Almquist, Nicki W

Bangsbo, Jens

Christensen, Peter M

Christiansen, Danny

Skovgaard, Casper

Thomassen, Martin

Physiological Reports

The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO2 -max): 56.4 ± 4.6 mL/min/kg) completed a 40-day intervention with 10 sessions of speed endurance training (5-10 × 30-sec maximal running) and a reduced (36%) volume of training. Before and after the intervention, a muscle biopsy was obtained at rest, and an incremental running test to exhaustion was performed. In addition, running at 60% vVO2 -max, and a 10-km run was performed in a normal and a muscle slow twitch (ST) glycogen-depleted condition. After compared to before the intervention, expression of mitochondrial uncoupling protein 3 (UCP3) was lower (P &lt; 0.05) and dystrophin was higher (P &lt; 0.05) in ST muscle fibers, and sarcoplasmic reticulum calcium ATPase 1 (SERCA1) was lower (P &lt; 0.05) in fast twitch muscle fibers. Running economy at 60% vVO2 -max (11.6 ± 0.2 km/h) and at v10-km (13.7 ± 0.3 km/h) was ~2% better (P &lt; 0.05) after the intervention in the normal condition, but unchanged in the ST glycogen-depleted condition. Ten kilometer performance was improved (P &lt; 0.01) by 3.2% (43.7 ± 1.0 vs. 45.2 ± 1.2 min) and 3.9% (45.8 ± 1.2 vs. 47.7 ± 1.3 min) in the normal and the ST glycogen-depleted condition, respectively. VO2 -max was the same, but vVO2 -max was 2.0% higher (P &lt; 0.05; 19.3 ± 0.3 vs. 18.9 ± 0.3 km/h) after than before the intervention. Thus, improved running economy with intense training may be related to changes in expression of proteins linked to energy consuming processes in primarily ST muscle fibers.</p

Christensen, Peter Møller

Almquist, Nicki Winfield

Copenhagen University Research Information System

English

Effect of speed endurance training and reduced training volume on running economy and single muscle fiber adaptations in trained runners

Victoria University Institutional Repository (VUIR)

Casper Skovgaard

Danny Christiansen

Peter M. Christensen

Nicki W. Almquist

Martin Thomassen

Jens Bangsbo

Crossref

Victoria University Eprints Repository

https://curis.ku.dk/ws/files/189662350/Skovgaard_et_al_Physiological_Reports_2018_Vol_6_3_e13601.pdf

Effect of speed endurance training and reduced training volume on running economy and single muscle fiber adaptations in trained runners

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Copenhagen University Research Information System

Victoria University Institutional Repository (VUIR)

Crossref

Victoria University Eprints Repository