I Walked Like John Wayne for Four Days

Let me set the scene. Four days. A cascade of terrible decisions, each one made with the quiet confidence of someone who absolutely should have known better.

Day one…walking lunges to failure with dumbbells. Not a few sets. Failure. As in, the point at which my legs simply declined to continue being legs. Who does that? Day two was traditional Irish stone lifting (Cloch Nirt, the discipline I’ve trained in for years and genuinely love), which under normal circumstances is fine, but which, stacked on top of the carnage of day one, was perhaps unwise. Days three and four, thirty thousand steps a day, multiple hours of cycling, more lifting, more accumulated damage to a body that was politely but firmly asking for a rest.

The result was four days of walking like John Wayne crossing a river in tight jeans. Every staircase was a negotiation. Getting up from chairs involved strategic planning usually reserved for military operations.

I am a historian of physical culture. I’ve spent years writing about how fitness trends rise, peak, injure people, and then quietly incorporate the lessons into the next iteration. And so, hobbling around my house in Ireland performing what my partner charitably described as “the shuffle of shame,” it occurred to me that I had, in miniature, reenacted one of the oldest patterns in exertional rhabdomyolysis.

Let me explain.

The Condition You Probably Haven’t Heard Of

Rhabdomyolysis (”rhabdo” to those familiar with it) is what happens when muscle fibres break down so rapidly that they flood the bloodstream with their contents, myoglobin, electrolytes, creatine kinase, cellular debris. The kidneys, suddenly confronted with a quantity of muscle protein they were not designed to process, begin to struggle. In severe cases, they fail. The condition can maim and in rare but documented cases, can kill.

The NCAA’s clinical description is strikingly specific. Muscle pain far beyond what you’d expect. Swelling. Profound weakness, particularly in the hips and shoulders. Limited range of motion. And the most alarming symptom: brown urine, the so-called ‘Coca-Cola urine’ of rhabdo, from myoglobin pouring through the kidneys. Incidentally, if you have severe swelling, profound weakness, or dark urine after training, stop reading fitness history posts and seek urgent medical advice.

I didn’t get there. What I had was firmly in the territory of severe delayed-onset muscle soreness verging on something more sinister, soreness that keeps building rather than peaking at 48 hours, muscles that feel wrong rather than merely sore, that makes you look up symptoms at 11pm with the quiet dread of a man who has studied this exact condition and is now wondering if he’s in a paper. But I was fine. And that’s almost the point. Because the gap between “fine but stupid” and “hospitalised” is smaller than most people in fitness culture would like to admit.

The First Recorded Outbreak: Marines and Squat Jumps, 1960

The first formally documented cluster of exertional rhabdomyolysis cases occurred not in a CrossFit box, not in a spin studio, not in someone’s garage gym, but in the United States Marine Corps in 1960, when a cohort of recruits were pushed through high-repetition squat jumps during basic training. Dozens of men in a single unit were affected. The syndrome was so novel it was given its own name, squat jump syndrome.

Think about that for a moment. The mid-20th century military, an institution that had been conditioning men for physical combat for generations, somehow found a way to break bodies through exercise at scale. The mechanism was straightforward: deconditioned civilians, sudden intense volume, no gradual ramp-up. Sound familiar?

It should. Because that mechanism (too much, too soon, too fast) is the thread running from squat jump syndrome through later military, collegiate, commercial, and functional fitness rhabdo scares. The NCAA Sports Medicine Handbook calls it “novel overexertion” and identifies it as the single most common cause of the condition. Not heat, not dehydration and not drugs. Novel overexertion as in doing something new, or returning to something after a break, at an intensity the body hasn’t been prepared for.

The military pattern repeated in police academies, firefighter training, and the post-break first week of collegiate athletics. Every institutional fitness culture operating on the assumption that harder is always better produced its own cluster.

Greg Glassman’s Remarkable Confession

The most extraordinary document in the history of fitness rhabdomyolysis is not a medical paper. It is a 2005 CrossFit Journal article by CrossFit founder Greg Glassman, titled, with admirable directness, “CrossFit Induced Rhabdo.”

By October 2005, CrossFit had documented five verified cases of exertional rhabdomyolysis, all resulting in hospitalisation. The shortest stay was two days. The longest was six, during which the victim “recounts that six days of intravenous morphine drip barely touched the pain.” Glassman listed the victims: a female college student hospitalised after her second-ever CrossFit class, which featured high-rep assisted pull-ups; a dermatologist in his late forties; a SWAT officer described as “famous for his exploits in a busy sheriff’s office”; a collegiate softball pitcher who accepted a challenge from her boyfriend; a special operations soldier who ignored all pre-seminar warnings. All fit, all experienced in their own training modalities, all hospitalised within their first two exposures to CrossFit.

What makes the article remarkable is not the cases but Glassman’s response to them. He didn’t bury the information. He didn’t minimise it. He published a cartoon of a clown hooked to a dialysis machine, branded “Uncle Rhabdo,” ran it alongside a frank acknowledgment that his programme could cause a potentially lethal condition, and then set about explaining why. His argument was simple. CrossFit generates power outputs that conventional training (bodybuilding splits, long-distance cardio, even military conditioning) simply does not prepare the body for. “Countless bad-asses from sporting and special operations communities, long regarded as bulletproof,” he had written earlier that year, “have been burned at the stake of ego and intensity.”

