Christensen 2016 J Appl Physiol (1985)

Christensen PM, Jacobs RA, Bonne T, Flück D, Bangsbo J, Lundby C (2016) A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics. J Appl Physiol (1985) 120:1319-27.

» PMID: 26846547

Christensen PM, Jacobs RA, Bonne T, Flueck D, Bangsbo J, Lundby C (2016) J Appl Physiol (1985)

Abstract: The aim of the present study was to examine whether improvements in pulmonary oxygen uptake (V̇o₂) kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age 26 ± 2 yr; mean ± SD) performed six HIT sessions (8-12 × 60 s at incremental test peak power; 271 ± 52 W) over a 2-wk period. Before and after the HIT period, V̇o₂ kinetics was modeled during moderate-intensity cycling (110 ± 19 W). Mitochondrial function was assessed with high-resolution respirometry (HRR), and maximal activities of oxidative enzymes citrate synthase (CS) and cytochrome c oxidase (COX) were accordingly determined. In response to HIT, V̇o₂ kinetics became faster (τ: 20.4 ± 4.4 vs. 28.9 ± 6.1 s; P < 0.01) and fatty acid oxidation (ETFP) and LEAK respiration (LN) both became elevated (P < 0.05). Activity of CS and COX did not increase in response to training. Both before and after the HIT period, fast V̇o₂ kinetics (low τ values) was associated with large values for ETFP, electron transport system capacity (ET-pathway), and electron flow specific to complex II (CIIP) (P < 0.05). Collectively, these findings support that selected measures of mitochondrial function obtained with HRR are important for fast V̇o₂ kinetics and better markers than maximal oxidative enzyme activity in describing the speed of the V̇o₂ response during moderate-intensity exercise.

• O2k-Network Lab: CH Zurich Gassmann M, CH Zurich Lundby C, US CO Colorado Springs Jacobs RA

Labels: MiParea: Respiration, Exercise physiology;nutrition;life style

Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue

Coupling state: LEAK, OXPHOS, ET Pathway: F, N, S, CIV, NS, Other combinations, ROX HRR: Oxygraph-2k

2016-09, MiR05, MitoEAGLE muscle buffer