'Tire' in the Bible

a wild donkey accustomed to the desert, sniffing the wind in her passion. When she's in heat, who can turn her away? None of the males who pursue her need to tire themselves out, for in her month they'll find her."

Indeed, if you run with others on foot, and they tire you out, how can you compete with horses? You are secure in a land at peace, but how will you do in the thicket of the Jordan?