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Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31 P ‐ MRS
Author(s) -
Yoshida T.,
Abe D.,
Fukuoka Y.
Publication year - 2013
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12081
Subject(s) - phosphocreatine , leg muscle , medicine , zoology , physical medicine and rehabilitation , energy metabolism , biology
To investigate the high‐energy phosphate metabolism by 31 P ‐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% W max) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate ( P i ) and phosphocreatine ( PCr ) peaks were determined. During the 5‐min recovery following the 60% W max, 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 P i to PCr ( P i / 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.