0
0
The Trinidad and Tobago star hit the fifth hurdle hard after her left leg appeared to buckle in the women's 100 metres hurdles heats.
John lay motionless on the London Stadium track as medical staff rushed to help.
The 27-year-old received treatment on the track for 10 minutes after the fall, which came in the final heat.
She was placed in a stretcher as a precaution and then carried out of the stadium.