5 mo hard training increases the na+,k+ pump concentration in
skeletal muscle of elite cross-country skiers.
Evertsen, Frank, Jon Ingulf Medb, Einar Jebens, and Kre Nicolaysen.
The Norwegian University of Sport and Physical Education, PO Box
4014, Ullev[sigma]l Hageby N-0806-4014 Oslo, Norway
APStracts 3:0437R, 1996.
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-1
at 60-70% (moderate intensity group, MIG) or 80-90% (high intensity
group, HIG) 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 the Na,K pump concentration by the [3H]
ouabain-binding technique. Before training the concentration was 343
( 11 nmol kg -1 wet muscle mass (mean SEM) for the men and 281 ( 14
nmol kg-1 for the women (18% less than for the men, P=0.003). The
Na+,K+ pump concentration rose by 49 ( 11 nmol kg-1 (16%, P< 0.001)
for all subjects pooled during the training period, and there was no
difference between the two training groups (P=0.3) or the sexes
(P=0.5) in this increase. The Na+,K+ pump concentration correlated
with the maximal O2 uptake (r=0.6, P=0.003), with the performance
during a 20 min treadmill run (r=0.6, P=0.003), and to the rank of
the subjects' performance as cross-country skiers (rS=0.76, P<0.001).
These data could mean that for elite cross-country skiers the
performance is related to the Na+,K+ pump concentration. However,
other studies have shown an equally high pump concentration for far
less fit subjects, suggesting that the pump concentration may not be
a limiting factor.
Received 22 August 1996; accepted in final form 28 August 1996.
APS Manuscript Number R420-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996