Possible Clues:

• Target of some herbs and pills
• Triathlete's quality
• Staying in a finish after a rug's turned over
• What marathon runner needs reproductive parts in bloomers?
• Workhorse's quality
• Ability to sustain prolonged effort
• Enduring ability -- in a man, it's exceptional
• Staying back with ants abot one in the morning
• The rug's been turned over in a staying way
• Staying power in a man - it's surprising