Shoes on track

What shoes do I wear on the running track to maximise my running performance and minimise my injury risk? 

This appears to be a relatively simple and worthwhile question to ask but it is a lot more difficult to answer.  Research, at least valid scientific research into these areas – economy of motion and injury prevalence – is difficult to tie down for the simple reason that there are a huge number of factors being dealt with to come up with two gross composites – less oxygen usage per stride and directly attributable tissue damage.

So lets start with some established facts: running a certain speed using less oxygen is a good idea, it means we have used less energy (as measured by oxygen burnt) to move the body (a fixed weight at that point in time) at a fixed velocity for a fixed distance.  We have become more energy efficient.  This means we should be able to run faster or further or even both as we will have some reserve capacity which we were using but now, because we are more efficient, we are not using.  Progressive training makes lots of different tissues in the body respond to the increasing load and react by adapting their functionality to become better at what they do.  Tendons can become stiffer and store more energy, the number of mitochondria in muscle cells can increase enabling us to burn oxygen more efficiently, we can increase our blood volume causing a better flow of red blood cells to transport oxygen and we can increase the strength of the heart contractions to pump more of our increased blood volume at each contraction, just a few of the examples of the effects of training.  BUT assuming, as is the case, these all take a little time to adapt can we adjust anything immediately to make us more efficient runners?  Well if we rule out external temperature change (the body is a lot more efficient in cooler temperatures than hotter ones, although freezing temperatures don’t work either), running with the wind behind us, or down hill or any other external environmental variable then we are left with what we can wear.

1. Clothing  The body likes a stable temperature environment and a lot of our energy when we run goes into getting rid of heat production.  Wearing clothing that sheds heat maintains a better heat equilibrium and therefore makes the body work more efficiently.  There is also a small resistance effect and if you believe in British Cycling’s marginal gains then you could argue a small drag effect from wearing flappy and baggy clothing.  (Please note we don’t run as fast as cyclists cycle so the drag gains are minimal especially compared to heat loss gains of tight v loss clothing (this may be different if you are running 100m v 10000m)
2. Shoes  Shoes weigh grams.  Racing flats around 150g to 180g per shoe and solid trainers 200+.  I am not going to do the maths but you can work out the ‘work’ {Work = Force = (Mass x acceleration) x displacement (distance) moved} if you want to.  In relative terms a 200g shoe to a 150g shoe is a 25% weight saving which will express itself in energy saving.  And remember the further away from the centre of mass the bigger the impact this weight has on energy cost and shoes sit on the end of our legs.  There has been a lot of recent research, pretty much all of it inconclusive http://www.ncbi.nlm.nih.gov/pubmed/25364479 on the efficiency of barefoot (no weight), minimalist (light weight) and normal (heavier) training shoes.  You would have thought that the barefoot, with no weight on the end of the limb, as well as no absorption of energy through the use of no external materials, would create more efficiency but there hasn’t been a consensus around this.  The consensus is around ground contact time and any shoe that encourages reduced ground contact time could result in greater efficiency.  http://www.ncbi.nlm.nih.gov/pubmed/26131304 is one that suggests mid to forefoot running (and I would read this as anything that isn’t heel strike) leads to more efficiency BUT I would suggest it is contact time that is the key differential here i.e. lower contact time, increased efficiency.  Train to decrease contact time will increase efficiency.  The view might then be that more wedged shoes encourage heel striking which prolongs foot contact time which is more inefficient.  However, I can’t find any evidence that the degree to which modern running shoes are wedged encourages heel striking.  From my coaching practice people tend to have a default running gait that it is very difficult to change, even at a very young age.  It is possible but requires a multi-discipline approach incorporating conditioning, flexibility and continual drilling and progressive loading with the new gait.  Even if change is possible I have never measured efficiency pre and post and just wouldn’t bother with athletes running over 800m and more than a few years into a running career.

The second part to shoes is the use of softening compounds to control motion and cushion our foot fall with the presumed intention of reducing impact or in some cases modifying our running action to increase efficiency.  Impact of a heel-striking athlete is greater than for a mid or forefoot runner with a double peak presented for heel strikers against a single for mid and forefoot.  Heel cushioning is designed to reduce the effects of this impact.   As far as I can ascertain there aren’t any definitive studies that say increasing (or decreasing) cushioning results in better injury rates.  Anecdotally but of huge importance is the perspective gained from watching a large number of elite athletes and the variances they show in running gait.  Many do not have great running technique but many still run very effectively (they are elite) which would suggest the variance of tissue ’strength’ from individual to individual is greater than the variance of individuals from the ‘perfect’  running gait.  You might also find that the variance of skeletal joint angles (as an example) also reduces the ability to define a ‘perfect’ gait – it is at some level an experiment of one.  A large internet company that can stew huge data sets is going to prove me wrong here but that is fine and is called scientific progress.

But what does this actually mean for what shoe should wear on the track.  Light weight and comfortable would appear to be the only robust answers at the current time – lightweight for the obvious energy cost savings and comfortable because who would wear an uncomfortable pair of shoes.

All other advice I would suggest isn’t currently robust enough to be called definitive, but if you pushed me to make a judgement call from experience, I would wear training shoes that are not worn out, feel as though they give me a good amount of ‘feedback’ from the track and make me feel fast.  If I feel fast I am going fast.

Martin Rush
Team Bath AC Coach