Jimmy Fallon once said,
"Don't keep reaching for the stars because you'll just look like an
idiot stretching that way for no reason." Turns out he may be
right. New research indicates that the flexibility that is a by-product
of pre-run static stretching may be a biomechanical factor that hurts
running economy, which is a measure of your overall efficiency. Do
something to worsen your running economy before a race or workout, and
you're going to go slower. That's why growing numbers of elites have
eliminated static stretching before their most important runs and
replaced it with a series of dynamic stretching exercises.
A study published in the Journal of Strength and
Conditioning Research in 2009 explains the logic behind the switch.
Researchers at Nebraska Wesleyan University enlisted male and female
collegiate distance runners to complete sit-and-reach tests to measure
flexibility, and then put them on a treadmill to determine running
economy. The result: An increase in hamstring flexibility generally
correlated with a decrease in running economy.
As the researchers
wrote, "[T]he less flexible distance runners tended to be more
economical, possibly as a result of the energy-efficient function of the
elastic components in the muscles and tendons during the
stretch-shortening cycle."
Ralph Reiff, a licensed athletic
trainer and director of sports performance for St. Vincent Hospital of
Indianapolis, has worked with collegiate and elite runners for many
years. He explains that static stretching isn't all bad, but from a
performance perspective, "static stretching causes an inhibition or a
breakdown of the excitability of the muscle tissue." The immediate
effects from static stretching actually include decreased muscle
function.
"To get a good static stretch you are asking the body
on a subconscious level to relax," says Reiff. "From a
muscle-recruitment standpoint, you don't want to turn the muscles off in
a relaxed state prior to asking them to perform. The elastic energy of a
tighter muscle is going to have more recoil and power than a heavily
stretched muscle.
The caveat is that simply eliminating static
stretching won't necessarily increase performance and decrease injury.
This is where dynamic stretching comes in. Rather than standing in one
place and forcing your muscles to stretch, this type of stretching
trains the muscles to warm up and fire the way you want them to through a
series of dynamic movements.
