Ultrarunners walk. It’s just one piece of ultrarunning and knowing when and how long is essential to finishing at your best. The easy answer to the question of when to walk, aka power hike, in an ultra is, you walk all the uphills. But if we wanted easy, we wouldn’t be ultrarunners now would we?
Do all ultrarunners power hike? Yes, at the 100 mile distance everyone is going to do some form of power hiking on the uphills. At the 50k distance, it will depend on how steep and long the hills are. At the 50 mile and 100k distances, pretty much everyone is doing some power hiking.
The factors that go into a decision to power hike rather than run are: the length of the race, the steepness of the hill, the length of the hill, your training/conditioning, current weather/trail conditions and your current physical status. None of these factors can be considered without thinking about the others. It’s a multifaceted decision. The only one that takes priority over the others is your current physical status.
Your current physical status is how all of your bodily systems are functioning. Uphills can be a perfect opportunity to rehydrate and refuel. The slower pace may allow your body to absorb water and fuel easier, but don’t count on it. Hiking up a long steep slope can be just as taxing as running hard on level ground. If it is, and your stomach protesting at everything you put into it, you may be better off trying to refuel on the downhill or on a flat. If you’re experiencing pain, hiking an uphill is a good time to assess the situation. You’ll be using different muscle groups to climb, which may help you rule in or out particular muscles as the problem. It will also give sore/cramping muscles a chance to recuperate.
There may be times where hiking flats and downhills is the most appropriate course of action given your physical status and you shouldn’t be ashamed of this, at least you’re still moving forward. If you’re vomiting or have diarrhea walking/hiking is a must. You need to give your body a chance to regulate and it can’t do that if you’re pushing the redline.
The length of the race plays a major roll in when you begin your power hiking. The longer the race the earlier you’re going to begin hiking. Changing to a hike allows you to engage different muscles from those you use for running. This change gives muscles a chance to rest and prepare for the next time they’ll be needed as the primary force. This is true even in a very flat race with little to no uphills.
The grade (steepness) of a hill can demand that you hike rather than run. At some point, a hill becomes so steep it’s just easier and often faster to hike. Whether this is an 8% grade or 15% grade depends on you. Research says a grade of 15% is the point at which it becomes more energy efficient to hike than to run up a slope. However, keep in mind this research was done with individuals who were fresh. In other words, they hadn’t already finished 75 miles and they didn’t have 95 miles to go. The best way for you to figure out where you are, is to practice. Train on all types of grades and hit them at different times in your long training runs.
The length of an uphill is important too. Maybe you’ve come to a hill with a moderate grade and thought, “It’s runnable.” But is it runnable for three miles? It’s okay to start running it and then decide a bit later that it’s no longer runnable. You can even take a run/walk approach to these types of uphills.
Weather and trail conditions can also dictate when you should be running or hiking. Rain and snow can change visibility. Swampy conditions can conceal rocks and other hazards. Heat can change a mild runnable slope into a death march.
What you don’t want to do is walk due to a mental block or because you’ve hit a psychologically dark mood during your run. The only way to avoid this is by having a plan of action. When you get the first inkling of a drop in your mood or mental state, ask yourself if you’ve kept up on hydration, electrolytes and fuel. If you haven’t, start there. If those systems are where they need to be, initiate your positive mood plan. You can use imagery, mantras, recalling when you’ve overcome other challenges, or repeating positive words. For these to be most effective, you need to develop them in your training.
Your training is the key to knowing when you should hike and when you should run. Training on hills is going to give you the strength (mental and physical) to conquer those hills that are within the realm of sensible and the wisdom to know when it’s not sensible. The definition of what is runnable and what’s not is going to change, and you need to be able to evaluate yourself and each hill under the current circumstances.