Offer 15 minutes of 'fetch.'
Identify a stretch of the room that’s at least 10 feet long, preferably 15 or 20 feet. Stand at one end of this “runway,” and toss a toy or ball for your dog (or cat, if it’s willing to play). Choose an item that won’t harm the floor, walls, or furniture—preferably one that makes noise. Most pets will get the hang of this game quickly and return the ball to you again and again. Every time you receive the ball, do a knee-bend as you take it from the dog’s mouth. Your dog may be doing more work, but the throwing, bending, and reaching is doing you some good as well.