Effect of training intensity on muscle XXXX transporters and @entity880 threshold of cross-country skiers.

@entity1 @entity3342 @entity4619 @entity880 @entity373 @entity3195
The training intensity may affect the monocarboxylate transporters @entity3195 and @entity3342 in skeletal muscle. Therefore, 20 elite cross-country skiers (11 @entity1 and nine @entity1 ) trained hard for 5 months at either moderate ( @entity373 , 60-70% of VO2max) or high intensity (HIG, 80-90%). The @entity880 threshold, several performance parameters, and the blood @entity880 concentration ( @entity4619 ) after exhausting treadmill running were also determined. Muscle biopsies taken from the vastus lateralis muscle before and after the training period were analysed for the two MCTs and for muscle fibre types and six enzymes. The concentration of @entity3195 did not change for HIG (P=0.3) but fell for @entity373 (-12 +/- 3%, P=0.01); the training response differed between the two groups (P=0.05). The concentration of @entity3342 did not change during the training period (P > 0.10). The concentration of the two MCTs did not differ between the two sexes (P=0.9). The running speed at the @entity880 threshold rose for HIG (+3.2 +/- 0.9%, P=0.003), while no change was seen for @entity373 (P=0.54); the training response differed between the two groups (P=0.04). The @entity4619 after long-lasting exhausting treadmill running correlated with the concentration of @entity3195 (rs=0.69, P=0.002), but not with that of @entity3342 (rs=0.2, P=0.2). There were no other significant correlations between the concentrations of the two MCTs and the performance parameters, muscle fibre types, or enzymes (r < or = 0.36, P > 0.10). Thus, the training response differed between @entity373 and HIG both in terms of performance and of the effect on @entity3195 . Training at high intensity may be more effective for cross-country skiers. Finally, @entity3195 may be important for releasing @entity880 to the blood during long-lasting exercise.
