Game changers

It’s a sunny Saturday in October, and the crowd at Stanford Stadium is roaring as the Cardinal football team pushes down the field. A wide receiver sprints toward the end zone and cuts sharply inward as the ball soars toward him. But before he makes the catch, he grabs the back of his leg and hits the ground.

Within seconds, Stanford Medicine orthopaedic surgeon Seth L. Sherman, MD, is at the player’s side. Within minutes, the injury has been assessed; within hours, it has been X-rayed; and by the next day, there is an MRI, a medical plan and a timeline to get back to practice.

“The urgency and intensity with which we get to these players’ injuries and start working them up and treating them is extraordinarily quick,” said Sherman, an associate professor of orthopaedic surgery who has also worked with the Chicago Bulls and Missouri Tigers.

Across town, a 40-year-old dad sustains the same hamstring injury playing soccer in the backyard. He ices it, takes some ibuprofen and props it up on the couch.

A week later, still limping around, he visits his primary care doctor. After a normal X-ray, the busy father is told he’ll need to try six weeks of physical therapy before insurance will pay for an MRI.

It seems, at first glance, that these two patients are being treated in entirely different worlds. But Stanford Medicine clinicians said the pressure to treat elite athletes with such speed and effectiveness is driving innovation in the universe of sports medicine.

Over time, that translates to new tools that benefit everyone, from weekend warriors and amateur athletes to average people who sustain a fall.

“This has actually been going on for decades,” said Marc Safran, MD, chief of the Stanford Division of Sports Medicine. “If you look back to when Joe Namath tore his ACL playing football in the 1960s, they developed the ACL brace to get him back on the field, and now ACL braces are very common.”

Today, braces aren’t the only treatment being developed for athletes to return to the field. Minimally invasive surgeries, new drugs and injections to promote healing are increasingly common. Digital technologies that assess movement patterns and an evolving understanding of how the body moves and heals are also in play. All are making their way off the field and into everyday medicine.    

At Stanford, this flow of knowledge is deliberate. The Wu Tsai Human Performance Alliance — a research initiative connecting Stanford’s sports medicine clinicians, bioengineers and scientists — was built on the idea that elite athletes can provide valuable insights for the rest of us.

Across sports medicine and orthopaedics, physicians treat college and professional athletes alongside everyone else, carrying what they learn from one patient to the next.

First, the diagnosis

In the early 2000s, Safran began noticing something unusual in his most flexible patients — ballet dancers, gymnasts and figure skaters. They showed up at his office with pain in their hips but no diagnosis.

Their symptoms didn’t fit with any known condition and scans didn’t show any obvious problems. Safran suspected that something was causing their hips to shift subtly out of position while they were moving; it reminded him of shoulder microinstability, a condition sometimes seen in the shoulders of swimmers.

“A lot of people in the field didn’t think it was possible to have microinstability like this in the hip,” said Safran, a professor of orthopaedic surgery.

But the extreme range of motion that dancers and gymnasts put their hips through made the condition stand out, Safran thought. He carefully tracked the athletes’ movements and what remedies made their symptoms improve.

“We are interacting with elite athletes on a daily basis, and it forces us to keep pushing these boundaries and advancing the field.”

Marc Safran, MD, chief of the Stanford Division of Sports Medicine.

In 2011, he published his first clinical paper on hip microinstability. It is now a recognized diagnosis with defined treatment options — physical therapy or minimally invasive surgery that tightens a component of the hip joint.

Recently, an active, middle-aged woman came to Safran with hip pain. Other doctors had dismissed her pain or told her she would never return to her previous level of activity. Safran quickly recognized it as hip microinstability and treated her surgically.

“I just got a note from her about how incredibly grateful she was that I’d been able to treat her and letting me know that she had just finished a triathlon,” Safran said. “That wouldn’t have happened if we hadn’t started out studying this condition in dancers and gymnasts.”

When top-level athletes have a joint, muscle or bone problem, physicians can quickly rule out factors such as obesity, improper training or lack of exercise that might complicate diagnoses in the general public. That makes it easier to notice new patterns of injury and test new treatments.

“We are interacting with elite athletes on a daily basis, and it forces us to keep pushing these boundaries and advancing the field,” said Safran, who has served as the chief orthopaedic consultant for the Women’s Tennis Association and as a consultant for the NBA and NHL players’ associations.

Then, the treatment

The same dynamic that produces new diagnoses among elite athletes also accelerates new treatments. Once a condition is identified in elite athletes, the pressure to get them back to competition quickly means those athletes are the first to try the latest drug or surgery.

