Hi there,
Lets take each thing step by step.

First Warm Up and Cool Down:

Warm Up, Cool Down and Stretching routines should be performed before and after any physical activity is undertaken.

Warming up before exercise involves a general, low intensity activity such as jogging, walking, skipping or calisthenics, followed by stretching. Cooling down after exercise is similar to warming up and helps the body to recover after exercise.

There is no doubt that time spent on warming up and cooling down will improve an athlete's level of performance and accelerate the recovery process needed before training or competition. As a result the coach/trainers must encourage the athlete/individual to regard the warm up and cool down as an essential part of both the training session and competition itself.

Warm Up:

Muscle stiffness is thought to be directly related to muscle injury and therefore the warm up should be aimed at reducing muscle stiffness.

Warming up should at least consist of the following:
·5 to 10 minutes jogging - to increase body temperature
·10 to 15 minutes dynamic stretching exercises - reduce muscle stiffness
·10 to 15 minutes general and event specific drills - preparation for the session or competition. e.g. for a runner
oLower leg drills
oLeg drills
oTechnique drills
o4 to 8 easy run outs over 30 to 60 metres - focus on correct running technique (Tall, Relaxed, Smooth and Drive)
Dynamic stretches are more appropriate to the warm up as they help reduce muscle stiffness. Static exercises do not reduce muscle stiffness.

What are the benefits of a warm up?

Performance may be improved as an appropriate warm up will result in an:
·Increased speed of contraction and relaxation of warmed muscles
·Dynamic exercises reduce muscle stiffness
·Greater economy of movement because of lowered viscous resistance within warmed muscles
·Facilitated oxygen utilization by warmed muscles because hemoglobin releases oxygen more readily at higher muscle temperatures
·Facilitated nerve transmission and muscle metabolism at higher temperatures; a specific warm up can facilitate motor unit recruitment required in subsequent all out activity
·Increased blood flow through active tissues as local vascular beds dilate, increasing metabolism and muscle temperatures


Cool Down:

Warming down should consist of the following:

·5 to 10 minutes jogging/walking - decrease body temperature and remove waste products from the working muscles
·5 to 10 minutes static stretching exercises- decrease body temperature, remove waste products from the working muscles and to increase range of movement.

Static stretches are more appropriate to the cool down as they help muscles to relax and increase their range of movement.

What are the benefits of a cool down?

An appropriate cool down will:

·aid in the dissipation of waste products - including lactic acid
·reduce the potential for DOMS
·reduce the chances of dizziness or fainting caused by the pooling of venous blood at the extremities
·reduce the level of adrenaline in the blood

With regards to scientific evidences, researches are still going on. I have trained international athletes mainly cricketers and sailors. They have told me that stretching prior to workout does help them to perform better. And stretching during cool down also helps them in reducing muscle soreness. Even though there is no conclusive scientific evidence there are such physical evidences shown by these athletes. So we have to go through our experiences until there is a concrete written proof.

I hope that i was of some help.

Cheers.