We investigated the effects of moderate-intensity training at low and high altitude on O-2 and kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy +/- A 7.1; 65.8 kg +/- A 11.7; 165 cm +/- A 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.Breath-by-breath O-2 and beat-by-beat at the onset of moderate-intensity cycling exercise and energy cost of walking (C (w)) 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.Mean response time of O-2 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 kinetics and C (w) 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).Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster O-2 kinetics at exercise onset.

Tam, E., Bruseghini, P., Calabria, E., Dal Sacco, L., Doria, C., Grassi, B., Pietrangelo, T., Pogliaghi, S., Reggiani, C., Salvadego, D., Schena, F., Toniolo, L., Verratti, V., Vernillo, G., Capelli, C., 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, <<EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY>>, 2016; 116 (1): 129-144. [doi:10.1007/s00421-015-3256-z] [http://hdl.handle.net/10807/214699]

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

Bruseghini, P
Secondo
;
2016

Abstract

We investigated the effects of moderate-intensity training at low and high altitude on O-2 and kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy +/- A 7.1; 65.8 kg +/- A 11.7; 165 cm +/- A 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.Breath-by-breath O-2 and beat-by-beat at the onset of moderate-intensity cycling exercise and energy cost of walking (C (w)) 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.Mean response time of O-2 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 kinetics and C (w) 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).Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster O-2 kinetics at exercise onset.
Inglese
Tam, E., Bruseghini, P., Calabria, E., Dal Sacco, L., Doria, C., Grassi, B., Pietrangelo, T., Pogliaghi, S., Reggiani, C., Salvadego, D., Schena, F., Toniolo, L., Verratti, V., Vernillo, G., Capelli, C., 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, <<EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY>>, 2016; 116 (1): 129-144. [doi:10.1007/s00421-015-3256-z] [http://hdl.handle.net/10807/214699]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/214699
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