Recurrent Injury. An injury of the same type and at the
same body location as a previous injury was classified as
a recurrent injury. The remaining injuries were classified
as first-time injuries. However, the time between injury
recurrences was not accounted for in the questionnaire.
Injury Severity. The severity of the soccer injury was
classified according to the number of days that elapsed
from the date of injury to the date of the player’s return
to full participation on his soccer team. We grouped injuries
as slight (7 days), mild (7-14 days), moderate (15-
21 days), and severe (.21 days). This classification was
independent of the type of injury because a medical attention
injury (which did not impede subsequent soccer training
or play) may need several days or weeks to be
completely rehabilitated (eg, a finger fracture). The questionnaire
also included whether the injury required surgical
treatment.