A complete study on condition loss would be too complicated. The factors that can influence it are many, some of which probably unknown, and you can't really make controlled experiments, because each match is different.

Have you considered the age of your players? Older guys seem to tire out faster, I've noticed. Do you play with the same tactics and formation each time? When using attacking mentality for example, your strikers will tire out faster than your defenders. Marking and pressing style also affect the condition loss.

Like LeManiaque suggested, I've also noticed that the opponent's players are an important factor in this. If for example you use an AMC, it will lose more condition if your opponent uses a DMC, compared to when he is left alone in that spot. Player ratings are also affected by this, so you may be able to find a correlation there, but nothing conclusive, I suppose.

I really like the idea, however, and would like to see this study pass the beta stage! I'll try running some friendlies and isolate tactics and factors that influence the condition, when I find the time.

Good Work!