MORE INFO:

In a concentric contraction, the muscle tension rises to meet the resistance then remains stable as the muscle shortens. During eccentric contraction, the muscle lengthens as the resistance becomes greater than the force the muscle is producing.

SOURCE:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899915/#:~:text=In%20a%20concentric%20contraction%2C%20the,force%20the%20muscle%20is%20producing.