I was at the climbing gym bouldering with my friend for about two hours. Usually, the last thing I could imagine doing afterward would be anything other than nothing. But the gym was closing in twenty minutes so I thought, what the heck, I wonder how long into the 20 minute run I can go. I was already warmed up so off I went!
It passed like a BREEZE. 2.1 miles without breaking a sweat (well, metaphorically!). I probably could have gone on for another five or ten minutes.
There IS a correlation between the cardio of running and the stamina and strength of climbing -- I've never found a solid physiological link, but it's definitely there. The best routine I've found is a warmup on a treadmill, climbing, and then running until you're completely spent.
Word of caution: If you do this late at night, the endorphin rush will keep you up ALL NIGHT!
At the end, I reckon I could have gone on a little bit more, but I was really happy to grab a shower and then go and drink a lovely German beer and eat a huge schnitzel and these amazing super thin and crispy French fries they serve over there.
It was amazing finishing that 20 minute run. I knew then I would be able to do the 30 minutes. In fact, I was pretty sure I could run any distance I wanted – not right away, but I knew I could run it with a little more training. Until then I didn't quite believe that.