From Spacewalks to Cage Walks: How High-Tech Training Is Rewriting What “Tough” Means
An astronaut rehearses extravehicular activity inside NASA’s Neutral Buoyancy Laboratory, using underwater resistance to mimic the effort and precision required on an actual spacewalk. Credit: NASA.
It is easy to think of spacewalks and cage walks as totally different worlds.
One happens in a white suit with a NASA patch, the other in four-ounce gloves under casino lights. But in both environments, you are stepping into a place that punishes hesitation, hides fatigue until it is too late, and gives you very little margin for error.
Over the past few months I have been digging into what NASA actually knows about human performance in a spacesuit, and how that maps onto the tech quietly seeping into MMA gyms. The short version: a lot of the sci-fi we imagine is already real, just not always where we expect.
And some of the strongest evidence we have about fatigue, timing, and head trauma is a lot less romantic than the highlight reels.
What NASA Really Knows About Working In A Suit
A gloved astronaut tests an EVA torque tool used for spacewalk assembly and repair tasks, demonstrating how pressurized gloves reduce grip strength and fine motor control. Credit: NASA.
Let’s start with the gloves, because if you have ever watched a fighter’s hands get wrapped, you know how quickly your whole game collapses when you cannot grip properly.
NASA has been measuring this for decades. In one widely cited study on the Phase VI extravehicular activity glove, engineers compared bare-hand grip strength to grip while wearing the glove at operating pressure. With the full thermal micrometeoroid garment on and the glove pressurized, subjects could only generate about 46 percent of their bare-hand grip strength. Even in more favorable configurations, they were still around half to two-thirds of their normal force.
Other work on EVA gloves found similar results. One NASA report summed it up bluntly: with EVA gloves, strength is reduced by nearly 50 percent, and dexterity drops as suit pressure rises.
That is before you even get to fatigue.
Pressurized suits increase the metabolic cost of movement and shorten how long you can sustain work at the wrist and shoulder. Studies on suited work show that endurance falls faster and time to fatigue comes sooner compared with shirt-sleeve conditions, because every flex of your fingers or push of your arm is fighting both the hardware and the pressure inside.
If you are imagining a spacewalk as a slow, graceful ballet, the physics is less kind. A lot of a spacewalk is just a human trying to maintain fine control in a heavy, stiff interface while grip strength is capped at about half of what they can do in a T-shirt.
That limitation changes how NASA trains.
From Neutral Buoyancy To VR Headsets
A wide view of NASA’s Neutral Buoyancy Laboratory in Houston, where a full-scale mock-up of the International Space Station sits submerged for astronaut spacewalk training. Credit: NASA.
Everyone has seen the big pool photos. NASA’s Neutral Buoyancy Laboratory in Houston is basically a warehouse-sized tank with a space station in it. Astronauts rehearse spacewalks underwater to simulate the feel of microgravity, long before they ever open a hatch in orbit.
But the training stack now goes way beyond that.
At Johnson Space Center, a dedicated Virtual Reality Lab lets crew members practice EVA and robotics tasks in immersive headsets. High-fidelity graphics and motion systems are wired into NASA simulation software so you can rehearse a complex task in VR, then go try the same choreography underwater or in an actual suit.
For Artemis lunar missions, NASA has already used VR built on real lunar terrain data to run “mini-sims” of moonwalk traverses, complete with suit-mounted virtual cameras and simulated ground-control audio.
Behind the scenes, researchers are not just watching video and taking notes. They are pulling signals.
Electroencephalography (EEG) has been used in aviation and space-related studies to track mental workload. An “engagement index” based on brainwaves was originally developed at NASA Langley to quantify attention, and more recent work has looked at alpha and theta band ratios as markers of cognitive load in demanding tasks.
Add in heart-rate variability, task timing, and subjective workload scores like NASA-TLX, and you end up with a pretty detailed picture of when someone is physically and mentally saturated, even when they can still technically “push through”.
None of that looks like a motivational poster. It looks like rows of time series, spikes where someone’s attention drops, and curves where muscle output starts to fall off.
Which brings us back to the cage.
The Cage As A Biomechanics Lab
Combat sports are not running full NASA-style dashboards on every athlete yet. But if you zoom out, you can see the same pieces coming together.
Three big ones:
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Force plates and AI movement analysis
Companies like Sparta Science combine high-fidelity force plates with machine-learning software. Their platforms record around 3,000 data points per second while an athlete jumps, balances, or holds planks, then use those signals to build a “movement signature” and predict injury risk or performance trends.
In practice, that means you can see asymmetries, power leaks, and fatigue patterns long before they show up as a torn ACL or a dead left hook.
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Smart strength systems
Keiser and similar setups turn resistance training into data. Their A-series machines track power, velocity, and range of motion rep by rep, displaying output in real time and letting coaches export it into analytics platforms.
Set a threshold for acceptable power drop-off and suddenly “three sets of ten” becomes “we stop this set when your output falls below the line we know correlates with sloppy form and higher injury risk.”
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Muscle oxygen sensors
Near-infrared spectroscopy (NIRS) has moved from lab curiosity to a mainstream tool in sports science. Worn over a working muscle, NIRS devices track local oxygen saturation and blood volume, giving you a window into how that tissue is coping with the demand. Reviews over the past few years have laid out how coaches now use NIRS-derived muscle oxygenation as a marker of workload, fatigue, and training status in everything from cycling to team sports.
Instead of guessing when an athlete is “redlining,” you can watch their quadriceps or forearm oxygen saturation fall, see how quickly it recovers between intervals, and adjust work and rest to target specific adaptations.
