The Science of Biomechanics How Do I Move? Chapter 7 The Science of Biomechanics

Biomechanics The study of the structure and functions of biological systems by means of the methods of mechanics Hatze, 1974 We might think of biomechanics as the “physics of human movement”

Biomechanics Examines the internal and external forces acting on the human body and the effects produced by these forces Aids in technique analysis and the development of innovative equipment designs Draws on knowledge from sports medicine, physical therapy, kinesiology, and biomechanical engineering

The 7 Basic Principals of Biomechanics They all fall under the following 4 categories Stability Maximum Effort Linear Motion Angular Motion

Principle 1 – Stability The lower the centre of mass, the larger the base of support, the closer the centre of mass to the base of support, and the greater the mass, the more stability increases.

Principle 2 – Maximum Force The production of maximum force requires the use of all possible joint movements that contribute to the task’s objective.

Principle 3 – Maximum Force The production of maximum velocity requires the use of joints in order – from largest to smallest.

Principle 4 – Linear Motion The greater the applied impulse the greater the increase in velocity.

Principle 5 – Linear Motion Movement usually occurs in the direction opposite that of the applied force.

Principle 6 – Angular Motion angular motion is produced by the application of a force acting at some distance from an axis, that is, by torque. The application of torque produces changes in angular motion.

Principle 7 – Angular Motion angular momentum is consistent when an athlete or object is free in the air. Once an athlete is airborne, he or she will travel with a constant angular motion.

Review of Movements from Anatomy Planes Sagital Frontal, Coronal Transverse Axis Horizontal Antereoposterior Longitudinal

Motion Kinematics Kinetics describing movements with respect to time and space Kinetics examines the forces that produce the movement and result from the movement

Qualitative Analyses Involves obtaining information, visually or auditorily, to asses performance It requires: A framework within which skilled performance can be observed A set of principles with which movement can be analyzed A checklist to use when identifying errors Techniques to use for error detection and correction

Quantitative Biomechanics

Types of Motion Angular motion General motion Linear motion

Types of Motion Translation refers to movement of the body as a unit without individual segment parts of the body moving relative to one another Linear Motion When all parts of the body move the same distance, in the same direction, at the same time Rectilinear motion occurs when movement follows a straight line Curvilinear motion occurs when the movement path is curved but also linear

Objectives: Identify the external forces acting on the human body Describe the resulting motion Describe the expected path and motion of any projectile Differentiate between similar skills Determine the degree of stability possessed by an athlete Understand the causes and effects of actions Qualitatively analyze simple sport skills that involve throwing, striking, or hitting an object

Preliminary Steps for Analyzing Human Motion Identify the system to be studied, which is to separate the object of interest from its surroundings Step 2 Identify the frame of reference in which the movement takes place Step 3 Identify the type of motion that is occurring, the body planes in which movement takes place (sagittal, frontal, or transverse), and Identify the axes of rotation about which rotational motion occurs (sagittal, frontal, or vertical)