Limits and possibilities of 2D video analysis in valuating physiological and pathological support phases of the food in runners

Three-dimensional movements of the lower extremities in support phases are usually evaluated with the help of video analysis. This analysis is mainly done two-dimensionally in a frontal and sagittal plane. Usually, the temporal ankle of the achilles tendon respectively rear foot are analysed in the frontal plane, the knee and upper ankle angle in the sagittal plane, because their values are made responsible for different sport injuries. However, so far a correlation between different injuries and biomechanical parameters could not be proven. Often, small changes in 2D video data are discussed without considering the reliability of this method of measurement. It was the aim of this study to evaluate these parameters in 2D video analyses (2D-VA) which characterize the support phases of the foot. A second goal was to find out whether a connection between these angles and chronic achillodynia can then be sensibly proven. 32 male test persons consisting of a control group (KO, n = 14) without injuries and a group with chronic achillodynia (AD, n = 18), have been examined with the test/retest method in weekly intervals. The biomechanical running analysis was done with the help of 2D-VA in the frontal and sagittal plane on a treadmill at a speed of 80% of the individual anaerobic threshold with different shoes. The test/retest variability was for all measuring points not at all satisfying. Both groups showed big mean variations in both shoes and minimal differences in the measured angles. Because of the poor capability of reproduction of the 2D-VA for angles in the frontal plane this measuring method is only usable with restrictions for the evaluation of the support phase.