Analyzing Movements: Joint Actions and Muscle Contractions
Understanding Movement Patterns
When we analyze any movement in sports or daily activities, we need to look at two key components:
- Joint Actions - How our joints move and in what directions
- Muscle Contractions - How our muscles work together to create these movements
Always break down complex movements into individual joint actions and muscle contractions to better understand the biomechanics involved.
Joint Actions
Types of Joint Movements
- Flexion and Extension
- Flexion: Decreasing the angle between bones (like bending your elbow)
- Extension: Increasing the angle between bones (like straightening your arm)
- Abduction and Adduction
- Abduction: Moving a limb away from the body's midline
- Adduction: Moving a limb toward the body's midline
- Rotation
- Internal (Medial) Rotation: Rotating toward the body's midline
- External (Lateral) Rotation: Rotating away from the body's midline
In a basketball jump shot:
- Ankle plantar flexion (pointing toes down)
- Knee extension
- Hip extension
- Shoulder flexion
- Elbow extension
Muscle Contractions
Types of Muscle Contractions
- Isotonic Contractions
- Concentric: Muscle shortens while contracting (like lifting a weight)
- Eccentric: Muscle lengthens while contracting (like lowering a weight)
- Isometric Contractions
- Muscle generates force without changing length
- Example: Holding a plank position
Multiple muscles work together in most movements through different types of contractions.
