Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P-MRS

Authors

  • T. Yoshida,

    1. Department of Regulatory Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
    Search for more papers by this author
    • Professor Takayoshi Yoshida passed away in 2007, and the paper was accomplished by coauthor of Dr Fukuoka.
  • D. Abe,

    1. Biodynamics Laboratory, Center for Health and Sports Sciences, Kyushu Sangyo University, Fukuoka, Japan
    Search for more papers by this author
  • Y. Fukuoka

    Corresponding author
    1. Faculty of Health and Sports Science, Doshisha University, Kyotanabe, Japan
    • Department of Regulatory Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
    Search for more papers by this author

Corresponding author: Yoshiyuki Fukuoka, PhD, Faculty of Health and Sports Science, Doshisha University, 1-3 Miyakodani, Kyotanabe 610-0394, Japan. Tel: +81 774 65 7530, Fax: +81 774 65 6029, E-mail: yfukuoka@mail.doshisha.ac.jp

Abstract

To investigate the high-energy phosphate metabolism by 31P-nuclear magnetic resonance spectroscopy during off-transition of exercise in different muscle groups, such as calf muscles and biceps femoris muscles, seven male long-distance runners (LDR) and nine untrained males (UT) performed both submaximal constant and incremental exercises. The relative exercise intensity was set at 60% of the maximal work rate (60%Wmax) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate (Pi) and phosphocreatine (PCr) peaks were determined. During the 5-min recovery following the 60%Wmax, the time constant for the PCr off-kinetics was significantly faster in the plantar flexion (LDR: 17.3 ± 3.6 s, UT: 26.7 ± 6.7 s) than in the knee flexion (LDR: 29.7 ± 4.7 s, UT: 42.7 ± 2.8 s, P < 0.05). In addition, a significantly faster PCr off-kinetics was observed in LDR than in UT for both exercises. The ratio of Pi to PCr (Pi/PCr) during exercise was significantly lower during the plantar flexion than during the knee flexion (P < 0.01). These findings indicated that the calf muscles had relatively higher potential for oxidative capacity than that of biceps femoris muscles with an association of training status.

Ancillary