By Dr. Aaron Case BSc, DC (November 2006)
Preventing injuries by stretching depends on how and when you stretch.
Stretching: Friend
Prolonged (static) stretching may increase the efficiency of your running.
Prolonged (static) stretching can result in an increased tolerance to stretch in the long term along with a potential increase in strength.
If you do prolonged (static) stretching, try to do most of it after or separate from your run because of the reasons outlined below.
You can also try dynamic stretching (example: strides) after a slow run/walk prior to your run.
Stretching: Foe
Stretching is a form of micro-trauma to the muscle/tendon and therefore may weaken and/or pre- aggravate a muscle/tendon prior to a run ESPECIALLY if the stretch is held for any prolonged period of time (i.e. more than 10-60 seconds depending on the runner). In other words, the longer the stretch is held before exercise, the more likely the potential for injury/weakness.
Since running uses the elasticity and stiffness of a muscle to spring or recoil passively, a certain amount of stiffness creates a conservation of energy. Some elite runners will avoid excessive stretching to maximize their stiffness and elastic recoil, to avoid having to “muscle” their way through each run. The trade off is that this stiffness may predispose them to certain injuries.
For stretching definitions check out this website.
