Abstract: BACKGROUND: The hip joint is a complex structure, and plays an important role in supporting weight and daily activities, and there is no objective way to assess its athletic ability.
OBJECTIVE: To analyze the time and space parameters of hip joint in the process of motion around sagittal axis, coronal axis and vertical axis, and to summarize the variation rules of motion parameters.
METHODS: Thirty subjects were selected to capture the movement track of hip forward flexion, backward extension, abduction, adduction, rotation in, rotation out and reduction through three-dimensional motion capture system, calculate and analyze the maximum amplitude and angle changes in different degrees of freedom movement.
RESULTS AND CONCLUSION: (1) By establishing the motion model of the hip joint to obtain the range of motion of the hip in the sagittal plane, coronal plane and horizontal plane. The extreme values of the motion of each plane were calculated. (2) The angle-time change curve of the motion of the hip in different planes was exported. The change rule of the motion of the hip was summarized: the flexion and extension range of the hip on sagittal plane was much larger than the adduction and abduction of the coronal plane and inward and outward rotation on a horizontal plane. The angular acceleration of the hip joint was larger in the active stages of forward flexion, backward extension, abduction and outward rotation, and the acceleration was smaller in the resetting movement. (3) The establishment of kinematic model based on motion capture technology and the analysis of kinematic data can provide some references for the accurate assessment of hip function, and the prevention or rehabilitation of injuries, sports training, biomechanical analysis and other studies.

Key words: bone, hip joint, motion capture, motion model, degree of freedom, athletic ability