At around the 400m mark of the 2nd heat of the 1500m semifinal, Craig Engels gives an arm-fully-extended shove to Hobbs Kessler, clearly breaking up Kessler's stride. I know Kessler seems to occasionally have difficulties finding his space while running in a crowd, but it didn't seem like he was cutting in or encroaching.
In the parlance of LRC, discus.