This article originally appeared in the July 1982 issue of UltraRunning Magazine
by Peter Riegel
Most ultrarunners are aware of the conventional wisdom which holds that a steady, even pace leads to optimum performance. Although some may disagree, holding that a little “money in the bank‘ never hurts, many strive to maintain the discipline implied by even pacing. For the faster runners, the even pace does not involve a serious question of gait: they run all the way. For the great mass of ultrarunners, however, a mixture of running and walking will determine their performance.
Some runners may be sensitive enough to their body’s rhythms and needs that they will instinctively know when it’s time for a walk. They are fortunate, and I don’t want to change their successful methods. Many of us, though, are fairly new to the game. and we don’t have an established sense of pace. However, it is not hard to plan and execute a race when a few simple calculations are made.
In order to plan successfully you need to know three things. The first is your actual, comfortable eat-up-the-miles-effortlessly pace. Most of us do our LSD work at this pace and have a pretty good idea of what it is.
Second, you need to know your walking pace. The best place to find this is at your local running track. A few walked quarters will quickly give you a good idea of how fast you walk.
The third pace is that which will allow you to finish the race within the time you set for yourself. To get this you must calculate it from your desired finish time and the race distance.
Once you have set your goal, go to work with the formulas and figure out the combination of paces that will lead you to it. If your race will be on a track, use the “track” formulas, and alternate your walks and runs by counting laps covered at each gait. This is hard to do on the road, so by using the ‘road’ formulas you can use your watch as your pacer. My own chronograph gives a beep every ten minutes, and every time it does I reward myself with a two to four minute walk, depending on the race distance and my goal.
Hills, heat, darkness and fatigue may combine to make a mess of all your calculating, but it is a place to start, and the process of thinking about the race beforehand will strengthen your confidence during the race itself. You will be surprised to see the amount of walking that you can allow yourself and still maintain a respectable pace.
Formulas for mixed pacing:
R=Running pace, min/mi to min/km
A=Average pace (or “goal” pace)
T=Fraction of time walked
D=Fraction of distance walked
To find required amount of walking when average pace is known:
Track: D=(A-R) / (W-R)
Road: T = W(A-R) / A(W-R)
To find average pace when amount of walking is known:
Track: A = R+D(W-R)
Road: A = RW / W-T(W-R)
Goal = 100 miles in 24 hours
Average pace = A = 24×60/100 = 14.4 min/mi
Running pace = R = 9 min/mi
Walking pace = W = 20 min/mi
How much walking should be done?
D= 14.4-9 / 20-9=.49
49 percent of the distance may be spent walking to reach the goal say 1 lap walked to 1 lap run.
T= 20(14.4-9)/14.4(20-9) = .68
68 percent of the time may be spent in walking. Say 6 to 7 minutes of walking for every 10 minutes on the road.
How far can you go in 12 hours if you run 7 laps at 9:00 alternated with a 1 lap walk at 20:00?
Fraction of distance walked = D = 1/8 = .125
A = 9 + .125(20-9) = 10.4 min/mi
12 hours of effort at 10.4 min/mi will produce 69.4 miles.