If you are going to be taking part in this medical research, just don't train.
If it bothers you too much not to train, then don't be a part of a study. Basically any activity above active daily living will create changes in your blood markers. Specific types of exercise will make more dramatic changes, such as eccentric intense training.
Just don't be that douche who screws up a study that somebody probably put a lot of time and effort into because you want to be selfish.