Sometimes, our muscles resist being stretched, not because they’re short, but because of reflexes and structural factors. Two common causes of limited mobility are reactive stretch resistance and intrinsic stiffness.
What is Reactive Stretch Resistance? Reactive stretch resistance is controlled by your nervous system. When a muscle is stretched quickly, your body activates the stretch reflex, causing the muscle to contract. This is a protective mechanism to prevent overstretching or injury.
Intrinsic Stiffness: This type of resistance comes from the physical properties of your muscles and connective tissues, such as fascia. Over time, inactivity, poor posture, or repetitive movements can cause these tissues to become stiff and limit movement.
Key Terms:
- Stretch reflex: A protective mechanism that causes muscles to contract during rapid stretching.
- Intrinsic stiffness: Tightness caused by physical properties of muscle and connective tissue.
Real-Life Example: Have you ever tried to stretch your hamstring and felt it tighten suddenly? That’s your stretch reflex kicking in. Alternatively, if you’ve been sitting all day and feel stiff, that’s intrinsic stiffness affecting your range of motion.
Practical Applications:
- Slow, controlled stretches reduce the activation of the stretch reflex, allowing muscles to relax and lengthen.
- Techniques like self-myofascial release (e.g., foam rolling) can break up adhesions in connective tissue, reducing intrinsic stiffness.
Test Your Comprehension:
- What triggers the stretch reflex?
- How does intrinsic stiffness develop over time?
- Name one way to address reactive stretch resistance.
Scientific References:
- Shumway-Cook, A., & Woollacott, M.H. (2016). “Motor Control: Translating Research into Clinical Practice.”