As others have pointed out, recovery for every injury will be different, and should be guided carefully by a trained physician. A brain injury versus a knee injury versus a collarbone injury would all require very different rehab, so having a single recovery plan would not suit all athletes in all situations.
Oftentimes, for recovery from injury we recommend Low Volume Traditional Base since it is a fairly easy, consistent effort to get your legs moving and your heart pumping, but obviosly this won’t work for all types of injury.