Eccentric contractions are contractions of muscles that occur only when the Force necessary to overcome the mass of the weight is greater than a muscle’s ability to do that Work.
As a result, our Eccentric Duration training technique is actually a misnomer, because in Eccentric Duration – abbreviated E-D – we are not subjecting trainees to supramaximal loads. What we are doing is having them begin at the top of the movement and spend the duration of the exercise in an eccentric pattern of movement.
This means lowering the weight through the trajectory of the exercise over the 1-minute work period. Certain muscles will absolutely contract eccentrically, especially if their fascial web is damaged and their contractile ability is limited.
Other muscles will give way to create a lowering phenomenon, but will not truly be in an eccentric contraction. Still others will be used as agonists and may be working isometrically in co-contraction or even working concentrically. The important thing to remember in E-D training is that you begin the exercise at the top of the range of motion and work to improve your body position and range all the way to the bottom.