How Lleyton Hewitt's unprecedented 20th straight Australian Open tilt this month will be the culmination of a brutal summer regime involving some 800km of high-intensity hitting, running, swimming, boxing and strength tennis training.
Long revered as one of Australia's most supreme athletes, Hewitt has worked ferociously on his game and fitness for almost six hours a day, six days a week - virtually non-stop - since early November in preparation for his Open swan song.
Attacking every session as if it were his last, the indefatigable former world No.1 has worn out a queue of hitting partners since commencing his exhausting eight-week block and left his decade-long conditioner in awe.
"In terms of endurance and durability playing professional sport at the highest level for 20 years, there wouldn't be many athletes who could match it with Lleyton for intensity on a day-to-day basis," fitness trainer Nathan Martin told AAP.
"He never gets sore. He turns up every day with the same...