title: Effects of training at mild exercise intensities on quadriceps muscle energy metabolism in patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  To study the effects of physical training at mild intensities on skeletal muscle energy metabolism in eight patients with chronic obstructive pulmonary disease (COPD) and eight paired healthy sedentary subjects.
  
  
  METHODS
  Energy metabolism of patients and controls vastus lateralis muscle was studied before and after 3 months of cycling training at mild exercises intensities.
  
  
  RESULTS
  The total amount of work accomplished was about 4059 ± 336 kJ in patients with COPD and 7531 ± 1693 kJ in control subjects. This work corresponds to a mechanical power set at 65.2 ± 7.5% of the maximum power for patients with COPD and 52 ± 3.3% of the maximum power in control group. Despite this low level of exercise intensities, we observed an improvement in mitochondrial oxidative phosphorylation through the creatine kinase system revealed by the increased apparent K(m) for ADP (from 105.5 ± 16.1 to 176.9 ± 26.5 μm, P < 0.05 in the COPD group and from 126.9 ± 16.8 to 177.7 ± 17.0, P > 0.05 in the control group). Meanwhile, maximal mechanical and metabolic power increased significantly from 83.1 ± 7.1 to 91.3 ± 7.4 Watts (P < 0.05) and from 16 ± 0.8 to 18.7 ± 0.98 mL O(2) kg(-1) min(-1) (P < 0.05) only in the COPD group.
  
  
  CONCLUSIONS
  This study shows that physical training at mild intensity is able to induce comparable changes in skeletal muscles oxidative energy metabolism in patients with COPD and sedentary healthy subjects, but different changes of maximal mechanical and metabolic power.
authors: Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France. rita.guzun@gmail.com
authors: R
authors: R
authors: Guzun
authors: B
authors: B
authors: Aguilaniu
authors: B
authors: B
authors: Wuyam
authors: P
authors: P
authors: Mezin
authors: C
authors: C
authors: Koechlin-Ramonatxo
authors: C
authors: C
authors: Auffray
authors: V
authors: V
authors: Saks
authors: C
authors: C
authors: Pison
mesh_terms: D000368:Aged; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology; D052097:Quadriceps Muscle / Q000378:metabolism* / Q000503:physiopathology; D012129:Respiratory Function Tests