How Fast Can You Go?
The goal of today’s post is to help you figure out how fast you should be trying to race. For example: You’ve run a 5k but you’re not sure what your pace should be for a 10k, half marathon or marathon. In the alternative, you have run a recent marathon and now you want to go back and try and set a personal best in the 5k.
Trying to guess a pace can be difficult. Running hard(er) workouts can make it easier, but there’s a good chance you still won’t know exactly how fast to run. Instead of going out too slow (and missing your potential) or going out too fast (and blowing up), check with Greg McMillan first!
Greg is an exercise scientist, runner and coach. He knows a lot more about running than I do, so I always check with him!
Last fall, I ran a 5k in early October and finished in 16:41. I was running a marathon several weeks later and wasn’t sure exactly what my pace should be. It had been years since I’d done a marathon. I knew I could probably run somewhere between 2:40 and 2:50, but other than that, I was only speculating. I went to the McMillan Running Calculator and punched in my 5k time. It indicated that I should be able to run around 2:42:34 – and sure enough, I ended up finishing in 2:42:55, only 21 seconds off!
Here’s another example. Suppose you are training for a marathon and you recently completed a 10k in exactly 50 minutes. If you use the McMillan Running Calculator, it will tell you that you can run a marathon in about 3:54:35. It also tells you that 3:54:35 is 8:57/mile. And there you have it – you have a realistic goal pace for your marathon.
An Additional Benefit
The calculator can help you out with pacing, but it can also help point out weaknesses in your training. For example, suppose you ran a recent half marathon in 1:30. The calculator says you should be able to run a 5k in about 19:26. If there’s no way you could do that, perhaps you aren’t doing enough speedwork. In the alternative, if you can run 19:26 for a 5k but you can’t run 1:30 for a half marathon, perhaps you are not doing enough long runs.
Does This Always Work?
Unfortunately, no. I have found several instances where this tool is not as reliable:
1) the elevation profiles are not comparable – for example, if I punch in a 5k time that was run on a flat course, I most likely will not be able to match the implied marathon time on a hilly course
2) the terrain is different – for example, if I punch in a time that was run on a road course, I most likely will not be able to match the implied time on a trail course
3) the inserted time was not a good result – for example, suppose you have a bad day and run a lousy 10k time. Do not use that time in the McMillan calculator – the resulting time would not accurately reflect your potential
The McMillan Running Calculator is not foolproof. However, I think it can be a very useful tool, especially if you are relatively new to running. Over the years, I’ve found it to be pretty reliable and it has most likely prevented blow-ups on more than one occasion.
Give it a try and let me know what you think!