Sunday, June 21, 2009

McMillan Running Calculator

Many of us use the McMillan Running Calculator to determine race times based on other race times. Usually I find this tool pretty accurate however, after last Wednesday speed workout I'm not so sure what to think. 

Last Wednesday we did 5x1000m at 5k pace (the intervals are the circled splits). Pacer Joe paced us through the workout and said that each of the intervals were right around 7:00/mi pace.

Just for kicks, I entered my 1000m split time into the McMillan Running Calculator to see what the actual 5k pace was. 

Now, McMillan lists 5k as 5000m. This is where I get confused. when I entered 4:23 as a recent 1000m time, McMillan determined that is equivalent to a 8:18 5000m (see picture left).

Who's right? Pacer Joe or McMillan? I find it hard to believe that the Nike pacers would be off by that much. Am I using McMillan wrong?


Matt said...

The Nike pacer is right but that doesn't make Mcmillan wrong. A 5:23 1k translates directly to a 7 min. mile. Mcmillan works only with race paces (it assumes an all out effort) so if 1k @ 4:23 was the best you could do for one, it extrapolates that to a 5K which always adds time. Just like you (or anyone) couldn't run their 5K pace for a marathon; a person "racing" a 4:23 1k couldn't hold that for a 5K.

When you put in your recent 5k PR (22:46) it gives you a time range-in the lower left corner- for 1k repeats. A 4:23 falls right in that range albeit in the faster end.

I would avoid using workouts in the calculator.

The Laminator said...

I agree. McMillian works with race pace, so you can't really use 1000m of a 5x1000m workout to calculate your 5k race pace. It's probably more accurate (and more informative) to extrapolate using recent road race results to determine appropriate 5k pace.

To put it in another way, 5k race pace means you're running at 95-98% of your max HR. I doubt you'd approach that in your 1000m workouts (and if you do, you're running them too fast!)

Trust your Nike coach!