Some runners don't worry much about their weight. They think: I run, therefore I can eat a cow for dinner. But these same runners gain 3.3 pounds per decade, according to a recent US analysis of 4,700 mid-life male runners by the National Runners

or she planned. You won't either. Stuff happens, life gets in the way, but you can deal with it as long as you stay focused on the big picture. Shrug off the bad days, get back on the programme, and you'll still achieve your goals. Remaining persistent

, enjoyable (and effective) way to run. It’s worth a try, isn’t it? Amby Burfoot is Editor of Runner's World US.