Most of my workout routine is cross-training. While I occasionally hit the gym just to lift, I am more likely to be in a group workout class that covers all the basics: dynamic stretching, sprint work, lifting circuits, and a cool-down. That means I spend a lot of time debating footwear. My go-to running shoes are too cushioned and flexible; great for cardio, but too soft and unstable when loading up a barbell. Weightlifting shoes offer the firm, grounded base your squats need, but they are punishing during sprints or any movement that requires your foot to move dynamically. For years, I have bounced between the two, accepting that no single shoe could do both jobs well. Then NOBULL launched the Outwork Flex, and I have finally found a solution to my biggest cross-training woe.
The Outwork Flex is NOBULL’s newest iteration of its popular Outwork training shoe. It is a silhouette already beloved by gym-goers who need a shoe that can handle both lifting and conditioning work. Think of the Flex as the Outwork evolved. It keeps the same foundational DNA—the 4mm heel-to-toe drop, the wide base, the stability-forward build—but introduces a handful of targeted updates that make it more versatile for dynamic, mixed-format training. It is not a reinvention, but a refinement.
The most significant change is an extra 1mm of stack height in both the heel and forefoot, paired with an extra 0.8mm of EVA strobel, or memory foam. These additions sound minor, but in practice, they translate to slightly more arch support and a more cushioned underfoot feel without dramatically compromising the shoe’s stability. When I put the shoe to the test in last week’s class, I was impressed by how well the new iteration absorbed impact during high-impact movements, like jump squats or box step-ups. The other major update is a more flexible upper. Where the original Outwork has a stiffer, more structured upper that locks your foot in place, the Flex allows your foot to move more naturally. During dynamic movements, such as lateral shuffles, burpees, and running sprints, that flexibility makes a real difference.
No shoe is perfect, and the Outwork Flex comes with a couple of honest caveats. The extra stack height, while beneficial for cushioning and arch support, does marginally reduce the ground-feel stability that makes the original Outwork so effective for heavy lifting. If you are a competitive powerlifter or someone who prioritizes maximum stability above all else, you may notice the difference under a heavy load. The Flex also has slightly less grip than the OG, which is worth noting if you train on slick surfaces or do a lot of lateral cutting movements that demand traction. There are trade-offs, but for most recreational and intermediate gym-goers, they are unlikely to be dealbreakers.
Before getting into how the Flex performed, it is worth pausing on why training shoe choice matters more than most people realize. Research consistently shows that footwear has a direct and measurable impact on squat biomechanics. A review found that weightlifting shoes decrease trunk lean and generate more plantar flexion compared to running shoes and barefoot lifting, meaning your torso stays more upright and your ankles move more efficiently through the range of motion. Another study found that weightlifting shoes reduced trunk lean and increased foot segment angle, and recommended them specifically for people prone to forward lean who want greater knee extensor activation. For athletes doing mixed training, the challenge is finding a shoe that supports both demands. That is exactly the gap the Outwork Flex is designed to close.
I wore the Outwork Flex to my regular Monday and Wednesday group fitness classes for one week. These classes are the kind that expose every weakness in a shoe. You need flexibility for the warm-up, responsiveness for the sprints, and a stable base for the weighted work. I also have a history of plantar fasciitis flare-ups, which has made shoe selection feel especially high-stakes. The flexible upper was immediately noticeable during the cardio portion of class. During running sprints and burpees, my foot could move naturally through each stride without the stiffness I sometimes feel in more structured training shoes. The extra EVA cushioning also helped absorb impact during high-rep jump movements. My feet felt less fatigued by the end of the conditioning block than they typically do.
This is where I was most skeptical, and most pleasantly surprised. Despite the additional stack height, the Outwork Flex still felt grounded and stable during weighted squats and strength circuits. I did not feel like I was squatting on a sponge. The shoe held its shape and gave me the base I needed 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, which aligns with the more upright, knee-forward squat position the Flex supports. This was the real test for me. I have had flare-ups triggered by everything from pickleball to long walks in unsupportive shoes. After two full sessions in the Outwork Flex, including sprint intervals, I had zero plantar fasciitis symptoms. The combination of the slightly elevated stack height and the EVA strobel seems to provide just enough cushioning and arch support to keep things comfortable without tipping into the overly soft territory that can actually destabilize the foot.
Both shoes share the same 4mm drop and NOBULL’s signature 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 possible. 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 your training is primarily barbell-focused, the OG Outwork is still the stronger choice. But if you are doing anything that blends cardio and strength, the Flex is the more versatile option. One thing I can confirm without hesitation: no break-in period required. I wore these straight out of the box to a full class and had zero discomfort. Sizing is consistent with the original Outwork.
