This indoor bike training block is designed to push your top-end aerobic engine — your VO₂ capacity — by working at intensities near your maximum aerobic power. These sessions feel demanding, with deep breathing and strong effort, and you’ll be riding above threshold for controlled periods. It’s challenging work, but it’s one of the most effective ways to raise your overall fitness ceiling, making race-pace feel more sustainable and giving you the power to respond to surges or hills with confidence. Workouts will use short, high-intensity intervals paired with structured rest to keep you in the VO₂ zone without tipping into pure anaerobic sprinting. Cadence targets and controlled recovery will help you stay smooth and powerful at high intensity, with a focus on maintaining form, pedal efficiency, and consistent output — not simply going flat-out and fading. This block builds the aerobic power and resilience crucial for stronger bike splits in triathlon. You’ll boost your ability to ride hard, recover quickly, and hold speed when the race demands it — whether that’s pushing up a climb, bridging a gap, or settling into a fast, efficient rhythm after a surge. Expect to emerge from this phase riding sharper, stronger, and better prepared for the intensity changes that racing and varied indoor sessions bring.