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Meet Tom Zheng, One of the 49ers’ Secret Weapons to Staying Healthy This Season

Skeptics beware: He can pinpoint injuries and issues that players have never disclosed. But he’s no psychic, just an expert in the human body.

Tom Zheng laughs. As it turns out, there are times when his job as a movement and performance specialist with the 49ers is not dissimilar to that of a psychic medium.

Ahead of a conference title game matchup with the division rival Rams, we’re talking about the old television show Crossing Over with John Edward, where a toothy, middle-aged man would address an entire audience claiming to have connections with the world beyond our own (there is a South Park episode about it). He would say he was hearing from a spirit named “Dan” and, assuredly, someone in the audience would have a connection to a person with the same name and raise their hand. From there, using context clues that popped up over their short conversation, Edward would be able to ascertain who Dan was, how he died and what kind of message he had for the audience member longing for closure. There was always a moment when Edwards would bring up something that the audience member had not previously shared or alluded to, which locked in a degree of certainty about his psychic powers. From there, they were putty in his hands.

Zheng, more earnestly, goes on a real fact-finding mission and finds that the buy-in from naturally skeptical 49ers players comes when he brings up a part of their injury history that they had never disclosed to anyone. Of course, this is due to his actual knowledge of the human body (an undergraduate degree in human biology and a graduate degree in applied exercise science) and desire to help players recover faster and prevent injury.

An example: One player came into his office following a serious ankle sprain after getting rolled up on by a defensive lineman in practice early this season. He had a history of ankle discomfort. After reviewing a previous medical history and asking some pointed questions, Zheng came back with a report:

I noticed that, when you’re walking, you’re way stiffer on that right leg. Your hip isn’t moving quite as well. You’ve been telling me the hamstring is tight? Mechanically, I think the problem is coming from the ankle not moving the way it should, stiffening the hip, causing you to overload your hamstring.

“‘I didn’t even tell you about my hamstring,’” Zheng recalls the player saying. “And you knew it was tight.’ So, a little bit of a buy in.”

49ers movement and performance specialist Tom Zheng

A few corrective or preventive movements are assigned. Perhaps a date with one of their space-age machines is scheduled.

As far as Zheng knows, he’s the only movement and performance therapist in the NFL (a quick glance at each team’s NFL staff pages confirmed as much). The 49ers boast one of the most robust and diverse medical staffs in the league in terms of title and description, composed of athletic trainers, nutritionists and strength and conditioning experts. His office of functional performance, headed by Elliott Willams, is an intermediary between the strength room and the training room; a complementary arm that seems to have contributed to some preventative injury success, Zheng says, as well as adding a stabilizing presence for athletes who were hurled out of their rhythm and comfort zone during the pandemic in 2021.

While Zheng freely admits he is just one cog in a very intricate and complicated machine, his presence here in San Francisco and his ability to weigh in on various diagnoses and contribute advice is another example of why the 49ers are knocking on the door of their second Super Bowl appearance in just a few seasons. Few organizations are set up like the 49ers. Few have a harmonious flow from department to department, be it scouting to coaching, or nutrition to strength. Last week before the team’s victory over the Packers, when the 49ers altered their practice schedule to mirror the game time and (hopefully, somewhat) force the team to acclimate to colder temperatures, nearly every member of the staff had some hand in designing some aspect of the overarching game plan, right down to what compression layers the players would wear to best deflect the dipping temperatures.

Creating such a culture takes time, but often reaps its rewards in small, unnoticeable ways. In this case, maybe a time-bomb injury never detonates. Maybe some in an NFL ecosystem who are rightfully suspicious of opening up about their medical history will have a kind of Edward-ian revelation and begin to believe in the system.

The 49ers stay healthy in ways the lay person cannot imagine, from tiny electromagnetic pulsing bands to a “microdosing” program that prescribes tiny, precision movements.

But before we get into that, Zheng has a bit of a party trick.


“Ok … just so you know I’m not bulls----ing you …”

Zheng has me stand up in front of my laptop, place my hands behind my head and butterfly my elbows out to the side. For the last few months, I’ve been dealing with runner’s knee after trying to maintain a moderately aggressive weekly mileage goal following a marathon. It hurts to walk down the stairs. I can’t run as far as I’d like. I can’t run nearly as fast. I’ve gone full conspiracy theorist, deep into the recesses of unlicensed-physical-therapist YouTube. A truly dangerous place. I’ve ordered books. I slathered my knees in cannabinoid oil. I let it slip during our conversation. He said it was time for show-and-tell.

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In that position, he has me relax my shoulders, close my eyes and begin marching in place. After a few steps he tells me to freeze, asking me where my weight distribution is. I scan my lower body and realize that I am almost entirely resting on my left foot.

