“Mushy bones and everything”

Part 1: You don't have to be injured to sit out a game.

READ PART 2: The ice is thinner than you think.


From time to time, the NBA releases official statements. If they are intended to quell controversy, that’s not how it has been working lately. The NBA’s first statement in response to Daryl Morey’s Hong Kong tweet seemed to stoke more fights than it calmed. The Mandarin-language version was reportedly different in key ways, and even the English version needed updating by the commissioner. In the following days, Adam Silver clarified the key point that the league supports freedom of speech. 

Similarly, last week the NBA issued a statement fining the Clippers $50,000 for … something confusing. It was related to the team’s decision not to play their star, Kawhi Leonard, for a nationally televised game against the Bucks. 

The first issue was that Leonard, for whatever reason, has never publicly disclosed an ongoing health issue. He sat out 22 games last year in a much-discussed injury prevention regimen managing something mysterious, sometimes whispered to be his knee. But despite a tangle of rules from the league and the government protecting the confidentiality of employees’ health information, the NBA sent out a press release last week telling the world: “Leonard is suffering from an ongoing injury to the patella tendon in his left knee.”

Kawhi said he was “shocked” the league shared his private health particulars. Understandable. 

But that press release had another issue. In my interpretation, the league fined the Clippers $50,000 for telling the truth. The league said Kawhi was out injured. Clippers’ coach Doc Rivers, on the other hand—who works and travels with Kawhi—said that Kawhi felt “great.” 

Which would mean Kawhi, in fact, sat out for the same reason he has sat out dozens of games in recent years: to avoid injury.

The league didn’t like that. Then they doubled down, evidently clarifying in a memo to teams that load management, itself, was not reason enough to sit out. I have talked to many around the league, all of whom take that statement as an order to lie—if you are sitting a player to prevent an injury, now you must claim the player is already injured.

Here’s a guess as to why the league would take that position: NBA fans generally hate load management. It reminds me very much of the early days of talking about climate change. Most people would rather the science just go away. Here are some typical sentiments:

But you know who supports reducing the number of games NBA stars play? Everyone who has spent time looking into the science. Just today, Mavericks governor Mark Cuban was quoted saying that he’s all for load management because the evidence favors it. “The dumb thing,” he told the Boston Herald, “would be to ignore the science.”

In other words, the NBA just did the dumb thing.

In some cases, there are giant reasons to sit players before they are injured.

“Wanna see stuff getting crushed by hydraulic press?” asks the description of YouTube’s Hydraulic Press Channel. “This is the right channel for you.” The vibe is after hours at a high-school physics class—if your high school had a giant hydraulic press and a Finnish man lurking just out of view. 

They’re doing something right. The most popular TV show in the NBA has 824,000 YouTube subscribers. The Hydraulic Press Channel has 2.3 million. After running the channel since 2015—they’ve crushed televisions, rubber duckies, Easter baskets, dry ice, and a giant stack of compact disks—the channel is looking for ideas. “If you have good ideas about stuff to crush,” it says on the screen near the end of an 11-minute video of soda cans, bottles, coconuts, and eggs being flattened, “please write them to comments!” 

The drama comes not only from seeing an item shatter, but from guessing when it will shatter. Sometimes there’s a sensor visible, measuring the press’s force in kilograms. With all that crushing, our unnamed, off-camera, Finnish narrator has developed a pretty good ability to guess how much force it will take to crush this or that item. 

When they put an empty soda can in the press, you find yourself thinking about what it would take. A big person could just step on it, right? But a child might have to add a stomp. There is a small thrill to see that a can collapses at about 170 pounds of pressure. Seems right.

An egg might feel like it could handle some squeezing in the palm of your hand, but the narrator guesses it will take only about 20 kilograms of force to crush in the press. The reason: the metal of the press is hard, not like “your hand, with mushy bones and everything.” He’s right.

“Mushy bones and everything” are the point of this story. 

It turns out the ligaments in your knee don’t have a hydraulic press pushing down on them. But they do have all the mass of your head, torso, arms, and upper legs—driving into the ground, and depending how you move, that can cause problems. 

Somewhere in here is where the conversation about load management goes off the rails. The crisis of 2019 in the NBA isn’t that players are soft now, nor that people want time off because they’re lazy. The crisis is that inside the hips, knees, and ankles of NBA players are big forces threatening extremely valuable “mushy bones and everything.” The crisis is that we are starting to know who will get hurt before they get hurt, thanks to the kind of high-school physics you can see in action on the Hydraulic Press Channel. 

We can’t shrug and consider injuries acts of God anymore. They are acts of basketball.

In motion sensor labs, outfitted with force plates and infrared cameras, the forces working within players’ bodies are as measurable as the press working on the egg. Between teams’ own facilities and vendors like P3 and Sparta Science, practically every NBA player has been measured in this way at least once, if not repeatedly. And just like the off-camera Finnish man can ballpark the the breaking point of an egg, there are people who are getting pretty good at anticipating the stress on this anterior cruciate ligament or that Achilles tendon. 

