Mobility is the ability of a joint to move actively through a range of motion.
Mobility is based on movement and motor control.
Flexibility is the ability of a muscle to move passively through a range of motion.
Flexibility is temporary.
You can’t effectively stretch a muscle that crosses a joint with limited mobility.
Proper execution of mobility exercises will improve free movement through a joints full range of motion. When performed consistently mobility training may help correct imbalances, help reduce the risk of injury, and help with the performance of resistance training and free movement.
Mobility movements are ideal to use as a lead in to resistance training as they prepare joints to move through their full range allowing proper form and full range throughout each exercise.
Stretching muscles prior to resistance training may result in decreased performance as stretching muscles sends a signal to the muscle to relax and will have a detrimental effect on the muscles ability to fully contract for maximum strength.
Stretching is most effective post resistance training.