None of this is fantasy. It just tends to live in corners of performance centers, military bases and Olympic programs that are not on Instagram.
The question is what happens when you start layering those tools onto a fighter’s camp the way NASA layers them onto an EVA plan.
What We Actually Know About Head Impacts
Now for the uncomfortable part.
There is a lot of marketing language around “safer” training and “smart” gear. The actual concussion biomechanics are not comforting.
Decades of research point to rotational acceleration of the head as a key driver of brain injury. In college football data, a widely cited study by Rowson and colleagues found that a rotational acceleration around 6,383 radians per second squared, combined with a rotational velocity near 28 radians per second, represented about a 50 percent risk of concussion. The average concussive impact in that dataset was over 5,000 rad/s², while sub-concussive hits were closer to 1,200 rad/s².
Work in unhelmeted sports like Australian football and rugby tends to land in the same ballpark, with concussive impacts associated with several thousand rad/s² of rotational acceleration and peak linear accelerations on the order of 80 to 100 g.
To turn those numbers into something actionable on a field, sports bodies have started wiring the mouth.
Instrumented mouthguards embed accelerometers and gyroscopes inside a custom guard to measure head linear and angular motion directly. World Rugby now has formal specifications for these “iMGs,” defining them as mouthguards with embedded sensors that track head kinematics.
Trials in elite rugby have already used thresholds like 75 g of linear acceleration for men, 65 g for women, and 4,500 rad/s² of rotational acceleration as automatic triggers for a head-injury assessment. If a hit crosses those thresholds, the mouthguard can flash and send an alert to medical staff, whether the player looks hurt or not.
In June 2025, UFC announced a collaboration with Sports & Wellbeing Analytics to explore similar instrumented “smart” mouthguards for performance monitoring and brain-injury research in combat sports.
The takeaway here is not that a mouthguard can magically “tell you” if someone has a concussion. Clinicians are very clear that these devices are one data stream among many, and they come with issues like false positives and calibration challenges.
But it does mean we are moving from “that sounded like a hard shot” to “we know roughly how big that head-rotation was, how often that athlete has seen similar loads this week, and whether this one crossed a risk line that deserves closer attention.”
That is a very NASA way to think about getting punched.
Where MMA Is Already Using This, Quietly
If you talk to physical-preparation coaches in top gyms, a familiar pattern pops up.
They are not trying to turn fighters into lab rats. They are trying to answer three simple questions with better information:
- Is this athlete ready to do what we are about to ask them to do today?
- Are we trending toward a version of them that can do more of it with less cost?
- Are we accumulating risk in a way we cannot see from the outside?
Force plates and bar speed systems help with questions one and two. They tell you if lower-body power is holding up late in camp, if one leg is quietly becoming the weak link, or if the same load is now moving faster because the athlete actually adapted.
Muscle oxygen sensors add another layer: is that brutal pad round actually tapping the muscle systems we think it is, or is the athlete cheating around their weak side? How fast do they re-oxygenate between bursts, and does that change when we shift their strength work?
Instrumented mouthguards, when they are used in sparring, change the tone of a session. A “technical” round starts to look less technical if the head is still experiencing match-level accelerations. A coach can see in black and white when sparring habits do not match the advertised intensity, and dial contact up or down accordingly.
Is every team doing this? No. A lot of fighters still live in the land of “how do you feel?” and “you look sharp today.” That intuition is still valuable. But the direction of travel is clear.
The Cultural Tension: Data, Trust, And Control
There is a reason astronauts tolerate all the sensors. If they do not, they die, or someone else does.
Fighters live in a messier world. They are independent contractors in promotions that are still figuring out their own relationship with safety, transparency, and long-term brain health. They have every reason to worry about who sees their data and how it might be used against them at the bargaining table.
The tech itself is neutral. The culture around it is not.
A smart mouthguard that flags a scary impact can be a tool for a ringside doctor who wants to make a hard call and pull someone early. It can also be a data feed a promoter might someday use to argue that a fighter is “too fragile” to re-sign, or that their risk profile is higher than the contract is worth.
A force-plate report that reveals asymmetry can be the first step toward a smarter training plan. It can also be something an opponent’s camp would love to see.
NASA’s world is full of similar tradeoffs. But the default expectation in that environment is that data is collected to keep you alive and help the team succeed, not to cut you loose cheaply as soon as the numbers dip.
MMA has to decide which version it wants.
What “Tough” Might Look Like In The Next Decade
Here is my bias, on the record.
I do not think toughness is proved by ignoring what your own nervous system is telling you, or by pretending we have no idea how big that last head impact was. We do have some idea, and the picture is getting sharper every year.
On the space side, we already accept that humans need help to function in hostile environments. We build suits that are barely within our strength envelope, then pile on pools, VR labs, EEG studies and muscle-oxygen research to give astronauts every possible edge against fatigue and error.
On the fight side, we have been slower to admit the same thing. But the same logic applies.
If a couple of extra data streams can help a fighter:
- Spend more of camp in the productive zone instead of the overcooked one
- Catch power leaks and asymmetries before they become surgeries
- Put hard boundaries around how much head trauma is considered acceptable in training
then that is not softness. That is professionalism.
In both a spacesuit and a cage, you still have to show up on the day, breathe through the fear, and execute. No force plate or smart mouthguard can do that for you.
What they can do, if we use them right, is make sure that the price you pay for that courage is as low as we can reasonably make it.
That, to me, is the version of “tough” that is worth fighting for.
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