[Purpose] Evaluation of the reliability of smartphones as measuring equipment for dynamic balance ability was the goal of this study. [Subjects and Methods] Subjects were 30 healthy young students in their 20s. The first and second rounds of measurements were taken at a one-day interval to confirm test-retest reliability. The subjects stood on the footboard of the Biodex Balance System. Balance was measured using a smart phone. [Results] Acceleration rates corresponding to subjects with open eyes were 2.7 ± 2.2 (first measurement) and 3.3 ± 1.5 (second measurement), and the interclass correlation coefficient ICC (1,1) was 0.8. Acceleration rates corresponding to subjects with closed eyes were 4.1 ± 2.4 (first measurement) and 4.5 ± 1.8 (second measurement), and the ICC (1,1) was 0.9. Gyroscope rates corresponding to subjects with open eyes were 1.7 ± 1.2 (first measurement) and 2.3 ± 1.5 (second measurement), and the ICC (1,1) was 0.7. Gyroscope rates corresponding to subjects with closed eyes were 6.7 ± 2.4 (first measurement) and 6.6 ± 2.3 (second measurement), and the ICC (1,1) was 0.6. [Conclusion] The results of this study suggest that smartphones have sufficient potential as measuring equipment for dynamic balance ability.

Objectives: Aquatic therapy is a significant intervention method for both patients and healthy individuals. However, in clinical practice, quantitative measurements are rarely applied in aquatic therapy due to the disadvantages of submerging expensive instruments in water. In this study, we used readily available smartphones and armbands to measure leg segments and joint angles during aquatic gait and evaluated the reliability of these measurements.Methods: Waterproof smartphones were strapped to the trunk, thighs, and shanks of 19 healthy young adults using armbands. The angles of the trunk, thigh, and shank segments were measured during aquatic gait. The measurements were repeated 1 day later. The data were analyzed to obtain the angles of the hip and knee joints.Results: Measurement repeatability, calculated using the intraclass correlation coefficient (ICC), was the highest for the shank segment range of motion (ROM) (first 46.79° ± 5.50°, second 50.12° ± 9.98°, ICC = 0.78). There was high agreement in trunk segment ROM (first 6.36° ± 1.42°, second 4.29° ± 1.83°, ICC = 0.73), thigh segment ROM (first 33.49° ± 5.18°, second 37.31° ± 8.70°, ICC = 0.62), and knee joint ROM (first 52.43° ± 11.26°, second 62.19° ± 16.65°, ICC = 0.68) and fair agreement in hip joint ROM (first 34.60°±4.71°, second 37.80° ± 7.84°, ICC = 0.59).Conclusions: Smartphones can be used to reliably measure leg segments and joint angles during aquatic gait, providing a simpler method for obtaining these measurements and enabling the wider use of aquatic motion analysis in clinical practice and research.

This research was conducted to see the correlation between changes of ankle Joint Position Sense and Sway Area through Unstable Surface training. For the study, 48 healthy males and females were randomly divided into an unstable surface group(n=24) and a stable surface group(n=24). Then, they were asked to carry out the same exercise program three times a week for six weeks. The unstable surface group and stable surface group performed the exercise program on the balance exercise pad and on the hard ground, respectively. As a result, the unstable surface group displayed significantly reduced error of ankle joint position sense and sway area(p<.05). Moreover, a significant correlation between variances of ankle joint position sense and sway area was only found in the unstable surface group. In conclusion, this study demonstrated that there was a significant correlation between changes of ankle joint position sense and sway area through proprioceptive sense training on the unstable surface.

ObjectivesThis study evaluated and validated the reliability of smartphones as measuring equipment for the dorsi-plantar flexion of ankle joint position sense (JPS) ability.MethodsThe 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.ResultsIn 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).ConclusionsThe 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.

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