Brooks Glycerin Flex review: Is the more flexible Glycerin worth it?

Max-cushion running shoes usually feel great at impact and stiff everywhere after that. All that foam cushions each step, but it also keeps your foot from bending naturally as you run. Brooks addressed that trade-off in the Glycerin Flex by cutting a groove across the midfoot of its softest trainer, so the shoe bends with the foot instead of holding it flat.

This Brooks Glycerin Flex review looks at how that one change affects long runs, daily miles, and gym workouts. Brooks makes some of the best running shoes we’ve reviewed, and both the men's and women's versions are currently $129.95, about 24 percent off.

Buy the Glycerin Flex for Men, now $129.95

A familiar softness, rebuilt from the midfoot up

Brooks kept the DNA LOFT v2 foam from the standard Glycerin, so the Flex still feels soft every time your foot hits the ground. That foam also springs back at toe-off, and runners don't get the slow, flat feeling some thick cushioning has. What's new is the FlexZone™ groove across the midfoot. Instead of holding the foot rigid on top of a tall stack of foam, the shoe now bends along the foot's natural motion path.

That difference matters most later in a run. In a stiffer max-cushion shoe, the foot can start to feel disconnected from the road after just a few miles because the sole won't bend with it. In the Glycerin Flex, the midfoot keeps flexing with each stride, so the road still feels close even with plenty of cushion underneath.

Where the Glycerin Flex earns its miles

The Glycerin Flex is at its best on long road runs. DNA LOFT v2 holds its softness over many miles, so landings at mile 8 feel about the same as they did at mile 1. Not every shoe at this price stays that soft for that long. Shorter daily runs work well too. On a 3- to 8-mile run at a comfortable pace, the flexible midfoot keeps the shoe from feeling heavy or overbuilt, even with all that foam underneath.

FlexZone also makes these trainers more useful indoors. On a treadmill or gym floor, the pliable forefoot bends during lateral moves and floor exercises, where a stiff platform would get in the way. That makes it easier to use one pair for both road miles and cross-training, and the women's and men's versions share the same foam and groove.

No shoe can be a perfect fit for everything. For race days and tempo runs, a lighter, more responsive shoe makes more sense, but for frequent training runs and a mix of workouts throughout the week, the Glycerin Flex is a comfortable everyday choice.

Buy the Glycerin Flex for Men, now $129.95

Buy the Glycerin Flex for Women, now $129.95

Who belongs in the Glycerin Flex?

Neutral runners are the best fit for the Glycerin Flex, especially those who run most days and want a lot of cushion without a stiff, rigid feel. This is not a stability shoe. On long-run days, that softness helps slow recovery miles feel easy instead of draining. If you split your week between running and the gym, one pair works for both without giving anything up. Walkers who want serious cushion will like it too, because the flexible midfoot keeps each step from feeling stiff. Both men's and women's versions are available now, and they even come in different colors.

More about the Brooks Glycerin Flex

What's the difference between Brooks Glycerin and Glycerin Flex?

Glycerin Flex uses the same DNA LOFT v2 foam as the standard Glycerin, but it adds a FlexZone™ groove across the midfoot. That groove lets the shoe bend with your foot instead of holding it flat on top of the cushioning.

Is the Brooks Glycerin Flex good for long runs?

Yes, the Glycerin Flex is at its best on long road runs. DNA LOFT v2 holds its softness over many miles, so the shoe still feels cushioned late in a run.

Is the Brooks Glycerin Flex good for walking?

Yes, walkers who want serious cushion will find it comfortable. FlexZone lets the shoe bend with each step, so walking in it feels natural instead of stiff.