I had a journal paper published not to long ago of a case study of a male masters time triallist based over four decades of his results. Bear in mind to do this, we didn’t have power data four decades ago so had to use other means to measure his decline. It’s free to access.

Here: https://eprints.bournemouth.ac.uk/...0paper%2025-9-20.pdf

Plus a blog entry illustrating my own cycling time trial performance over 20 years: https://www.precisionhydration.com/...performance-decline/