Possible Clues:

• One is not expected to live on them
• Final competition stages? If you're on them it's almost over
• Survive stages on them? You're nearly finished!
• Things are bad when you are on these!
• Going soon but not yet to final parts of competition
• Near-exhaustion metaphor
• Nearly finished on them over one foot each
• Final Limbs denoting ebbing strength
• Final dregs of energy - of lower limbs?
• As a walker you're almost finished on them