In the video, Nicole Carroll is grimacing, tears welling in her eyes. She’s in the final set of a workout — three rounds of 50 squats, seven “muscle-ups” (pull-ups on two overhead gymnastic rings) and 10 lifts of a 95-pound weight from hip to shoulder level.
This isn’t just any workout; it’s a timed CrossFit workout of the day, and the two women Ms. Carroll began with have left her in the dust. She has only two reps to go, but as she clenches her teeth and throws the weight bar with her chiseled arms, she buckles into a deep squat and loses control. The bar slides to the ground. Undeterred, she gets up and tries again. On the final rep, her right knee collapses, but she keeps pushing, muscling the bar to her shoulders. She finishes the workout dead last, yet her grit and determination have made her its star.
CrossFit combines weight lifting, sprinting and gymnastics into ritualized routines that are posted each day at CrossFit.com and on whiteboards at thousands of CrossFit affiliates. Most W.O.D.s, as the workouts of the day are called, last less than 20 minutes, but their intensity and lack of rest can acquaint even the ultrafit with CrossFit’s unofficial mascot, Pukey the Clown. Each new workout comes with a video demonstration; the 2005 one featuring Ms. Carroll became known as “Nasty Girls” and turned her into a hero.
Count J. C. Herz among her admirers. A former New York Times technology columnist and the author of “Joystick Nation” and “Surfing on the Internet,” Ms. Herz took up CrossFit after her husband, a devotee, adopted the first rule of CrossFit — always talked about CrossFit. Soon she too was extolling its virtues. Her narrative introduces an array of characters, including CrossFit’s founder, Greg Glassman, who created the enterprise in Santa Cruz, Calif., in the 1990s; Capt. Brian Chontosh, a Marine who discovered that CrossFit made ideal training for combat; and women like Ms. Carroll who find self-empowerment at the CrossFit gym, or “box,” where women are celebrated for their strength and encouraged to compete with men.
What makes CrossFit appealing to members and confusing to outsiders is that it’s more than a workout — it’s a cultural identity. CrossFit doesn’t just transform bodies, it changes the way people think of themselves. Workouts are scaled according to ability, and effort counts as much as results. “Everyone fights to finish,” Ms. Herz writes. “Everyone belongs.”
Small class sizes promote a sense of community that is missing at “globo-gyms,” the CrossFit epithet for chain fitness centers packed with cardio machines and individual headsets. The tribal nature of CrossFit and the “paleo” diet that many members adopt have led to cult comparisons.
“Maybe it is a cult,” Mr. Glassman allows — one “where people get really fit and support each other.”
The book is loaded with tales of lives transformed by CrossFit, but after a while, all born-again stories sound alike. Multiple chapters on CrossFit competitions quickly become tedious, with their overwrought prose and forced drama. Readers looking for an impartial examination of CrossFit will be disappointed to find that the workout’s theoretical basis and scientific-sounding claims are annotated almost entirely by articles from the company’s own publication, CrossFit Journal. Still, the book is sure to become the Gideon Bible of the CrossFit movement — one that “fire-breathers” (as CrossFit devotees often call themselves) give to co-workers, friends and spouses in their efforts to convert them.
But some words of caution are in order. The weight lifts used in CrossFit can intimidate, and they require practice and good technique.
“Torquing your back on a dead lift hurts,” Ms. Herz acknowledges, but it also teaches that “improper barbell technique is a bad thing to avoid in the future.”
“You learn not to do it again,” she added.
Debates about CrossFit’s safety have raged online since reports came out of participants developing rhabdomyolysis, a potentially life-threatening condition that occurs when broken-down muscle tissue floods the bloodstream. “It can kill you,” Mr. Glassman told The Times in 2005. “I’ve always been completely honest about that.”
There’s a hint of bravado in the warning — try it if you dare, but be forewarned: This workout is so potent you could die. Even “Uncle Rhabdo,” a cartoon character CrossFit created to spread the word about the condition, seems to convey a hint of swagger.
Ms. Herz argues that rhabdomyolysis isn’t caused by CrossFit, but by ego. “The athlete spoiling for rhabdo is a guy who used to run triathlons and therefore considers himself a badass under the spare tire, who comes back from an extended break and matches the intensity of three-days-on, one-day-off CrossFit veterans.”
The safety debate boils down to how you think about risk — is it something to avoid or something to manage? If your goal is to avoid it, find a globo-gym. CrossFit is for risk-takers. Most of its boxes offer beginner courses to teach skills and judgment, but they won’t shackle you with training wheels or unnecessary safety equipment. It’s your responsibility to stop before you are hurt, the author implies, but the culture documented here glorifies those who struggle beyond pain. The guy who was wise enough to quit yesterday’s W.O.D. before rhabdomyolysis set in never warrants a mention.
Ms. Carroll’s struggle in the “Nasty Girls” video makes it easy to understand why. The same shattered technique and disregard for fatigue that raises safety concerns for some is precisely what makes CrossFit and its heroes so inspiring. The line between breakthrough effort and injury or overtraining can be seen only after it has been crossed. The pursuit of that boundary holds the allure of self-discovery — CrossFit’s ultimate appeal.
Related: Read an excerpt from the book.