Clark et al also noted that pacing, despite substantially reduced power, showed no difference for athletes whose first trial was at either 200 or 1200 meters, while those whose first trial was at the higher elevations tended to mis-pace that effort significantly.
Here is where the research and the reality intersect.
On The Road
Cycling is an aerobic sport interspersed with high intensity non-aerobic efforts. Introduce the added element of altitude and performance is easily impacted in a number of ways. First, let's think of the athlete who travels to Colorado on a shorter time window than the 2 to 3 weeks commonly recommended for acclimatization—he or she can be expected to have problems sleeping and may be more prone to illness and extended feelings of fatigue.
More: Even Fit Athltetes Can Fall to Altitude Sickness
In addition, out on the road they will suffer impaired peak VO2 values and, perhaps most importantly in a stage race, may mis-pace efforts at all intensities, most especially at VO2 max. Mis-judge an effort at 10,000 feet and you will not only suffer that day, but recovery and repeatability will also be impaired.
For those athletes who can spend adequate time at altitude will reap some benefits, but there are also some potential downsides. Above 1500 meters (4500 feet) the partial pressure of oxygen is about 10 to 15 percent lower than at sea level. This means you simply cannot move enough oxygen to supply the working muscles.
Peak power and VO2 max will always be lower at altitude. If those athletes were competing at sea level they may well see improvements in lactate clearing, blood pH buffering, and sea level VO2 max, but given that the race in Colorado is entirely above 5000 feet these benefits are much less well established.
More: Altitude Training for Athletic Success: Part II
The type of training and preparation the teams undertake with early arrival is called Live High Train High (LHTH) and represents a necessary approach for the racers. There is speculation as to whether any performance gains to be seen by this approach and if it is due to physiological improvements or simply the after effect of a focused block of training free of daily distractions.
One notable study by Daniels and Oldridge in 1970 saw a 3 percent improvement in 3-mile race pace at the end of two 14-day training blocks where normal sea level training loads were employed throughout the camp. It is interesting to watch the racers try to deal with the altitude and its effects!
More: Acclimating to Altitude Before a Race: Part II
Summary
This weeks USA Pro Cycling Challenge presents a unique experience for the athletes participating. With the entire parcours above 5000 feet the athletes will face the effects of decreased oxygen availability and lower peak power values across all durations. Research has shown that altitude training, or more specifically sea level training with altitude living—the so called Live High Train Low approach—has a substantial impact on physiological markers like blood lactate production/buffering, enzymatic and mitochondrial efficiency and blood pH.Whether these differences are to be reaped by those who have spent the last month or more training and racing at altitude remains to be seen, but those athletes who took no such approach will most certainly suffer from the decreased oxygen available and will likely mis-pace their efforts on both power production and ratings of perceived exertion. Should make for an interesting race!
More: How to Prevent the 6 Most Common Cycling Injuries
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