According to several studies patients with PCL injuries treated without surgery go back
to their previous level of sports or activities:
as they were able (doctors call this "as tolerated")
after regaining full knee range of motion
after getting full strength back
Your doctor, physical therapist, or athletic trainer can test your muscle strength. Safe
return to sports activity depends on near normal-to-normal strength.
Some experts suggest looking at joint laxity before resuming sports activity. However studies also show that joint laxity may not be that important. No matter how little or how much laxity is present, 50 percent of all patients are able to go back to their
former level of sports participation. Some even get back into sports at a higher level than before the injury!