Just get out and do it.

People often just sit at home watching the tv and think about going for a run or just doing some good old exercise, but instead they just sit there because they couldn't be bothered. 9 times out of 10 once you have finished your exercise you you would be glad that you did it. So stop reading this and get out there, give it everything you've got and then once you've gave it everything you've get give it a little more.