The Story of the 8mm Sneaker

Once upon a time, there was a runner.  He tried on a "traditional" running shoe, but it was too high in the heel. Then, he tried on a "zero-drop" shoe, but it was too low in the heel. Finally, he put on one of Saucony's new 8mm shoes and it was just right. Yes, thanks to the most ridiculous(ly awesome) product promo shirt ever, we've all heard about Saucony's "new 8mm concept". So, what's this all about? Traditional running shoes have ~12mm drop from heel-to-toe. Minimalist shoes have a 0-4mm drop and very little cushioning. However, there are also "zero-drop" shoes (that aren't necessarily minimal), but still use a 0-4mm platform (like the Kinvaras and the PureProject line... there are others too). And, to further complicate things, there are shoes that don't have a lot of cushioning, but still feature a 10+ mm  heal-to-toe drop. And... just kidding :-)

Ok, 8mm, why is this so special? Well, lets start off with why all sneakers aren't 8mm. Turns out, there's really no good reason. Back in the 80's, sneaker manufacturers started making more cushioned, supportive shoes. This was in response to an increase in the number of running related injuries... specifically Achilles tendinitis, metatarsal fractures, and tibial stress syndrome. In order to reduce these numbers, manufacturers built up the heels of sneakers to reduce some of the stress on the lower leg. Additionally, the number of people suffering from plantar fasciitis and runner's knee was also on the rise, which was attributed to the need for increased support. So, manufactures started making the medial sides of running shoes stiffer to prevent pronation. Makes sense... unless you consider that these injuries weren't the result of how the shoe was made, but rather the result of poor running form (I believe heel-striking was still recommended at this point). How they settled on 12mm exactly is anyone's guess.

However, due to the recent barefoot running trend, manufactures have begun to take a second look at how they construct sneakers. Basically, after reading Born to Run, a whole bunch of people started running in minimalist shoes because the Tarahumara did, and they're pretty awesome. Then, a whole bunch of people got injured from trying to jump right from traditional sneakers to no sneakers too quickly. So, "the experts" started looking at why, and found it wasn't so much the lack of cushioning, but rather the heel-to-toe offset. Then, manufacturers made the first round of "kind of minimal but not really" sneakers... namely a 0-4mm drop with cushioning. However, people still complained, so they went back to the labs and averaged the drops (I have no idea if they really did this, but (12+4)/2 = 8). People found the 8mm platform to be ideal in terms of "stride smoothness"... I'm guessing by chopping 4mm off the heel, it encourages mid-foot striking just enough without putting excessive stress on your calf/Achilles.