Weight Status Below 18.5 Under Weight 18.5 - 24.9 Normal 25.0 - 29.9 Overweight 30.0 and above Obese

successor, Usain Bolt, is not, but that is because he's 200ft tall and runs on wheels. How elite athletes' BMIs comparePaula RadcliffeHeight 5'7" Weight (kg) 54BMI 18.0 (Underweight) Haile GebrselassieHeight 5'4" Weight (kg) 56BMI 20.5 (Normal Weight

. If your BMI drops below 18.5, you're at risk of becoming weaker and slower. WEIGHT LOST 5K 10K HALF-MARATHON MARATHON 900g 12.4 secs 25 secs 52 secs 1:45 2.3kg 31 secs 1:02 2:11 4:22 4.5kg

's not impossible. But a person who is overweight would be faster if he lost weight. Theoretically, a loss of about two pounds will increase speed by about a metre per minute of running. So if a runner runs a 5K in 20 minutes, a two-pound weight loss would make him

in Days 2-5 are for Runner's World magazine subscribers only. (The good news is that you can get instant access to the articles, 12 issues delivered to your door, AND 30% off here). To begin with, here's how to make the most of running for weight loss

. GGWell, sure, it's not impossible. But a person who is overweight would be faster if he lost weight. Theoretically, a loss of about two pounds will increase speed by about a metre per minute of running. So if a runner runs a 5K in 20 minutes, a two

-Venturi. "Otherwise your glycogen levels dip and that compromises your performance."Both experts recommend you have your Body Mass Index (BMI) measured by a dietician to help identify your ideal weight. This is one that's not too heavy, which will slow you down, nor