Warm up and Cool down; it's not a waste of time.

We are all pressed for time and sometimes are trying to squeeze workouts into a small window. The one thing you don't want to do, however is take short-cuts on your warm-up or cool down. Usually we are exercising because we want to improve our bodies, it makes us feel better, healthier. Well nothing can discouraged you more or set you back further than getting an injury.
Your body is an amazing thing, but there are limits to it. When muscles are cold they are stiff, non-pliable, think cold taffy. Cold taffy is hard and just breaks apart. Muscles similarly can pull, tear, or strain. But given time to properly warm up they, like taffy, will more easily bend and stretch to the work you are doing.


So what's proper? Start out with slow movements, i.e. jogging in place,  and increase in intensity for about 5 minutes. Your heart rate should increase with the intensity, pumping needed nutrients to your muscles. Ballistic stretching is best at this point, meaning active stretching, like a boxer jumping around, a swimmer shaking his arms out, etc. Short superficial stretches. Then you are ready to go, hit that workout with intensity and stay safe from injury.
After your workout, assuming you worked really hard, your muscles tend to stay in a state of contraction. This leads to muscle soreness and makes it difficult to begin the healing and rebuilding. The cool down gives your muscles time to relax and stretch back out. A proper cool down is however long it might take for your heart rate to come under 100, and then stretch out whatever muscle group you have been working. Stretching can range from the minimum 10-15 seconds per muscle of normal extension to an extended stretch that will improve flexibility.  If the later is intended make sure to do at least 20 minutes of warm up/ workout. Well that's it, stay safe people!