The validity of image analysis freeware in calculating physical angles in two dimensions

Abstract

[Purpose] The aim of this study was to examine the validity of an image analysis freeware for calculating physical angles in two dimensions. [Subjects and Methods] Eleven young adults (5 males, 6 females) analyzed a moving image while performing the sit-to-stand movement using image analysis freeware in order to estimate hip flexion, knee flexion and ankle dorsiflexion angles. The time and subjective fatigue of the task were measured. The angles estimated using the image analysis freeware were compared with the angles calculated using motion analysis share software. [Results] The average time spent analyzing 115 images was approximately 20 minutes, and the subjective fatigue degree was approximately 30 mm on a visual analog scale. The differences in the maximum values of joint angles between the two methods were 0.12 ± 0.25° for the hip joint, 0.14 ± 0.30° for the knee joint, and 1.02±0.38° for the ankle joint. [Conclusion] The results of this study indicate that this image analysis freeware is a useful tool for simple motion analysis.