Objective: To summarize the medical encounters (injury/illness) for runners
and the meteorologic data collected in the medical area of a large maratho
n race. Design: Prospectively transcribed medical records were analyzed for
encounter rate, injury/illness type, treatment rendered, and outcomes. The
environmental conditions for each race day are compared with injury/illnes
s rates and types. Setting: An urban 42-km marathon located at 44 " 53'N la
titude and 93 " 13'W longitude, scheduled on the first Sunday of October wi
th an early morning start time. Participants: 81,277 entrants in the Twin C
ities Marathon from 1982 to 1994. Main Results: The start temperature range
was -4 to 16 degrees C and the 4-h temperature range was 5-20 degrees C. T
he average dew point was 3 degrees C at the start and 4 degrees C at 4 h. T
he finish area medical encounter rates for marathon runners were 18.9 per 1
000 entrants and 25.3 per 1000 finishers. Mild injury/illness accounted for
90% of finish line medical encounters. Runners presented with exercise-ass
ociated collapse (59%), skin problems (21%), musculoskeletal problems (17%)
, and other medical problems (3%). Only 112 runners received intravenous fl
uids and 30 runners were transferred to emergency medical facilities. One d
eath occurred in 1989. Conclusions: Marathon racing in cool conditions is a
safe activity and most of the medical encounters are of minor severity. An
early morning start time contributes to a cool racing environment and a lo
w injury rate. More than 99.9% of runners who finish this race leave the fi
nish area without hospital or emergency room care. The injury/illness profi
le can be used to tailor medical care at the finish area of marathons.