For doctors ministering to aging baby boomers, the welcome news is that many seem to be exercising more than they have in years. That is improving their cardiovascular and psychological health, but it’s also contributing to a parade of sore knees, back sprains, and other injuries.

Whether discovering the joys of fitness in mid-life, or attempting to reclaim athletic glory after decades of relative inactivity, boomers in their 50s and 60s tend to throw themselves into exercise with the same intensity they might bring to new jobs, hobbies, or grandchildren. Many, however, neglect the importance of working up gradually to a smart fitness regimen.