Many runners have become reliant on their Garmins or smart phone running apps to provide instant feedback on their pace and distance. I know I’m not alone in wondering: which one is the more accurate in terms of GPS for running? It turns out that there is not a lot of readily available information on the subject. Anyhow, I did try to dig up some information based on user feedback.
Some runners report that the Garmin GPS data is better than the apps you can purchase for your smart phone, which actually makes sense since the entire Garmin company is centered around GPS technology and devices. Based on my own experience (with the iPhone 4), I have only had one incidence of a wildly inaccurate reading. However, I do know runners who have experienced more than a few of these GPS fails.
It seems that the benefit of the Garmin wristwatch models is the convenience of being able to look at your wrist for pace, splits, distance, etc., rather than trying to hold your iPhone while running or try to fidget with your armband. Although the older models were definitely a little clunky on the female wrist, the newer models have a slimmer profile. Other benefits include the availability of monitoring heart rate and the ability to use the Garmin for other sports including biking and swimming (only with certain models).
In terms of smart phone apps, I have tried the Jog Log and Map My Run. I like features of each of the programs and tend to use them interchangeably. I also have the Garmin FR60, which is not GPS-enabled. It uses a foot pod to check acceleration (similar to the Nike plus system). While it will give you a baseline for where you are at in terms of pace, I think readings can vary pretty wildly, and I don’t trust its accuracy very much. I actually tend to carry my iPhone more often (for music and safety reasons) and I will use one of the apps for tracking my pace and distance. I also like the audible splits that are available from Jog Log, a feature that is not available with the Garmin.
Disadvantages of smart phone apps include possible discrepancies in accuracy of measured distances and the drain on your battery that accompanies using them. Because GPS works by continuously making calculations about your position and time, the smart phone has to work pretty hard and that takes a lot of juice from the battery. People have reported starting out on a full battery and returning a few hours later with an iPhone that is almost completely dead. A Garmin can last a lot longer on a charge. So, if you are planning an ultramarathon, I would definitely go with a Garmin!
BOTTOM LINE: If you want more accurate GPS data and you have the money to spend, go for the Garmin. If you would rather not spend a couple of hundred dollars (and you have a smart phone), try one of the smart phones apps. If you do go with the apps, I recommend measuring the distance with your car first, so you have an accurate reading with which to compare the app data.
Garmin and iPhone app users out there, which do you prefer and why?