title: Wrist flexor muscles of elite rowers measured with magnetic resonance spectroscopy.
abstract: We used phosphorus magnetic resonance spectroscopy to study skeletal muscle metabolism of trained vs. untrained humans. The forearms of highly trained rowers (n = 10) and age-matched controls were placed in a 1.9-T magnet so that the wrist flexor muscles were placed over a 4-cm transmitting and receiving coil. The subjects performed work by depressing a handle attached to an isokinetic ergometer. Relative concentrations of Pi, phosphocreatine (PCr), and ATP were measured along with intracellular pH. Measurements were made at rest, during steady-state and ramp exercise protocols, and during recovery from exercise. At rest the rowers had Pi/PCr that were not different from control. During steady-state exercise rowers (n = 4) had lower Pi/PCr at the same relative power levels, and the slope of the power vs. Pi-PCr curve was significantly greater than for controls. Rowers (n = 4) also had faster rates of PCr recovery after exercise than controls (T1/2 of 24 +/- 2.0 s for rowers and 47 +/- 8.4 s for controls) when power level was adjusted so that all subjects recovered from the same level of Pi/PCr. During a ramp exercise protocol, the initial slope of the power vs. Pi-PCr curve was greater in three of six rowers compared with controls and at the highest power level rowers had lower Pi/PCr values with less drop in pH. At the end of the ramp test, the same degree of muscle fatigue was associated with much lower levels of H2PO-4 (5.7 +/- 0.70 mM) in rowers compared with controls (13.0 +/- 1.8 mM).(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104.
authors: K K
authors: KK
authors: McCully
authors: B P
authors: BP
authors: Boden
authors: M
authors: M
authors: Tuchler
authors: M R
authors: MR
authors: Fountain
authors: B
authors: B
authors: Chance
mesh_terms: D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010806:Physical Education and Training; D010807:Physical Endurance; D013177:Sports; D014953:Wrist
chemical_list: D010710:Phosphates; D010725:Phosphocreatine