If your goals are endurance, then it may seem counter intuitive to do short sprints. And yes, we agree you’d struggle to go for 5 hours if you only ever do 30 second sprints, but they do have a big impact when integrated into a wider program.
Doing short, maximal efforts helps to train your aerobic system (more about this in our VO2 max post). Increasing your anaerobic threshold, i.e. the point at which your body is not using oxygen to fuel the work, means that you will be able to sustain a higher aerobic output.
Short sprints also help develop raw power in the legs. As a quick example, and let’s keep the numbers easy, if you’re current FTP is 200W and your max 10s output is 600W, then you’re FTP is 33% of your max.
If you can boost your short duration capacity to pump out 800W then your FTP is now only 25% of your max. Since your body is now capable of producing a higher output, that 200W doesn’t seem as hard, and you should be able to maintain for longer, or increase your FTP.
There is a bit more to it than that. but its an easy way to think about how sprints boost endurance. Check out our video below for more reasons why going short helps you go long!