Sports Medicine: Quite a stretch of a theory

There are several studies that reported that stretching does not help prevent injuries.

By YONATAN KAPLAN
There is some research that supports the claim that stretching is effective at reducing injuries.
Such an opinion maintains that stretching prevents injuries because it increases the flexibility of muscles, which makes muscle contractions smoother, thereby reducing injuries.
Others have found that stretching was also effective when it was when it was combined with a warm-up.
Some scientists recommend that stretching is most effective when done within 15 minutes of engaging in physical activity.
Another study has found that stretching helps to lower the risk of musculotendinous injuries.
Conversely, there are several studies that reported that stretching does not help prevent injuries. One study found that general fitness was more important in injury prevention than stretching.
When it comes to stretching itself, some studies have found that stretching can actually hurt muscle strength and reduce power.
Other scientists discovered that when stretching was added after warming up, it did not lower the incidence of injuries that resulted from overuse.
The extra flexibility in rangeof- motion was reported to not be as beneficial as initially thought, and was found to lead to injury as well as to impede performance.
Six different investigations found that static stretching did not reduce the prevalence of injuries caused by exercise and only one found that it helped reduce them.
Another researcher testified that when stretching is done either before or after physical activity, it does not aid in the prevention of muscle soreness and did not reduce the risk of injury.
Among the postulated reasons that stretching before exercise would not prevent injuries are the following: 1. In animal studies, it was found that when muscles were heated up (for instance, by a hot pack), this resulted in tissues rupturing more easily.
2. Certain activities (such as jogging) do not require extremely long muscles so stretching is unnecessary.
3. Most often, muscle strain occurs during activities that put pressure on the muscles, forcing them to elongate, such as slowly stepping down off of a step.
4. Stretching has been found to bring about damage at the cytoskeleton level.
One of the biggest problems with the literature on stretching is that many studies contain fatal design flaws.
Many of them did not distinguish between the types of physical activity performed when they examined the effect of stretching on injury reduction.
This is an important factor that should not be overlooked.
One researcher found that when studies differentiated between different types of physical activity, the effect of stretching depended on the type of activity performed.
For instance, certain activities such as gymnastics or dancing require stretching beforehand and therefore, stretching led to an increase in performance capabilities.
However, for activities such as jogging or cycling, which require less flexibility, there was found to be no positive effect of stretching. (It should be noted that there wasn’t a negative effect found either.) While some studies did not distinguish between the type of physical activity performed, others found that several studies did not differentiate between type of injury incurred.
This factor is also extremely important. Many studies did not differentiate between sprain, strain, overuse injury.
All of this makes information from studies rather confusing and therefore it is problematic to draw conclusions from faulty data.
A general conclusion reached by nearly all researchers was that there needs to be more research done in this area to clarify as to whether or not stretching reduces, increases or is ineffective when it comes to injury reduction.
This is one of the most heavily debated issues in sports medicine and while I would wish to give a definitive answer, it appears that it would be more realistic to conclude that more research really needs to be conducted.
Only once there is research that distinguishes between different types of injuries, as well as different types of athletic activities, with proper definitions and carefully constructed investigations, can proper and most importantly, accurate conclusions be drawn.
For the time being it appears that there is more evidence supporting that stretching is not as effective as it commonly thought.
The above information is supplied by Yonatan Kaplan PT PhD (Candidate). Director, Jerusalem Sports Medicine Institute, Lerner Sports Center, Hebrew University.

For further details, e-mail: sportmed@zahav.net.il, call Yonatan at 054-463-9463 or visit www.jsportmed.com