therapist and biomechanist Irene Davis from the University of Delaware's Running Injury Clinic. "Your threshold could be at 10 miles a week, or 100, but once you exceed it, you get injured." Various studies have identified injury thresholds at 11, 25, and 40

't prevent injuries or improve performance, so there's no reason to do it. The time to do your stretching is after your run, or even later in the evening." Stretch (without straining) your calves, quads and hamstrings for a total of 10 to 15 minutes. Expect a

was already a marathon runner, and most of my runs were long and slow. My cross-country conqueror took a different tack. He focused on hard 1,200m intervals, subjecting his muscles to the kind of stress he’d face in competition. At times he also ran 400m

ran 2:42:24 in 1975, and Joan Benoit Samuelson ran 2:22:43 in 1983. ("World best" was the euphemism instead of "world record" for road-race performances before January 1, 2004.) This year saw a course record set in the men's race, but, at 2:07:14

. 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

of the participants running a 62-mile race consumed 14,000 millilitres of liquid; another who ran only 26 miles, drank only 280 millilitres. The latter runner, not surprisingly, showed the most loss of vascular fluid, resulting in thickened blood plasma and impaired

medicine groups, which have generally advised endurance athletes to drink 600ml to 1,200ml per hour. This is more or less where things stood before the NEJM publication last spring. A trio of triggersAfter the NEJM article appeared on 14 April, I waited a