Tremor, timing, and the difference between strength and control
Rock climbing is the epitome of embracing the outdoors. Using the side of a mountain to propel yourself to higher ground felt invigorating and terrifying at the same time.
I didn’t stick with the sport for long. There was more gear and planning than I could muster at that stage of my life.
But I remember the shake.
Halfway up a climb, my leg felt like a jackhammer. I couldn’t control it.
“Hold on!”
“You got this!” my buddy yelled.
Thank goodness I was harnessed in. I knew if my leg gave out completely, I wouldn’t fall to my death.
That memory came rushing back after working with Mark.
Mark was an athlete. He and his wife were animals—and I mean that as a compliment. They’d climb mountains, ski backcountry, and run distances I’d only attempt in a car. He was also an emergency medicine doc. He understood the body pretty well and wasn’t easily rattled.
Which is why hurting his back bending over to pick up his dog’s poop was so frustrating.
“I can’t even put my shoes on in the morning without my back hurting.”
I went through the usual exam. No referred pain. No red flags. And his legs were strong. Really strong. But he was guarded. Compared to the rest of him, his trunk wasn’t doing its share of the work.
Core.
I had Mark lie on his back while I found his comfortable, neutral spine position. Then I asked him to slowly move an arm. A leg. One of each.
“Now don’t lose your alignment. Keep your abs engaged.”
Shake…shake…shake…
SHAAAAAKE.
Whoa, I thought.
“What was THAT?” Mark said, almost laughing.
We tried it again.
Same thing.
It brought me right back to my jackhammer leg, hanging off the side of that rock face.
Researchers have described this phenomenon. Muscles are controlled by nerve cells that send tiny electrical “fire” signals telling individual muscle fibers when to twitch. Normally, thousands of these signals arrive at slightly different moments, so the twitches blend into one smooth, steady contraction. But underneath that, there’s a faint, built-in rhythm — a 2000 review in the journal Brain found that even a healthy, relaxed nervous system naturally paces out these signals about 8 to 12 times a second, all the time. Usually it’s too subtle to notice. But under certain conditions — fatigue, pain, an old injury — more of those signals become synchronized instead of being staggered, and the twitches stop blending smoothly. That’s when a shake becomes visible.
Most people have seen tremor before, like with Parkinson’s disease. But that one’s different. It shows up at rest, when a hand or a limb is doing nothing at all, and it settles once the person starts moving on purpose. Mark’s was the opposite. His hands were perfectly still sitting across from me. The shake only showed up the instant we asked his core to hold still and work.
“I think we have a coordination problem,” I said.
His eyebrow raised.
Mark was curious and a little self-deprecating, which made me like him even more.
We talked about how injury doesn’t always make us weak. Sometimes it just changes the timing, and the nervous system loses some of the fine control it once managed automatically, without him ever having to think about it.
The exercises I gave him weren’t super hard. They were slow, controlled movements that asked his trunk to stay steady while his arms and legs moved around it. To someone used to squats, Peloton rides, and mountain adventures, they were surprisingly difficult.
He loved that.
Over the next few months, we built on them a little at a time, once a month, adding a new layer each visit. Less shaking. Better coordination. More control.
At a follow-up, our forth time together, we tested it again.
Rock solid.
No shaking.
Mark was never weak. He didn’t need to get stronger. His nervous system just lost some of the coordination it once managed automatically.
Sometimes the body doesn’t need more strength—it just needs better timing.