Quesiton:
Is stretching prior to exercise bad for your muscles?

Answer:
The issue of stretching and flexibilty is one under much debate. You will find articles stating both benefits and negatives of stretching prior to exercises. The truth is that real answer is unkown. We do know a few things about stretching before exercise. Firstly, muscles should never be stretched until they have been properly warmed up. This will reduce the risk of pulling or straining muscle and connective tissue. Stretching will reduce the power of the muscle and reduce proprioception (part of the nervous system that place a role in balance and stability. If these muscles are weak and unstable you are at a risk for injury as well as a decrease in performance. If you do stretch before a workout allow 10 minutes for your nervous system to adequately prepare for the work. It is a good idea to stretch muscle that are known for being tight and that should not be used during the workout. For example if you experience tightness in the neck and shoulders while running it is a good idea to stretch these muscles to help relax them.

Some basic guidelines for stretching are make sure you are adequately warmed up. Before a workout or activity it is a good idea to use dynamic stretching to warm up and not effect the nervous systems responce. Static stretching is usually better after a cool down period.

Mike