Week 1 - Linear Kinematics & Kinetics, Free Body Diagrams (FBD)

biomechanics

the study of mechanical laws relating to the movement or structure of living organisms, biological systems

qualitative analyses

• observation or video recording

• can involve graphs, but focus is on their patterns

• non-numerical

• subjective measurement

• to differentiates between individuals or team

qualitative pros

• no expensive equipment

• field-based

• if done properly highly systemic

• movement patterns speak more loudly than words

semi-quantitative analyses

involves qualitative analysis plus a simple test

quantitative analyses

• image-based motion analysis, marker tracking systems, electromyography, force & pressure plates

• involves statistical analysis, computers

• objective measurement

• to predict injury risk

• to aid in rehabilitation protocol

• to aid in performance comparisons

• to provide quantitative feedback

quantitative pros

• provide detailed, specific measurement of movement

• reliability & objectivity can be easily assessed

distance

• magnitude of area covered, complete length

• scalar quantity

displacement

• magnitude & direction between a start position and end position

• vector quantity

• indicates direction with words or symbols

slope

• rise over run

speed

• how fast an object is moving

• rate of change in distance

• scalar quantity

velocity

• speed of an object in a particular direction

• rate of change in displacement

• vector quantity

• indicate with direction

acceleration

• rate of change in velocity

• vector quantity

• indicate direction

forces

• magnitude & direction

• vector quantity

• length of arrow = magnitude

internal forces

• act within the object or system whose motion is being investigated

• cannot change the motion of the body center of mass

external forces

• act on an object as a result of its interaction with the environment surrounding it

• can change the motion of the body center of mass

frictional force - contact force

friction contact force - parallel

normal contact force - perpendicular

F_f = F_N x u

coefficient of friction (u)

• ratio of friction force and normal force

• dependent on materials and conditions