Today, The New York Times has a piece out on the maximalist running shoe, a trend now old enough to warrant an article written with characteristically Times-ian remove from rigorous examination of its subject. The thing about these shoes, though, is that even if the Times had wanted to conduct a more thorough examination of the subject, it probably couldn't have. There isn't much else to go on, and that's by design.
For the uninitiated, maximalist running shoes are shoes with an excess of cushioning that—if you believe the evangelists—helps mitigate injury. The shoes are a relatively recent conceit, born out of the minimalist running fad in 2009 and thriving over the last three years thanks to their adoption by ultramarathon runners and the decline of minimalist shoes, which culminated in the Vibram settlement last year. Now, the claim is that the benefits of these shoes ought to spill over to the casual runner, with the blessing of your local running specialty shop, for somewhere around $135.
In this piece, you can see the ways in which the ghosts of minimalist running inform how new fads are covered. The believers in the Times piece speak a language of modest expectations, rather than in the the all-encompassing generalities that accompanied the barefoot craze. A biomechanist likens the difference between this new type of shoe and its predecessors to that between a road bike and mountain bike—different tools for different jobs!—and a product manager cites market research indicating that people want cushioning. Still, this is functionally following the pattern laid out by most every other gear fad. From the Times:
Lauren Fleshman, a national champion in the 5,000 meters, likened the maximalist upswing to past footwear phenomena, now rejected as passé.
"To me, maximalist shoes fall right in the line of every other shoe trend," she said. "There's some good reasoning, but we don't know enough about how it affects the body longer term, and we won't know until everyone has been using it a while and all the other research comes out about how it destroys your body or whatever, and then there's a lawsuit, and then there's a campaign about how to use the technology properly, and then in the midst of all this confusion the next trend takes off. There is no shoe savior coming for us."
The Vibram settlement has made this particular cycle uniquely hilarious. The lesson that's come out of that case seems to have been that if you don't cite actual research, no one can call you out on inconsistencies or inaccuracies. From the Times again:
Mindful of the Vibram lawsuit, Hoka has been careful not to make any evidence-based health claims, and few studies exist on the effectiveness of extreme cushioning. One prominent University of Colorado study in 2012 found that the benefits of cushioning underfoot were finite: 10 millimeters of cushioning on a treadmill saved energy, while 20 millimeters of cushioning did not.
There has been some other research, usually in the context of the broader minimalist debate (remember, maximalist shoes are just now being thrust on the public at large), like Daniel Lieberman at Harvard finding that excess cushioning could lead some runners to make harder impact than normal, seeking the feedback of proprioception. Broadly, though, the perverse lesson from Vibram is that research is bad and scientific claims are what kill you. That doesn't mean you can't have the appearance of research and claims, though.
Here's an official video for the Hoka One One, a popular maximalist shoe:
Going by this video, you'd have a hard time telling that maximalist running was any less researched than its minimalist forebearer. Here's a partial transcript:
The width of the outsole provides a broad base of support. Together, these provide better shock attenuation. Uniquely engineered active footframe midsole geometry features a high sidewall wrap that allows the foot to sink into the shoe, as opposed to simply rest on top of the midsole, and is adaptable to a wide range of feet and running styles. Part of the magic to the Hoka ride quality is in the midsole geometry. Hoka midsole geometry incorporates a meta-rocker that is specifically engineered with a low heel-toe differential and a sculpted outsole radius in the heel and toe. The positioning of the meta-rocker is specific to the shoe model, and the model's primary purpose.
Do you see what's happening in the negative space there? Those are all the attendant descriptions of a claim, without any claim actually being made. The high sidewall wrap allows the foot to sink into the shoe, it says. Sinking into the shoe must be amazing, why haven't I been sinking into my shoes? you're meant to finish.
Maybe sinking into the heels of your shoes really does have some benefit—it seems to be working out fine for those ultramarathoners, at least—and maybe it's enough to offset any of that extra force Dan Lieberman observed. But without broad, independent studies, the gaps between the sell and the suckers who fall for it are even wider, and the ground that covers things like improper form for the type of shoe, or unexpected complications that rise from the correct form, is left unsurveyed. Take for example one of the many lessons from barefoot:
The above is a chart by Ross Tucker, redrawing a chart that had originally compared the impact of a runner striking with her heel in a traditional running shoe with the same runner striking with her forefoot in a minimalist shoe. Proper form, it shows, can in fact make up for the absence of cushioned shoes. What about the up to 50 to 60 percent of barefoot converts who continue heel striking when they make the change, though? They get obliterated!
We don't know if there are injury risks in wearing maximalist shoes, or what the calculus on the trade-offs in performance might be. In large part that's because this is still a relatively new concept. In some also large part, it's because making actual claims about your product has proven dangerous, and good branding carries all the same benefits.