The issue with training is simple. To progress, you apply alterations to each workout as follows:
- Increase Work Interval Intensity (Via interval percentage or overall FTP, as compared to the prior workout)
- Increase Work Interval Duration (as compared to the prior workout)
- Decrease Rest Interval Duration (as compared to the prior workout)
You can do any or all of these, and each one (or possible combination) may lead to subtle, but intentional differences in the demand on our bodies (and the desired adaptation we want from that stress).
The many workout versions apply some level of those changes to get altered stress on our bodies. The differences may seem small, but they can and will drive our bodies in different ways. The simple path to progression is to gradually, and in a controlled fashion, increase stress over time to drive further adaptations. These are the tools to do it, even if they don’t look different to everyone, they really are.