Hard-start intervals use an initial hard effort at a power output above what would be sustainable for the intended interval duration, to enhance oxygen uptake and cardiac output. Let's talk about some of the reasons for why we might want to perform hard-start intervals, when they might be appropriate for our training, and when they might not be.
Here are some of my current thoughts and questions on the topic of VO2max trainability, time near VO2max, hard-start and intermittent intervals, and adaptations toward capacity and efficiency.
I want to look at my other favourite VO2max workout, the Rønnestad style Hard-start 30/15s VO2max workout. This was the protocol I arrived at based on Rønnestad, Seiler, Buchheit & Laursen, and others' research into optimizing interval prescription for maximizing adaptations to VO2max.