Sunday, August 7, 2016

Race Faster With Racing Flats

Used to race in the Nike Duellist PR when I was a kid
I've had a few patients ask me this past week what shoes to wear for their upcoming races especially since they want to achieve a personal best timing. Other than definitely no new gear on race day, I am happy to share what I know regarding racing flats.

Why racing flats? You can definitely turn your feet over much faster if your footwear is lighter. Think about this or try it out if you want. If you had to, would you prefer to run 5 km wearing a 10 kg weight vest or run with a 5 kg dumbbell in each hand (or 5 kg ankle weights strapped to each ankle)?

Hence, I would definitely suggest investing in a good pair of racing flats, as light as possible without sacrificing support of course.

Racing flats aren't minimalist shoes like the Vibram Five Fingers, they are ultralight running shoes designed to give runners an additional edge in competition. No fancy cushioning or support, just the bare basics.

I also recall the most famous published article on the topic. Subjects ran in the exact same pair of shoes in that research with lead weights inserted into a sleeve sewed onto the sides of the shoe so both toe and heel drop remained the same. So only weight adjustment was tested in the study, with no variables like midsole height difference.

The researchers found that the "effect of carrying extra weight on the foot during running has been measured at 1 percent (increased aerobic demand) per 100 grams per foot".

100 grams is about 3.5274 ounces. Each extra ounce will cost 0.2835% more (1 divided by 3.5724). So if you're running a t 5:40 min per mile pace, every mile will save you 0.83 seconds per ounce less weight.

Although that Nike funded study was done a long time ago that message has always stayed with me. Ever since I started racing track and cross country in my teenage years I would warm up in my normal training (usually a lot heavier) shoes and then switch to race in the lightest racing flats.

Before you run out and get the lightest racing flat you can find, please bear in mind that cutting down shoe weight usually means sacrificing on cushioning. That's the reason why you never see elite marathoners competing in Vibrams. They may train with it, but never race with it.

Here's the reason. "As shoe weight went lighter, the cost (energy of the runner) also dropped some, but when the weight went too light, then the cost went up because there was getting to be less midsole cushioning and the runner's muscles had to start absorbing more landing shock and that costs more energy."

The surface you run on is also important. A nice soft artificial track will absorb some landing shock (so you can get away with minimalist spikes) but on the road, you'll definitely need some cushioning and that adds a little weight to the shoe.

So, your ideal racing flat will differ from another runner and vary according to speed and race distance. More time spent on your feet generally requires more support. You can probably get away with a lighter shoe for a 5 or 10 km race.

The lighter your footwear, the faster you can turn over your feet ......  Now you know.


Frederick EC (1984). Physiological And Ergonomics Factors In Running Shoe Design. Applied Ergonomics. 15(4): 281-287/ DOI: 10.1016/003-6870(84)90199-6.

Another racing flat, my Air Streak from 1997


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