The art of pacing

Next weekend I am racing the Wokingham half marathon and I think this is an opportunity to attack my personal best. Apart from the desire that most runners have to log a PB once in a while, I think that running a quick half marathon at this stage will give me great confidence with eight weeks to go until the London marathon. So the first step in my planning for the race is always to work out what pace I need to run at to hit my target time. For me, with a half marathon personal best of 1:14:03, I want to know what pace I will have to run to hit 1:13:00. So, 73 minutes (or 4,380 seconds) divided by 13.1 miles… erm, give me a second…yep, nearly there… ahhh, one moment…

Actually I always use an online calculator. The easiest one as far as I am concerned is the Runners World Pace Band Generator. All you have to do is input the finish time you are after, the distance and whether you want the target splits in kilometers or miles (worth checking what the markers will be in at your target race if you are not 100% sure) et viola!

The other option is the McMillan Running calculator. This is actually supposed to help you estimate a range of finish times for every conceivable distance based on previous race results. But you can simply enter your target race time and then check the pace splits under that distance (which are given in per-mile and per-kilometer numbers).

And the target pace is…

Having used the Runners World Pace Band Calculator, I know I need to run each mile of the half marathon in 5min 34secs to finish in 73 minutes.

Not too much technology

Mile Markers are there to be used. Image from Finbar on Tour

Now I know my target pace, I must admit that I tend to shy away from technology on race day. When it comes to training I am happy to use my Garmin to check on my paces and I really enjoy downloading my stats and updating my training diary. But when it comes to racing, I take a different view – simplicity is everything. I simply write the target pace on the back of my left hand and hit the lap button when I reach every mile (or kilometer marker). If the number on my watch is equal to or less than the number written on the back of my hand, then I am on track (and visa versa). To hammer the point home I once ran a marathonĀ  with a friendĀ (his debut by the way) and he checked his pace using his GPS watch, while I used my less-tech trusted method. He finished in 3:01:02 with a GPS telling him that he had run 27 miles! He is such a hard-working athlete that I am convinced that he would have finished in under 3 hours if he hadn’t been relying on a GPS watch that was giving him the wrong pace data. You have been warned.

So I’m off to find a biro and get that number well and truly inked on the back of my hand. The count-down begins!


  1. My training and pace times are very low-tech. I measure my distances with a piece of string marked off in Kilometre scale and use my A-Z (I also have a mile marked on the string). In races I work out what pace I want for each mile or kilometre (depending on how the race is marked) and then check my very cheap Casio watch as each marker is passed and adjust my speed accordingly – although it is usually pretty accurate (surprisingly). The reason for my (rather sad) Heath Robinson approach is that I feel I would become obsessed if I owned a Garmin. A session on the treadmill in the gym every now and then gives me a sense of what different speeds feel like as do regular races, parkruns and timed track training sessions with the Club. I do wonder though if perhaps I should rely less on instinct and invest in something more sophisticated.

  2. I tend to use a combination approach come race day.

    I write up my own pace band, and attach it to the strap of the garmin. I use the garmin to help guide my pace selection, and the pace band and course markers to ensure that im actually on pace for the desired result.

    sure relying solely on the garmin can lead to the situation you describe with your mate, but its not unheard of for the oncourse markers to be a bit off as well.

  3. Nice post Simon and good luck for the halfer!

    I tend to vary what I do. Maybe I’ll take your approach as I tend to work the other way around to you. I don’t wear a garmin during training, but roughly know the pace I’m at, then on race days I wear the garmin to check I stay on target pace – give or take. But my times are a little less fast as yours so I probably have room for a bit more error!

    I wonder what the big guns swear by?

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