The importance of a warm up is to prevent an injury during exercise, you should look at a muscle as an elastic band its tight when cold and you need to move around to warm it up and get the most out of exercise. A warm up stretch is usually a dynamic stretch things like lunging with a twist and arm circles. A great warm up is a good range of motion and getting yourself ready for exercise. Warming up has a variety of different benefits like giving the muscle group being worked oxygen, avoids muscle, tendon and ligament injuries and has many more benefits.
Cool downs are always at the end of exercising after you’ve finished, they are called static stretches an example of these are the cobra pose and overhead tricep stretch. When you exercise your body builds up lactic acid when you cool down your body opens up the capillaries to get rid of this resulting in you feeling less ache than if you didn’t cool down. Cool down stretches increase your flexibility which can benefit you with day to day life or just trying to get into a deeper squat at the gym. It is proven when you cool down it increase blood flow around the body which is vital pre/post workout to give your body the oxygen it needs.