At the risk of being branded a heretic, I’m going to ask the question so many podiatrists don’t want to hear: Is Root biomechanics dying?

I don’t want to sound too dire, but the Root biomechanics of foot function model is under attack by modern scientific research methods. Let me first describe a very recently published research study and then attempt to put the issue into perspective.

Jarvis, Nester and colleagues examined the relationship between the deformities found during the nonweightbearing Root orthometric examination and kinematic aspects during gait¹.

As a very quick reminder kinematics is the study of bone and joint motion while kinetics is the study of the forces causing the movement. Jarvis and colleagues, then compared the findings of the biomechanical exam with what is actually seen during gait to see if there was a relationship predicted by Root. The question was essentially, “Does the static orthometric exam predict what occurs during gait?”

The researchers screened 140 individuals and found 100 symptom-free participants between 18 and 45 years of age. They performed the following examinations:

These exams looked for the presence or absence of the following structural deformities:

They obtained kinematic data by sectioning the participants’ feet into six segments and placing markers on each segment and then having the subjects walk at a self-selected pace while being video monitored by a 12-camera system. The movement directions of each segment were tracked in a 3D coordinate system. Each subject did eight walks, creating 800 total patient walks (4800 segment data points). Statistical analysis was performed to determine the relationship between the data.

Of the 100 participants, all of them were found to have at least two structural deformities of the foot and all had at least one forefoot deformity. The authors also found that the Root examination assessments had “no relationship with foot kinematics during gait”¹.

Let’s make this clear:

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“The Root examination performed on symptom-free individuals, and all with some deformity, did not in any way predict what would occur in the foot during gait.”

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In light of this study and several others that found similar results, the authors stated the following CONCLUSIONS and RECOMMENDATIONS:

This study agrees with findings from a series of other research including the following non-comprehensive list.

To put this in perspective, modern research methods (which are well accepted to be superior to methods performed when Root and colleagues did their seminal work), have demonstrated that the foundational principles of Root biomechanics are incorrect and should be replaced by something else. From a podiatric standpoint, that seems pretty Earth shattering.

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“Modern research methods have demonstrated that the foundational principles of Root biomechanics are incorrect and should be replaced by something else.”

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For the last several years of my professional life, the evidence against the Root theory in favor of other methods has been building in my mind. The first breach of the armor was reading the original studies on which Root, Orien, and Weed based their theory. These were relatively weak in comparison with modern methods (for example, modern research has clearly shown that the axes of motion of foot joints are bundled helical axes and not fixed hinge-like ones). The next step was learning about other theories and their utility in explaining pathological function (think Kevin Kirby’s rotational equilibrium and tissue stress theory). This last body of work we’re discussing today adds another nail to the coffin.

However, I still remain somewhat ambivalent and not mentally ready to completely give up Root biomechanics. Everything discussed here is in relation to asymptomatic patients. However, the game may be different for patients with symptoms. The deformities codified by Root when corrected in symptomatic patients (anything from plantar fasciitis to diabetic wounds) - either surgically or nonsurgically - create highly successful outcomes. Perhaps these successful treatments result from a non-Rootian mechanism, such as redirecting previously abnormal kinetic forces and reducing stress on tissues rather than positioning the foot in an “ideal” position.

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“Everything discussed here is in relation to asymptomatic patients. However, the game may be different for patients with symptoms.”

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The scientific method is brutal in its unflinching turnabout from previously held truths, but if we are going to be honest and rigorous then it may be time to consider pivoting from Root to something new. More on this to come in the future.