If stretching is done during the cool-down, it can the muscle 1- increase flexibility 2- decrease flexibility 3- prepare for activity

1. increase flexibility

Explanation:

    After a strength or cardio workout, your muscles will be warm, which  makes them more elastic and flexible. This is the best time to work on your flexibility.  Although stretching is not directly related to injury prevention as many people believe - ideally for this, it is warming up before starting a workout - it is effective in reducing or treating pain after training.

   This is because stretching helps the muscles relax and lessen the tension caused by exercise.  In addition, it helps maintain higher blood circulation in the muscles, which increases oxygen and nutrient “delivery”, thus favoring recovery.