A while back I wrote a blog on stretching where I discussed the benefits of dynamic stretching in terms of warm up and injury prevention and the limitations of static stretching.
I have just discovered some new research that further condemns static stretching.
Before I discuss that I want you to think about why we stretch in the first place?
What is the point of stretching?
Most peoples reasons for stretching fall under three different categories. They stretch because they want to improve their flexibility, reduce or prevent injury or reduce post exercise soreness.
As mentioned in the previous blog on stretching there is no research at all that suggests stretching helps reduce post exercise soreness.
That leaves us with increasing flexibility and reducing preventing injury.
What do we mean when we say increase our flexibility? The answer will vary for everyone but in general we want to increase our flexibility so we can move more effectively and efficiently. We tend to notice our lack of flexibility when we go to pick something up off the floor or duck under something or twist around to reach for an object. Essentially we want to have more flexibility when we move.
Stretching to prevent injury is probably the number one reason for stretching. Often injuries can be caused a muscle becoming so tight that it starts to strain or tear.Other times a tight muscle can place strain on other muscles overloading them causing an injury. Either way if we can maintain or improve our range of movement when we move we can prevent either scenario from occurring.
Improving active range of movement is the primary motivation for most people to stretch.
What other range of movement is there you might ask?
Active and Passive range of movement
The opposite to active range of movement is passive. Passive range of movement is the range of movement you have when somebody or something is helping you create the movement. For example if you are lying on your back and you use your hands to try and lift one leg up off the ground as much as possible that is passive range. If you stand on 1 leg a kick your leg up as high as possible that is active range.
Unfortunately the two dont correspond. Your active range of movement can be far less than you passive range of movement as a study published in the Journal of Sport Rehabilitation, 18(4), November 2009 discovered.
The study measured the effect that static stretching of the calf had on the range of ankle dorsiflexion during walking. Dorsiflexion is what happens in your ankle when you stretch your calves.
The study compared two groups , one that stretched their calves regularly over a three week period and another did no stretching. At the end of the three week period the group that stretched their calves had no more dorsiflexion when they walked than the group than the group that didn't. They did improve their passive range of movement however.
So static stretching has no benefit if we want to improve the range of movement of a joint when we move. Obviously we can only infer from this study that a 3 week calf stretching program has no effect on dynamic flexibility of the calf muscle, it may have been different if they stretched for more than 3 weeks and other muscles may act differently but if it takes more than 3 weeks to produce ANY improvement in a active joint range of movement then it could take a very long time to see an appreciable difference.
So if static stretching has no effect on active range of movement what does?
You may also be asking yourself why if your passive range of movement increases doesnt your active range increase as well.
The answer to the first question is relatively straightforward. Dynamic stretching is not only a far better way to warm up compared with static stretching it is also a far better way to improve active range of movement.
As to why passive range doesnt equal active range, it comes down to safety. The body wont give you an increased range of movement unless it is confident it can control that increased range. In much the same way as the bigger the engine in a car the better the brakes need to be. The body will only give you whatever range of movement it feels it can control without risk of injury. To increase that range we need to give the body the strength to control that additional range. This is why dynamic stretching is so much more effective, dynamic stretches teach the body to both increase the range of movement and give it the strength to control the movement
Is static stretching a waste of time?
There are some situations where static stretching may still be useful. Recovering from injury is one. When muscles tear the body lays down scar tissue to repair the damage. This scar tissue is not laid down in the same direction as the muscle fibres and needs to be be gently stretched to reallign it with the muscle fibres.Static stretching is good for this but must be followed by a dynamic stretching program before returning to full function