How advancements in prosthetic limbs could impact future of sports

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He hadn't played more than a few garbage-time minutes since the accident, but when Coach called to him down the bench midway through the first quarter, he loaded his CO2 cartridge into "AK," whipped off his one-legged warm-ups, checked in with the scorer's table, clicked in his mouthpiece, found his defensive assignment (who gave him an affirmative, friendly nod -- everyone has been so friendly since he came back) and recorded his longest stretch of continuous playing time since the season opener.

The prosthetic, which he likes to call "AK," as in "above the knee prosthetic," held up well. But now, during halftime, the team's director of health technology and the prosthetic engineer are trying to stabilize the spring in the ankle because something felt just a little bit off when he was stunting back and forth laterally in half-court defensive situations. They're working like a pit crew at Daytona to finish up the repairs, as his teammates and the coaching and support staff filter out of the locker room back toward the court. If need be, he's got a backup ("AK Senior"), but the microprocessor has been wonky, which makes his gait cycle a little awkward.

But, hey, this technology is young, and even with the occasional malfunction, he's far more comfortable on the floor than he ever could've imagined. His rebound rate is nearly double his career average since coming back. Is it the prosthetic, and, if so, what are the implications for the future of basketball?

Prosthetics are on their way

This player and AK don't exist, but talk to enough people in the field of biomechanics, prosthetic design and adaptive sports technology and there's near unanimity that the machinery needed for an amputee with the necessary talent and drive to play basketball at a world-class level isn't far off.

"The question in basketball is not if but when," says Dr. Rory A. Cooper, Director of Human Engineering Resources Laboratories at the University of Pittsburgh who is also the founding director of the Veteran Affairs Rehabilitation Research and Development Center. "Basketball is a little behind, but it's already happened in track and field."

Oscar Pistorius had both of his legs amputated below the knee as an infant, yet by his preteen years, he was a full-on jock who excelled at multiple sports. By his 18th birthday, he was a Paralympic gold-medal winner in track and began to compete in national able-bodied races in his native South Africa. After tangling with the International Association of Athletics Federations for several years over his eligibility, he won a silver medal at the 2011 World Championship as a member of South Africa's 4 x 400 relay team and became the first amputee to participate in an Olympic track event in 2012. Though Pistorius was a hero to many, a court found him guilty of culpable homicide in the 2013 death of his girlfriend.

When the IAAF weighed in on Pistorius and his flex-foot Cheetah blades, they cited their own study, which found, "The positive work, or returned energy, from the prosthetic blade is close to three times higher [emphasis IAAF's] than with the human ankle joint in maximum sprinting." A durable, powered prosthetic leg with a smart microprocessor, custom engineered to play basketball, might have the same kind of advantage over the weary limbs of guys playing 2,500 minutes a season. The league's players, organizations and New York office have never been more attuned to the cost of wear and tear, and they might cast a jaundiced eye on a player less vulnerable to the attrition that's plaguing the rest of the NBA.

"You'll never be able to replace the limb, but we can get things like ground reaction force, the spring in the feet, things like that. And now we have athletes who are using these devices to beat world records." John Spillar, market manager for sports prosthetics for Ottobock

Wheelchair basketball has typically been the preferred competition for amputees who play, largely because the biomechanical demands of basketball are so intricate: the change of directions, lateral movement, constant stopping and starting and irregular extension and flexion of the limbs. And that's before you ever shoot a basketball or collect a rebound, each of which require very specific motor functions in the upper body.

"What I found very early on is the combination of directional motions when you're playing basketball are the main challenges," says Kim De Roy, VP of Sales, Marketing & Education/Prosthetics for Ossur Americas. Ossur is an Icelandic manufacturer of prosthetics. De Roy was also a competitive basketball player in Belgium before suffering an accident and single-leg amputation at the age of 19. "You have to overcome these things if you want to design the ultimate device that allows a player to get back on the court."

Performing these motions with proficiency requires state-of-the-art prosthetics that display incredible mastery. But that technology is in the pipeline -- and in some cases already here -- and the science behind it is advancing quickly.

"The technology in the last five years is leaps and bounds ahead of where it was the previous 15 years," says John Spillar, market manager for sports prosthetics in North America for Ottobock, a manufacturer of prosthetics. "We're making more and more custom devices for people who want to climb mountains, for people who want to play specific sports. You'll never be able to replace the limb, but we can get things like ground reaction force, the spring in the feet, things like that, and now we have athletes who are using these devices to beat world records."

This trend toward customization is what has engineers and scholars such as Cooper and executives such as Spillar so optimistic. For years, virtually all prosthetics were what's called "passive." The energy a passive prosthetic releases is some percentage of the energy the user puts in. This is the concept of perpetual motion, where that amount would be 100 percent, but in the real world, there's always some loss of energy. That might allow an athlete to have minimal function in a casual basketball game, but it wouldn't cut it in the NBA.

Where hardwood and battlefield meet

What if a robotic lower leg had its own motor, and what if its movements were governed by a computer that knew what it took for a basketball player to pivot in the post, or turn the corner on a pick-and-roll or how much pressure to exert on the ankle to get the precise lift he needs to make a layup? These are the kind of questions Cooper and his colleagues at Pitt and manufacturers like Ottobock are considering as they push the science of prosthetics forward.

Like most functional technology, that means taking something that has traditionally worked manually and incorporating motors and computers to make those functions more efficient and more precise. This is where the military and the world of athletics share a common priority.

"Sports and the military have driven most of the technical advances in lower limb prosthetic devices," says Cooper, a veteran who suffered a spinal cord injury. "Both have pushed technology to achieve higher levels of performance, one for sports and one for tactical movement. Energy-storing feet, carbon fiber sockets, shock-absorbing pylons are all examples of advances from striving to improve performance in sports and military activities."

