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Can Stretching Do More Harm Than Good?

  • By Paul Moore
  • Published August 26, 2009

Stretching is good for you, right? Everyone knows that. Well, according to Matt Allyn conventional theories on stretching might be doing you more harm than good.

Think twice before you do your next 10-second toe touch. A more flexible body isn’t a faster one. New research shows that having a greater range of motion is linked to less efficient running. Researchers at Nebraska Wesleyan University recruited eight of the school’s top distance runners and compared their flexibility with their running economy.

The athletes gauged their flexibility with a sit-and-reach test and then had their oxygen intake measured against their effort on a treadmill. Less flexible runners used the least amount of oxygen while running.

So, within a group of equal-ability runners, the least flexible will be the fastest. That’s because their muscles store more elastic energy, explains lead study author Tamra Trehearn, PhD. When you run, your muscles act like rubber bands. As each leg swings forward, your hamstrings lengthen beyond their normal resting length, which adds tension to them.

Then, when you pull that leg back, all the elastic energy you’ve built up releases and adds to your total muscle power.

But when you do a lot of stretching to increase your range of motion, your hamstrings lose some of that elastic recoil, so they contract with less force and generate less power. They’re like a rubber band that has been stretched to the limit over and over. It’s now longer than it used to be, but less elastic.

Having a shorter range of motion is a good thing for triathletes, says Michael Yessis, PhD, an exercise science expert and the author of Explosive Running. Also, by stretching muscles around a joint, you loosen it, making it harder for your muscles to protect the joint, says Yessis.

Before races and before run workouts are the most important times to avoid certain stretches. Recent research on the effect of pre-exercise stretches on performance has accumulated. These studies demonstrate that stretching hurts performance in short duration, explosive efforts such as sprinting.

That means that when you’re hitting the weights or performing a speed workout, you shouldn’t stretch beforehand. Even in a race situation, stretching 20 to 30 minutes before the gun could give you a slower start.

However, not all stretches will slow you down or hurt you. The culprit we’re talking about here is static stretching—think reach-and-hold exercises. Dynamic stretches can be a great way to warm up and reduce muscle tightness. Instead of simply pulling at muscles and ligaments, dynamic stretches engage muscles through your normal range of motion.

Holding a lunge position is an example of a static stretch for the hip flexors. The dynamic version of that stretch is a set of ten walking lunges. And there’s as much research supporting the effectiveness of dynamic stretching as a tool for priming the muscles to perform as there is research to dissuade you from doing that next 10-second toe touch.

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Paul Moore

Paul Moore

Paul Moore is the Online Editor for Triathlete Europe. When not glued to a computer he can be found writing books - most recently Ultra Performance: The Psychology of Endurance Sports and The World's Toughest Endurance Challenges. Both are available on Amazon. Paul has also written Ultimate Triathlon: A complete training guide for long-distance triathletes which is also available on Amazon.