Below is an article by Skeeter McGee which I thought would be very helpful.
Do you find that after running for a while, you hit the wall? You just can't muster up the energy you need to finish your run. This is very typical among runners, and to the first step to get over this problem is to understand that it's a mental challenge, and can be overcome.
By utilizing some tricks that marathon runners use on a daily basis, you may find yourself busting past that wall and breaking personal records. Marathon runners are experienced and wise in the ways of running long distances. Have you ever heard the saying "Don't recreate the wheel." That is how you should look at being a more productive runner. You may have no desire to run 26 miles in a single stretch, but no one can argue that marathon runners haven't got it figured out. So the simple fact is that if you learn to do what they do, you will become a better, more effective runner. Here are 3 basic steps anyone can take to get over mental blocks and premature exhaustion.
The first way is to simply distract yourself. When you're running, don't look way off into the distance and long for that invisible finish line your after. You shouldn't focus on how much more ground you have to cover. This will just psych you out. Instead, find other things to focus on. Things that are in no way related to what your doing. Try singing a song out loud, or even in your head. Or you could choose a random number, and count backwards from it. Then count forward in 3s. If you're following other runners, study them. Focusing on other people can help you keep your mind off your running. You could try planning your next workout in your head, going over your sets and rep counts.
Another useful way to help with your running is to change the way you think. If you've been running for 20 minutes, don't think of it like you still have another 30 minutes to go. This can be very discouraging. Instead, praise yourself a little. Pat yourself on the back. Think "I've already ran 20 minutes!" Compare that to half an hour ago, when you haven't ran at all yet. 20 minutes is great. Now you can just keep on running, and after awhile, check your time again. Thinking ahead about how much time is left in your run, or how much distance is left, can be discouraging.
You can also just try and relax. This may sound difficult, but try it. If your out there running in a race, or just getting some normal exercise, it's a bad idea to get bogged down by your negative emotions that come with being tired. Maybe you feel anxiety if you don't finish as planned, or embarrassed because you haven't gone as far as other runners around you, or stressed because you just want to be healthy and running feels strenuous. Try to relax your mind. Don't get caught up in what you thought you could accomplish if realistically you can't quite reach those goals yet. Try finding a running partner, or partners, someone to run along side with. This helps you worry less because you'll be around others who perform at the same level.
So try these things out next time your running. Remember, distract yourself, think positively about your progress, and relax your mind. Follow these steps and you could very well find yourself breaking through those mental blocks.
I hope you found this article as interesting as I do. Right now I don't get bored when out running but what will happen when I start running 15km and more?