WARMING UP
t is very important to take time first to warm up properly as keen as you may be to just rush out the door and start running.Running  on a cold ,stiff tense body can lead to injuries. It is one of the most crucial elements of any exercise and you need to make it a habit before each and every run whether you are a beginner or seasoned runner. Warming up also means preparing yourself properly so you can really enjoy your run.It increases the blood-flow around your body and warms up your muscles helping them become more supple and flexible while allowing your body to gradually adjust to your training session. An ideal warm up should be 5-10 minutes till you feel adequately warm. You can now start and do a few stretches although if you don't this is still ok as the body is now warm and the chances of injury greatly reduced As a rough guide you shouldn't feel breathless or unable to talk during a warm-up-if you are ,slow down and adapt an easier pace.

COOLING DOWN
Just as your body needs to be warmed up before your run it needs to cool down again afterwards.A sprint finish followed by a sudden collapse and no movement for hours wont help Stopping suddenly after vigorous exercise can cause all sorts of unearthed side-effects such as cramps, dizziness, and general soreness.Don't sit down, and avoid having an immediate warm shower until you've cooled down properly. cooling down allows your body to return to its pre-exercise state it helps your heart rate and breathing to slow down also and lessens muscle stiffness/soreness.It also prevents blood pooling which can occur after a hard run.As your running session comes to an end slow down your pace for the last 5 mins, then walk.Do not stretch yet until your breathing has returned to normal. As your muscles shorten during exercise it is now important (a must) to stretch holding each stretch for approx 25/30 seconds to give those muscles a chance to lengthen and get back to pre-exercise state.Failure to do this over time can lead to increased soreness, stiffness, cramps, and bad posture. If possible do your stretches lying down on a mat as it allows for a greater stretch to be reached. Hope this helps