Here's a secret about ultras- learning to walk fast usually means the difference between finishing near the front of the mid-pack and the back of the back-of-the-pack.
Most runners run as much as they can in ultras, then walk the rest. The running pace is usually relatively fast. The walking pace is not. Most people, in a state of fatigue, are content to sort of meaner around as if they were perusing futons at IKEA.
With a little practice at walking a little faster, they could shave hours off their finish time. Here's an example:
Let's say we're running a 50 miler. You run 30 miles and walk 20. The running part takes 6 hours (running at a 12 minute/mile pace). If you walk at a 20 minute/mile pace, the walking portion would take 6 hours and 40 minutes for a total finish time of 12 hours 40 minutes.
If you speed up to 15 minutes/mile, you will lower that walking time to 5 hours for a total finish time of 11 hours. You'd save an hour and 40 minutes. Pretty good, huh?
The best part- it's easy to practice walking fast. We walk around a lot in our daily lives. All you have to do is make it a point to start walking faster. The gait feels a little odd at first, but you'll adapt quickly.
You can take this up a notch by increasing the walking you do in your day-to-day life. Try parking at the far end of parking lots. Walk around the house once on the way to the mailbox. Look for opportunities to walk more often.
It is also a good idea to walk one or two of your training runs each month. Don't run at all, just walk. Fast. Try to maintain at least a 13 minute pace, faster if possible. It's tough, but the training pays off.
In my early days of ultra training, I was doing one of the “all walk” runs. I was doing laps around a block on gravel roads around my rural home. On one of the laps, I passed an elderly lady who also happened to be walking. I felt like a badass for out-walking her, but also a little guilty for leaving her in the dust. I pondered this thought for a few minutes, then the guilt got the best of me.
I glanced over my shoulder to see how much distance I put between us. The lady was 20 feet behind me! The look on her face was unmistakable- she was pissed and seeking revenge! My guilt disappeared as I tried speeding up. I glanced back again.
She was gaining on me. Shit. Over the next 100 yards, I battled to keep my lead. As we neared the crossroad and end of the block, she caught up to me then pulled ahead. She reached the end, turned around, smiled, and exclaimed “Son, I think you need to train a little more.”