Energy cost of free technique and classical cross-country skiing at racing speeds.

Purpose: First, to measure the O(2) uptake ([OV0312]O(2)) and the blood lactate concentration during cross-country skiing at competition speed. Second, to compare these entities for the free technique and the classical technique. Further, to establish the subjects' [OV0312]O(2max) and the [OV0312]O(2) corresponding to the onset of blood lactate accumulation (OBLA, 4 mmol.

Effect of training intensity on muscle lactate transporters and lactate threshold of cross-country skiers.

The training intensity may affect the monocarboxylate transporters MCT1 and MCT4 in skeletal muscle. Therefore, 20 elite cross-country skiers (11 men and nine women) trained hard for 5 months at either moderate (MIG, 60-70% of VO2max) or high intensity (HIG, 80-90%). The lactate threshold, several performance parameters, and the blood lactate concentration (cLa) after exhausting treadmill running were also determined.

Examination of four different instruments for measuring blood lactate concentration.

Information on the performance of different instruments used to measure blood lactate concentration is incomplete. We therefore examined instruments from Yellow Springs Instruments (YSI 23L and YSI 1500) and three cheaper and simpler instruments: Dr. Lange's LP8+, Lactate Pro from Arkray in the KDK corporation and Accusport from Boehringer Mannheim.

Effect of training on the activity of five muscle enzymes studied on elite cross-country skiers.

This study examines the effect of training intensity on the activity of enzymes in m. vastus lateralis. Elite junior cross-country skiers of both sexes trained 12-15 h weeks-1 for 5 months at either moderate (60-70% of VO2max, MIG) or high training intensity (80-90% of the VO2max, close to the lactate threshold; HIG).

Hard training for 5 mo increases Na(+)-K+ pump concentration in skeletal muscle of cross-country skiers.

To study how training affects the Na(+)-K+ pump concentration, 11 male and 9 female elite junior cross-country skiers trained 12-15 h/wk at 60-70% (moderate-intensity group) or 80-90% (high-intensity group) of their maximal O2 uptake for 5 mo. Muscle biopsies taken from the vastus lateralis muscle before and after the training period were analyzed for Na(+)-K+ pump concentration by the [3H]ouabain-binding technique. Before training, the concentration was 343 +/- 11 nmol/kg wet muscle mass (mean +/- SE) for the men and 281 +/- 14 nmol/kg for the women (18% less than for the men, P = 0.