I can't tell you why a particular athlete would leave a certain coach, but I can tell you there could be many reasons. They could have personality conflicts. They could have misunderstandings. Lots of stuff can happen.
Alberto SalazarTrust me, my runners aren't going to run one event while looking past it to the second event. When they get on the line for the 10K, that's a do-or-die situation for them.
Alberto Salazar