Benno M. Nigg, Anja Behling, Sandro R. Nigg
The subtalar joint axis is a functional axis associated with one anatomical joint, the subtalar joint. The longitudinal foot axis is a theoretically constructed axis not associated with one specific anatomical joint. Experiments quantifying foot pronation have usually quantified foot eversion. “Excessive” foot pronation/eversion was typically considered as the reason for many injuries.
The “pronation-injury” paradigm should be considered with caution because (a) it is difficult to quantify “pronation”, (b) “pronation” is a natural movement and (c) many epidemiological results don’t support the pronation-injury paradigm.
Problems with the quantification
Foot eversion has been “quantified” using 72 different static and dynamic variables.
Natural movement and variability of runners
“Pronation” is a natural movement during gait. This indicates that some pronation is healthy, natural, and necessary for locomotion, and the question should focus on the optimal amount of pronation instead of trying to reduce pronation to a minimum.
One study with a large sample size (Nielsen et al., 2014) assessed foot posture of novice runners with a static foot posture measurement and grouped the 1854 feet of the 927 participants from very supinated to very pronated. They showed after a one year period of running significantly less injuries per 1000 km for the pronated group compared to the neutral group. Thus, “pronation” as assessed with a static calcaneus position measure is not an injury predictor. Based on these results, one may even speculate that ‘pronation’ reduce the likelihood of sustaining running related injuries.
Since “pronation is a topic with many aspects that are not clear, a new study was performed were all 72 previously used and published “pronation” measures were quantified. With these results, the following questions were addressed:
- What is the correlation between the static and the corresponding dynamic variables.
- What is the correlation between the different pronation variables.