Athletics - 'Sluggish' Bolt does enough in 100m heats

By Scott Malone and Gene Cherry RIO DE JANEIRO (Reuters) - Jamaican Usain Bolt won his 100 metres heat after what he called a "sluggish" start on Saturday, but looked pained after the race as he prepared to fend off the challenge of American Justin Gatlin for the Olympic crown. Bolt, who turns 30 on the final day of the Games, is aiming high in what he has said will be his final Olympics, bidding to continue his streak of gold in the men's 100m, 200m and 4x100m relay, the unprecedented "triple-t