how big is a jockey
The Kentucky Derby, for example, has a weight limit of 126 lb (57 kg) including the jockey's equipment. The weight of a jockey usually ranges from 108 to 118 lb (49 to 54 kg). Despite their light weight, they must be able to control a horse that is moving at 40 mph (64 km/h) and weighs 1,200 lb (540 kg). Though there is no height limit for jockeys, they are usually fairly short due to the weight limits.