That’s not only because of resources — teams and coaches willing to put money toward treatments that aren’t yet covered by insurance — but also because collegiate or professional athletes might weigh risks and benefits differently than most people do.

“For them, every minute of time loss equates to an impact on their career and future prospects,” Sherman said. “Sports medicine is driven by the search for those holy grail treatments that can get athletes back in the action as fast as possible.”

The path to platelet-rich plasma therapy is one of the clearest examples of this. The therapy, in which growth factors from the patient’s blood are concentrated and injected back into an injury site, had early scientific promise but wasn’t widely used. Then, athletes began using it for tendon injuries.

When sports stars like Rafael Nadal and Tiger Woods spoke publicly in the late 2000s about their use of the therapy, known as PRP, to recover from injuries, patients began asking about it.

In some ways, the celebrity endorsements outpaced the science. The large randomized controlled trials needed to find out how well it works, and for which conditions, are still ongoing. Today, PRP is commonly used in sports medicine clinics, even as researchers build the evidence base behind it. Most major insurers still classify it as experimental and require patients to pay out of pocket.

“It’s not that athletes are trying things that have absolutely no evidence,” Sherman said. “It’s that they try to be early adopters of new treatments. They start using things before the randomized trials and insurance policies have caught up to the science.”

“The goal is to have an Olympic-level coach in your pocket. You shouldn’t have to be a professional athlete to get that insight.”

Scott Delp, PhD, director of the Wu Tsai Human Performance Alliance

To keep advancing that science, Stanford’s orthopaedic team tracks every platelet-rich plasma injection its clinicians deliver, studying how different preparations vary and how well it works for different conditions. The nuanced findings will likely first impact the athletes seen at Stanford Medicine and later move toward personalized treatment for all.

Blood flow restriction followed a similar trajectory. It uses a cuff to restrict blood flow to a limb during light exercise, forcing muscles to work harder than they otherwise would and making it possible to build and maintain muscle that protects and stabilizes a healing injury. It was developed to rehabilitate injured soldiers, then moved into NFL training rooms and collegiate athletic programs. Now, Safran said, it’s “kind of everywhere.”

But like with PRP, the science of blood flow restriction is still catching up to the hype. Studies show promising results and physical therapists across the country use it routinely with everyone from elderly patients with muscle loss to recreational athletes recovering from injury. But researchers say more rigorous trials are needed. A Stanford Medicine clinical trial is being conducted to determine whether it can help improve grip strength in people with wrist pain.

Safran and Sherman both hesitate to predict what the next treatment to move from elite athletes to the average clinic might be. Stem cell treatments, new biologics and peptides are all in the pipeline. But they said whatever the next big thing is will likely be tested at Stanford — in athletes and non-athletes alike.

“Stanford is built for that kind of translation,” Safran said. “We have 900-plus elite student-athletes and work with a lot of other teams in different sports. But we also have a multi-translational network of researchers from biomechanics, stem cell biology, mechanical biology and imaging technology that allows us, when we’re able to collaborate, to be much greater than the sum of our parts.”

After an injury

When a Stanford Cardinal athlete finishes formal rehab after an ACL reconstruction, recovery doesn’t end there. As they begin attending practices again, coaches and trainers watch their every move. Force plates measure the symmetry of their jump landings. GPS sensors track their motions.

The answer to whether they are ready to return to competition — the track, the football field or a court — is predicted by a continuous stream of data.

“There are all these sophisticated tools and technologies that the elite athlete has access to,” Sherman said.

For an average person having the same ACL reconstruction, the pathway out of recovery is different. The patient goes home with a set of exercises, a limited number of insurance-covered physical therapy sessions, and a follow-up appointment scheduled for three months out.

“Sports medicine is driven by the search for those holy grail treatments that can get athletes back in the action as fast as possible.”

Orthopaedic surgeon Seth L. Sherman, MD

The gap between the end of formal rehab and any return to sport — what Sherman called the black box — is managed, for most people, with very little information. A patient may have to rely on gut feelings to decide whether to try going on a run, playing in a weekend pickup game, or even something as simple as carrying groceries up a flight of stairs.

That gap inspired Sherman to launch a collaboration with the Wu Tsai Human Performance Alliance’s Digital Athlete program. His team is helping test whether smartphone-recorded movements, like squats or jumps, can predict healing and recovery patterns as effectively as in-person trainers.

“This kind of surrogate test on their phone could give someone powerful information about their relative risk of reinjury,” Sherman said, “even if they’re on a grass field two hours from the nearest clinic.”

