Just watched a topic on The One Show during the week where 2 people were given a 5 weeks training schedule, 1 would run 3 times a week at moderate pace & the other would run 3 times a week 30 seconds flat out & 30 secs walking for only 4 mins & the results were remarkable. The guy who had been doing the sprints improved his cardiovascular fitness by 50%, dropped his bodyfat % by a 1/5 & lost a stone in weight. The Girl doing the moderate running improved also but nowhere near the same figures as the guy doing the sprints. So it seems more sprint training seems the way. I do most of my running in 30 secs sprints, 30 on 30 off, depending on how I`m feeling will depend for how long I do it. David Haye for his last fight with Fraudley Harrrison was doing 100m sprints then walking back continuously for an 1hr & 1/2, quite remarkable. Sprint sprint & more sprinting!!!!!