In last week’s article, Introduction To Running Biomechanics, we took a look at the individual components that make up a single stride, collectively referred to as the Gait Cycle.

We considered two phases: the Stance Phase (during which your foot is in contact with the ground) and the Swing Phase (during which the same foot is off the ground). We divided the stance phase up into four stages:

• initial contact - when the foot of the front leg first touches the ground
• braking/absorption - the body making a controlled landing and absorbing elastic energy to use later in propulsion
• midstance - the moment when the supporting leg takes maximum load as the body passes over it
• propulsion - the ankle, knee and hip all extending (triple extension) to push the body up and forwards using the elastic energy absorbed during braking, up to the moment when the foot leaves the ground (toe off). This marks the beginning of the Swing Phase, a passive stretch reflex mechanism that fires the now non weight-bearing leg forwards, until the Gait Cycle for that particular leg starts once again with initial contact.

Although running depends on whole body interaction, being aware of the individual components of the Gait Cycle can help you appreciate how slight modifications to your running form can have a knock on effect that can lead to overall improvement in performance and less susceptibility to injury. The key words in that sentence are your running form.

Despite claims made by marketed running styles like Chi, Pose and Evolution, differences in our biological make-up strongly suggests that what works for one runner will not necessarily work for everybody.

The fact that elite, world class runners possess different running styles strengthens the argument against a one-style-fits-all approach. However, there are some elements common to almost all successful running styles, and it is these that we shall begin to look at in this week’s article.

Initial contact

Over the last couple of years, the rise in popularity for barefoot running and minimalistic shoes has fueled debate over what part of the foot should touch the ground first – the heel, the midfoot or the forefoot.

In the excellent article “Is there an Ideal Footstrike for Runners?,” John Davis puts aside claims made by supporters and opponents of minimalistic footwear and instead takes a look at what scientific studies to date tell us about different footstrike styles.

As you will see from his article, much of the data seems to contradict itself, advantages being uncovered only to later reveal disadvantages. However, what studies do suggest is that the issue is not so much what part of your foot touches the ground first, but how close that initial contact is to underneath your hips, i.e. your centre of mass.

Heel striking

Over the last couple of years, the heel strike (also known as a rearfoot strike) has been increasingly labelled as the chief perpetrator of running injury. This is curious when we consider the results of a study done by Pete Larson at the 2009 Manchester City Marathon. Using a high speed camera, Larson filmed runners at the 10km and 32km points of the race, and later classified them according to their foot strike.

At the 10K mark, his results for 936 runners were as follows:

Heel strike: 88.9%; midfoot: 3.4%; forefoot: 1.8%; asymmetrical 5.9%

At the 32K mark, Larson identified 286 runners of the above runners, displaying the following:

Heel strike: 93% (87.8% were also heel striking at 10k.). Forefoot: 0%

In light of these performance results, how can heel striking be regarded as inefficient?

The answer could well be in what we saw earlier: running efficiency is not so much a question of what part of the foot touches the ground first, but how close initial contact is to underneath the hips, i.e. your centre of mass.

In other words, a heel strike that lands close to the hips and on a bent knee causes no significant over-braking or over-loading to the knee.

It is what coaches often refer to as a “glancing” or “proprioceptive” heel strike and should not be primary cause for concern or preoccupation. This is the heel-strike sometimes seen in elite athletes, a classic example being that of American long distance specialist Mebrahtom “Meb” Keflezighi, silver medalist in the 2004 Olympics men’s marathon, winner of the 2009 New York City Marathon, 4th place in the 2012 Olympics.

Meb Keflezighi in the 2010 Boston Marathon
(Courtesy of Peter Larson)

Overstriding

In contrast to the above is the act of overstriding, where the foot comes into contact with the ground well ahead of the hips.

More often than not with overstriding, it is the heel that strikes first but of more relevance is the fact that, as seen in the photo below, the knee is straight and locked out.

Overstriding is commonly associated with the creation of greater braking forces and excessive impact. Research has shown that a more extended knee contact angle can increase the forces experienced by the body and therefore increase injury potential.

Overstriding runner
(Courtesy of Peter Larson)

An interesting observation of runners who overstride is the fact that they take fewer steps per minute (at a given running speed) than runners who do not over-stride. In other words, they have a lower stride-rate.

