Related Clues:

• Did a 10K, e.g.
• Three-legged endeavor
• Bolted
• Olympic event
• Run quickly
• Breed
• Hastened
• See 65-Across
• Wasted no time
• See 18-Across
• Humans, e.g.
• See 15-Down
• Go full tilt
• Competed in a marathon
• Kentucky Derby, e.g.