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FACTORS AFFECTING PERFORMANCE IN A 100-MILE Murphy CA, Glace BW, McHugh MPNicholas Institute of Sports Medicine and Athletic Trauma, New York, NY - last modified 2013-02-10 00:00
Medicine and Science in Sports and Exercise. 32: S198, 2000.


Ultraendurance races challenge the athlete to meet hydration and energy needs while avoiding gastrointestinal distress. There is minimal literature on intake strategies in ultramarathons, and none published on the intake of female ultra-athletes.

We monitored food and fluid intake during the Vermont 100 in 26 volunteers (21 male/5 female) on a day when temperatures were >35 deg C. Pre-race anthropometric data, medical/running histories, and 12-hour pre-race dietary records were collected. Intake during the race was recorded by direct observation and questioning approximately every 8 miles. The table shows intake data for men and women, combined, +/- SEM.

Pre-race, women consumed more fat (1.6 vs. 0.89 g/kg, p=0.014) and kcals (42.3 vs 28.4 kcals/kg, p=0.049) than men. During the race, women ate more protein than men (0.04 vs.0.02 gm/kg/mi, p<0.001), but had a similar amount of Kcals. Runners with gastrointestinal symptoms (GiSx) ate more carbohydrate (0.3 and 0.2 gm/kg/mi, p=0.045) and Kcals (1.4 and 0.9 gm/kg/m, p=0.05) than those who did not. Cramping was associated with lower potassium intake (p=0.045).

Finishers did not differ from non-finishers for intake of any nutrient, however finishers had completed longer runs during training (63.9 vs. 41 mi, p=0.015) and weighed less (65.5 vs. 74.2 kg, p=0.049) than those who dropped out. Food and fluid intake did not affect finish rate in a 100- mile race in extreme heat, but did affect the occurrence of GiSx and cramping.