Men run 110m while women run 100m hurdles.
The height of the hurdles is 106.7cm for men and 83.8cm for women (400m: 91.4cm for men and 76.2cm for women).
There are 10 hurdles in all the three races.
Technique: the runner needs to pass as close to the hurdles as possible, because a runner loses speed in the air.
The most important thing is for hurdlers to quickly find their optimal running frequency and for them to maintain a constant centre of gravity.
In the 100m/110m races most hurdlers take three strides between the hurdlers while in the 400m race most take 13 strides between hurdles.