It's1948-1952, Jamaica has the worlds three best 400m sprinters in George Rhoden, Herb McKenley and Arthur Wint and a stud 100/200 in Les Laing, McKenley also a 100/200 cat, wining an Olympic 100m silver.
They broke a handful of world records and won a slew of Olympic medals.Then here came Dennis Johnson in the 50's he ran the 9.3 world record 4 times, Lennox Miller showed up in the 60;s, winning Olympic medals in the 100, Right after him came Don Quarrie he won the Olympic 200 with a 100m silver.
Point....Jamaica has had sprinters for a long time. With most being US trained, All those guys above but Wint attended USA schools.
1951 400m world ranking
1951 1....................George Rhoden (Jamaica)
2.....................Herb McKenley (Jamaica)
3...........................Arthur Wint (Jamaica)
4................................. Mal Whitfield (US)
5................................Charlie Moore (US)
6.................................Dick Maiocco (US)
7..............Hans Geister (West Germany)
8............Schalk Booysen (South Africa)
9...Karl-Friedrich Haas (West Germany) 10...............................John Bradley (US)