Well Thanks for the answer. What I observed was the eccentric phase only controls the speed of flexion (as the subjects were asked to maintain a uniform speed). Hence the sEMG amplitude was less then concentric phase. Please note that I observed the very same muscle during concentric and eccentric phase, and the task failure depend on inability to extend the elbow.

Unfortunately, the experiment had already been performed and I cannot measure the blood flow or any other thing. My question was whether it is important to assess the eccentric phase also? what is extra information the eccentric phase contain which concentric phase don't?

Dear Jawed,

this is a very relevant aspect. I think the eccentric phase is worth to analyze although fatigue-induced differences are smaller. See Article Muscle fatigue during concentric and eccentric contractions

As during the eccentric phase the preactivated muscle is stretched and thus, the muscle mechanic is far different from the concentric contraction mode, the changes in EMG may code informations beyond the regular ones obtained in the concentric mode of action.

Regards,

Ramona

Thanks Dr. Ritzmann,

I am looking into the article. Thank you very much for the summary as well.

ecc can be seen in function of con. So a faster ecc triceps extension can gain momentum for the con phase. IT also has more elastic energy and more use of connective tissue that can also be used. It all depends on how the exercise is done.