Validation of Joint Position Sense of Dorsi-Plantar Flexion of Ankle Measurements Using a Smartphone

OBJECTIVES This study evaluated and validated the reliability of smartphones as measuring equipment for the dorsi-plantar flexion of ankle joint position sense (JPS) ability. METHODS The subjects were 20 healthy young students in their 20s. We confirmed the concurrent validity by comparison with existing electrogoniometer data. The reliability of the smartphone was confirmed using the test-retest method. RESULTS In the case of dorsiflexion, there was no significant difference between the smartphone and electrogoniometer groups (p > 0.05). Regarding the correlation, it was significantly high (r = 0.65, p < 0.05), and ICC(3,1) was good (ICC(3,1) = 0.79). For the case of plantar flexion, there was no significant difference between the smartphone and electrogoniometer groups (p > 0.05), the correlation was significantly high (r = 0.69, p < 0.05), and the ICC(3,1) was very good (ICC(3,1) = 0.82). In the case of dorsiflexion, there was no significant difference between test and retest (p > 0.05), the correlation was intermediate (r = 0.59, p < 0.05), and the ICC(3,1) value was good (ICC(3,1) = 0.74). For plantar flexion, there was no significant difference between test and retest (p > 0.05), the correlation was significantly high (r = 0.63, p < 0.05), and the ICC(3,1) was good (ICC(3,1) = 0.76). CONCLUSIONS The results showed that smartphones provide high validity and reliability as measurement equipment for JPS of dorsi-plantar flexion of the ankle. Finally, the study also considers that smartphone-based JPS measuring methods may replace the traditional and expensive methods that are currently being used for the same purpose.