AUTHOR=Schmitt Laurent , Willis Sarah J. , Coulmy Nicolas , Millet Gregoire P. 

TITLE=Effects of Different Training Intensity Distributions Between Elite Cross-Country Skiers and Nordic-Combined Athletes During Live High-Train Low

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.00932

DOI=10.3389/fphys.2018.00932

ISSN=1664-042X

ABSTRACT=<p><bold>Purpose:</bold> To analyze the effects of different training strategies (i.e., mainly intensity distribution) during living high – training low (LHTL) between elite cross-country skiers and Nordic-combined athletes.</p><p><bold>Methods:</bold> 12 cross-country skiers (XC) (7 men, 5 women), and 8 male Nordic combined (NC) of the French national teams were monitored during 15 days of LHTL. The distribution of training at low-intensity (LIT), below the first ventilatory threshold (VT1), was 80% and 55% in XC and NC respectively. Daily, they filled a questionnaire of fatigue, and performed a heart rate variability (HRV) test. Prior (Pre) and immediately after (Post), athletes performed a treadmill incremental running test for determination of <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub> and <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> at the second ventilatory threshold (<inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2V T2</sub>), a field roller-skiing test with blood lactate ([La-]) assessment.</p><p><bold>Results:</bold> The training volume was in XC and NC, respectively: at LIT: 45.9 ± 6.4 vs. 23.9 ± 2.8 h (<italic>p</italic> &lt; 0.001), at moderate intensity: 1.9 ± 0.5 vs. 3.0 ± 0.4 h, (<italic>p</italic> &lt; 0.001), at high intensity: 1.2 ± 0.9 vs. 1.4 ± 02 h (<italic>p</italic> = 0.05), in strength (and jump in NC): 7.1 ± 1.5 vs. 18.4 ± 2.7 h, (<italic>p</italic> &lt; 0.001). Field roller-skiing performance was improved (-2.9 ± 1.6%, <italic>p</italic> &lt; 0.001) in XC but decreased (4.1 ± 2.6%, <italic>p</italic> &lt; 0.01) in NC. [La-] was unchanged (-4.1 ± 14.2%, <italic>p</italic> = 0.3) in XC but decreased (-27.0 ± 11.1%, <italic>p</italic> &lt; 0.001) in NC. Changes in field roller-skiing performance and in [La-] were correlated (<italic>r</italic> = -0.77, <italic>p</italic> &lt; 0.001). <inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub> increased in both XC and NC (3.7 ± 4.2%, <italic>p</italic> = 0.01 vs. 3.7 ± 2.2%, <italic>p</italic> = 0.002) but <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2V T2</sub> increased only in XC (7.3 ± 5.8%, <italic>p</italic> = 0.002). HRV analysis showed differences between XC and NC mainly in high spectral frequency in the supine position (HF<sub>SU</sub>). All NC skiers showed some signs of overreaching at Post.</p><p><bold>Conclusion:</bold> During LHTL, despite a higher training volume, XC improved specific performance and aerobic capacities, while NC did not. All NC skiers showed fatigue states. These findings suggest that a large amount of LIT with a moderate volume of strength and speed training is required during LHTL in endurance athletes.</p>