"The three days of rest did me a world of good," said Belgium's Boonen.
"During the workout I didn't feel any particular pain to my rib, just a slight discomfort. Now I'll participate in the first three stages of the Tour de Wallonie as planned.
"Right now I'm more optimistic regarding the Olympics, but it will be important to see how I react in a racing situation, in which my body will undergo a different type of stress and more intense effort than in training."
Boonen, the 2005 world champion, broke a rib when he crashed in the Tour of Poland last Saturday.
The Olympic road race will be held on July 28.