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Zillagreybeard 3 years, 10 months ago.
What do we need to know about eccentric & concentric contraction?
Discussion in 'Training' started by Zillagreybeard, Sep 10, 2021.You must be logged in to reply to this topic.
DeusChem replied 3 weeks, 6 days ago
Kristenmitchell replied 4 weeks ago
DominicThomas replied 1 month, 1 week ago
What do we need to know about eccentric & concentric contraction? ⭕️
When we normally exercise with weights, we typically perform both contractions by lifting and lowering the weights..
When the muscle fibers shorten during an exercise contraction, like hamstrings when lifting the barbell from the ground in a deadlift, or the pectoralis muscles during the lifting part of the bench press.. these muscles are performing a “concentric contraction”.
The force produced during concentrics comes from the Active Elements, aka the contractile machinery found inside each muscle fiber, that allows contraction: Actin & Myosin cross bridges.
On the other hand eccentric contractions occur when the muscles lengthen under load: For example the hamstrings during the lowering part of a RDL, or the pectoralis muscles during the lowering part of the bench press.
The force produced comes not only from the Actin & Myosin cross bridges, but also from the passive elements that produce force by resisting deformation: such as Titin [1].
This allows greater force production during the eccentrics (up to 25-30% more weight!) that can be used to maximize hypertrophy through eccentric overload blocks.
Even though overall increases in muscle volume are similar, recent research has shown that eccentric-only strength training causes greater gains in muscle fiber length, while concentric-only strength training leads to greater increases in muscle fiber diameter. [2]
When deformations occur that involve temporary increases in length and reductions in diameter (as during eccentric-only strength training), this stimulates the fiber to grow in volume by increasing in length. This effect might be mediated by titin sensing the stretch that is imposed upon it, when the fiber is deformed longitudinally.
When deformations occur involving temporary increases in diameter (by bulging outwards in the middle of each sarcomere) and reductions in length (as during concentric-only strength training), this stimulates the fiber to grow in volume by increasing in diameter.