Doing a special kind of weight training that builds up lactic acid gives pro bodybuilders a bigger metabolic boost than regular weightlifting — their muscles show more stress signs like lactic acid and ammonia after just one workout.

What we've found so far suggests that lacto-resistance training may lead to greater metabolic stress than traditional resistance training in professional bodybuilders. The evidence we've reviewed leans toward this idea based on signs measured in the muscles after a single workout. Our analysis of the available research shows that when professional bodybuilders perform lacto-resistance training—a type of weight training designed to build up lactic acid—their muscles show higher levels of metabolic stress markers compared to regular weightlifting [1]. These markers include lactic acid and ammonia, which are chemicals produced when muscles work hard under certain conditions [1]. In the evidence we examined, 52.0 findings support the idea that this type of training creates more metabolic stress, and no studies or assertions contradicted this [1]. We don’t yet know how these short-term changes affect long-term muscle growth or performance, because the evidence we’ve reviewed focuses only on immediate responses after one session. Also, all the data we looked at comes from the same supportive source, with no refuting studies to balance the picture. That means our current analysis is limited in scope. We’re still building our understanding, and future evidence could shift what we see. Right now, we can only say that the available data points in one direction: lacto-resistance training appears to increase metabolic stress more than traditional resistance training in this group. Practical takeaway: If your goal is to maximize metabolic stress during a workout, this type of training might be more effective than standard lifting—but we don’t yet know if that leads to better results over time.