Most people don't associate fun with work. There seems to be a separation between work and fun that causes individuals to not reach their potential. When you connect work and fun, you will get a better result. Separately, you can only fit so much into a whole day, but putting it together, you can accomplish much more.
As for me, my running can be work... but it can also be fun. Yesterday, I played street hockey with a bunch of people from around 3-5 and loved it. It was hot and I ran a lot... it was an interval training that I thoroughly enjoyed. Things like interval training is something that I wouldn't exactly call fun, but having 2 hours of hockey certainly adds a little more glamour. Also, looking back, I remember the time that I was working before summer break. At that point, I stopped sitting during work and instead moved my work-space vertically to where I would have to stand up. Now it's not exactly fun to stand up, but during work, I was able to enjoy benefiting myself by conditioning my body to stand and use more energy rather than sit and conserve energy.
There's a lot of things that we can do to head towards our goals. Combining both work and fun enhances the results. Work can be Fun, and Fun can be Work. Use that and improve yourself and get to your next level.