Stretching has been a go-to practice for athletes, fitness enthusiasts, and physical therapy patients alike. But what’s really happening inside your body when you stretch? More importantly, is stretching as beneficial as we’ve been told?
For years, the idea was simple: stretch to improve flexibility, prevent injuries, and enhance performance. However, modern research paints a more nuanced picture. While stretching does have benefits, how, when, and why you stretch matters. In this post, we’ll explore the science behind stretching, the differences between dynamic and static stretching, and how to make your stretching routine more effective.
What Happens at the Cellular Level?
When you stretch, your muscles don’t just "loosen up"—a series of complex physiological reactions occur at the cellular level.
1. Muscle Fibers and Fascia Adapt
Muscle fibers (sarcomeres) temporarily elongate during stretching, but lasting flexibility gains occur when connective tissues, like fascia, gradually adapt over time. This aligns with Davis’s law, which states that soft tissues remodel in response to consistent mechanical stress. Research also shows that fascia is dynamic and can adapt to mechanical forces, influencing long-term flexibility (Schleip et al., 2019).
2. Neuromuscular Inhibition (Stretch Reflex)
The stretch reflex protects muscles from overstretching by triggering a contraction when a muscle is rapidly lengthened. However, consistent stretching can reduce this reflex's excitability, allowing for greater flexibility. A study found that repeated stretching, especially when muscles remain relaxed, can attenuate stretch reflex activity, supporting the idea that long-term stretching helps muscles tolerate greater lengthening without resistance (Ogawa et al., 2022).
3. Increased Blood Flow and Tissue Elasticity
Stretching improves blood circulation, which brings oxygen and nutrients to the muscles. This can enhance recovery, reduce muscle stiffness, and even contribute to long-term joint health.
Has Science Proven That Stretching is Beneficial?
Yes and no. While stretching can improve flexibility, studies show that static stretching before exercise doesn’t significantly reduce injury risk or enhance performance (Behm et al., 2016). However, dynamic stretching and long-term flexibility training have been shown to improve range of motion, recovery, and even reduce chronic pain when done correctly (Oppert & Babault, 2018).
Dynamic vs. Static Stretching: How to Use Each Effectively
Not all stretching is created equal. The type of stretching you do should match your goal:
Dynamic Stretching:
Best Before Activity
Dynamic stretching involves active movements that take your joints through their full range of motion. Instead of holding a stretch, you move fluidly through it—mimicking the movements you’re about to perform.
Benefits:
Increases blood flow and muscle temperature
Activates the nervous system for movement
Improves range of motion without reducing muscle power
EXAMPLES:
Leg Swings – Swing your leg forward and backward to activate hip flexors and hamstrings.
Lunges with a Twist – Engage core, hips, and spine before running or sports.
Arm Circles – Increase mobility in the shoulders before upper-body activities.
Bottom Line: Use dynamic stretching before workouts to prepare your muscles for activity without reducing power output.
Static Stretching:
Best After Activity
Static stretching involves holding a position for an extended period (15–60 seconds), allowing muscles to relax and lengthen.
Benefits:
Improves long-term flexibility
Helps muscles recover and reduces post-exercise stiffness
Promotes relaxation and stress relief
EXAMPLES:
Hamstring Stretch – While lying on your back, use a strap to anchor around your foot and pull your leg up towards the ceiling, feeling a stretch in the back of your leg
Chest Opener – While sitting, clasp hands behind your head and open your chest to counteract hunching, opening your elbows out and away from you
Quad Stretch – While standing, grab one ankle behind you to stretch the front of your thigh.
Bottom Line: Use static stretching after workouts or as part of a flexibility routine to improve long-term mobility.
When to Stretch
(And When Not To)
When You Should Stretch:
✔ Before a workout? – Yes, but only dynamic stretching.
✔ After a workout? – Yes, static stretching can aid in recovery.
✔ To improve flexibility? – Yes, but hold stretches for 15-60 seconds & perform them regularly.
✔ To address muscle imbalances? – Yes, targeted stretching can help correct asymmetries.
When You Should Avoid Stretching:
❌ When muscles are cold – Jumping into static stretching without warming up can lead to injury.
❌ If you're experiencing sharp pain – Stretching shouldn’t cause pain; if it does, you may have an underlying issue.
❌ If you suspect a sprain or strain – these types of injuries involve the tearing of ligaments or muscles/tendons, respectively (sometimes these tears are minimal). If there’s any torn tissue, stretching is not advised
❌ When you have a history of dislocation or subluxation – joints that are likely to pop out of place are not suited for stretching
TOOLS FOR OPTIMIZING YOUR STRETCHING ROUTINE
A stretching strap promotes better alignment and controlled muscle lengthening, while a yoga mat provides joint support and stability—both enhancing safety and effectiveness through improved biomechanics.
Addressing Muscle Imbalances: Focusing on the Tighter Side
If you notice one side of your body is significantly tighter than the other, this could indicate:
An imbalance in muscle strength
A previous injury that caused compensatory patterns
Postural habits affecting mobility
How to Fix It:
During warmups, spend extra time dynamically stretching the tighter side.
During cooldowns, hold static stretches longer on the less flexible side.
If asymmetry persists, consider working with a physical therapist to address underlying issues.
Conclusion: Smarter Stretching for Better Movement
Stretching isn’t just about flexibility—it’s about training your nervous system and connective tissues to function optimally. Keep in mind that your body needs time to adapt to a new stretching routine, so start slow and don’t stretch more than once a day.
Here’s what to remember:
✔ Dynamic stretching before workouts prepares muscles for movement.
✔ Static stretching after workouts improves flexibility and recovery.
✔ Stretching should be intentional—focusing on imbalances and avoiding overdoing it.
✔ Flexibility is a long-term process—consistency is key.
Rather than mindlessly holding stretches, use stretching as a tool to enhance movement, prevent injury, and improve overall mobility. If you’re struggling with flexibility issues, a structured stretching routine (or a visit to a physical therapist) could make all the difference.
References
Schleip, R., Gabbiani, G., Wilke, J., Naylor, I. L., Hinz, B., Zorn, A., Jäger, H., & Klingler, W. (2019). Fascia is able to actively contract and may thereby influence musculoskeletal dynamics: A histochemical and mechanographic investigation. Frontiers in Physiology, 10, 336.
Ogawa, Y., Hasegawa, N., Nakazawa, K., Akai, M., & Murayama, M. (2022). Effect of repeated fast stretches on stretch reflex excitability in individuals post-stroke. Frontiers in Neurology, 13, 764650.
Behm, D. G., Blazevich, A. J., Kay, A. D., & McHugh, M. (2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: A systematic review. Applied Physiology, Nutrition, and Metabolism, 41(1), 1–11.
Opplert, J., & Babault, N. (2018). Acute effects of dynamic stretching on muscle flexibility and performance: An analysis of the current literature. Sports Medicine, 48(2), 299–325.