Possible Clues:

• A mother ran out – one in London race?
• Mum more properly binds leg for one in the long run
• One going the distance?
• Runner who may 'hit the wall'
• Athlete who may ''hit the WALL''
• Polish king going after revolutionary competitor in long run
• Long-distance runner
• Another disaster during month for athlete
• Horse mostly eating grass, perfect for runner
• One on the run