MR-compatible pedal ergometer for reproducible exercising of the human calf muscle.
A pneumatic MR-compatible pedal ergometer was designed to perform dynamic contraction exercises of the human calf muscle in a whole-body 3T MR scanner. The set-up includes sensors for monitoring mechanical parameters, such as pedal angle, cadence as well as applied force and power. Actual parameter values during the exercise were presented to the volunteer as a visual feedback to enable real-time self-adjustment of pedal deflection and cadence to the target reference value. Time-resolved dynamic (31)P-MR spectroscopic measurements of phosphocreatine (PCr), inorganic phosphate (Pi) and pH were performed in a pilot experiment before, during, and after the exercise by a single volunteer. Two different load strengths were applied in these experiments (15% and 25% of the maximum voluntary contraction, MVC). As expected, mechanical and metabolic parameters differed for the two load levels. Small variations of the cadence, power and metabolic changes (time constants of PCr depletion and Pi accumulation) during the experiments demonstrate a highly reproducible mechanical output by the volunteer mediated by the ergometer.
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany. Electronic address: kevin.tschiesche@med.uni-jena.de.
Kevin
K
Tschiesche
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany; Medical Engineering and Biotechnology, Jena University of Applied Sciences (EAH Jena), Germany.
Markus
M
Rothamel
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany.
Reinhard
R
Rzanny
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany.
Alexander
A
Gussew
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany.
Patrick
P
Hiepe
Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Germany.
Jürgen R
JR
Reichenbach
D004734:Energy Metabolism / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D016552:Ergometry / Q000295:instrumentation*; D006801:Humans; D007866:Leg / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010710:Phosphates / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D014584:User-Computer Interface; D055815:Young Adult
D010710:Phosphates; D010725:Phosphocreatine
Calf muscle; Ergometer; Magnetic resonance spectroscopy