Stretching to prevent injury works on two levels. The first is a warm type stretch which will increase circulation and bring blood to muscle you intend to use. The second is greater overall flexibility can reduce injury frequency. I will discuss this under the improved flexibility goal. A warm up stretch is of course best done before any vigorous exercise. The type of stretching is the key. Static stretching, eg the sit and hold a pose, is not the best choice before exercise. When your muscles are cold they have less flexibility and blood flow. You won't gain much in terms of flexibility stretching cold, and you won't get the blood flowing in a static posture. Dynamic stretching is best pre-exercise. Leg and arm swings anterior/posterior and lateral, shoulder shrugs, high knees and leg kicks are all good examples of dynamic stretches. Focus on the muscle groups you intend to use, start slow and build up intensity for 5 to 10 minutes.
Stretching to improve flexibility comes in different forms. Many people think of yoga or ballet and the extremes of flexibility. Increasing your flexibility can reduce injuries, up until a point. There is a trade off of strength for flexibility. Think of it as a bell curve, or inverted U curve. Inflexible people are prone to injury because their limit of flexibility is low and they push their boundaries easily. Extremely flexible people can give up strength for more range at their end limits which can lead to injury as the muscles become a larger portion of stability than the joint capsules and ligaments. More is not always better. That said, extreme flexibility is far less of an issue than limited flexibility. The best time to increase flexibility is when muscles and ligaments are already warm. Traditional static stretching will receive the most benefit following exercise. Balance is key, if you stretch your hamstrings, stretch your quads as well. Also, do not stretch into pain. Dynamic stretching such as during a yoga class is a great way to increase flexibility. If you have attended a class before you may have noticed that they generally start out light and build in intensity. The most vigorous stretching is near the end where you will get the most benefit. Yoga also incorporates balance work, which I personal feel is a great attribute to improve. Consistency is important which ever method you choose. If you stretch once a week then you may see benefits a year later. If you stretch 3 times a week or do a 40 day yoga challenge you may see benefits much more quickly. Everyone's body composition is unique and will progress and different speeds.
Stretching is a vital component of recovering from injury. After an injury your body lays down scar tissue to hold together the damaged tissue. Initially scar tissue is disorganized and has a random arrangement. Movement breaks through that randomness and helps your body remodel the scar tissue to have a similar function to the tissue it is replacing. It is best to stretch without pain and at a mild or moderate level. The key for injury recovery is consistency. Stretching 3 or 4 times a day will help the tissues regain their former flexibility. It is an organic process that can take up to a year or more depending on the age and severity of the injury. Chiropractic care can facilitate this process by breaking scar tissue in difficult to stretch areas.
Dr. Nelson