Following a recent study published on-line by the journal Medicine and Science in Sports and Exercise titled “Foot Bone Marrow Edema after 10-Week Transition to Minimalist Running Shoes”, several headlines raised alarm about the safety of Vibram Fivefingers (VFF) shoes. “Barefoot Running Can Cause Injuries, Too” stated the New York Times. “Whoa there! Quick switch to ‘barefoot’ shoes can be bad to the bone” was the Sciencedaily.com headline. Well, don’t chuck your minimal shoes without first putting on your research hat. Let’s dig deeper:
The study concluded that switching from “regular” running shoes to VFF caused increased bone marrow edema of bones in the feet. Sure, bone marrow edema doesn’t sound pleasant, but is some swelling and tissue change in response to a change in conditions really such an aberrant and worrisome response? Muscles adapt to stress by forming micro-tears before they grows stronger. Think of lifting weights at the gym. It’s not the lifting the weight that strengthens the muscle. It’s the micro-tears that form in the muscle, followed by repair and remodeling of the muscles that makes them stronger. This remodeling in response to stress is called Davis law. There exists a similar law for the stress response in bone…Wolf’s law describes how bone adapts to stress in order to better withstand future stress.
The researchers found no differences in soft tissue response amongst the two groups of runners, putting worries about possible Achilles tendon and plantar fascia damage to rest. It’s the difference in bone response that is under consideration. About two thirds of the runners in the VFF group experienced an amount of bone edema (swelling) that would classify them as suffering from a “stress injury”. Two of these people even developed stress fractures. It takes longer for bone to change than muscle. Bones remodel upon micro-damage, thanks to osteoclasts and osteoblasts, which travel around and chew up damaged bone and replace it with fresh new bone. Since this process occurs sequentially, bones can actually get weaker before they get stronger. If a new stress is introduced more quickly than the bone can repair itself, the bone can become micro-damaged and form a stress-fracture. Edema in bone is one sign of remodeling! As Peter Larson at Runblogger.com points out in his analysis of this study, any change that causes stress may cause bone edema. He cites evidence that changing from walking to running, adding a metatarsal arch pad, or increasing training intensity can all cause bone edema.
A fundamental design flaw threatens the validity of this study. It is missing a CONTROL GROUP! We have no way of knowing whether it is switching to VFF, or switching to ANY different running shoe that is causing the bone edema. Run far away from this study! But make sure you do it with slow, controlled increments of added stress, to ensure maximum health of your bones and soft tissues. And if you’re having foot pain, knee pain, or hip pain when you run, give us a call to find out how an Oakland chiropractor can help!
Originally published April 7th, 2013 at www.sandybaird.com.
1. Foot Bone Marrow Edema after 10-week Transition to Minimalist Running Shoes
Ridge, Sarah T. et. al, Feb 22, 2013
Picture attribution/credit: Schneelocke/Wikimedia Commons License