Markers of CrAT Protein Activity and Carnitine Availability

• Skeletal muscle acetylcarnitine off-kinetic after one-legged exercise and carnitine acetyltransferase (CrAT) protein content/activity[ Time Frame: MRS+Exercise test day 2 ]
  The correlation between skeletal muscle acetylcarnitine off-kinetic after one-legged exercise and CrAT protein activity will be determined.
• Skeletal muscle CrAT protein activity, from muscle biopsy, and PCr breakdown rate during one-legged exercise[ Time Frame: MRS+Exercise test day 1 ]
  The correlation between CrAT protein activity and PCr hydrolysis/breakdown will be determined
• Skeletal muscle acetylcarnitine formation capacity upon exercise and total carnitine availability in skeletal muscle[ Time Frame: MRS+Exercise test day 2 ]
  The correlation between acetylcarnitine formation upon exercise and total carnitine availability will be determined

This study aims to measure skeletal muscle metabolism in vivo during exercise using the non-invasive MRS technique. Specifically, acetylcarnitine and phosphocreatine (PCr) kinetic will be determined at resting, during exercise and during the recovery post exercise. The target population is adult healthy men, with a wide range of maximal physical capacity.

• Other: Exercise metabolism
  Participants will perform a series of exercises inside and outside the MRS/MRI scanner.

• : CrAT0X
  13 healthy adult men, with a wide range of maximal aerobic capacity will be included. Subjects will be classified as trained, physical active and untrained according to their VO2max. Subject will perform one-legged knee extension and flexion exercise inside the MRS scanner and cycling outside the scanner