Back in the early eighties I was involved with a charity which helped hospital inpatients to a speedier recovery by playing their favorite tunes over the hospital "radio" (it was a cable service - we didn't actually broadcast using radio waves.) This charity was known as The League of Friends.
Then when their funds ran low, I offered to rectify this by raising sponsored funds by running in our local half marathon.
As part of training, a good mate of mine (who is straight, now married with two kids) beckoned me to go out training with him. He knew what to do, he ran full marathons.
We started off with short distances, increasing with every session. When I reached a certain level, we did alternating sprint/jog over the entire course. This is known as Fartlet Training, which improves both speed and stamina. It was not long before we could crack off ten miles and more, and by Spring 1983, I completed the half marathon in less than two hours, and raised enough cash to stabilise the League of Friends bank balance.
Afterwads I kept on training with my mate (I found this much easier than going out alone - perhaps that was because he depended on me to be there for him, was adequate motivation to step out into the cold outside). I ran half marathons in 1984 (two at different venues in that year) and in 1985. All runs were to raise further funds for the League of Friends, which by 1985, its finances was showing a profit. By Summer of 1985, I handed my reigns to my successor and left the charity to join a triathlon club, where running evolved to Swim-Cycle-Run, which I competed in for several years to come.