Purpose: We investigated the effects of moderate-intensity training at low and high altitude on (Formula presented.)O2 and (Formula presented.) kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery. Methods: Breath-by-breath (Formula presented.)O2 and beat-by-beat (Formula presented.) at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking. Results: Mean response time of (Formula presented.)O2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas (Formula presented.) kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016). Conclusions: Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport–utilization systems witnessed by faster (Formula presented.)O2 kinetics at exercise onset.
Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women / E. Tam, P. Bruseghini, E. Calabria, L. Dal Sacco, C. Doria, B. Grassi, T. Pietrangelo, S. Pogliaghi, C. Reggiani, D. Salvadego, F. Schena, L. Toniolo, V. Verratti, G. Vernillo, C. Capelli. - In: EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY. - ISSN 1439-6319. - 116:1(2016 Jan), pp. 129-144. [10.1007/s00421-015-3256-z]
Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women
C. Doria;G. VernilloPenultimo
;C. CapelliUltimo
2016
Abstract
Purpose: We investigated the effects of moderate-intensity training at low and high altitude on (Formula presented.)O2 and (Formula presented.) kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery. Methods: Breath-by-breath (Formula presented.)O2 and beat-by-beat (Formula presented.) at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking. Results: Mean response time of (Formula presented.)O2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas (Formula presented.) kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016). Conclusions: Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport–utilization systems witnessed by faster (Formula presented.)O2 kinetics at exercise onset.File | Dimensione | Formato | |
---|---|---|---|
art%3A10.1007%2Fs00421-015-3256-z.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
664.63 kB
Formato
Adobe PDF
|
664.63 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.