Column 38, March 2011

Is a shorter, faster stride beneficial to runners?

I’m sure many of you have heard the debate over the benefits of barefoot running, or wearing minimalist shoes on injury risk. Much of this focuses on the effect both forms of running have in influencing us to run on our forefoot, rather than heel toe, as we tend to do in more cushioned shoes. Several studies show that forefoot landing tends to reduce load rate – the amount of force your body must absorb when the foot strikes the ground – which may reduce injury risk.

Rather than debate the pros and cons of ‘minimalist running’, I wanted to bring to light a new study from the University of Wisconsin which found that runners who simply shortened their stride also reduced load rate and achieved many other positive biomechanical changes similar to those observed when running barefoot or in minimalist shoes.

In this study 45 recreational runners in there early 30’s ran on a treadmill in their usual training shoes, at their normal pace (5:47 per km) and stride frequency (173 strides/min). They were then asked to run with a stride frequency 5-10% below their usual (164-156 strides/min), and 5-10% above (182-190 strides/min) - prompted by a metronome – without altering pace. Forces and motions produced were measured.

Some of their findings:

As stride length decreased (and stride frequency increased) the runners bounced less, landed closer to their centre of mass (ie when the ball of the foot lands under the hip), and produced less braking forces against the ground.
A shorter stride also allowed the knee to do less work absorbing energy. And with a 10% higher cadence the hips also did less work.

The Pose method of running, developed by Olympic Coach and Sports Scientist - Dr Nicholas Romanov - in 1977 (see www.posetech.com), is also associated with a shorter stride length. A scientific trial carried out in 2004 to compare the biomechanical changes during natural heel-toe running with learned midfoot and Pose running found similar results to the study above. With the Pose method there were smaller vertical oscillations (bounce), and lower eccentric work and power absorption at the knee.

Less bounce and braking forces would theoretically mean more efficient running as well as reduced injury risk. Another unpublished trial comparing the Pose method to ‘usual’ running technique, found that the Pose method was associated with a reduced heart rate (10 beats per minute) at the same pace.

Is there an ‘ideal’ stride-rate?

In the Wisconsin study, their runners averaged 173 strides per minute. Increasing this to 182-190 cadence resulted in positive biomechanical changes. Dr Romanov recommends a similar rate of 180-200 strides/min, and suggests that we more effectively utilise the stored elastic energy in our muscles at this high cadence.

Interestingly, coach, author and physiologist Jack Daniels counted runners stride rates at the 1984 Olympic Games, and found that virtually all mid- and long-distance runners had stride rates between 180-200 per minute. Haile Gebrselassie ran at 197 strides per minute when he set the current world marathon record of 2:03:59.

Putting it into practice

Running barefoot or in minimalist shoes seems to automatically shorten up our stride as we try to avoid the ‘ouch’ factor. However, in the Wisconsin study participants did so in their usual training shoes with the help of a metronome.

Start by counting your stride rate. This can be done on easy runs, as the stride rate varies only modestly between slow and fast running (it’s primarily the longer stride that makes you go faster). If you fall below 180 strides per minute, practice taking a shorter stride until you cadence is between 180 and 200.

If you train with music you may be interested in www.beaTunes.com, which can be used to measure the BPM (beats per minute) to all of your itunes songs. You can then make a playlist suitable to run in time with!

Initially runners may feel quite strange adopting this new technique, but researchers suggest that after 2-3 weeks of practising, neuromuscular adaptive changes would have taken place so that it begins to feel normal.

Marnie Oberer.