“In an exercise that involves a range of motion—not a static hold like a plank—the muscles undergo a shortening and lengthening phase,” says fitness trainer BB Arrington, NASM-CPT. “The shortening phase is called the concentric phase, the lengthening or lowering phase is called the eccentric phase.” In the concentric stage, your muscle is shortening, says Danielle Gray, NASM-CPT, and founder of Train Like a Gymnast. Some examples of this motion include pressing yourself off the ground during a pushup, standing up, and extending your arms overhead. On the flip side, “An eccentric exercise is one that focuses on the lengthening of the target muscle,” says Gray. This includes the lowering phase of a pushup, or slowly returning to the ground during a Pilates roll-up. Eccentric movements are also thought to cause more muscle damage, says Gray, which is necessary for muscle building. “Some people like to incorporate eccentric-only training,” says Arrington, “or finish a set eccentrically, which is where they have a partner help lift the weight up and they lower the weight down with control.” That said, it is important to note that eccentric movements are known to leave you more sore than concentric-focused workouts, says Arrington. “However, don’t let the soreness discourage you from making greater use of them in your workouts.” As for eccentric training specifically, it’s imperative to engage your muscles as much as possible, says Arrington. “Oftentimes, when performing an eccentric movement, the client will do the minimum work possible to lower the weight, instead of contracting the muscle as much as possible to lower it down slowly and controlled.” And while you can separate concentric and eccentric training for more focused workouts, ultimately, both movements are important to your overall fitness. “In sport or in everyday life, we move in various patterns, lifting, lowering, and holding; from picking up your child (concentric), to lowering them down carefully in the crib (eccentric),” says Arrington. “It’s important to give attention to each to build our strongest most capable selves.”
