Arrive at the TD Garden before security allows fans into the building, and you will probably see just one player shooting. His body, although not especially bulky or strong, looks created by an ice sculptor, and his jump shot looks like an evening summer breeze. Thirty-five years old, thirty-six next month, Ray Allen still moves with the power of youth, still treats his body like a golden god, still prepares for each game sticking to a strict schedule influenced heavily by his military upbringing.

As his jump shots float to the rim like feathers equipped with tracking devices, you wonder how much longer Allen can stiff-arm age. Many men his age have beer bellies. They complain about aches in their joints after the shortest runs. They bitch about back pain after playing a single pickup basketball game. They breathe heavily after walking up a long flight of stairs. They watch NBA games in their living rooms, and on certain nights they even stay awake for the whole game. These average men don’t have Ray Allen’s natural talent, nor do they work to preserve their bodies like Allen does. They don’t ride their bikes for 30 miles in one outing and they don’t shoot hundreds of jump shots each day. They don’t maintain diets designed to eliminate body fat and they could never say with any honesty, “When I’m on the floor, I’m not going to break down. I’m not going to be breathing heavy or panting. I’m either chasing somebody or they’re chasing me. But I can outlast them. When that happens, I’m going to make my move and get my shot off before they can stop me.”

Years after his retirement, fans will remember Allen’s shooting stroke. Prettier than Mila Kunis in Forgetting Sarah Marshall, the stroke will define Allen’s career. It has helped him become the NBA’s all-time three-point king, has helped him make 2,612 regular season three-pointers and counting. To say Allen’s stroke looks effortless would be like saying Yao Ming looks tall. Reggie Miller failed aesthetically, clacking his wrists against each other in an almost spastic motion every time he drilled another trifecta, but Allen’s shooting form reminds of a desert sunset, picturesque and almost always excessively hot. Perhaps there has never been a more beautiful shooting motion, as Allen combines perfect form—legs spread shoulder width apart, elbow under the ball, follow through straight at the rim—with a ballerina’s fluidity. Long after Allen retires that stroke will remain intact, and I assume he will forever swish far more jumpers than he misses. But conditioning remains the most impressive aspect of Allen’s game.

To play Allen’s role takes a body equipped to run miles around the court and still have enough energy to set his feet, rise and send a ball into its home that rests 23 feet, nine inches away. He often defends the opposition’s best player, like he does when the Celtics play Dwyane Wade or Kobe Bryant, and still scampers around screens on offense with the energy of a seven-year old attending a birthday party at Chuck E. Cheese. Every opposing coach designs a defense in part to limit Allen’s open shots. Every opposing coach instructs his players, “Under no circumstances should you leave Ray Allen.” Yet Allen continually finds himself open, because he works hard enough running to open spots and also because he reads plays so well.

A shooter needs intelligence to read his defender and create enough space to release the ball. Some shooters float to open spots rather than circle around screens. Think Eddie House. House can’t create shots for himself and rarely shoots after running around a series of screens. Rather, he relocates on the perimeter to take advantage of his defender’s help defense. House’s defender will sag into the middle of the lane and House will shuffle into the corner, maximizing space to release his lightning-quick jump shot. Allen often utilizes the same method, especially when Rajon Rondo penetrates. But he also excels where House does not, losing his defender in a maze of screens before planting his inside foot, balancing himself and throwing a dart at the rim.

Watch Allen utilize screens all game long and you will receive a free clinic. Trail Ray Allen around a screen and he will curl it. Double him on the curl and he will find his screener wide open. Go underneath the screen and Allen will fade into a jump shot. Get stuck on the screen and he will pop straight out. Trail him perfectly and he will switch speeds or directions until you lose his scent. Almost always, Allen makes the right choice, a quality that has led to as many three-pointers as his perfect stroke.

After exercising a player option yesterday, Allen will remain a Celtic for at least one more year. He will be 36 years old when the season starts, well past the age most shooting guards become obscure. But age has proven itself a poor indicator for Ray Allen, who I’m sure will still feel the same way about each one of his defenders as he always has:

“I’m either chasing somebody or they’re chasing me. But I can outlast them.”

And then he will split the nets with a shot that supports both sides of the nature or nurture argument.