Brazil Finds a Shoe That Transitions From Squats to Sprints

June 12, 2026

A training shoe that works for both weightlifting and cardio has long been a challenge for cross-training athletes. The NOBULL Outwork Flex, released this month, aims to solve that problem.

The shoe is an updated version of NOBULL’s Outwork training shoe, a model already popular among gym-goers who need footwear for lifting and conditioning. The Flex keeps the same 4mm heel-to-toe drop and wide, stable base as the original but adds several updates to make it more suited for mixed-format workouts.

The most notable change is an extra 1mm of stack height in both the heel and forefoot, plus an additional 0.8mm of EVA strobel, a type of memory foam. These additions provide more arch support and a cushioned feel underfoot without greatly reducing stability. In a test during a group fitness class, the shoe absorbed impact well during high-impact moves like jump squats and box step-ups.

The upper part of the shoe is now more flexible. The original Outwork has a stiffer upper that locks the foot in place. The Flex allows the foot to move more naturally during dynamic movements such as lateral shuffles, burpees, and running sprints. This flexibility helps the foot respond to the ground rather than fight against a rigid exterior.

There are trade-offs. The extra stack height slightly reduces the ground-feel stability that makes the original Outwork effective for heavy lifting. Competitive powerlifters who need maximum stability may notice a difference under heavy loads. The Flex also has less grip than the original, which could be an issue on slick surfaces or during lateral cutting movements that require traction. For most recreational and intermediate gym-goers, these trade-offs are unlikely to be dealbreakers.

Why footwear matters for lifting

Research shows that footwear has a direct impact on squat biomechanics. One review found that weightlifting shoes decrease trunk lean and generate more plantar flexion compared to running shoes and barefoot lifting, meaning the torso stays more upright and the ankles move more efficiently through the range of motion. Another study found that weightlifting shoes reduced trunk lean and increased foot segment angle, recommending them for people prone to forward lean who want greater knee extensor activation.

For athletes doing mixed training that includes both lifting and conditioning in the same session, finding a shoe that supports both demands has been a challenge. The Outwork Flex is designed to close that gap.

How the shoe performed in testing

The Outwork Flex was worn during regular group fitness classes for one week. These classes include warm-up flexibility, sprint work, and weighted exercises. The tester also has a history of plantar fasciitis flare-ups.

During sprints and dynamic movements, the flexible upper was noticeable immediately. The foot moved naturally through each stride without stiffness. The extra EVA cushioning helped absorb impact during high-rep jump movements, and the feet felt less fatigued by the end of the conditioning block than usual.

During strength circuits and squats, the shoe felt grounded and stable despite the additional stack height. It held its shape and provided a base that felt confident for loading up weight. Research on CrossFit athletes has shown that weightlifting-style shoes produce a lower hip torque contribution and a higher knee torque contribution compared to conventional footwear, which aligns with the more upright, knee-forward squat position the Flex supports.

For plantar fasciitis, the tester reported zero symptoms after two full sessions, including sprint intervals. The combination of the slightly elevated stack height and the EVA strobel provided enough cushioning and arch support without becoming overly soft.

Outwork vs. Outwork Flex

Both shoes share the same 4mm drop and NOBULL’s wide stable base. The differences are subtle but meaningful depending on training style. The original Outwork has a stiffer upper, slightly lower stack height, more grip, and maximum ground-feel stability. It is best for lifters who prioritize heavy strength work and want the most locked-in, stable platform.

The Outwork Flex has a more flexible upper, an extra 1mm of stack height, an extra 0.8mm of EVA strobel, and slightly less grip. It is best for mixed-format training, anyone whose workouts include both lifting and conditioning, or those who want a single shoe that can handle a group fitness class from warm-up to cool-down.

If training is primarily barbell-focused, the original Outwork is still the stronger choice. For workouts that blend cardio and strength, such as HIIT, group fitness, CrossFit-style workouts, or circuit training, the Flex is the more versatile option.

Fit and sizing

The shoe required no break-in period. It was worn straight out of the box to a full class with zero discomfort. Sizing is consistent with the original Outwork model.