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Time to step up?

Nurturing

A QUESTION OF CADENCE Runners should get to know their stride rate, or cadence, before deciding whether to increase their steps per minute and by how much.

Health

Andrew O'Brien

A fortnight ago in these pages, we looked at the relative insignificance of foot strike in relation to running injuries. For those who missed it, the simple conclusion was that there is very little to suggest that landing on any one part of the foot is inherently better than landing on any other part. As for many arguments that are presented in black and white, there are actually countless contextual variables that make it impossible to have a definitively ‘correct’ answer. As a result, by getting no real answer, all we get is a new question, in this case; if foot strike doesn’t matter, what does?
All pain is multi-faceted, but for some reason running injuries tend to be seen as entirely biomechanical, an error that needs to be corrected by all health professionals. So, before we even look at the physics of what may cause running injuries, it’s worth considering some of the other variables.
A key factor in the development of running-related pain is a change in load, something that is relevant regardless of the level of experience or expertise an athlete has. In simple terms, if you increase your load too quickly, there’s a good chance you’ll get hurt. In a running context, load can be considered as mileage, intensity and frequency. Increase any or all of those variables too quickly or without sufficient recovery in between sessions and problems may well arise.
Lifestyle load is another factor that is often overlooked. A high stress work environment, combined with poor sleep patterns and being taxi driver-cum-chef for three kids drains a significant amount from the relatively limited pot of energy we have to get through the day, even before training is considered. Many of the top African runners are 100 percent full-time runners, to the extent that many of those with families will move into training camps to remove all external stresses and distractions in the build up to major competitions.
Perhaps our new question should be a Monty Python-esque; if foot strike doesn’t matter, aside from sleep, training load, stress and recovery patterns, what does matter?
From the biomechanical perspective, studies have shown a link between loading rate, stride rate, tibial angle and injury. Loading rate refers to the speed at which weight is loaded onto the foot and leg; stride rate and cadence refer to how many steps are taken per minute; and tibial angle measures the angle of the shin in relation to the ground at impact. All of these variables can be said to be de facto measures of whether a runner is over-striding.
While there is no clear line to define over-striding exactly, the term refers to landing too far in front of the body when running. A runner whose foot hits the ground a long way in front hits the ground harder, increasing the loading rate and typically showing a higher tibial angle. A runner with a low stride rate often looks like they are speed-walking, with the foot again hitting the ground a distance in front of the body.
For a runner, the easiest of these variables to measure is stride rate; count how many steps you take in 15 seconds while running at a comfortable pace, and multiply that number by four to get your cadence.
Elite runners typically run with a cadence in the range of 170-185 steps per minute, whereas recreational runners often exhibit rates in the 150-160 steps per minute range. Increasing cadence by as little as 5 percent has been shown to have an effect on running injuries. It’s worth noting, of course, that just because increasing by a bit is good, increasing by a lot isn’t necessarily better.
Once you know your current cadence, download a metronome to your phone and set it to 5-10 percent higher. Try running at a very easy pace on a treadmill with the metronome playing; if you can run roughly in time with the metronome on the treadmill, try running with the same pattern outside. A tip to bear in mind though: don’t take your metronome out for a long run or the beeping will send you demented!
It should be noted that changing running technique is only useful if it’s necessary, and technique changes will change loading patterns of muscles. Which in turn is a change in training load, and takes us all the way back to the top of the page and begets even more questions.

Andrew O’Brien is a chartered physiotherapist and the owner of Wannarun Physiotherapy and Running Clinic at Westport Leisure Park. He can be contacted on 083 1593200 or at www.wannarun.ie.