Concentric versus eccentric
If you lifted a heavy pan up from the cooker the biceps would contract concentrically; if you slowly lowered it down again the same muscle would contract eccentrically.
A concentric muscle contraction is one in which the muscle shortens as it contracts.
If you lifted a heavy pan up from the cooker the biceps would contract concentrically; if you slowly lowered it down again the same muscle would contract eccentrically.