ON shoes are increasing in popularity. As a previous owner of ON's "Cloud" shoes I can attest to their comfort under foot. They are lovely for long walks or jobs involving standing and moving for long periods of time (coaching in the gym for example). Increasingly I see more athletes wearing them in the gym. In many cases I find myself observing these shoes having a negative effect on lifting capacity and form in the gym. So here is the case against ON-Cloud shoes in the gym.
This is not the first shoe to try this type of pourous sole which looks different and provides a different feel. Reebok launched the Reebok ZigTech back in the day (2010) with the idea being the sole ergonomically helped you forward as you run (picture below). Don't get me wrong, for some recreational gym work these shoes (ON's or RBK) are fine. But for the athlete training to win I think they can hold you back. Looking at the research, here are some key reasons why a real weightlifting shoe is a better option for performance:
Stability
Having a solid connection to the floor when lifting is important. When lifting heavy and moving slow, any imbalance can force the body to make adjustments that could effect output, or lead to injury. Putting the body in a position where it has to compensate for imbalance may yield undesired outcomes. Comparatively, running shoes have cushioned, compressible midsoles designed to absorb impact during repetitive foot strikes in running. This compression reduces stability under heavy loads, leading to energy loss (force "leaking" into the sole) and a less solid base for pushing against the ground. Weightlifting shoes provide a hard, flat (or heel-elevated) sole that minimizes compression, allowing better force production, greater overall stability, and reduced side-to-side sway.
Biomechanics and Form
Multiple studies indicate weightlifting shoes promote a more upright torso, reduced forward lean (e.g., by ~2.2 cm in some comparisons), greater knee flexion/flexibility, and quad-dominant loading during squats. This enables deeper squats with better posture, especially beneficial for those with limited ankle mobility. Typically with athletes in On Clouds or similar, this poor form is first seen in the ankles and has a domino effect up through the knees, hips, and spine. Ankles collapse inward, knees follow suit, and the hips are not able to maintain correct positioning. Don't get me started on hinge patterns from the knee/hip! (Sato et al., 2012; Leg et al., 2017; Pangan et al., 2021; Abelsson, A., 2025)
Performance Metrics
Lifters often report feeling more stable and powerful. For example, weightlifting shoes allow deeper squats (e.g., +3.3° knee flexion) and improved control/alignment under heavy loads (50–90% of 1RM). Running shoes can slow force application into the ground (e.g., in deadlifts) compared to socks or barefoot conditions. Often the best quick fix for improvement metrics is no shoe lifting, and a mini band round weak ankles. My work with VBT supports this as output improves when switching from cushioned runners to lifting in just socks. (Lee et al., 2019; Brice et al., 2022; Abelsson, A., 2025)
Recent Findings
A 2025 analysis and review confirms lifters stay more upright, experience less ankle bend, and shift more load to the knees in weightlifting shoes vs. running shoes or barefoot. Another 2025 study on high-level athletes squatting heavy loads highlighted boosted stability, body alignment, and force transfer in weightlifting shoes. A 2020 study showed better upright posture and knee flexibility in squats with weightlifting shoes vs. running shoes. Earlier supportive work (2016–2018) noted increased perceived stability in squats and reduced ground force application speed in deadlifts with running shoes. (Abelsson, A., 2025)
Overall if you're depending on your S&C to have a positive effect on the outcomes of your competitions, then weight lifting shoes might be the way to go. However, if you need more freedom for dynamic movements like those seen in HYROX, then weight lifting shoes might not be the best option. Price will also play a part and its important to keep an eye on the typical fit of the shoe, compared to your own feet. Are they narrow, or have they a wide toe box? The latter will help with balance. Regardless, if youre lifting heavy then give yourself the best chance of success with appropriate footware!
