motor units. If this is not the case, then in the split second available to correct an error or react to an unexpected change in terrain, all is lost. He explains how force output could be depressed, or recruitment strategy could be altered, during exercise in ischaemic conditions. Since contractile forces as low as 20% of maximal will occlude blood supply to human calf muscles and quadriceps, it is easy to imagine exercise conditions in which this occurs (e.g. the low tuck position of a downhill skier). In other circumstances, force may be dramatically reduced at low frequencies of stimulation, which can last for up to 48 h postexercise. The influence of such low-frequency fatigue from an unexpectedly difficult qualifying event (such as ice hockey) on the medal-deciding rounds is evident. Ben Levine and colleagues (Chapman et al. 2010) explain how motor programmes in many events need to be retrained to take account of the lower resistance encountered when moving through air at altitude. Their example of the shorter time taken to rotate the body during a spin in ice dance is compelling. Proper allowance for a period of acclimatisation to these environmental conditions must be included in the preparation schedules for competition and also, importantly, on return to normal training back at lower altitudes. Failure to allow this time is likely to increase the risk of potentially serious injury in a fall or on incorrect landing. While recruitment of motor units is modulated by muscle ischaemia, this may be mediated by afferent feedback to the motor pool or brain. The role of muscle afferent feedback in driving sympathetic vasoconstrictor tone to active and inactive muscles (Sheel et al. 2010), as well as the role of mechanoreceptive afferent feedback in baroreflex function and cardiac vagal tone (Coote, 2010), reveal the extent to which truly integrative physiology is required to allow the fine control needed to compensate for conflicting stimuli. The biathlon is an obvious example of where high aerobic capacity is a prerequisite for success, and the role and limitations to performance set by the respiratory system at altitude and in the cold (Sheel et al. 2010), and how the cardiorespiratory system adapts to training (Coote, 2010) and altitude (Chapman et al. 2010), are explored. However, the biathlon also involves accurate shooting. Missing a target incurs a time and effort penalty added by skiing a lap of a circuit, and this invariably influences the outcome of a race. At this point, Martin Lakie’s expertise on tremor (Lakie, 2010) and John Coote’s understanding of heart rate recovery postexercise (Coote, 2010) come to the fore. It is clear from these articles that we still don’t know whether a high or low pulse rate during shooting, especially