Creatine phosphokinase after submaximal physical exercise in untrained individuals

Prediction of physical performance through muscle enzymes activity

Physical performance deteriorates during strenuous exercise as manifested by a decrease in maximal aerobic power and increased activity of serum muscle enzymes. The relationship between these parameters was investigated in 41 trained subjects during 24 h marches and the following recovery period. Peak O2 uptake and serum activity of creatine phosphokinase (CPK) and glutamic oxalacetic transaminase (GOT) were measured. During the marches there was a simultaneous, significant elevation in serum CPK and GOT activity and a significant reduction in peak O2 uptake. During the early recovery period (24 h) no significant changes occurred in muscle enzyme activity and peak O2 uptake; thereafter (up to 72 h after the end of the march), a gradual decline in enzyme activity levels with a concomitant increase in peak O2 uptake was observed, reaching pre-march values. A "mirror image" relationship between muscle enzyme activity and peak O2 uptake was found during three clearly distinguished phases: a) 24 h march, b) early recovery stage and c) late recovery stage. These findings suggest that muscle enzyme leakage from muscle cells is closely related to the decline in muscular function and aerobic power. Thus, muscle enzyme activity might be a practical measure of physical performance capacity during the early and late stages of recovery from prolonged endurance exercise.

The effect of hydrocortisone on the serum creatine kinase activity of muscles diseases

Intravenous administration of a single dose of hydrocortisone to patients with the Duchenne type of progressive muscular dystrophy, carriers of Duchenne dystrophy gene caused a short-lasting rise of the serum creatine kinase activity. Administration of hydrocortisone also raised the serum CPK activity in some carriers with a primarly normal CPK level. This phenomenon was observed, though to a lower degree, in limb-girdle muscular dystrophy. The serum CPK activity was sometimes increased after hydrocortisone administration in patients with polymyositis and Kugelberg-Welander spinal muscular atrophy. This phenomenon was never observed in the control group or in cases of myotonic dystrophy. The mechanism of this effect of hydrocortisone on the CPK level is still unknown.

The effect of a short burst of exercise on activity values of enzymes in sera of healthy young men

We report the effect of exercise on the activity values of five enzymes in sera as studied in four healthy male volunteers. The underlying purpose of this present study was to produce an increase in the activity values in the sera of selected enzymes found in muscle. Then by observing the decay rate of these enzymes, we computed the inter-individual differences in clearance rates serum half-life) of these enzymes. Blood specimens were collected just prior to exercise, 1 h after excerise, and on eight additional times up to 93 h after exercise. All specimens were assayed on one occasion for activity values of creatine kinase, asparate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase. We found increases in the three muscle enzymes with average increases being: creatine kinase, +116%; asparate aminotransferase, +41%; and lactate dehydrogenase, +32%; all of which remained above baseline values for 53 h or longer. In the case of creatine kinase, a monoexponential decay curve depicted the data (from the 19-h specimen to the 67-h specimen). The calculated "apparent serum half-life" for creatine kinase varied from 38 h to 118 h in the subjects tested.