In the 2011 paper “Effects of step rate manipulation on joint mechanics during running”, researchers from the University of Wisconsin-Madison investigated whether they could reduce impact forces in runners by increasing their stride rate.

By monitoring load changes following +/-5% and +/-10% modifications to stride rate, they concluded that “subtle increases in step rate can substantially reduce the loading to the hip and knee joints during running and may prove beneficial in the prevention and treatment of common running-related injuries.”

Cadence

Another word for stride rate is cadence. It is measured in strides per minute (spm). You can easily determine your own cadence by counting the number of times your left foot hits the ground whilst running for 30 seconds. Let’s imagine yours was 40. Double that to get the total for 60 seconds (80); then double it again to get the total for both feet (160). Your cadence (for that particular running speed) is therefore 160spm.

A cadence of less than 160spm is typically seen in runners who overstride.

It is important that we make a distinction between jogging and running. Jogging (including warming up) is performed at a lower speed and is bound to involve a lower cadence. Though some one-size-fits-all running styles pitch an optimum cadence that should be maintained at all speeds, even elite athletes are seen to drop their cadence slightly for different running paces.

What cadence should I aim for?

Once again, you have to be careful what you read.

As the subject of cadence has become more main-stream, so too has the emergence of the “magic” optimum stride-rate of 180spm. The reason for this is as follows: at the 1984 Olympics, famous running coach Jack Daniels counted the stride rates among elite distance runners. Of the 46 he studied, only one took less than 180spm (176spm). Daniels also noted that in his 20 years of coaching college students, he never had a beginner runner with a stride rate of over 180spm.

Unfortunately, Daniels’ studies have been misquoted and as a result lead to all too frequent claims that everybody should be running at 180spm. These claims ignore the fact that Daniels noted stride rates of at least 180spm, not exactly 180spm. History clearly shows Haile Gebrselassie running 197spm en route to his world record time of 2:03:59 at the 2008 Berlin Marathon, and Abebe Bikila used a 217spm to become the first man to run a 2:12 marathon (2:12:13, Tokyo 1964).

As was suggested at the beginning of this article, differences in our biological make-up means what works for one runner will not necessarily work for all. If you do one day become an elite distance runner (and we sincerely hope you do!) it is highly likely your race cadence will be over 180spm. However, and this is the important part, your journey to 180spm and beyond needs to be gradual.

The average recreational runner has a cadence closer to 150-170 spm. How quickly you progress and in what direction your running form develops will be affected by factors unique to you – your height, hip mobility, level of general fitness, to name a few.

The safest and most appropriate way to increase your cadence is in the University of Wisconsin-Madison paper we considered earlier: increase your cadence by 5% to 10% at a time.

How do I increase my cadence gradually?

1. Using the counting your steps method described above, determine your current cadence for a speed you would use for a 5km+ race. Let’s imagine it is 160spm. Adding the 5% increase (10% could well be too much of a jump), your new target is 168spm.
2. Start by adding short distances into your runs in which you try to maintain your new target. This can be done through use of a metronome (available from Amazon or downloadable as an app for your phone). Be careful as many of these gadgets still regard 180spm as the “magic” number and will only provide beats of 180spm+. Sites like JogTunes can be used to find music with beats per minute (bpm) to match your desired spm. Otherwise, you can always just monitor your progress with a 30-second one foot count (then multiply it by 4).
3. Practicing your new stride rate on a treadmill can sometimes be handy as you can set the speed to stay the same.
4. Once you have can comfortably run your a 5km+ pace at your new spm (without thinking about it – remember we are seeking unconscious competence), add another 5% and repeat the process.

In next week’s article, we shall to look at some more elements common to successful running styles. In the meantime, if you are a runner who has managed to modify your cadence gradually and seen an improvement in running efficiency, we would love to hear from you. Maybe you have also seen a reduction in injury? Or, maybe you tried to jump straight to 180spm and ran into new problems? Whatever your experience, we are as always keen to hear from you!

Happy Running!

Matt Phillips is a Run Conditioning Coach, Video Gait Analyst & Sports Massage Therapist with over 20 years experience working within the Health & Fitness Industry. Follow Matt on Twitter

References

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