Lee’s Law (yes that is me, not just a coincidence) states that the amount of effort (work) required to improve follows the square-cube law for work and attitude.
This is pure pseudo-science based on a cross between an actual theory which is important in biomechanics (the square-cube law described by Galileo) and actual made up stuff by me.
The simple idea is that for every 10% improvement in performance, you need to improve your work by 100% and you attitude and approach by 1000%.
Work means not just the time on the track, but all the elements that make up being a better athlete: nutrition, hydration, flexibility, rest, recovery and so on.
Improvement is a matter of diminishing returns. The better you are, the harder it is to get better. So you have to work harder, which means you have to focus more and your attitude to work needs to improve: every session, every set, every rep, every step needs to be everything you’ve got.