“And which knee hurts?” he asked, already knowing the answer.

From there, he assigned me two quick corrective, upper body movements and a 30-second wall sit, where I had to be sure my knees were aligned with the second toe on each foot. The ankles should be slightly ahead of the knees.

About an hour later, I ran on the treadmill pain-free. I ran a second day in a row, almost entirely pain-free. I don’t dread a trip to the basement as much as I used to.

“This is similar, sometimes, if I have time with the players, like not right before practice,” he said. “Analytically, I’ll go through all of this with a player. I can see what I see, but I just want to make sure they’re feeling what I think they should be feeling.”

As it turns out, slumping at a kitchen chair while working during the pandemic and being dominantly left-handed rotated my shoulder girdle, so I put more weight on one side of my body and increased loading on the left side.

In a hyper-simplistic way, this is how Zheng contributes to the greater good in Santa Clara. He observes. He gathers information, almost like a friendly anthropologist. Then, when he feels he has developed the trust of a player, he approaches and diagnoses.

There are so many times, he says, when an athlete just doesn’t feel right but can’t describe what’s going on. It folds into the crude analogy of the car owner and the mechanic, one simply knows there is an issue while the other is an expert at fixing it. Depending on how your knees hinge, you could be at a greater risk of ACL tears. Where is your body asymmetrical? Is there an upper body issue or a lower body issue? Is your hip too tight? Is your head a little crooked?

And then, much like I did in the basement, they go for a walk in place. They’ll test for balance. Remove all extraneous factors and strip the injury down to its root cause. Somewhere along the line, somehow, the body was displaced. The kinetic chain got tied in knots.

The difficult thing about Zheng’s occupation is that empirical evidence of success is hard to come by. Each and every down, all of his players endure the bodily equivalent of taking on a bull at Pamplona. In 2020, the 49ers were decimated by injury and ended the season with the most players on injured reserve. In ’21, their losses have been far less debilitating. A program can be perfect and one helmet torpedoed at a vulnerable, twisting knee can ruin a player’s season

“Because the NFL is a contact sport, it’s not like we can say ‘O.K., if we do these nine things nothing bad is ever going to happen,” Zheng said. “That’s hard to say. But this year, we focused on pre-hab. We were able to nip the bud of a lot of potentially developing issues.”


On the plane ride from Santa Clara to Green Bay, many of the 49ers were wearing FireFlies below their knees.

Shaped like enlarged Band-Aids with a button face in the middle, the device stimulates the peroneal nerve in the shin, forcing it to contract and dilate. If you’re sitting for long periods of time, it helps retain fluid and keep the blood pumping. The goal was to avoid the dead leg feeling upon landing.

Zheng loves assorted healing products, which makes his elastic budget in San Francisco something of a dream job. The 49ers have infrared and red light therapy, which is a preferential treatment option to a pre-practice dip in a heated tub. The light therapy warms the muscles without causing lethargy. They have NormaTec compression boots to aid recovery, anti-gravity beds to reduce stiffness and the load a spine takes over the course of a long day, and a Bemer system that uses pulsed electromagnetic fields to allegedly increase circulation in the body and decrease soreness.

But he also values simplicity. He calls it “microdosing,” or adding just a few minor movements into the repertoire each week as a preventative measure against further injury. Among the 49ers’ greatest hits: backward sled walks, shoulder rotations, thoracic spine rotations, hip range-of-motion exercises to get both femurs to even out.

Of course, none of this works without trust, without an ability to prove his usefulness. Zheng said what many in the strength, nutrition and recovery fields will attest to around football is that players come into the NFL with certain fears and biases. They are rightfully wary of disclosing injuries out of concern that the trainer or therapist would simply phone up the general manager and label the player damaged goods. They have their own personal trainers, diet gurus and nutritionists that make them feel better prepared, and whose livelihoods depend on that individual player’s success.

He mentioned the budding situation with former Buccaneers receiver Antonio Brown, who claims that he didn’t want to go back into a regular season game against the Jets due to an injured ankle, which sparked his on-field tirade and eventual release.

“You’re a young kid being scouted since the age of 7, a lot of people are in your ear saying, Do this and you’ll go to the top. It’s hard to trust people,” Zheng said. “You need to build a base layer. You have to show them you’re knowledgeable. That you’re not just throwing stuff against the wall. That you have their best interest in mind. So, I try to start with a conversation.”

A conversation, a walk in place, a brief meditation on what hurts, what has always felt funny and what he can do to fix it. Zheng isn’t speaking to some mystic on the other side, but he is stabbing at common sense fixes to serious problems. The 49ers hope that approach continues to grow their own receptive audience. 

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