I was a big runner before I started lifting weights. (If I could, I would just run all the time). If you’re a big runner like me, this is the app for you. It's not only helpful when you are balancing lifting/cardio in your workout, but also when you just want to run as far as possible. As the first “essential” workout app I ever found, it has a special place in my heart. Try it out!
I have tried a lot of apps to track my running distance/time/speed/goals: MapMyRun, NikeRun, MapMyTrack, RunKeeper, etc. This is, by far, my favorite. It is sleek and easy to use and it lets you easily switch back and forth between goals. I usually use "Distance Goal" but you can also set a time or calorie goal. You can even try to beat a friend, beat yourself, Interval Running, or a Running Test. My favorite thing about this app is that it doesn't take forever to load. When I am ready to run, I pull up the app and hit "start." When I'm done I click stop. It doesn't ask me a million questions about what shoes I'm wearing, etc.