AUTHOR=Børve Jørgen , Jevne Steffen N. , Rud Bjarne , Losnegard Thomas 

TITLE=Upper-Body Muscular Endurance Training Improves Performance Following 50 min of Double Poling in Well-Trained Cross-Country Skiers

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00690

DOI=10.3389/fphys.2017.00690

ISSN=1664-042X

ABSTRACT=<p>This study investigated the effect of muscular endurance training on O<sub>2</sub>-cost and performance in double poling (DP) on a rollerski treadmill. Twenty-two well-trained cross-country skiers (31 ± 4 years, 77 ± 9 kg, 181 ± 8 cm, VO<sub>2max</sub> running: 64 ± 5 mL·kg<sup>−1</sup>·min<sup>−1</sup>) were counter-balanced to either a combined muscular endurance and running interval training group [MET; <italic>n</italic> = 11 (♂ = 9, ♀ = 2)], or an endurance running interval training group [ET; <italic>n</italic> = 11 (♂ = 9, ♀ = 2)]. Both groups continued their normal low-and moderate intensity training, but replaced 2 weekly high intensity-training sessions with two project-specific sessions for 6 weeks. In these sessions, MET combined upper-body muscular endurance training (4 × 30 repetitions, 90 s rest between sets) and running intervals (3 × 4 or 2 × 6 min, 3 min rest), while ET performed running intervals only (6 × 4 or 4 × 6 min, 3 min rest). The DP test-protocol consisted of 50 min submaximal poling for O<sub>2</sub>-cost measurement, followed by a self-paced 1,000-m performance test. In addition, subjects performed a VO<sub>2max</sub> test in running. MET increased muscular endurance (<italic>P</italic> &lt; 0.05) and 1RM in simulated DP (<italic>P</italic> &lt; 0.01) more than ET. Further, MET reduced the 1,000-m time and O<sub>2</sub>-cost compared to baseline values (<italic>P</italic> &lt; 0.05), and tended to improve the 1,000-m time more than ET (<italic>P</italic> = 0.06). There were no changes in VO<sub>2max</sub> running or VO<sub>2peak</sub> DP in either MET or ET. In conclusion, 6 weeks of muscular endurance training increased both muscular endurance and 1RM in simulated DP. Further, specific upper-body muscular endurance training improved DP performance and thus, seems as a promising training model to optimize performance in well-trained cross-country skiers.</p>