What is "concentric" training?

What is "concentric" training?

John Spencer Ellis (Author, TV Show Host, Trainer and CEO, National Exercise & Sports Trainers Association) gives expert video advice on: What is the most common fitness mistake?; What is the difference between fitness and physical activity?; Why is exercise so important? and more...

Concentric training means shortening of the joint angle by contracting the muscle. I will use the example of the bicep curl because everyone is familiar with that. So if your arm is extended and you shorten it, you are shortening this angle here by flexing this muscle, that's a concentric contraction, and this type of action happens during concentric training. By contrast, eccentric is the elongation and the opening up of the joint space.