Greg took a training session at the Eldon Square shopping centre as part of the launch event.
He won gold at London 2012 long jump and says now it's his turn to inspire others.
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Emma Jesson brings you Sunday night's forecast
Cold and clear with widespread frost on Sunday night. Sunny Monday then showers
A number of Britons are feared stranded on Mount Everest after the Nepal earthquake triggered a deadly avalanche on Saturday.