Usain Bolt warns fellow athletes: stop doping or the sport will die

• Jamaican sprinter offers stark warning but says sport is on the mend
• ‘The only way track and field has left to go is up’Usain Bolt has issued a stark warning to his fellow athletes that they must stop doping otherwise track and field will die. The triple Olympic 100m and 200m champion insisted that the sport was on the mend following the staggering revelations of state-sponsored doping in Russia but conceded more needed to be done to tackle the scourge of performance-en