I thought I'd put pen to paper on something that I'm asked about quite often – "Why is it that Get Running uses times rather than distances"?
Get Running follows the timings in Cool Running's Couch to 5K plan. The plan also provides distances. So instead of week three having runs that last for 90 seconds, the runs could last for 200 yards, and the GPS would be used to check you are running that distance.
The original answer to why I chose times rather than distances was that when I first wrote Get Running, I wrote it for the iPod touch that I had, and that didn't have a GPS in it, so I didn't have a whole lot of choice! Pretty soon after I got an iPhone too, and from there on I could have changed Get Running over to use distances. However, it seems to me that actually, using times has a significant advantage…
People who use Get Running will come to it with varying fitness levels. We're all unique right? Some users are in high school others are sixty plus. Some users are short, others are tall with a big stride. Some are slim, other are heavy. There's lots of variation. A lovely thing about times is that it creates something of a level field for everyone and lets you see improvement against yourself. Each runner can determine and jog along at their own comfortable speed without feeling any pressure that what they are doing is not good enough.
That's really important for me: perhaps more than anything else, I intend that Get Running is accessible – I want it to undo some of the stupid conception that running is what athletes, or at least, really healthy people do, because that's just silly nonsense.
So, I think it's likely that Get Running will probably be sticking with times rather than distance.
However, I also get asked, "So, when I'm running for 30 minutes, how will I know if I'm running for 5K"? Well, that's a great questions. An "average" person (let me know when you meet one!) who goes through Get Running will probably be running close to 5K by the end of it. Personally, I was running about 4.8 by the end. Plenty of people will be running 4.5 by the end. If you're running 4 or 3, splendid! You've done it – you've got out there, and you're at a place you can stay at, or improve from if you want to. Some people will be running 5.5K, and maybe some will be running 6 or more. I don't actually have statistics on this I'm afraid, so it's hard to be too sure, but an average will be around the 5K point.
Having reached 30 minutes (and done that regularly for a couple of weeks), I'm pretty sure that almost all runners would feel comfortable to then run a full 5k at their personal pace, even though it might take them a bit more than 30 minutes.
Okay – so that's the reasons why Get Running doesn't use distances. There are arguments the other way though. It can be satisfying and motivating to see your distances improving, and while a single absolute distance goal is not applicable to all runners, it is still useful to have a personal distance goal. For these reasons I'll keep on considering whether to add in GPS features to Get Running, even if they just measure overall distance.
So, what about if you really really want to know how far you are running today? Here are some suggestions (but promise me you won't get hung up on distance, and that you'll remember what you're doing is awesome, how ever far you're getting):
A couple of iPhone App options are Run Keeper (the Pro version of Run Keeper now seems to be fee) and Run Meter. Both seem to be good. There are others, but these two seem to be the leaders (that doesn't necessarily mean they're the best, of course). If you're using a device with multitasking then you'll be able to use one of these Apps at the same time as Get Running.
If you don't have GPS or multitasking, apparently the Nike+ sensor can be really quite accurate, but I've no personal experience of this, and I'm a little surprised to hear that it is as accurate as I've heard reported. Could be worth a try though. The Nike+ App will multitask with Get Running even on a device that doesn't have multitasking – Nike+ has been specially made by Apple so it can do that.
A simple solution is this is a great web App that will let you draw your run on a map and will then tell you how long it is or was, and you can even create a link for sharing the map if you fancy

Finally – if you just have to have a couch to 5k running app with built in GPS, then take a look at C25K App which has an in App purchase for GPS.

Thanks for reading. I hope this is useful and makes sense

Cheers,
Benjohn Barnes (Get Running developer)