This is the starting line, not the finish!
Out of curiosity I went home and Googled "backward running". To my surprise and delight, there is a whole world of backward running! It seems that backward running (also known as reverse running and retro running) is a legitimate sport and exercise in its own right. It has its own clubs and races, has many websites dedicated to its practice, and boasts an impressive list of benefits. One of those benefits is, as you may have guessed, that it is great for the abdominal core muscles. I think I am going to find somewhere safe and level and obstacle-free (such as the local high-school track) and incorporate some backward running drills into my routine so if you see me waving at you and running but getting smaller and smaller, it's not an illusion. I'm running backward!