Stretching Q & A

I'm not an advocate of stretching as part of training sessions, in particular not as part of the warm-up or during the session. This is a conscious decision from my perspective, preferring dynamic warm-up and dynamic stretching via drills, stride-throughs, etc.

Stretching post-session is a good idea, however, as part of muscle maintenance in the same way as a routine massage - self-massage or from a masseur - is a good idea.

The following is a great Q & A that appeared on a thread on the Coolrunning forum recently. A sports physio was responding to questions posed by other forum members. The answers he gives support the approach I take in relation to stretching...and provide some really great background and reasoning. Thanks to whoever the "SportPhysio" member is!!


Is there any empirical evidence regarding the most efficient stretching routine (as in how long to hold the stretch for and for how many reps)?

There is no evidence to suggest that one set of parameters is more effective than any other. We do know that the longer a stretch is held, the longer the muscle will be in a lengthened state. In saying that, it basically works out that a 5 minute stretch will lengthen the muscle for 5 minutes. So by the time you've stretched your left hammy, the right one has returned to it's original length. This brings us to the inevitable discussion of "what are stretches good for?".

Based on available evidence we know that:

1. Stretches alone DO NOT lengthen muscle except for the temporary change in length mentioned above. They can improve the tolerance of a stretching sensation which can be useful for dancers, hurdlers, etc.
2. Stretches DO NOT prevent injury.
3. Stretches DO NOT prevent/reduce DOMS.
4. Stretches CAN improve motor performance (ie. agility).
5. Stretches CAN improve power performance (ie. jump height, sprint start speed).
6. Stretches CAN help reduce the loss of range after eccentric exercise.

So the message is that stretching can be personal preference, used for one of the reasons above or part of a routine. We shouldn't scrap it altogether based on the injury prevention studies as there are plenty of other reasons to use it, if applicable to the individual.

So taking those 6 points as read then, is there any evidence to recommend dynamic stretching (walking lunges and the like) over warmed-up static stretches? Or is the relaxed feeling I get in my muscles from dynamic stretching purely due to a placebo effect?

Dynamic stretching is certainly more popular and there is some evidence to support it over static stretches. Early research suggested that static stretching actually reduced power performance, although more recent studies suggest that it may improve power. Dynamic stretches have always shown an improvement.

Aside from this, both types of stretches have similar effects as listed above so it comes down to personal preference and specificity to task (eg. AFL kickers can use a dynamic stretch that resembles kicking). As for the relaxed feeling, refer back to rule 1: If it feels good, do it. Placebo or not, it's working for you.

I have been told that I have tight hamstrings - how do I fix this problem if stretching does not lead to increased muscle length? Does stretching increase the flexibility of the muscle (rather than changing its length when at rest)? If this is the case does holding a stretch for 30 seconds increase the flexibility less than holding it for 5 mins?

Have you been told that your hamstring length is inadequate for a specific task or has it just been deemed too short relative to "normal"? Many people can't touch their toes (me included) but never have problems with their hamstrings. This is because some tasks (eg. running) do not require particularly long hammy's. The furthest a hammy would get stretched in normal running is probably less than it would during an every day task such as putting socks on.

"Tight" hammy's is usually a separate issue. In short, the muscle's job is to decelerate the leg as the foot is about to hit the ground and to add some early propulsion after heel strike.

The muscle feels tight due to overactivity or poor motor control. The muscle can get overworked in a runner who is overstriding. Another problem can arise if the hammy is trying to contribute to pelvic stability by bracing. This leads to contradictory roles where it tries to remain switched on all the time to assist stability as well as switching on and off to control leg movement. This leads to a feeling of tight hammy's and is not due to short hammy's.

These types of problems can usually be fixed by technique modification and control exercises. Note that stretching the hammy's can provide temporary relief from symptoms and that hammy strengthening can actually make the problem worse.

So if you wanted to improve flexibility, how do you do it? If stretching doesn't work?

Glad you asked.

Based on current research, we know that:

1. Stretching only temporarily lengthens muscles and
2. Muscle adapts to task.

Therefore we can temporarily lengthen muscle with stretching and then use it in a lengthened position with any task that has the muscle functioning towards it's end range. The muscle should adapt to this new length and become more "flexible".

As an example, a ballet dancer is flexible and stretches regularly. But it's the ballet itself that keeps them flexible; the stretching only gets them accustomed to the stretching sensation.

The same applies to yoga. It's not the stretching but the muscle functioning to stabilise or move the limb towards the end of its range that improves muscle flexibility.