June 12, 2026
Braelyn Wood, Deputy Commerce Editor at mindbodygreen, reports on a new training shoe designed for cross-training routines.
Most of Wood’s workout routine involves cross-training. She attends group workout classes that include dynamic stretching, sprint work, lifting circuits, and a cool-down. She has spent years debating footwear choices. Running shoes are too cushioned and flexible for lifting. Weightlifting shoes provide a firm base for squats but are punishing during sprints. Wood says she has accepted that no single shoe could do both jobs well until NOBULL launched the Outwork Flex.
What is the NOBULL Outwork Flex
The Outwork Flex is a new version of NOBULL’s Outwork training shoe. The original Outwork is popular among gym-goers who need a shoe for both lifting and conditioning. The Flex keeps the same 4mm heel-to-toe drop, wide base, and stability-forward build. It adds targeted updates to make it more versatile for dynamic, mixed-format training. Wood describes it as a refinement, not a reinvention.
What’s new in the Outwork Flex
The most notable change is an extra 1mm of stack height in both the heel and forefoot. This is paired with an extra 0.8mm of EVA strobel, a type of memory foam. These additions provide slightly more arch support and a more cushioned underfoot feel without compromising stability. Wood tested the shoe during a class and was impressed by how well it absorbed impact during jump squats and box step-ups.
The other major update is a more flexible upper. The original Outwork has a stiffer upper that locks the foot in place. The Flex allows the foot to move more naturally. This flexibility makes a difference during lateral shuffles, burpees, and running sprints. The foot can respond to the ground rather than fighting against a rigid exterior.
What you need to know
Wood notes that the Outwork Flex has some trade-offs. The extra stack height reduces the ground-feel stability that makes the original Outwork effective for heavy lifting. Competitive powerlifters may notice the difference under a heavy load. The Flex also has slightly less grip than the original, which is worth noting for training on slick surfaces or doing lateral cutting movements. 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. This means the torso stays more upright and ankles move more efficiently through the range of motion. Another study found that weightlifting shoes reduced trunk lean and increased foot segment angle. The study recommended them for people prone to forward lean who want greater knee extensor activation. For athletes doing mixed training, which includes both lifting and conditioning in the same session, the challenge is finding a shoe that supports both demands. The Outwork Flex is designed to close that gap.
How Wood tested it
Wood wore the Outwork Flex to her regular Monday and Wednesday group fitness classes for one week. These classes include flexibility for the warm-up, responsiveness for sprints, and a stable base for weighted work. She also has a history of plantar fasciitis flare-ups, which made shoe selection feel high-stakes.
Performance breakdown
During sprints and dynamic movements, the flexible upper was noticeable during the cardio portion of class. During running sprints and burpees, her foot could move naturally through each stride without stiffness. The extra EVA cushioning helped absorb impact during high-rep jump movements. Her feet felt less fatigued by the end of the conditioning block than they typically do.
During strength circuits and squats, Wood was skeptical but pleasantly surprised. Despite the additional stack height, the Outwork Flex felt grounded and stable during weighted squats and strength circuits. She did not feel like she was squatting on a sponge. The shoe held its shape and gave her a base to feel confident loading up. 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. This aligns with the more upright, knee-forward squat position the Flex supports.
For plantar fasciitis, Wood had zero symptoms after two full sessions in the Outwork Flex, including sprint intervals. The combination of the slightly elevated stack height and the EVA strobel provides enough cushioning and arch support to keep things comfortable without destabilizing the foot.
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 how you train. The NOBULL 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 NOBULL Outwork Flex has a more flexible upper, plus 1mm stack height, plus 0.8mm EVA strobel, and slightly less grip. It is best for mixed-format training, anyone whose workouts include both lifting and conditioning, or who wants a single shoe that can handle a group fitness class from warm-up to cool-down.
If training is primarily barbell-focused, the OG Outwork is still the stronger choice. But for anything that blends cardio and strength, such as HIIT, group fitness, CrossFit-style workouts, or circuit training, the Flex is the more versatile option.
Fit and sizing
Wood confirms that no break-in period is required. She wore these straight out of the box to a full class and had zero discomfort. Sizing is consistent with the original Outwork.
