Metabolic Cost of Diagonal Striding and Double Poling in Cross Country Classic Skiing

Several studies have compared physiological demands of two classic skiing techniques:double poling and diagonal striding. In diagonal striding, the skis propel theskier by alternating kick and glide phases between the left and right ski. Each skikicks simultaneously with a push from the opposite pole. In double poling, the skierplants and pushes through with both poles simultaneously while the skis glide anddo not contribute to impulse generation. Previous studies found that double polingwas more economical by 10-26% than striding on flat and low grade surfaces at severalspeeds1,2,3. However, if the oxygen consumption in double poling is lower at all givenspeeds, then why do skiers prefer to stride at slow speeds? The purpose of this studywas to measure metabolic factors for the striding and double poling techniques inorder to explain why skiers choose to stride under some conditions.Nine elite male skiers performed a test on a rollerski treadmill. The treadmill wasset to a 4% uphill grade and the speed was increased from 6km/h to 15km/h byincrements of 3km/h. At each speed, the skier reached metabolic steady state for boththe striding and double poling techniques. During the test, oxygen consumption andthe respiratory exchange ratio (RER=CO2 produced/O2 consumed) were measuredcontinuously.The average oxygen cost for double poling was found to be 10% lower comparedto striding across all speeds. However, for all but the highest speed, the RER valuesfor double poling were 12% higher. RER indicates the intensity to which the recruitedmuscle mass is working. Therefore, these results suggest that double poling, althoughmore economical, is likely more demanding on the recruited musculature and mightlead to fast local fatigue. These results explain why double poling is not the preferredtechnique at slower speeds