Velocity

Static

Also called "isometric", static exercises involve holding a position for time, with no movement and no change in muscle length.

Dynamic

Dynamic exercises involve contracting the muscles (concentric phase) and extending them back to their starting position (eccentric phase) in a cycle. One cycle counts as one repetition.

Explosive

Also called "plyometrics", explosive exercises involve a rapid change in muscle length, such as when jumping or throwing.