Arm, Trunk and Leg Contributions to Double Poling Performance in Cross-Country Skiing

Abstract

0123 In classical cross-country skiing, the double poling (DP) technique has become increasingly used as equipment, track preparation, waxing and skier fitness have allowed faster race performances. On flat or moderately rolling terrain, DP is often faster and more economical than other techniques and is used extensively even for extremely long events such as the 90 km Vasaloppet. Generating propulsive force in DP involves a coordinated movement pattern using muscles crossing elbow, shoulder, trunk, hip and knee joints. Weakness in any of these links is disadvantageous. PURPOSE: To determine the relative costs and power contributions to performance of arm, trunk and leg segments in DP. METHODS: A rowing ergometer was adapted for DP measurement. Whole-body (WB) poling characteristics were compared with those with legs locked (TA; trunk and arms) and with legs and trunk locked (A; arms). The 3 poling conditions were tested in an all-out 20 second max, a 5-minute all-out, and a 5-minute submaximal test. Mechanical power was measured with the ergometer's internal software while poling forces were measured with an axial transducer in the right pole. Oxygen uptake, lactate concentration and heart rate were measured with conventional methods. In this preliminary data collection, two Norwegian university student ski racers were evaluated on separate days for each poling condition. RESULTS: Peak VO2 in WB poling was 87% of running max VO2 while TA was 76% and arms alone were 62%. Average power in the all-out 5-minute test was 176, 150 and 83 watts (WB, TA, A), while for the 20 second test it was 247, 245 and 173 watts, respectively. Poling forces and impulse were reduced substantially by the restricted motion of the TA and A conditions while poling frequency increased compared to WB poling. CONCLUSIONS: With ergometer based double poling, legs contributed about 10% and trunk about 14% to peak VO2. Power was reduced by about 15% with restricted leg motion and more than 50% with just arm contributions to propulsive force. This emphasizes the necessity of both arm and trunk power for effective double poling performance in cross-country skiing.