by LaoDan on Sun Jul 03, 2022 11:27 am
Not to speak for Yeung, but eccentric strength is more predominant in one’s leg muscles while descending stairs, whereas concentric strength becomes more predominant while climbing stairs. This translates into how we use our legs in TJQ. Rather than pushing or bracing against the ground in order to push back against (or to ‘resist’) an opponent’s force (equivalent to “climbing stairs”), we train to receive their force into the ground (“loading the spring” or “bending the bows”, i.e. equivalent to “descending stairs”). This can also be used elsewhere in the body and, for example, one can use their arms to receive an opponent’s pressure into our structure (which is maintained like a rubber ball; again “bending the bows”), rather than extending our arms to push back against, or resist, the incoming force.
Eccentric strength is the quality of the muscles that allows us to withstand pressure without resisting, but also while not collapsing. Eccentric strength is lengthening muscles while they are under loads (rather than shortening the muscles under loads = concentric). It is my understanding that eccentric strength is the start of the “stretch reflex” which returns the limb angles back to where they were after being suddenly moved due to the incoming pressure on our structure (like a rubber ball’s rebounding force that will bounce incoming force away, and can be equated with “pengjin”).
While this terminology is not traditional, I do think that it explains physiologically what we are trying to achieve for TJQ. When we resist incoming pressure by pushing back against it, we are relying on concentric muscle contractions. When we receive incoming force while emphasizing eccentric strength, then we are neither resisting (pushing back against the incoming force), nor collapsing. I do think that this is the type of strength that we are trying to develop in TJQ training.