The average hike is between 6,336 and 10,560 steps. And we all know those last 1,000 steps often feel harder than the first. (Especially if you’re in the Grand Canyon, and that last mile is all uphill!)

So we wondered, what if we could make each step feel easier?

“What if we could build the most efficient hiking boot on the market? That was our call,” says Will Schuh, KEEN global product line manager, performance. “As shoemakers, we’re always looking for ways to improve comfort and performance, but this was much bigger. By increasing flexibility and reducing energy, we wanted to see if we could change how people hike.”

And that's where bellows come in. (This 1-minute video shows why.)


If you have an old pair of leather hiking boots in your closet, you might notice some cracks on the top of the forefoot area. We’ve noticed the same thing in boots that have been worn for miles and miles — they all crack and wear in the same spot. Right where the boot flexes!

When we dug into it, we also discovered that this same area is where overlapping materials build up, creating friction in the boot. You’ve experienced it – when you bend down to get water out of the river for your dog, drive in a tent spike to set up camp before dark, or get through your last mile of your 10-mile weekend hike.

When a foot is in motion, something’s got to give. We came up with a way to add that give.


The inspiration behind KEEN.BELLOWS FLEX: bellows

After searching for inspiration from everywhere, we found that bellows made the most sense. Bellows help busses turn and industrial parts move, and they even help straws flex. We took this principle and created KEEN.BELLOWS FLEX.

Made from a proprietary TPU-based material, our new flex technology is built to bend with an accordion-like design. We’ve added it to key friction points in two of our hikers: Ridge Flex, our rugged leather hiker built with the same out-of-the-box comfort as our iconic Targhee hiking boot, and Tempo Flex, our new light and fast hiker built on our more streamlined hiker-sneaker platform.

Creating hiking boots with KEEN.BELLOWS FLEX


We spent hours and hours testing out our Ridge Flex design, and we noticed the ease of flex right away — in the forefoot where the toes bend, and also where the ankle articulates. Third-party flex testing by bio-mechanical labs backed up what our feet felt. When compared to similar hiking boots, our Ridge Flex hiker with KEEN.BELLOWS FLEX technology required 60% less energy to bend. And because it flexes easier, every step on the trail feels easier (by our math, three times easier).

We also put both hikers on our Flex Test machine. After 1 million flexes submerged in water, there was no cracking, and no water seeping in.

“At KEEN, we’re big believers in the idea that the more comfortable you are out there, the longer you’ll stay out there,” Will says. “Ultimately, we hope that’s what folks enjoy most with this new technology.”

Backpacking in KEEN hiking boots with KEEN.BELLOWS FLEX