The following text is a summary of a lecture by Vidar Jakobsen at a Norwegian Ski Association Coaches’ Seminar in June 2004.
Differences between free technique skiing (skating) and running, measured on treadmills:
Junior skiers 2002: Lactate values are higher when skating than running
The oxygen uptake for skating versus running is very variable
Senior National Team: Oxygen uptake is higher for running than for skating (tested in May, August and October), in October the average values were 75 mL when skating and 83 mL when running.
The oxygen uptake for running increases as expected from May through August to October. However, the oxygen uptake for skating decreases from August to October, without a clear answer to why. This may be caused by more altitude-skiing on glaciers in October, and the skiing technique varies a bit between skiing on snow and rollerskiing on a treadmill. A change in training-priority may also be causing the results.
The oxygen uptake improves between May and August, even though intensity training is not prioritized. During the competition season (winter), the oxygen uptake decreases (as measured in April). This may be caused by less training during the race season, and that training drop even more after the race season in is finished in March.
Certain skiers have high oxygen uptake when skating. One skier that has prioritized skating is tested at 85 mL. This skier is so technically advanced in skating that his values are close to the same as when running. His values have increased from year to year. Following a skier over 3 years shows that lactate measurements at sub-maximal speed result in less lactate from year to year. Measurements of heart rate when uphill skating using V1 versus V2 shows a lower HR when using V1. It has also been shown that the oxygen uptake is lower when using V1 versus V2 (at the same speed). However, no research has concluded which skating techniques (V1 or V2) are most efficient in uphill skating.