Get Familiar with these as best you can, as I will be programming these a lot!
This is something that I learnt from PowerSpeedEndurance and their Art of Breath Program and is one of the most amazing things for your conditioning training once you understand it and utilise it!
Think of these exactly the same as the gears on your bike, you can only go so fast in each gear. I like to use these as intensity regulators. Working within certain gears will ensure you maintain a certain speed/intensity.
Something else that we do is called ‘going through your gears’. This is basically starting at Gear 1, and as you get to the stage where you cannot maintain it, you move to the next and so on until you are at Gear 5. This is usually done over shorter sprints.
I advise saving this image to your phone for future reference.