Usain Bolt makes sluggish start to world 100m after beef with the blocks

• Bolt wins his 100m heat but admits he has to improve his start• Bolt: 'These are the worst blocks I have ever experienced' Usain Bolt always manages to retain a veneer of being unbothered by his rivals but he was unable to hide his distaste for the starting blocks being used at the world championships. The Jamaican wants to sign off with one final 100m title to add to his 11 world and eight Olympic golds but admitted he needs to repair his relationship with the blocks in order to triumph o...