Some kind of intervention is called for. Until the league figures out a way to protect players vulnerable to injury, some players and teams are sure to take matters into their own hands.

In 2006, the league learned about the relationship between elite athleticism and heart problems like hypertrophic cardiomyopathy, which caused the sudden death of players like Hank Gathers and Jason Collier. They quickly made a difficult, life-saving choice: they forced every player to be screened, and barred those with dangerous heart conditions. It has probably saved lives while also ending some NBA dreams. Harsh but effective.

This is a miniature version of that discovery: What if, instead of banning a player from an NBA career in the name of his heart, you could ban him for a few games here and there to prevent a crisis to his ACL or Achilles? Wouldn’t you have to do that? 

Can anyone make the case we should keep things as they are?

One way or another, science-driven changes to the NBA schedule are coming. Many general assessments from things like wearable electronics assessing blood values, brain scans, and sleep studies tell us that elite athletes are overworked. Years ago, a study showed that players in top European soccer leagues have six times the injury rate if they play two games instead of one per week. The study might not be the most relevant to the NBA—it’s a different sport—but it’s a home run that the schedule itself causes injuries. Tired bodies don’t have the same strength, and they are more likely to move inefficiently. 

In Australia, football injuries tumbled when stars started wearing sensors and sitting when fatigue began to affect movement patterns. An ESPN project with sleep expert Cheri Mah has consistently predicted “schedule losses,” defined as games in which a team couldn’t compete well, due to hard travel logistics interfering with sleep. 

A lot of the most relevant insight comes from assessing exactly how a body moves. Sparta Science’s Phil Wagner recently told me that his startup can assess an NFL roster and accurately predict 18 percent of that team’s injuries. (He suspects injuries could be reduced 20-50 percent with better management. I suspect better management might look a lot like what Kawhi Leonard is doing.)

Eric Leidersdorf is the director of biomechanics at P3 in Santa Barbara, and has a job assessing how much force it takes to break something—kind of like Hydraulic Press Channel guy. At P3, they often say what they do is “high-school physics.” P3 straps little sensors all over an athlete’s body, and asks them to, say, jump off a box and land on a force plate. What happens on the computer screen in the back of the gym looks confusing as hell. But after visiting three times, for multiple days each time, I’ve come to understand that to Eric, the profusion of data is more or less like the Hydraulic Press Channel. Watching things under force.

How people move is very personal; in some ways we are each unique. But there are recurring themes, which often overlap with the conventional wisdom of weightlifting, dance, and every other tradition of strength in movement. A favorite example: knees that dip inward toward each other as they bend. That’s a big worry. It’s called valgus collapse and—Google it—it’s associated with a lot of injuries. 

The Bucks’ Kyle Korver first visited P3 13 years ago, when he played for the Jazz. He told me that at that time he was considering retirement because his knee was in so much pain. He wasn’t strictly injured, though. Instead, he was like a lot of players—managing soreness. Up until that point, he was deep into treating the issue with the normal trainer toolkit: ice, heat, and ultrasound.

When he saw the slow-motion video from his P3 assessment, though, he says he almost threw up in his mouth. Now, for the first time, he was staring at the cause of his pain: When his left knee bent, it dove toward his other knee so hard that it often bumped it. This said terrible things about the forces inside his left knee, which is not designed to carry forces at that angle. And the collisions themselves weren’t helping.

What he needed was a new way to jump. P3 trainers worked to improve his symmetry and to strengthen the glutes he’d need to hold his leg on a healthier track as it bent. They drilled him in healthier mechanics. Over time, recurring assessments showed that Korver learned to land without putting a hydraulic press on the more delicate parts of his knee. After a couple of weeks at P3, Korver says he felt a noticeable difference. 

Korver might not have technically been injured. But he was at risk of ending his career. 

There are 800 NBA players in P3’s database—that data would tell you that it’s nearly impossible to have a long, fruitful career with those body forces moving like Korver’s were. 

I don’t know anything about the insides of Kawhi’s knee, but I know that there are times nowadays, when “just go out there and play” is a ridiculous approach. Enough NBA players are injured already. Kawhi uses more useful language: he should play when his body is “ready.” As in ready to take on big forces without big risks. It’s a much healthier way to discuss it (except that if a coach does it, the NBA might want $50k).

Korver liked the results so much that he bought a house and moved his whole family a few miles away from P3’s gym. Now a player who once considered early retirement has become one of the NBA’s longest serving. He and LeBron are the only players left from his draft class. 

Sometimes what P3 sees is absolutely alarming. For the NBA players they assess, the worst thing that can show up—the thing most likely to lead to an injury—is when bending your knee features an upper leg rotating one way while the lower leg rotates in the opposite direction. Picture wringing out a dish towel. Now imagine doing that to your knee, every time you land. It’s quite common, and a scary predictor of injury. 

It can also be addressed, just like Korver’s issue. But it takes some time.

If you coached a player who landed like that, with big force, he might not be injured …yet. But it would be crazy to play him.

READ PART 2: The ice is thinner than you think.

Friday: David Thorpe on killer coaching.