Dynamic stretching uses controlled movement to take joints through progressively larger ranges of motion. Leg swings, walking lunges, arm circles, hip openers.
Mechanism: Raises core temperature, increases synovial fluid viscosity, activates the nervous system for performance. Unlike static stretching, it doesn't transiently reduce force output.
Use case: The first 5-10 minutes of any training session. Replaces the static hold-and-wait warmups that hurt power output.
Caveats: Static stretching has its place (after training, for chronic stiffness), just not before performance.