Burned at the stake of ego and intensity. It is one of the more accurate descriptions of how exercise-related injury happens across all eras of fitness history. Glassman also identified something the medical literature would later formalise, which he called “cold rhabdo.” Every case CrossFit had seen occurred in sessions of twenty minutes or less, at mild temperatures, with athletes who showed no visible signs of excessive distress during the workout. They left looking fine. The damage had already been done. This cut against existing medical understanding, which associated rhabdo primarily with exhaustion, dehydration, and extended exertion. CrossFit’s version arrived quietly, in short bursts, to people who felt like they’d simply had a hard session.

The Hardest Workers Break Down Worst

One of the most consistent findings across rhabdomyolysis case studies is the particular danger of eccentric exercise or the lengthening phase of a muscle contraction. When you lower yourself from a pull-up, sit back into a squat, or lower a weight after a curl, the muscle contracts while lengthening. This places distinctive stress on muscle fibres, and the NCAA guidelines note that rhabdo often occurs when exertion is pushed beyond the point at which fatigue would normally compel a person to stop.

Crucially, this is especially likely in group exercise under demanding supervision or peer pressure. The social dynamics of fitness are not incidental to rhabdomyolysis. They are causally implicated in it.

The NCAA’s case studies make grim reading. Thirteen Division I football players hospitalised after the first team workout post-winter break, 100 timed back squats, coaches having told the players the session would demonstrate “who wanted to be on the team.” A high school football team whose new coach introduced an intense tricep-focused drill on day one of summer camp of chair dips and push-ups, five consecutive bouts, fast repetitions, competitive motivation, with no rest periods. Half the squad were hospitalised, twelve admitted, three requiring surgery for compartment syndrome. A Division I swim team whose new coach opened the season with max-effort push-ups and body squats before their usual two hours of swimming. Multiple athletes were hospitalised with dark urine and severely swollen muscles.

In every case, the formula is the same, novelty plus intensity plus social pressure, often delivered by someone in institutional authority. And in every case, the hardest workers break down worst. The lacrosse player who did the most pull-ups had the worst and longest course of rhabdo, the footballer who pushed furthest through the squats or the swimmer who matched the coach’s drill with maximum effort.

Novelty, Authority, and the Promise of Transformation

Every era produces this. Every decade’s breakthrough training format carries within it the conditions for this exact injury, not because the exercises themselves are uniquely dangerous, but because each new format arrives with a promise of transformation that is, by design, incompatible with gradual preparation. The lesson is not that hard training is dangerous. The lesson is that hard training without preparation is not toughness. It is bad programming dressed up as character.

The 90-day programme, the first-time race, the opening day of team camp, the initial CrossFit class, all of them recruit motivated, ambitious people and expose them to intensities they haven’t earned through progressive adaptation. The intensity is the product. Risk is folded into the price.

The 1980s aerobics boom did not produce rhabdo mythology in the way CrossFit later would, but it did popularise a familiar formula: high-volume repetitive movement, transformation through discomfort, and the belief that ordinary people could reshape themselves through punishing consistency. The P90X era produced the first documented case explicitly linked to a proprietary home workout programme — a 23-year-old with a solid fitness background hospitalised after just two sessions.

The uniform changes. The format changes. The mascot, occasionally, is a clown on a dialysis machine. But the body’s response to too much, too soon, too fast has remained, since 1960, stubbornly consistent.

Back to the John Wayne Walk

What rhabdomyolysis keeps revealing, across every format and every decade, is this: knowing it can happen is almost never sufficient to stop it from happening. Because the mechanism isn’t ignorance. It’s enthusiasm. It’s ambition. It’s the accumulated pressure of a culture that has always found ways to frame excess as virtue and rest as weakness.

My four days of accumulated stupidity did not land me in hospital. I knew better. That’s the historian’s particular embarrassment. I had read the papers, written the articles, taught the case studies. I knew about squat jump syndrome and Uncle Rhabdo and the NCAA football cluster. I still did walking lunges to failure with dumbbells because I was on a roll and it seemed like a good idea at the time.

Pain is information. Every generation learns this the hard way, then builds a new format that makes it slightly easier to forget. The Marines had repetitive squat jumps. CrossFit had Uncle Rhabdo. Football coaches had their hundred-squat auditions. I had walking lunges in a home gym in Tallaght, followed by three days of accumulated poor decisions.

The difference, in my case, is mostly that I didn’t have a coach shouting at me. I had only myself to blame – which, it turns out, makes me exactly as susceptible as everyone else.

1. Glassman, G. (2005). “CrossFit Induced Rhabdo.” CrossFit Journal, Issue 38 (October 2005). PDF: https://library.crossfit.com/free/pdf/38_05_cf_rhabdo.pdf

2. Greenberg, J. & Arneson, L. (1967). “Exertional rhabdomyolysis with myoglobinuria in a large group of military trainees.” Neurology, 17(3), 216–222. https://pubmed.ncbi.nlm.nih.gov/6066951/

3. Eichner, R. (2013). “Exertional Rhabdomyolysis.” NCAA Sports Medicine Handbook, pp. 1–6. https://ncaapublications.com/products/sports-medicine-handbook

4. Paidoussis, M. et al. (2012). “Severe Rhabdomyolysis Associated With a Popular High-Intensity At-Home Exercise Program.” Journal of Medical Cases, 3(6). https://www.journalmc.org/index.php/JMC/article/view/875/469

5. Clarkson, P.M. (2017). “Perspectives on Exertional Rhabdomyolysis.” Sports Medicine, 47(Suppl 1), 67–75. https://pmc.ncbi.nlm.nih.gov/articles/PMC5371628/