What Our Gearhead(R) Experts Are Saying:"I was surprised by how fluid and natural the Glycerin Flex feels. The midsole grooves and flexible outsole work together to give me a smooth roll and responsive toe-off without feeling overly soft. It's a great option when I want something nimble that still protects underfoot."We lace up the Glycerin Flex Running Shoe when we want more from every step-more flex, more cushion, more flow. Brooks tuned this trainer to move with the foot, not just under it. A uniquely sculpted midsole with strategically placed flex grooves works with a decoupled lateral outsole to provide freedom through the forefoot, while still delivering plush landings with nitrogen-infused DNA TUNED cushioning. The updated flat knit upper feels secure yet adaptive, breathing easily while wrapping the foot in soft support. With a lower 6mm drop and total stack height of 35. 5mm, the Glycerin Flex balances flexibility and protection in one smooth, responsive package. Whether we're cruising through easy miles or adding flow to faster sessions, this shoe lets our stride take center stage.