This overlap between the rehabilitation of the combat soldier and the rehabilitation of the athlete has created a symbiosis of sorts. Advancements in one area boost the fortunes of the other. Cooper emphasizes that being a warrior, in effect, means being a tactile athlete whose training and rehab regimen share many commonalities. A soldier using an advanced prosthetic has to be agile, responsive to conditions and must have the physical capacity to ensure the safety of himself and those in his unit.

For basketball, where "mechanics" and "fundamentals" and "body control" determine success or failure, functionality is also vital. The prosthetic has to, quite literally, know how to do these things, and this is where the fancy technology comes into play.

What players can teach prosthetics

Ever seen EA Sports' Capture Lab? NBA players fly up to the company's headquarters in Vancouver, put on that funny costume with the motion sensors on it, then head into the special gym for a full battery of drills that capture their movements. This is the process that enables Damian Lillard the "NBA Live" video game character to look identical to Damian Lillard, human point guard.

"We do the same thing," Cooper says. "We put the tights on them. We put the markers on them. We can measure those motions you have to go through to be an NBA level point guard. The nice thing about the labs for the video games and some of the labs the NBA players use to improve their own performance is there might be data on other athletes performing at that level, so we could get the required range of motion for the design of the foot and ankle. We would know what forces we'd have to apply, how much energy and how fast it would have to be able to dump that energy in order to be able to jump three feet in the air, or to make a pivot at full speed, or stand firm when you're getting pushed around by someone who's 6-foot-8 and 250 pounds."

Hypothetically, this means that if the team at Pitt or Ottobock could snag Russell Westbrook for a couple of hours, they would have the ideal prototype for the modern-day scoring point guard -- his explosiveness, his postural control, his lateral mobility. If the wish list is a big man with balletic footwork, developers could do a lot worse than an afternoon with Jahlil Okafor -- his pivot, his drop step, his ability to establish a strong base with his legs.

"The ability to identify muscle movement patterns and allow the prosthesis to do that is here today," says Mark Edwards, Director of Professional Clinical Services at Ottobock. "We have now what is called pattern recognition, where sensors can pick up the pattern of muscle movement and replicate them in a prosthesis."

Not unlike the young player who plays, has a tough time, pursues some individual work with his coaches, maybe watches some film, identifies areas for improvement, tries again, gradually gets better and continues to work to perfect his game, the prosthetics' brain will partake in its own player development.

"There would be a machine-learning component not all that different from what Google uses to tell you what your shopping preferences are based on your previous experiences," Cooper says. "We'd have the software learn by bringing the player in, putting the prototype on them, then having them perform those various moves. And as we tune the software, we'd have them tell us when it's working best and when it's not -- 'this feels natural. This doesn't.'"

The speed of the game presents another hurdle to those developing this technology. Consider how many bodily movements occur in the three seconds it takes for John Wall to cross his defender over, explode into the lane, change direction, stop, pivot, lurch past the help defender and elevate for a reverse layup. Now imagine your computer on a slow day and how long it takes your browser to respond.

"This is a very complex environment of multiple motions and directions," De Roy says. "As fast as computers are, they might still be too slow to interpret it on time and direct a mechanical device. You would not only need to have a fast-thinking computer, but then you need the actuation, the motor that is so fast that it can respond like a muscle twitch."

This technology isn't fully there yet, in some part because the market isn't, either. A prosthetic with the capabilities being described here could run well into the six figures. The Venn diagram where those who can afford such a luxury and those who want to play high-level basketball is a tiny sliver of a space.

"One of the biggest challenges to prosthetics is making them affordable," says Jeff Huber, founder at Standard Cyborg, which makes a variety of prosthetic limbs with specific functions, including a 3D-printed waterproof leg. "For a performance athlete making $8 million a year, you can invest a million bucks, but for most people, that's not a reality."

This is one reason Cooper believes that the first athlete to compete with an advanced prosthetic in the NBA will be a player who had previously been in the league.

"They'll already have the talent, the experience and the training, and they'll have the resources, the support of the team if they help him get a prosthetic design to help him return to play," Cooper says. "In some ways, the Rocky Bleier story."

Is the hoops world ready?

How the NBA and its fans would respond to a Rocky Bleier with a gas-powered leg is a matter of speculation. Neither the league nor USA Basketball have had any internal conversations about whether athletes with external enhancements like prosthetics would be permitted to take the floor in an NBA game.

Some might question whether the player's production is truly his own creation. As Huber says, "Are you observing the talent of a human, or are you observing the talent of a software engineer?" Sports is where people go to test the physical potential of the human body, and there will be those who believe that a creation like a robotic prosthetic introduces an inhuman element to a fundamentally human endeavor. For people nervous about the prospect of artificial intelligence colonizing the human race, this might seem like the gateway technology to cyborgs.

Mechanization has a prominent place in sports, whether the advent is compression sleeves, cryo chambers or platelet-rich plasma therapy. Laser eye surgery requires no permission, and professional athletes are on the frontier of medical advancement, whether they're traveling to Germany for surgery or tracking their exertion by running around the floor with a GPS device attached to their bodies. These innovations don't rouse fears primarily because they're available to every competitor.

Enhancement, whether we're talking about a powered prosthetic or an athlete whose parents elected to have his blood's oxygen content increased while he was in the womb, will almost certainly land on sports' ethical agenda in the next few decades. It will also do something not seen since the advent of the Olympics, or the introduction of women teams, or the rise of advanced surgical procedures that would've been inconceivable a generation ago: It will test the world's definition of "athlete."