Is isokinetic eccentric exercise dangerous for the heart?

BACKGROUND: Very strenuous exercises can be performed on an isokinetic dynamometer in order to evaluate the resistance to fatigue of different muscular groups. Good cardiac function is necessary in order to perform these very intensive exercises; otherwise an acute myocardial dysfunction could theoretically appear in predisposed patients.
OBJECTIVE: Our study aimed to observe the cardiovascular impact of a maximal intense isokinetic eccentric exercise performed by a population of sedentary young men.
METHODS: Resting and post-exercise (just after, 3 hours and 24 hours after the exercise) blood samples were taken from 12 young male sedentary healthy subjects. These subjects performed an intense maximal eccentric isokinetic exercise of the quadriceps muscle.We evaluated markers of cardiovascular risk (troponin I, highly sensitive troponin T, NT-proBNP,myoglobin), of inflammation (hsCRP) and of oxidative stress (myeloperoxydase, lipidic peroxides, reduced and oxidized glutathione).
RESULTS: The following observations were made: no significant increase in cardiac (NT-proBNP, troponins) or inflammation (hsCRP) biomarkers; a significant increase in myoglobin, myeloperoxidase, lipidic peroxides, oxidised glutathione just after the exercise.
CONCLUSIONS: No modification in cardiac biomarkers were observed after the maximal eccentric isokinetic exercise. We were thus able to prove that the exercise could be performed without any risk to cardiac function in young sedentary subjects. However, a significant level of oxidative stress was induced by this exercise.