Strength training improves double-poling performance after prolonged submaximal exercise in cross-country skiers.

Abstract

The purpose of this study was to investigate the effects of adding strength training with or without vibration to cross-country (XC) skiers' endurance training on double-poling (DP) performance, physiological, and kinematic adaptations. Twenty-one well-trained male XC-skiers combined endurance- and upper-body strength training three times per week, either with (n=11) or without (n=10) superimposed vibrations for 8weeks, whereas eight skiers performed endurance training only (CON). Testing included 1RM in upper-body exercises, work economy, neural activation, oxygen saturation in muscle, and DP kinematics during a prolonged submaximal DP roller ski test which was directly followed by a time to exhaustion (TTE) test. TTE was also performed in rested state, and the difference between the two TTE tests (TTEdiff ) determined the ability to maintain DP performance after prolonged exercise. Vibration induced no additional effect on strength or endurance gains. Therefore, the two strength training groups were pooled (STR, n=21). 1RM in STR increased more than in CON (P<.05), and there were no differences in changes between STR and CON in any measurements during prolonged submaximal DP. STR improved TTE following prolonged DP (20±16%, P<.001) and revealed a moderate effect size compared to CON (ES=0.80; P=.07). Furthermore, STR improved TTEdiff more than CON (P=.049). In conclusion, STR superiorly improved 1RM strength, DP performance following prolonged submaximal DP and TTEdiff , indicating a specific effect of improved strength on the ability to maintain performance after long-lasting exercise.