Chapter 2 Linear Kinematics - sp05 运动生物力学 (第二章)专用课件.ppt

Chapter 2 Linear Kinematics Describing Objects in Motion Define Motion: Motion is... Define Motion: Motion is a change in position over a period of time. Types of Motion Linear Motion (translation) all points on the body move the same distance in the same direction at the same time Rectilinear Translation: straight line figure skater gliding across the ice Curvilinear Motion: curved line free-fall in sky-diving Simultaneous motion in x y directions Horizontal and vertical motion superimposed Types of Motion Linear Motion (translation) Angular Motion (rotation) all points on the body move through the same angle Whole body rotation giant swing, pirouette Segment rotation flexion, abduction, yada yada yada …. Types of Motion Linear Motion (translation) Angular Motion (rotation) General Motion combines angular linear motion most common pedaling a bike walking drawing a straight line Large Motions Large Motions Small Movement Linear Kinematics Study of the time and space factors of motion Linear kinematic quantities Kinematics is the form, pattern, or sequencing of movement with respect to time. Kinematics spans both qualitative and quantitative form of analysis. Linear kinematic quantities For example, qualitatively describing the kinematics of a soccer kick entails identifying the major joint actions, including hip flexion, knee extension, and possibly plantar flexion at the ankle. Linear kinematic quantities A more detailed qualitative kinematic analysis might also describe the precise sequencing and timing of body segment movements, which translates to the degree of skill evident on the part of the kicker. Linear kinematic quantities Although most assessments of human movement are carried out qualitatively through visual observation, quantitative analysis is also sometimes appropriate. Linear kinematic quantities Physical therapists, for example, often measure the range of motion of an injured joint to help determine the extent to which range of motio