Possible Clues:

• Carotene derivative has succeeded for six showing endurance
• They turn up underfoot in a way of staying there
• Dropping back, short of energy, revitalises, showing fortitude
• Ability to keep going makes lively mounts expend energy
• The rugs have been turned over in a way that's staying
• Turn the rugs over in a way to make one bear it
• A minute with a saint to start showing legs
• The ability to sustain prolonged physical or mental effort
• It's a man revitalised showing endurance
• The rugs are turned over in a staying way