Inclusion of sprints in moderate intensity continuous training leads to muscle oxidative adaptations in trained individuals
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Inclusion of sprints in moderate intensity continuous training leads to muscle oxidative adaptations in trained individuals. / Gunnarsson, Thomas Gunnar Petursson; Brandt, Nina; Fiorenza, Matteo; Hostrup, Morten; Pilegaard, Henriette; Bangsbo, Jens.
I: Physiological Reports, Bind 7, Nr. 4, e13976, 2019.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Inclusion of sprints in moderate intensity continuous training leads to muscle oxidative adaptations in trained individuals
AU - Gunnarsson, Thomas Gunnar Petursson
AU - Brandt, Nina
AU - Fiorenza, Matteo
AU - Hostrup, Morten
AU - Pilegaard, Henriette
AU - Bangsbo, Jens
N1 - CURIS 2019 NEXS 072 © 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
PY - 2019
Y1 - 2019
N2 - This study examined adaptations in muscle oxidative capacity and exercise performance induced by two work- and duration-matched exercise protocols eliciting different muscle metabolic perturbations in trained individuals. Thirteen male subjects (V˙O2 -max 53.5 ± 7.0 mL·kg-1 ·min-1) (means ± SD) performed 8 weeks (three sessions/week) of training consisting of 60 min of moderate intensity continuous cycling (157 ± 20 W) either without (C) or with (C+S) inclusion of 30-s sprints (473 ± 79 W) every 10 min. Total work performed during training was matched between groups. Muscle biopsies and arm venous blood were collected before as well as immediately and 2 h after exercise during the first and last training session. Plasma epinephrine and lactate concentrations after the first and last training session were 2-3-fold higher in C+S than in C. After the first and last training session, muscle phosphocreatine and pH were lower (12-25 mmol·kg d.w.-1 and 0.2-0.4 units, respectively) and muscle lactate higher (48-64 mmol·kg d.w.-1) in C+S than in C, whereas exercise-induced changes in muscle PGC-1α mRNA levels were similar within- and between-groups. Muscle content of cytochrome c oxidase IV and citrate synthase (CS) increased more in C+S than in C, and content of CS in type II muscle fibers increased in C+S only (9-17%), with no difference between groups. Performance during a 45-min time-trial improved by 4 ± 3 and 9 ± 3% in C+S and C, respectively, whereas peak power output at exhaustion during an incremental test increased by 3 ± 3% in C+S only, with no difference between groups. In conclusion, addition of sprints in moderate intensity continuous exercise causes muscle oxidative adaptations in trained male individuals which appear to be independent of the exercise-induced PGC-1α mRNA response. Interestingly, time-trial performance improved similarly between groups, suggesting that changes in content of mitochondrial proteins are of less importance for endurance performance in trained males.
AB - This study examined adaptations in muscle oxidative capacity and exercise performance induced by two work- and duration-matched exercise protocols eliciting different muscle metabolic perturbations in trained individuals. Thirteen male subjects (V˙O2 -max 53.5 ± 7.0 mL·kg-1 ·min-1) (means ± SD) performed 8 weeks (three sessions/week) of training consisting of 60 min of moderate intensity continuous cycling (157 ± 20 W) either without (C) or with (C+S) inclusion of 30-s sprints (473 ± 79 W) every 10 min. Total work performed during training was matched between groups. Muscle biopsies and arm venous blood were collected before as well as immediately and 2 h after exercise during the first and last training session. Plasma epinephrine and lactate concentrations after the first and last training session were 2-3-fold higher in C+S than in C. After the first and last training session, muscle phosphocreatine and pH were lower (12-25 mmol·kg d.w.-1 and 0.2-0.4 units, respectively) and muscle lactate higher (48-64 mmol·kg d.w.-1) in C+S than in C, whereas exercise-induced changes in muscle PGC-1α mRNA levels were similar within- and between-groups. Muscle content of cytochrome c oxidase IV and citrate synthase (CS) increased more in C+S than in C, and content of CS in type II muscle fibers increased in C+S only (9-17%), with no difference between groups. Performance during a 45-min time-trial improved by 4 ± 3 and 9 ± 3% in C+S and C, respectively, whereas peak power output at exhaustion during an incremental test increased by 3 ± 3% in C+S only, with no difference between groups. In conclusion, addition of sprints in moderate intensity continuous exercise causes muscle oxidative adaptations in trained male individuals which appear to be independent of the exercise-induced PGC-1α mRNA response. Interestingly, time-trial performance improved similarly between groups, suggesting that changes in content of mitochondrial proteins are of less importance for endurance performance in trained males.
KW - Faculty of Science
KW - High-intensity interval training (HIIT)
KW - Human performance
KW - Metabolic stress
KW - PGC-1a mRNA
KW - Skeletal muscle single fibers
U2 - 10.14814/phy2.13976
DO - 10.14814/phy2.13976
M3 - Journal article
C2 - 30793541
VL - 7
JO - Physiological Reports
JF - Physiological Reports
SN - 2051-817X
IS - 4
M1 - e13976
ER -
ID: 213856247