Threshold training sits right on the line between comfortable endurance swimming and hard, anaerobic effort — the level where you’re working strongly but still in control. It targets the pace just under your lactate limit, where the body can still clear by-products efficiently, and your breathing is deep and steady. Think of it as the fastest pace you could realistically hold for around 20–30 minutes, or your tested CSS-pace. It’s challenging, but sustainable with focus and good form. In these sessions, you’ll swim repeat efforts at or near that pace, with short, structured recovery to help you maintain consistency. The sessions in here are designed to keep you working right at threshold without fading. The aim is not to swim flat-out but to hold a strong, controlled pace from start to finish, using the pace clock or watch to stay honest and protect technique as fatigue builds. This training block is designed to lift your ability to hold speed efficiently over time — a powerful asset for both pool racing and open-water triathlon. By raising your threshold, you’ll develop stronger aerobic capacity, smoother pacing, and greater resilience when the pressure rises in a race. Expect to feel more composed at faster speeds and better equipped to handle surges, settle quickly, and finish strong.