caa a22 4500 46794010X CHVBK 20180406153009.0 cr unu---uuuuu 170328e20061001xx s 000 0 eng 10.1007/s00421-006-0280-z doi (NATIONALLICENCE)springer-10.1007/s00421-006-0280-z Interspersed normoxia during live high, train low interventions reverses an early reduction in muscle Na+, K+ATPase activity in well-trained athletes [Elektronische Daten] [R. Aughey, S. Clark, C. Gore, N. Townsend, A. Hahn, T. Kinsman, C. Goodman, C. Chow, D. Martin, J. Hawley, M. McKenna] Hypoxia and exercise each modulate muscle Na+, K+ATPase activity. We investigated the effects on muscle Na+, K+ATPase activity of only 5 nights of live high, train low hypoxia (LHTL), 20 nights consecutive (LHTLc) versus intermittent LHTL (LHTLi), and acute sprint exercise. Thirty-three athletes were assigned to control (CON, n=11), 20-nights LHTLc (n=12) or 20-nights LHTLi (4×5-nights LHTL interspersed with 2-nights CON, n=10) groups. LHTLc and LHTLi slept at a simulated altitude of 2,650m (FIO2 0.1627) and lived and trained by day under normoxic conditions; CON lived, trained, and slept in normoxia. A quadriceps muscle biopsy was taken at rest and immediately after standardised sprint exercise, before (Pre) and after 5-nights (d5) and 20-nights (Post) LHTL interventions and analysed for Na+, K+ATPase maximal activity (3-O-MFPase) and content ([3H]-ouabain binding). After only 5-nights LHTLc, muscle 3-O-MFPase activity declined by 2% (P<0.05). In LHTLc, 3-O-MFPase activity remained below Pre after 20 nights. In contrast, in LHTLi, this small initial decrease was reversed after 20 nights, with restoration of 3-O-MFPase activity to Pre-intervention levels. Plasma [K+] was unaltered by any LHTL. After acute sprint exercise 3-O-MFPase activity was reduced (12.9±4.0%, P<0.05), but [3H]-ouabain binding was unchanged. In conclusion, maximal Na+, K+ATPase activity declined after only 5-nights LHTL, but the inclusion of additional interspersed normoxic nights reversed this effect, despite athletes receiving the same amount of hypoxic exposure. There were no effects of consecutive or intermittent nightly LHTL on the acute decrease in Na+, K+ATPase activity with sprint exercise effects or on plasma [K+] during exercise. Springer-Verlag, 2006 Na+, K+-pump nationallicence Muscle fatigue nationallicence Altitude nationallicence Aughey R. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut Clark S. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut Gore C. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut Townsend N. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut Hahn A. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut Kinsman T. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut Goodman C. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut Chow C. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut Martin D. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut Hawley J. Exercise Metabolism Group, Division of Exercise Sciences, School of Medical Sciences, Faculty of Life Sciences, RMIT University Australia, Melbourne, Australia aut McKenna M. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut European Journal of Applied Physiology Springer-Verlag 98/3(2006-10-01), 299-309 1439-6319 98:3<299 2006 98 421 https://doi.org/10.1007/s00421-006-0280-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-006-0280-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Aughey R. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Clark S. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut NATIONALLICENCE 700 1- Gore C. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut NATIONALLICENCE 700 1- Townsend N. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut NATIONALLICENCE 700 1- Hahn A. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut NATIONALLICENCE 700 1- Kinsman T. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut NATIONALLICENCE 700 1- Goodman C. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Chow C. School of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Sydney, Australia aut NATIONALLICENCE 700 1- Martin D. Department of Physiology, Australian Institute of Sport, Canberra, Australia aut NATIONALLICENCE 700 1- Hawley J. Exercise Metabolism Group, Division of Exercise Sciences, School of Medical Sciences, Faculty of Life Sciences, RMIT University Australia, Melbourne, Australia aut NATIONALLICENCE 700 1- McKenna M. Muscle, Ions & Exercise Group, Centre for Aging, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, MCMC, PO Box 14428, 8001, Melbourne, VIC, Australia aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 98/3(2006-10-01), 299-309 1439-6319 98:3<299 2006 98 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer