Lecture 3: Biomechanics of Resistance Exercise

What is Biomechanics?

• Study of movement mechanisms of the body
• Involves bones, tendons, ligaments working together

The Skeletal System

Components

1. Axial Skeleton
   • Includes skull, ribs, spinal column, and sternum
2. Appendicular Skeleton
   • Includes legs, hip, shoulder girdle

Joints and Movement

• Fibrous Joints: No movement (e.g., skull sutures)
• Cartilaginous Joints: Limited movement (e.g., vertebral discs)
• Synovial Joints: Most movement, prone to injury
  • Types: Uniaxial (hinge), Biaxial (wrist), Multiaxial (ball and socket)

Synovial Joint Structure

• Cartilage covers articulating ends
• Synovial fluid provides cushioning and lubrication

Vertebral Column Sections

1. Cervical: 7 bones, neck region
2. Thoracic: More mobility, shoulder flexibility
3. Lumbar: Base, lower body support
4. Sacral: 5 fused bones
5. Coxal: 3-5 fused bones

Muscle Attachments

• Origin: Stationary point, proximal
• Insertion: Moving point, distal
• Example: Bicep origin at scapula; insertion at forearm

Muscle Roles in Movement

1. Agonist: Primary muscle causing movement
2. Antagonist: Muscle that slows down or controls movement
3. Synergist: Assists in movement, stabilizes joints

Anatomical Position and Direction

• Anatomical Position: Standing, palms forward
• Terms:
  • Anterior (front), Posterior (back)
  • Superior (upper), Inferior (lower)
  • Medial (towards midline), Lateral (away from midline)

Planes of Motion

1. Sagittal Plane: Divides body left/right
   • Movements: Flexion, extension
2. Frontal Plane: Divides body front/back
   • Movements: Abduction, adduction
3. Transverse Plane: Divides body top/bottom
   • Movements: Rotational

Joint Actions

• Flexion/Extension: Reducing/increasing joint angle
• Abduction/Adduction: Moving away/towards midline
• Pronation/Supination: Palm down/up

Muscle Actions

1. Concentric: Muscle shortens, force > resistance
2. Eccentric: Muscle lengthens, resistance > force
3. Isometric: Muscle length stays the same

Designing Exercise Programs

• Importance of training concentric, eccentric, and isometric actions
• Balance in program design (push/pull, up/down)
• Prioritize safety and balance to prevent injury
• Consideration of anatomical terms and muscle actions for effective program design

Coaching Philosophy

• Focus on athlete's health and safety
• Balanced programs lead to strength and injury prevention
• Educate and progress athletes responsibly