Your muscle's electrical activity (measured by EMG) can predict most of how hard your butt muscles are working — especially when comparing the same person doing similar exercises.

What we've found so far is that muscle electrical activity, measured by EMG, appears to predict a large portion of how hard the glute muscles are working during exercise [1]. Our analysis of the available research suggests this is especially true when comparing the same person performing similar types of movements. We looked at 28 studies or data points that support this idea, and none that contradict it [1]. This means the evidence we’ve reviewed leans toward EMG being a useful indicator of glute muscle effort in controlled, comparable conditions. For example, if someone is doing two different glute exercises and we measure their muscle activity with EMG, we can likely tell which one activates the muscle more strongly. However, we only have evidence for specific situations—mainly within-person comparisons using similar exercises. We don’t yet know how well EMG predicts actual force across different people, different movement patterns, or real-world conditions where form, speed, or fatigue vary widely. Electrical activity gives us a signal, but muscle force also depends on other factors like muscle length, joint angle, and fatigue, which EMG alone doesn’t fully capture. Our current analysis shows that while EMG is a helpful tool for estimating glute muscle effort, it may not reflect the full picture of how much force the muscle is actually producing in all scenarios. We’re still building our understanding, and future evidence could clarify its limits. Practical takeaway: If you're comparing two similar exercises for glute activation—like two types of squats—EMG can help show which one turns the muscle on more. But don’t assume higher EMG always means more strength or growth.