His personal best in this event before the Games was 4 : 02 : 13 .
He bettered best by clocking a time of 3 : 56 : 48 , a new national record .
His personal best in this event before the Games was 4 : 02 : 13 and he bettered it by clocking a time of 3 : 56 : 48 , a new national record .