Effects of Immobilization on Muscles and Joints

Passive Stretching

• Passive stretching involves movement beyond a joint's normal range of motion.
• Immobilization affects the structures involved.

Effects of Immobilization

• Sarcomeres:

  • When immobilized with muscle on stretch, sarcomeres increase.
  • When immobilized with muscle in a shortened position, sarcomeres decrease.

• Muscle:

  • Type I (endurance) muscle fibers atrophy and weaken more quickly than Type II fibers.
  • A shortened position during immobilization reduces the number of sarcomeres in series.
  • Adhesion formation and decreased extensibility occur due to increased fibrofatty tissue in atrophied muscle and connective tissue (CT).

• Joint:

  • Decreased synovial fluid production leads to articular cartilage atrophy.
  • Tensile strength of articular and periarticular structures decreases.
  • Position and movement awareness diminishes.
  • Shortened position immobilization leads to increased connective tissue and a decrease in the number of sarcomeres in series.
  • Lengthened position immobilization increases the number of sarcomeres in series and can cause permanent change in muscle length (e.g., dynasplint, serial casting).
  • Effects are temporary if the affected area returns to its resting length.

Precautions/Contraindications

• Precautions:

  • Avoid forcing movement (strain, not pain).
  • Be cautious with fractures and osteoporosis.
  • Connective tissue has reduced tensile strength after prolonged immobilization.
  • Gradual strengthening and stretching are advised.
  • Discontinue if pain persists for over 24 hours.
  • Address edema and weakness.

• Contraindications:

  • Bony block.
  • Recent fractures.
  • Acute inflammation or infection.
  • Sharp, acute pain during movement.
  • Hematoma.
  • Avoid if selective stability is needed.

This quiz explores the impact of immobilization on muscle and joint structures, focusing on passive stretching techniques. It covers the effects on sarcomere length, muscle fiber types, and connective tissue dynamics. Test your understanding of the physiological changes that occur due to immobilization.