Minimal shoes not the same as barefoot

Earlier in the year a study by Bonacci et al was released that compared the mechanics of barefoot running to that exhibited running in the Nike Free 3.0, Nike Lunar Racer and a traditional self selected running shoe. The runners in the study were highly trained and fast – averaging < 34 minute 10km ability. Runblogger Pete Larson did a great job of summarizing the study in his article so I won’t repeat too much of what was covered.

I took a keen interest in this work for the useful objectives of the study and because one of the contributing authors was none other than Dr Philo Saunders, who a few years ago was kind enough to write the foreword to my book. It was Philo that got me interested in running in Frees, although it took a bit of convincing given all the negative things I’d heard about them from various sources. More on that below.

It’s the little differences

The bottom line was that joint angles and forces were different between the barefoot and shod running conditions, with the Nike Free 3.0 having more in common with the traditional shoes than barefoot running. This seems to stand in contrast to a lot of advice runners are given about the Free and how potentially dangerous it is to run in.

The Free 3.0 has some cushion and is built on a 4mm ramp from heel to toe. It’s not the shoe I’d usually suggest that runners try if they’re keen to dip their toes into the Free water so to speak. Usually I’d start with the 5.0 or the 4.0 depending on the fit. So I was very interested to see that even this relatively minimal platform didn’t present as being a great deal different to running in regular trainers.

Nike Free 3.0 version 3 by running technique tips

In a way it reenforces my view that Frees are just another running shoe with slightly different properties. There’s no doubt if you’re unfamiliar with Frees and very heavy on your feet they can present some challenges, the cushion isn’t as forgiving as some plushly padded shoes you might have been more used to.

Adopted sensibly and slowly Frees can become another shoe you regularly wear. For some runners this might be for short jogs on grass, strength training, walking or for doing some running drills for others they could be part of the mix for easy and longer runs. One runner we helped some time ago ran a sub 3 hour marathon in his Free 3.0s and refused to wear anything else in training.

Time to update the marketing?

After this study was released I wondered if shoe companies would re-examine their marketing spin on a wide range of minimal shoes that are often described as barefoot-like or providing a barefoot experience. I’m more comfortable with the promotion of particular shoe models providing different properties such as flexibility and feel for the ground.

Some people might be disappointed with the finding that their relatively minimal shoes are not providing a barefoot ride. Personally I’m happy because I know that I and many runners don’t do as well if we forgo all cushioning and a bit of ramp in our shoes.

It’s interesting that many runners skipped shoes like Frees and went straight to barefoot running or zero drop zero cushion. I’m happy for those that can pull off that big jump, but for me and many others there are risks to be considered before making such a big leap.

Spreading the load

As an aside, earlier in the year I visited and blogged about a clinic in Melbourne that offers use of the Alter-G anti gravity treadmill to the general public. While I was recovering from the sensory confusion of running inside the confines of the Alter-G I had the chance to try out another piece of kit they had onsite. Where do they get those wonderful toys?

The Zebris treadmill is a device that took a range of measurements on foot alignment, rotation, stride rate, stride length, progression and I’m probably getting this wrong, but also a distribution of pressure on different parts of the foot. This treadmill had the capacity to measure lower leg and foot movement and produce a pressure map that shows the distribution of pressure across the foot.

Why is this relevant? Well I took the chance to run barefoot and then compare the results with running in a cushioned zero drop shoe – the Saucony Virrata. Not a shoe I’d describe as providing a barefoot experience at all.

Saucony Virrata Production model side view

You can see the impact of the shoe cushion on the distribution of pressure in the images below. I wouldn’t describe myself as an experienced bare footer but I have done a bit of unshod running in the last two years. Mostly I’ve stuck to running on softer surfaces and looking at the readouts below that is exactly what I’ll continue to do. When the weather warms up of course!

Barefoot imprint & Virrata

LHS Barefoot RHS Saucony Virrata

This pressure distribution suggests to me that I should be cautious about the quantity of any barefoot running that I do and also be mindful of sticking to surfaces where there is a little inherent give i.e. grass.

Stride length and cadence

Some of the other readouts from the treadmill tend to support other research and barefoot running anecdotes. Stride length was 6cm shorter barefoot at 254cm versus 260cm wearing the Virrata. Stride rate or cadence was 184 versus 179 steps per minute. I think I was running at about 14kph, which is just a bit slower than 4 minute kilometer pace.

Interestingly the stride length and rate of the elite runners in the study was 294cm barefoot versus a touch over 300cm in footwear. They were running faster, over 16kph, but there’s a big gulf in stride length while maintaining higher cadence 188 barefoot versus 184. That’s talent for you.

Other useful insights

Pretty much anytime you get some more information about your running it helps build knowledge and sometimes understanding. I think the most useful piece of information I received was an indication that certain things I’d been practicing were leading to my feet pointing a touch inwards, producing a moderate pigeon toed impact – not what I was seeking to achieve.

There were various other asymmetries (unevenness between left and right) identified which were interesting but not necessarily significant. Pretty much everyone is uneven and whether it is a problem or not is likely a judgement call from someone smarter than me.

Certain asymmetries may also be fine for a particular volume or intensity of training but cause grief when you venture into unchartered training waters – such as building up for your first marathon.

Conclusion

I don’t have any major pearls of wisdom that flow from this post but two things seem worth summing up. The first is that Frees and other relatively minimal shoes cannot be considered to be the same or similar to barefoot running.

However, this isn’t an invitation to treat a Free or a Virrata for example as being the same as your favourite more traditional trainer – any change in form or equipment will impact your body and cause forces to shift about. Proceed cautiously.

It does however suggest to me that these moderately minimal shoes are not such a big step away that they should be considered as dangerous as the Black Snakes that keep visiting my garden at the moment! It’s all relative to your personal situation.

The second thing to consider is that if you are seeking to make changes to technique or take up barefoot running it’s a good idea to get some objective outside analysis to check that what you’ve been working on isn’t producing undesirable impacts.

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