A force that reaches its maximum value earlier than 50 ms after the first contact between two bodies. An impact force occurs during the take-off and landing phases of jumps; for example, when a long-jumper strikes the take-off board, the contact time is about 100 ms with the first 20–30 ms being the duration of the impact force. Compare active force. See also coefficient of restitution.
Subjects: Sports and Exercise Medicine.