London 2012: USA's Allyson Felix undecided on sprint selection

American 200m specialist Allyson Felix is still undecided whether or not to also compete in the 100m or 400m at London 2012.

The 26-year-old ran both the 400m and 200m at the World Championships last year but failed to win either event, and says the final decision will lay with her coach Bobby Kersee.