If you’re looking for a fast time or a Boston qualifier, you need to be concerned not only with your pace, but also with your splits. It can be challenging for any marathoner to run your goal pace accurately, kilometre after kilometre, and it’s equally stressful to be checking your watch every few hundred metres. Unless you’re in the front of the elite corral, the time on the race clock when you pass the 10K, 21.1K or 30K timing mats will not correspond to what your watch says. So the best way to know if you’re on track to meet your goal is to create and wear a pace band.
Luckily, there are lots of websites that will calculate your splits based on your goal finishing time (simply Google “free marathon pace calculator”) and format them in a column you can print out, cut out, and “laminate” between sheets of packing tape. On race day, wrap it around your wrist and fasten with a bit of tape. Voilà–your pace band bracelet. (Some will even let you specify which splits you want, like 10K, 21.1K, 30K and 40K, for example. You can get a split for every single kilometre if you want, but unless you enjoy stressing yourself out, we don’t recommend it.)
You can then check the split against the time-elapsed field on your watch to see if you’re on track to achieve your goal, and adjust your pace accordingly. Sometimes pace bands are available at race expos.
For example, let’s say you’re pretty much on pace throughout the first half of your marathon. Then you come to some hills, and you’re starting to get fatigued. And when you compare your 30K split with what’s on your pace band, you’re suddenly two minutes behind schedule. It may not be easy to make up the time over the next 12K, but at least you have reliable data, and you know what your task is over the next portion of the race.
Similarly, maybe you started out too fast (an almost universal issue among marathoners, especially on the Boston course, which starts out with some steep downhills). Your pace band will tell you if you’re too far ahead after 10K, and you can slow down to avoid trashing your legs too early in the race.
(Tip for masters runners: make sure to print your pace band in a font size you can actually read.)