Originally Posted by mcjimbosandwich

given your strong mathematical background, i'll go into even more gory details.

CTL and ATL are nothing but exponentially moving averages.

CTL = (exp(-1/42))CTL (of yesterday) + (1-(exp(-1/42)))TSS (of today). ATL is the same, except the decay constant is over 7 days as opposed to 42. At the beginning, you have to "seed" the CTL and ATL in order for the numbers to be meaningful. Otherwise, you'll need to wait 35-42 days and then start using it.

Fatigue (TSB) is calculated based on yesterday's training load = CTL (of yesterday) - ATL (of yesterday)

TSS is basically a product of time and intensity. The intensity is determined by the ratio of the normalized power of the entire ride over your FTP.