To Stretch or Not To Stretch


I’ve been stretching before I run for as long as I can remember. I started stretching before runs because my uncle always did and since he was the “adult” runner I knew I did it too. Now I do it because it feels good, and if I don’t stretch before I run I feel like something’s missing.

It’s always made sense to me that stretching muscles before using them will prepare them and help avoid injury. I mean every exercise magazine, website, and blog writes about stretching. And it seems like someone is always tooting a new great stretching technique.

A few months ago I read a piece in Runner’s World about stretching that surprised me.  According to the article published in 2004 stretching does increase flexibility, but this increased flexibility doesn’t prevent injuries. I noted this and kept on stretching knowing it may not protect me from injury, but it still felt good and was part of my pre run routine.

Today while reading Runner’s World online I came across information which may actually make me decide to change my ways. In Amby Burfoot’s blog “Peak Performance,” she writes about a new study published in the Journal of Strength and Conditioning Research that found stretching actually lowered performance in endurance runners. The study “looked at 10 highly fit male runners who were averaging at least 20 miles a week in their training. Before a treadmill test run, they either sat quietly for 16 minutes or did 16 minutes of static stretching exercises. They then ran for 60 minutes on the treadmill–the first 30 minutes at a relaxed pace, and the last 30 minutes as fast as they could.

With stretching, they covered an average of 5.8 km in the last 30 minutes. Without stretching, they ran 6.0 km, an increase of 200 meters or about 3.4 percent. Eight of the 10 runners performed better without stretching; one performed better with stretching; and one performed essentially the same under both conditions. On average, the stretchers hit a max heart rate 5 beats per minute higher than the non-stretchers in the final 30 minutes. In other words, the stretchers were working harder but covering less distance.”

This is amazing. Yes, other studies may show different results in the future. But for now, I think I’m going to try to not stretch before my next long run (20 miles) and see what happens.  Now here’s the real question – what effect does stretching have on blood sugar?

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13 years ago

I like your blog, keep on the good work. BTW – Amby Burfoot is a ‘he’ not ‘she’. I guess we can talk about it on our flight to Amsterdam :)

13 years ago

Wear a heart rate monitor — you’ll see some interesting data in real-time.  The act of getting dressed, lacing your shoes, stretching, all of that is going to raise your resting heart rate (not significantly, but you will see maybe 10 bpm increases).  My guess with the study is that stretching for 10+ minutes got those runners HRs going earlier, therefore starting running at a higher HR (making the rise to max HR all the quicker). Increasing HR is going to eat into your BG, but 10 bpm for 10 minutes is far less significant than 168 bpm for an… Read more »

Katy Killilea
13 years ago

That is really interesting.  Stretching is almost like religious dogma….it’s funny that anyone even tried to question it.  I would bet that stretching affects blood sugar…it seems like EVERYTHING affects blood sugar.

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