Lecture 9 - Linear Kinetics - Kinetic Data Acquisition

Lecture Outline

  • Main topics discussed include:

    • Force Platform

    • Force plates

    • ForceDecks

    • DANU socks

    • Pressure Platform

    • Isokinetic Dynamometry

Force Plate

  • Definition:

    • A force platform is a device designed to measure the forces exerted by a body on an external surface, such as the platform itself.

    • Reaction force: Measures ground reaction force (GRF), which is equal in magnitude and opposite in direction to the action force applied to the plate according to Newton’s third law.

Components of Ground Reaction Force (GRF)

  • Orthogonal Components:

    • Fx: Mediolateral component of GRF (side to side)

    • Fy: Anterioposterior component of GRF (front to back)

    • Fz: Vertical component of GRF (up and down)

Uses of Force Plates

  • To understand whole-body motion during various activities.

  • Application of Newton's Laws of Motion to analyze kinetics and kinematics.

  • Evaluates how the whole body is loaded during activities involving impacts.

  • Assesses cushioning properties of surfaces, shoes, and sports protective equipment.

Applications of Force and Pressure Platforms

  • Research Examples:

    • Analyzing vertical kinetics and kinematics during running.

    • Clinical biomechanics studies in journals.

    • Research on footwear cushioning properties and accelerometer data.

ForceDecks

  • Purpose:

    • Equipment for measuring dynamic performance metrics including force and power during athletic movements.

Pressure Platform

  • Difference from Force Plate:

    • Monitors pressure distribution during ground contact, rather than net loading profile.

    • Measures distribution of force over contact area utilizing an array of sensors.

Applications of Pressure Platforms

  • Gait analysis

  • Clinical analysis of movement

  • Shoe and orthotics design

Isokinetic Dynamometer

  • Muscle Contraction Types:

    • Isometric: Contraction without muscle/joint length change.

    • Isotonic: Force remains constant during contraction.

    • Isokinetic: Speed of movement is controlled, allowing for dynamic analysis.

    • Measures joint moment exerted during constant angular velocity movements.

Applications of Isokinetic Dynamometry

  • Measurement of muscle strength.

  • Assessment of training and rehabilitation programs performance.

  • Predicting performance and mitigating injury risk.

Research Methodology

  • Example of a study with a control group and a training group assessing hamstring injury risks using isokinetic dynamometry.

  • 4-week program with evaluations of knee flexor and extensor strength.

Potential Exam Question

  • Topic: Compare and contrast various methods for collecting kinetic data for biomechanical analysis.

    • Subtopics to consider:

      • What each method measures.

      • Principles of operation.

      • Applications in sports and health.

      • Examples from journal literature.