When it comes to exercising, many people focus on the concentric contraction, the shortening of the muscle, when lifting weights or performing other exercises. However, eccentric contractions, the lengthening of the muscle, also play a crucial role in building strength and muscle mass. In this article, we’ll explore what happens to a muscle during an eccentric contraction.

Firstly, it’s important to understand the difference between concentric and eccentric contractions. Concentric contractions occur when a muscle shortens as it generates force, such as when curling a dumbbell. Eccentric contractions, on the other hand, occur when a muscle lengthens as it generates force, such as when lowering a dumbbell back down.

During an eccentric contraction, the muscle is still actively contracting, but is simultaneously being stretched by an external force. This external force can be gravity, a weight being lowered, or a resistance band being stretched. The muscle fibers are recruited to resist this external force, creating a controlled stretching of the muscle.

Research has shown that eccentric contractions can produce greater force output than concentric contractions. This is because eccentric contractions involve more muscle fibers and create more tension within each fiber. Additionally, eccentric contractions can produce more muscle damage, which can lead to greater muscle growth and strength gains.

When a muscle lengthens during an eccentric contraction, it undergoes several physiological changes. The muscle fibers are pulled apart, causing small micro-tears in the fibers. This damage is thought to be a key factor in muscle growth and repair, as the body responds to these micro-tears by building new muscle tissue. The muscle also goes through a process called the stretch-shortening cycle, where the stored elastic energy created during the stretch is used to help produce force during the subsequent concentric contraction.

In terms of energy usage, eccentric contractions can be more metabolically demanding than concentric contractions. This is because the muscle fibers must work harder to control the external force while simultaneously contracting. This increased demand on the muscle can lead to greater calorie burn and metabolic benefits.

In conclusion, eccentric contractions are a key part of building strength and muscle mass. During an eccentric contraction, the muscle lengthens while actively contracting against an external force, leading to greater muscle damage, force output, and metabolic benefits. Incorporating eccentric contractions into your workouts can help you achieve your fitness goals and improve your overall health and wellness.