Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P‐MRS |
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Authors: | D. Abe Y. Fukuoka |
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Affiliation: | 1. Biodynamics Laboratory, Center for Health and Sports Sciences, Kyushu Sangyo University, , Fukuoka, Japan;2. Faculty of Health and Sports Science, Doshisha University, , Kyotanabe, Japan |
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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. |
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Keywords: | 31P‐MRS calf muscles biceps femoris muscles PCr off‐kinetics time constant |
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