Generally, it is true if all of the conditions between a younger and an older person are kept the same, except for age. However, it greatly depends on the injury and the functional state of the muscles and joints of the specific person. For example, take a knee injury due to running:  A 20-year-old will be able to recruit their muscles faster and resume running more quickly. A 60-year-old will take longer to resume running because of compensations of muscles that occurred over many years.  But in general, the message is - you CAN heal, you CAN get better. You CAN live pain-free! The age and the state don’t matter.