Maximal strength training improves work economy in trained female cross-country skiers

Purpose: The present study examines the hypothesis that maximal strength training improves work economy and anaerobic threshold in trained female cross-country skiers while working on a ski ergometer. Methods: Fifteen female cross-country skiers (17.9 +/- 0,3 yr, 166.7 +/- 1.3 cm, 60.1 +/- 1.9 kg, and 55.3 +/- 1.3 m/kg(-1) min(-1)) participated in the study. Eight skiers made up the high-intensity strength-trained group, and seven served as the control group. Endurance performance was tested on a specially instrumented ski ergometer. Strength training and testing simulated double poling in cross-country skiing. Results: A significant (P < 0.001) improvement in double poling economy on the ski ergometer was observed among the strength-trained group, Anaerobic threshold did not change during the experimental period for either group. After a 9-wk training period, time to exhaustion increased from 5.2 (+/-0.9) to 12.3 (+/-1.6) min (P < 0.001) and from 4.0 (+/-0.9) to 6.3 (+/-0.9) min (P < 0.01) for the strength and control group, respectively. Time to exhaustion was significantly higher (P < 0.001) for the strength group compared with the control group after training. One repetition maximum increased 14,5% (1.8) (P < 0.001) in the strength group but was unchanged in the control group. Expressed in relation to peak force at one repetition maximum, strength training resulted in a significant reduction in the relative available force employed working on the ski ergometer (P < 0.01). Time to peak force at maximal aerobic velocity on the ski ergometer was significantly reduced in the strength-training group (P < 0.01). Conclusions: It is concluded that maximal strength training in the upper-body improved the double-poling performance by improved work economy. Work economy was improved by a reduction in relative workload and time to peak force while double poling.