by Roy M. Wallack.

Ken Bob Saxton is a barefoot running machine.

When a publisher offered me the opportunity to write a book about barefoot running in the spring of 2010 (which was published in May as “Barefoot Running Step by Step,” co-written with barefoot pioneer Ken Bob Saxton) , a happy irony was that it helped me avoid a knee operation and saved  my running career.

I became a guinea pig for the principles Ken Bob and I outlined in the book because I had been unable to run without pain in shoes — cushioned and minimalist, even Vibram FiveFingers — ever since March 2009, when a fall off of a fence at the finish line of the Tour of California bike race resulted in a torn meniscus and a partially-torn ACL in my right knee.  My surgeon scoped the meniscus and shaved off the broken barbs from the ACL that May, advising me to see if I could live with an ACL now at 70% of its former strength.  Well, I could ride a bike  no problem, but anything that involved running and walking motion was painful. Switching exclusively to running in Vibrams did reduce the pain quite a bit, as the forefoot landing does what all the research indicated: reduce impact and put my foot in a biomechanically correct position. Still, long downhill stretches in my neighborhood, though relatively pain-free during the run itself,  would leave me wracked with pain for the next three or four days. I grew worried that I was doing structural damage to my knee. So while Ken Bob and I started researching and writing “Barefoot Running Step by Step” last summer, I had effectively given up running on land (I was still doing pool running.)

The problem was, like most people, I equated running in Vibrams with barefoot running. Well, as Ken Bob has been saying for a long time, it’s not.

Feeling like a fraud — writing a running book without actually running –I went out for a 20-minute barefoot run in July. And something strange happened:  Nothing.  No pain — not during the run itself or afterward.  Over the next weeks and months, as I pushed my barefooting to hour-long stretches, same thing:  No pain.  Ken would smile whenever I told him. “You have to put that in the book,” he said.

Here’s the explanation of why I can run barefoot but not in VFFs: Vibrams facilitate a forefoot landing that does a great job of reducing the impact forces of a heel strike in a cushioned trainer (as esteemed researchers from Timothy Noakes to Daniel Lieberman have discovered),   but still deprive you of the ground feel you need to get an exactly correct and balanced foot placement.  In 2002, British Columbia researchers mapped the sole and found it contained an overwhelming preponderance of mechanoreceptors that are focused mainly on balance. Block those sensors with even the most flimsy of shoes, and you are actually slightly off-balance.

That slight lack of balance was enough to cause pain to my ACL-impaired right knee .  It is that that lack of balance, coupled with the high impact of a heel strike, that Ken Bob and I  believe is the cause of the high injury rate among all runners. Because of my experience, I can say without any doubt that impact is only half of the story when it comes to injury-reduction.  Balance, which of course gets worse as the footwear gets thicker and more cushioned, may be an even bigger contributing factor.

I’m up to running 90 minutes now barefoot, pain-free.  I also strength train quite a bit, and hit my knees hard, thinking i can build protection that way. But I was still worried about the long-term prospects of my knee, and wondered if I should have the ACL totally replaced. So last month, I visited a sports-specific knee surgeon, who took x-rays and compared the “loose-ness” of both knees by grabbing each and torqueing sideways.

“You don’t need an operation,” he said, “because your right knee is as solid as your left knee, despite the weakened ACL.  It appears that whatever you are doing is working.”  When I told him I was strength training and running barefoot, he looked surprised; he hadn’t heard of barefoot running.

But when I explained it  (and showed him my book), he just said, “That makes sense. I can’t argue with results. And can I get this on”