Evaluating runners with and without anterior knee pain using the time to contact the ankle joint complexes' range of motion boundary

- Biomechanical studies have not supported the link between excessive pronation and anterior knee pain.
- One reason a link has not been found could be that excessive pronation is being evaluated in the wrong context.
- Time to contact can evaluate pronation in the context of both an individual's range of motion and velocity.
- Using this technique, runners with anterior knee pain were found to have less time before reaching end range.

BackgroundLittle biomechanical evidence exists to support the association between excessive foot pronation and anterior knee pain (AKP). One issue could be the way excessive pronation has been defined. Recent evidence has suggested that evaluating pronation in the context of the joint's available range of motion (ROM, anatomical threshold) provides greater insight on when pronation contributes to injury. Theoretically, quantifying the amount of time the joint has to respond before reaching end range (neuromuscular threshold) could provide additional insight. Therefore the purpose of this study was to use a neuromuscular threshold, the time to contact (TtC) the ankle joint complex's ROM boundary, to evaluate runners with and without AKP.MethodsNineteen healthy and seventeen runners with AKP had their ROM and running biomechanics evaluated. The TtC was calculated using each individual's angular distance from end range (eversion buffer) and eversion velocity. Data were recorded over ten stance phases and evaluated using a one way analysis of variance and 95% confidence intervals.ResultsRunners with AKP had significantly shorter TtC the joint's ROM boundary when compared to healthy runners (64.0 ms vs. 35.6 ms, p = 0.01). While not statistically significant, this shorter TtC was in large part due to having a smaller eversion buffer, however velocity was found to have a substantial influence on the TtC of select individuals. These results provide evidence that a link between pronation and AKP exists when using anatomical and neuromuscular based thresholds.