You might laugh but once upon a time I thought if you stretched you would lose the muscle tissue you have built and so I used to leave it. I must add before I go into this post any further and lose my validity, this was before all of my courses and private reading, I was young and very silly for thinking this. Stretching and performing mobility work is a great way to keep seeing results, especially if you pound the heavy weights and want to get bigger. Not only for this reason should you stretch however, and in this post I will explain further why this is the case.
The main reason for stretching is to keep the correct balance in your body to prevent injury and to keep your body supple and being able to move. When you exercise for a short period of time the muscles are shortening due to the tension and load you are putting on them. So in essence, stretching is going to alleviate and relax tight muscles without causing discomfort to you. Think of your muscles like elastic bands because when you stretch one, it will go so far and then return to it's original state. Stretch it too far however and it will snap, just like your muscles, so ensure you follow a good stretching program.
When To Stretch
Your stretching routines should be as regimented as your training, so doing some at the start and the majority at the end is key in my opinion. Depending on where you're at with your flexibility will determine how long you should spend stretching and what type of stretches you should perform. I believe you should do some stretches/mobility work before your workout and then again after to relax the muscles.
A good class to attend once a week (or more) is a yoga/pilates/body balance class which is focusing on stretching and keep you supple.
Dynamic and Static Stretches
These types of stretches will help keep you mobile and supple when performing vigorous workouts. These are different types of stretches you can utilise within your very own program depending on what you think is best. Dynamic stretches are generally best before a workout as they mimic the moves you are going to perform. Static stretches are best performed when warm and they will help improve your general flexibility. Both in my opinion are worthwhile and have there own place within your routine, be sure to use them both.
How Long Should You Stretch?
Stretch as much as you can, you can't stretch enough in my opinion. Most of your emphasis is on training and getting your physique in good shape which is ideal, however make sure you spend time on the stretching side. 15 minutes twice a day is a great start, I recommend doing this around your training when you're warm so that you get the full benefits.