Mechanical Analysis

Quiz 1 material

Define Biomechanics

The application of mechanical principles to the study of biological systems, the study of the structure and function of biological systems by means of the methods of mechanics

Why do we want to study biomechanics

Improve performance (Modify technique), Reduce injury risk (Modify equipment)

When are concerned with human performance?

human performance is NOT limited to high-achieving athletic competitions, performance occurs during any human activity

Reducing injury risk

you can never eliminate ALL injuries, but you can decrease the potential for injury

Mechanopathology

The mechanics that result in injury (an incorrect landing that leads to an ankle injury)

Pathomechanics

The mechanics that are a result of an injury (changing your gait due to an ankle injury)

Two areas of classical mechanics

Statics and Dynamics

Dynamics

interested in changing systems, broken into kinematics and kinetics

Statics

interested in unchanging systems

Kinematics

the study of motion without concentration of the cause

Kinetics

The study of the causes of motion

Statics are used frequently in material science which includes the following

material properties, response to loads, in biomechanics setting the analyses are often referrd to as “tissue mechanics”

Multisegment principles

composed of connects segments, requires coordination of segments (throwing, reaching, walking, running)

Why are biological principles important to biomechanics

Human bodies are all different, and those differences influence how movement works and how forces act on the body

Top Level of The Hierarchical Model

Performance measure/ result

Second Level of The Hierarchical Model

Factors that determine the top level variable, mechanical correlates

Third Level of The Hierarchical Model

Factors that determine the second levels variables, determining the correlates

Rules of The Hierarchical Modeling

1. Factors included in the model SHOULD be mechanical quanities

2. Each of the factors in the model should be completely determined by those factors linked in the level below

3. Annotate those boxes that you can not control (by crossing them out)

Top-down Approach

Body level

whole body level - total limb level - joint level - tissue level

Bottom-up Approach

Tissue level

Tissue level - joint level - total limb level - whole body level

Degree of freedom

Independent way a joint can do on its own

A four step approach

Determine movement objective - identify mechanical correlates - analyze movement solution - conduct intervention

Identify mechanical correlates

create hierarchical model

Analyze movement solution

List phases of movement - determine critical elements - identify constraints

Step 1: Determine the Objective of the Movement

you can not understand the mechanics of the movement without understanding the purpose of the movement

ex: pitching - speed and accuracy

Step 2: Identify the Mechanical Correlates of Performance

Focus is on the performer and what they are trying to do. The best way to keep track of these factors is a hierarchal model (outline)

Step 3: Analyze the Movement Solution and Identify Faults

Focus on how the performer is doing

• (what are the movement patterns being used to optimize the mechanical criterion)

• Proficiency

Proficiency

How well a person performs a movement and achieves the goal of the task

Three classes of movement

Discrete, Serial, Cyclic

Discrete movement

Clear beginning and ending points, without a movement repeating (tennis serve)

Serial movement

has a distinct beginning and end, but links at least two distinct, discrete movement (long jump)

Cyclic movement

Movement pattern that repeats several times, continuous (swimming, running, walking)

Phases of a Discrete Task

Preparation, Propulsion, Braking

Preparation

preparing to propel max displacement

Propulsion

Proximal to distal

Braking

Energy not transferred to object, is absorbed by the body

Phases of a Cyclic Task

Propulsion, recovery (over and over again)

Critical Elements

Aspects of a movement that are necessary for optimal performance. The magnitude are generally not discrete values, but fall in range of acceptable values. The timing is as important as the critical elements themselves.

Three types of Constraints

Organismic (Intrinsic Dynamics), Environmental, and Task

Organismic (Intrinsic Dynamics) Contraints

The kinematic (range of motion) and kinetic (strength, power, endurance) capacities of each degree of freedom involved in a task

Environmental Contraints

due to the physical surroundings

Task Constraints

due to the nature of the performance

Identifying Faults

• determination of what the person is doing wrong/ or what can be improved

• must be evaluated against some criteria

  • exemplary performance or guiding principles

  • past performance

  • normalized scores/ times