eccentric and concentric

[jay monkey]

wat are eccentric phase and concentric phase when ur workin out

[NotSmall]

Concentric = contracting the muscle/lifting the weight.
Eccentric = relaxing the muscle/lowering the weight.

[bluethunder]

Also,concentric=shortening of the muscle-eccentric=lengthening of the muscle. I might add there is also another principle called isometric action which neither lengthens nor shortens the muscle but the muscle is still activated & has force with no joint movement. Static holds & iso-tension techniques are some examples. Using a wall to support your back to do a bb curl and then holding the arm with no movement is a specific example. Other names are used such as "positives"(concentric) and negatives(eccentric). Increasing strength or breaking platueas can be helped by the proper use of negatives as the 1RM can be increased considerably.