Muscle XXXX turnover rate during isometric contraction in @entity1 .

@entity1 @entity1734 @entity6546 @entity1295 @entity880 @entity855 @entity3776
@entity855 turnover and glycolytic rates during isometric contraction in @entity1 have been investigated. Subjects contracted the knee extensor muscles at two-thirds maximal voluntary force to @entity1295 (mean +/- SE, 53 +/- 4 s). Biopsies were obtained before and after exercise and analyzed for high-energy @entity6546 and glycogenolytic-glycolytic intermediates. Total @entity855 turnover was 190 +/- 7 mmol/kg dry muscle, whereas the average turnover rate was 3.7 +/- 0.2 mmol . kg dry muscle-1 . S-1. The average @entity855 turnover rate was positively correlated with the percentage of fast-twitch fibers in the postexercise biopsy (r = 0.71; P less than 0.05) and negatively correlated with contraction duration to @entity1295 (r = -0.88; P less than 0.05). At @entity1295 , @entity1734 ranged from 1 to 11 mmol/kg dry muscle (86-99% depletion of value at rest), whereas lactate ranged from 59 to 101. The mean glycolytic rate was 0.83 +/- 0.05 mmol . kg dry muscle-1 . S-1 and was positively correlated with the rate of @entity3776 accumulation (r = 0.83; P less than 0.05). It is concluded that a major determinant of the @entity855 turnover rate is the muscle fiber composition, which is probably explained by a higher turnover rate in fast-twitch fibers; @entity1295 is more closely related to a low @entity1734 content than to a high @entity880 content; and the increase in prephosphofructokinase intermediates is important for stimulating glycolysis during contraction.
