Research
Discrepancy between cardiorespiratory system and skeletal muscle in elite cyclists after hypoxic training
1 Department of Biochemistry and Biophysics, University of Pennsylvania, USA
2 Department of Preventive Medicine and Public Health, Tokyo Medical University, Tokyo, Japan
3 Norwegian Olympic Committee and Confederation of Sports, Oslo, Norway
4 Norwegian University of Sport and Physical Education, Oslo, Norway
Dynamic Medicine 2003, 2:4 doi:10.1186/1476-5918-2-4
Published: 22 August 2003Abstract
Background
The purpose of this study was to determine the effects of hypoxic training on the cardiorespiratory system and skeletal muscle among well-trained endurance athletes in a randomized cross-over design.
Methods
Eight junior national level competitive cyclists were separated into two groups; Group
A trained under normoxic condition (21% O2) for 2 hours/day, 3 days/week for 3 weeks while Group B used the same training protocol
under hypoxic condition (15% O2). After 3 weeks of each initial training condition, five weeks of self-training under
usual field conditions intervened before the training condition was switched from
NT to HT in Group A, from HT to NT in Group B. The subjects were tested at sea level
before and after each training period. O2 uptake (
O2), blood samples, and muscle deoxygenation were measured during bicycle exercise test.
Results and Discussion
No changes in maximal workload, arterial O2 content, O2 at lactate threshold and O2max were observed before or after each training period. In contrast, deoxygenation change
during submaximal exercise in the vastus lateralis was significantly higher at HT
than NT (p < 0.01). In addition, half time of oxygenation recovery was significantly
faster after HT (13.2 ± 2.6 sec) than NT (18.8 ± 2.7 sec) (p < 0.001).
Conclusions
Three weeks of HT may not give an additional performance benefit at sea level for elite competitive cyclists, even though HT may induce some physiological adaptations on muscle tissue level.
