KINGSTON, Jamaica – Nathaniel Martin of Jamaica College continued his giant killing act after he completed the boys under-20 sprint double on Sunday’s final day of the JAAA national championships by winning the 200m in a personal best 20.82 seconds (0.9m/s). Martin had come out of the blue to win the 100m on Friday and proved on Sunday that it was not a fluke after he took the lead with 50 metres to go and got to the finish line first. Holland High’s world under-20 leader Shanoya Douglas obliged the form books as she also completed the double.