Shericka Jackson Withdraws from Olympic 100 Meters

Shericka Jackson won't run in the 100 meters when Olympic track starts Friday.

She suffered an injury at a tuneup race earlier this month.

The injury played a part in her decision to withdraw from the 100 meters.

Jackson was expected to give Sha'Carri Richardson her toughest competition in the sport's marquee event.

She will still run in the 200 meters, where she is the only woman other than the late Florence Griffith Joyner to finish in under 21.5 seconds.

Jackson won national titles at both distances earlier this summer.

She was expected to be part of a typically strong pool of Jamaican sprinters.

The Olympic track events start on Friday, and Jackson's focus will be on the 200 meters.

She has a strong record in this event, with a finish time under 21.5 seconds.