TY - JOUR
T1 - Reduced volume but increased training intensity elevates muscle Na+-K+ pump alpha1-subunit and NHE1 expression as well as short-term work capacity in humans
AU - Iaia, F. Marcello
AU - Thomassen, Martin
AU - Kolding, Helle
AU - Gunnarsson, Thomas Gunnar Petursson
AU - Wendell, Jesper
AU - Rostgaard, Thomas
AU - Nordsborg, Nikolai
AU - Krustrup, Peter
AU - Nybo, Lars
AU - Hellsten, Ylva
AU - Bangsbo, Jens
N1 - CURIS 2008 5200 003
PY - 2008
Y1 - 2008
N2 - The present study examined muscle adaptations and alterations in work capacity in endurance-trained runners after a change from endurance to sprint training. Fifteen runners were assigned to either a sprint training (ST, n = 8) or a control (CON, n = 7) group. ST replaced their normal training by 30-s sprint runs three to four times a week, whereas CON continued the endurance training ( approximately 45 km/wk). After the 4-wk sprint period, the expression of the muscle Na(+)-K(+) pump alpha(1)-subunit and Na(+)/H(+)-exchanger isoform 1 was 29 and 30% higher (P < 0.05), respectively. Furthermore, plasma K(+) concentration was reduced (P < 0.05) during repeated intense running. In ST, performance in a 30-s sprint test, Yo-Yo intermittent recovery test, and two supramaximal exhaustive runs was improved (P < 0.05) by 7, 19, 27, and 19%, respectively, after the sprint training period, whereas pulmonary maximum oxygen uptake and 10-k time were unchanged. No changes in CON were observed. The present data suggest a role of the Na(+)-K(+) pump in the control of K(+) homeostasis and in the development of fatigue during repeated high-intensity exercise. Furthermore, performance during intense exercise can be improved and endurance performance maintained even with a reduction in training volume if the intensity of training is very high.
AB - The present study examined muscle adaptations and alterations in work capacity in endurance-trained runners after a change from endurance to sprint training. Fifteen runners were assigned to either a sprint training (ST, n = 8) or a control (CON, n = 7) group. ST replaced their normal training by 30-s sprint runs three to four times a week, whereas CON continued the endurance training ( approximately 45 km/wk). After the 4-wk sprint period, the expression of the muscle Na(+)-K(+) pump alpha(1)-subunit and Na(+)/H(+)-exchanger isoform 1 was 29 and 30% higher (P < 0.05), respectively. Furthermore, plasma K(+) concentration was reduced (P < 0.05) during repeated intense running. In ST, performance in a 30-s sprint test, Yo-Yo intermittent recovery test, and two supramaximal exhaustive runs was improved (P < 0.05) by 7, 19, 27, and 19%, respectively, after the sprint training period, whereas pulmonary maximum oxygen uptake and 10-k time were unchanged. No changes in CON were observed. The present data suggest a role of the Na(+)-K(+) pump in the control of K(+) homeostasis and in the development of fatigue during repeated high-intensity exercise. Furthermore, performance during intense exercise can be improved and endurance performance maintained even with a reduction in training volume if the intensity of training is very high.
U2 - 10.1152/ajpregu.00666.2007
DO - 10.1152/ajpregu.00666.2007
M3 - Journal article
C2 - 18094063
VL - 294
SP - R966-R974
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6119
IS - 3
ER -