As Ceri does his training,he shouldthink of Martin Thomas of Worcester (@Welsh_Tommo on Twitter) who is, with others, going to run 69 miles from Carlisle Castle to the Gateshead Millennium Bridge in June, for charity!

You are one fast dude Jack!!!!!

Jack, Theoretically you are moving at a rate of 0 mph on the "Stationary Stamina Cycle." LOL

No, I don't think it's anything to do with the fall on the bus - I was fine after that. I had surgery 10 years ago for dislocation and it's just suddenly a problem. I'm back at Pilates anyway, and stationary bike; can't do the jogging machine (in my case fast walking, not jogging) at the moment. I think Ceri should do intervals of walking during his training.

I can walk at 5mph (not at the moment though, due to blydi knee) so what's the point in running? I've often asked myself what the point of running is (unless being pursued by an anaconda). Power walking is the way to go.

Running at most speeds will burn approx. 110 calories per mile. Therefore, the 13.1 mile distance will burn approx. 1441 calories. Cycling at 30 m.p.h. will burn approx 59 calories per mile. Using those numbers, you would need to cycle 24.4 miles to get the same caloric burn. Cycling approx. 50 minutes @ 30 mph would do the trick. However, most average people will cycle around 10 mph. Cycling at 10 mph will burn around 26 calories per mile, thus needing a 55 mile distance and a 5.5 hour commitment to burn the same number of calories burned in the 1/2 marathon distance. Since a 30 mph bike ride over an extended period of time is not realistic for most people, running or walking would be the best bet for the largest caloric burn for the time spent exercising.