Eccentric Action

When we lift weights, there are two primary muscle actions we perform. The concentric (lifting the weight up) and eccentric (lowering the weight down). It is common for people to only focus on the concentric to lift up as much weight as possible for a certain number of repetitions. But we need both a quality concentric and eccentric to get the most benefits.
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A 2017 meta-analysis shows the eccentric (lowering down) part of a lift is at least as important as the concentric (bringing up) for muscle growth [1]. This is in line with a 2009 systematic review by the University of British Columbia [2]. So whenever you lift the weight up, make sure your muscles are controlling the weight down.
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You can also consider slower-than-normal eccentrics as a way to progress in your training while training with limited equipment at home [3]. One study compared a relatively fast (2 seconds per rep with heavier weight) and slow (6 seconds per rep with lighter weight) rep tempo during strength training. Both approaches were effective for gaining muscle [4]. So if you don’t have much equipment at home, slower eccentric reps are a great way to make an exercise more challenging.
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