Human Movement

Movement Science Fundamentals

Kinematics and Kinetics

  • Kinematics: Describes human motion.
    • Examples: joint angle, step length, step width. You should be able to visualize and draw these aspects.
  • Kinetics: Explains the causes of human movement.
    • Examples: force. How much force is being applied during movement and what muscles are generating them?
  • Combining kinematic and kinetic data reveals the biomechanical mechanisms of movement.
  • Movement is measurable

Measurement and Reference Points

  • To measure movement, you need a reference point.
  • A single point in space is meaningless without a reference.
  • Example: Gait velocity vs. gait speed.
    • Gate velocity is a vector: shortest distance (e.g., 130 meters).
    • velocity=displacementtimevelocity = \frac{displacement}{time}
    • Gait speed is a scalar: total distance covered (e.g., 300 meters).
    • speed=distancetimespeed = \frac{distance}{time}
  • Gait speed and velocity are the same only when motion is in a straight line.

Biomechanical Science

  • Converts what we cannot understand into what we can understand by number using kinematic and kinetic information.

Perspectives on Human Movement

Historical Perspective

  • Perspectives change over time (e.g., attitudes toward smoking).

Personal Control vs. External Factors

  • Many people believe they have full control over their movement.
  • Scientifically, movement is the outcome of interaction between ourselves and their environment.
  • Example: Walking on the moon vs. Earth. The gravity affecting the subjects ability to walk.

Interaction with the Environment

  • Movement is the outcome of interaction between internal and external factors, e.g., the external enviornment.
  • Therapeutic Environment: By modifying the environment, movement can be optimized.
    • Change in environment can drive interaction and optimize movment.
    • Examples: placing a patient in water, using resistance bands.

Demonstrations of Environmental Influence

  • Resistance Example: Intention vs. actual motion. Intention was horizontal movement but added the resistance that caused the diagonal movement.
  • Observed motion is the product of interaction between the individual and the applied force.
  • When observing movement deviations, consider both the individual and external factors.
    • Sometimes the subject can't be changed but the external force/resistance can be changed.

Joint Torque and Muscle Response

  • Every motion has joint torque; muscles respond to control external forces.
  • External forces without control lead to collapse.
  • Apply external forces to induce desirable movement.
  • Knee flexion torque is controlled by the quadriceps via knee extension.
  • Movement is optimized interaction between external environment and muscle.

Static Analysis

  • Static analysis: formula to calculate the static analysis, especially if you wonder about muscle force relative to the joint torque. (Refresher from previous studies).

Therapeutic Tools

  • Aquatic therapy: relieves hypertonia in cerebral palsy patients.
  • Anti-gravity treadmill: eliminates gravity to induce better movement.
  • Exoskeletal robots: assist body to overcome external environment and facilitate movement.

Command Centers

  • Brain: internal command center.
  • External environment: external command center.
  • Address issues by modifying the external environment to encourage desirable movement.

Psychological and Cognitive Impact

  • Movement is not solely physical; psychological factors matter.
  • Example: Walking overground vs. on a high walkway.
  • Fear avoidance patterns: patients avoid movements due to fear.
  • Communication with other health professionals (doctors, occupational therapists, psychologists) is crucial for understanding patient movement.
  • Cognition impacts movement.

Task and Intensity

  • Same task can have different mindsets and behaviors based on intensity.
  • Design therapeutic environments to optimize movement.
  • Clinicians should be designers and thinkers, not just "bodybuilders."

Parkinson’s Disease Example

  • Two patients with Parkinson's may have the same number of falls, but different physical activity levels and fear avoidance behaviors.
  • Fall rate is higher in low activity patients.
  • Assess physical activity to understand the patient's condition better.
  • More movement is safer than minimal activity.

Impact of Fear

  • Fear negates external environment or task.
  • Enabling patients to confront fear leads to recovery.
  • Strong rapport with clinicians helps patients overcome fear.
  • Professionalism involves making patients feel safe and trust you so they can have the courage to overcome the fear.
  • The fear can be measured by looking at the hesitation of of the movement.
  • Virtual reality quantifies fear by measuring hesitation.
Frames
  • Internal Environment (human body).
  • External environment.