In the context of the match simulation, a player's condition affects their in-game performance via a fixed function. A fixed amount of the player's rating is weighted by their condition rating.
Given an Elo rating and a condition then the player's rating in the game is:
A player has an Elo rating of 2000 and
A condition of 100%:
A condition of 80%:
A condition of 50%:
Relationship between fitness and condition
During a match, a player's condition decreases, meaning they get tired and their performance worsens. The rate at which a player loses condition is dependent on their fitness, however, the rate at which they recover is independent of fitness.
When decreasing a player's 0-100 condition, using the below formula we convert the number to an Elo value, a domain that is easier to operate over mathematically.
We decrease the condition, then convert it back to a condition value (0-100) using the below formula
Players recover whilst they're not playing in a game.