Before it happens

Treating injuries is one thing, but the loftier goal of clinicians who work in sports medicine is to prevent injuries in the first place. For elite athletes, that means constant monitoring of their weaknesses and imbalances and staying on the lookout for the earliest signs of overtraining or breakdown.

“An NBA team has 15 athletes and 15 coaches and trainers,” said Scott Delp, PhD, director of the Wu Tsai Human Performance Alliance. “Your average high school athlete or casual runner doesn’t have that kind of individual attention.”

Delp wants to change that, with technology. “The goal is to have an Olympic-level coach in your pocket,” he said. “You shouldn’t have to be a professional athlete to get that insight.”

Toward that end, Delp is leading the development of OpenCap, a tool that uses two ordinary phone cameras to generate the kind of three-dimensional motion analysis that typically requires an advanced lab and technician. It captures a person’s movement patterns — their running gait, how they shift from sitting to standing, or how their knee buckles when they land a jump.

Using video of that movement, the program creates a kind of digital double of the person, then models biomechanical data, such as how much force their bones and muscles are experiencing. That data, in turn, can be used to assess injury risk or to help a physical therapist figure out how to adjust someone’s movements to take pressure off a damaged joint.

The tool runs more than 1,000 analyses a day for researchers worldwide, in clinics that could never have afforded the technology it replaces.

Delp uses his technology to screen the Stanford football players for hamstring injury risk, and Germany’s national volleyball team has used it to evaluate injuries. But Delp is quick to point out that, by sheer number, most injuries don’t happen to elite athletes but to ordinary kids on rec league fields.

A 10-minute test on a smartphone could change that, making it easier to identify kids and adults who aren’t moving their bodies optimally or are at higher-than-usual risk of an injury. Today, the setup isn’t designed for consumers, but clinicians and researchers can use the open-access software for free.

“If we can solve the problem of identifying injury risk for the elite athlete, we’ve solved it for everybody,” said Delp, the James H. Clark Professor in the School of Engineering, a professor of bioengineering and of mechanical engineering.

Evening the playing field

Historically, the gap in sports science hasn’t only been between elite athletes and amateurs but also between genders. A study of six leading sports and exercise medicine journals over a six-year span found that 34% of study participants were women and 6% of studies focused on women.

Emily Kraus, MD, is among the Stanford Medicine physicians most focused on those gaps. A clinical assistant professor of orthopaedic surgery, she directs the Wu Tsai Performance Alliance-supported program FASTR, Female Athlete Science and Translational Research.

Early in her career, Kraus worked on a study of bone stress injuries in collegiate runners that was led by Michael Fredericson, MD, a professor of orthopaedic surgery and director of physical medicine and rehabilitation sports medicine at Stanford Medicine.

“A lot of these takeaways are super important for all women, whatever level they compete at or whether they compete at all.”

Emily Kraus, MD, director of the Wu Tsai Performance Alliance-supported program FASTR

The project found that female runners were sustaining bone stress injuries at unusually high rates. The data revealed that the pattern was linked to undereating: When female athletes didn’t consume enough calories to support their training, their hormones were disrupted and their bones were weakened, a condition called the female athlete triad.

Researchers now understand it as one piece of a broader syndrome, relative energy deficiency in sport, or REDs, in which chronic underfueling ripples out to affect many body systems beyond bone.

The starting point for treatment was surprisingly straightforward: Many of these athletes simply weren’t eating enough to support their training. Correcting that with a team that typically includes a physician, a dietitian and a mental-health professional is the foundation of care, and studies link better-fueled athletes to healthier bones and fewer bone stress injuries.

Now, Kraus — who co-chairs the U.S. Olympic and Paralympic Committee’s REDs expert panel — screens for the condition in all active females she sees.

“This is not just information for the elite 1% of the athletic population,” she said. “A lot of these takeaways are super important for all women, whatever level they compete at or whether they compete at all.”

But evening the playing field doesn’t mean erasing every difference. Sherman was careful to note that even with the same information, the calculus of how much risk to take often differs between elite athletes and everyone else.

A recreational skier recovering from an injury might postpone a weekend trip to Tahoe. An Olympic hopeful who may not get another shot at the Games might chose to get back on the mountain more quickly.

Risk tolerance aside, the knowledge that elite athletes use in their training to prevent, diagnose and treat their injuries is slowly making its way to the rest of us. As Kraus put it, the goal is simply to help people move better, “whether it’s going out on a stroll around the block or running your fastest hundred-meter sprint in the Olympics.”