How Stretching Actually Changes Your Muscles, According to Physical Therapists

Reviewed by Dietitian Katey Davidson, M.Sc.FN, RD, CPT

Key Points

• Stretching can improve flexibility by changing how your nervous system responds.

• Dynamic and static stretching can each have a place in your fitness routine.

• A consistent stretching routine can help support mobility and range of motion.

If you’ve ever stuck with a stretching habit for an extended period, you may have noticed that you can reach a little farther than you used to, which may have you thinking that your muscles have lengthened.

But is that really the case? According to physical therapists, the reality is more nuanced, and much of it has to do with your nervous system rather than changes to the muscles themselves.

In this article, physical therapists share what the research says about stretching, including which type of stretching you should choose and how to build a simple routine you can do a few times a week. Let’s dive in.

Does Stretching Change Your Muscles?

The short answer? Somewhat, but not in the way you might expect. “Regular stretching can help maintain flexibility and support mobility and range of motion,” says Dhara Shah, PT, D.P.T. “However, flexibility is more complex than simply thinking about a muscle becoming longer.”

Studies suggest that much of the early progress happens in your nervous system rather than in the muscle itself. “Most early flexibility gains appear to come from increased stretch tolerance and changes in how the nervous system responds,” explains Alex McRobbie, PT, D.P.T., OCS. “As you stretch regularly, your nervous system becomes more tolerant of the tension and is less likely to inhibit elongation of the muscle, allowing you to move through a greater range of motion.”

Additionally, research suggests that when you move deeper into a stretch, sensory signals from your muscles and surrounding tissues register increasing tension and discomfort. “In other words, some of the increase in range of motion comes from a change in how the nervous system perceives and responds to the stretch rather than the muscle simply becoming longer,” explains Kaylee LeCavalier, PT, D.P.T., SCS, CSCS, CAPS.

Static vs. Dynamic Stretching

Not all stretching is the same. Static stretching involves moving into a lengthened position and holding it for a certain period of time, which is likely what comes to mind when you think of stretching. Dynamic stretching, on the other hand, involves actively moving through a range of motion, such as with leg swings, walking lunges or arm circles.

“A general rule is to use dynamic stretching before exercise and static stretching after exercise,” Shah says.

That said, static stretching before a workout isn’t off-limits. Just keep in mind that holding static stretches for longer than 60 seconds has been shown to reduce lifting performance. “Prolonged static stretching immediately before activities requiring maximal strength, power or speed can temporarily reduce performance, so I would avoid longer holds immediately before those activities,” says LeCavalier.

Stretching Routine

Aim to do this beginner-friendly stretching routine two to three times per week, ideally after a workout or on its own. For static stretches, hold each one for 15 to 30 seconds and repeat two or three times per side.

Supine Hamstring Stretch

Lie on your back and bring one leg toward you, holding behind your thigh or looping a strap or towel around your foot. Slowly straighten your knee until you feel a comfortable stretch along the back of your thigh. Keep your other knee bent if that’s easier on your lower back.

Half-Kneeling Hip Flexor Stretch

Kneel on one knee with your opposite foot planted in front and your knee bent. Shift forward until you feel a stretch at the front of your hip on your kneeling side. Keep your torso upright with good posture and avoid arching your lower back.

Standing Calf Stretch

Face a wall with one foot stepped back. Keep your back heel down and your back knee straight as you lean forward to stretch your upper calf. To target your lower calf (soleus), slightly bend your back knee while keeping the heel on the floor.

Open-Book Rotation

Lie on your side with your hips and knees bent and your arms extended straight out in front of you. Keep your knees together and slowly rotate your top arm and upper back toward the opposite side and toward the floor, then return to the starting position. Since this is a dynamic stretch, aim to perform 5 to 10 slow, controlled reps per side.

Getting Started

As always, warm up before beginning this stretching routine. Doing a few minutes of brisk walking or marching in place can help increase blood flow before stretching. “Start gradually and don’t force your range of motion,” says McRobbie. “More flexibility isn’t necessarily better.”

Physical therapists recommend these tips as you incorporate stretching into your routine:

• Never Bounce During Static Stretches. Instead, hold steady and try to relax into the position.

• Be Consistent. Like anything related to health or fitness, a sustainable routine done regularly beats an intense session done occasionally.

• Combine Stretching with Resistance Training. Building up your strength through resistance training that includes full ranges of motion can help improve flexibility.

• See a Health Care Professional. Check with a physical therapist or health care provider if you experience persistent pain, numbness, tingling, weakness or sudden loss of mobility. Also get clearance if you had a recent injury or surgery, or have a preexisting health condition.

Our Expert Take

Stretching can change how your muscles function by increasing your tolerance to muscle stretching and reducing tissue stiffness. A good rule of thumb is to do dynamic stretching before strength training and static stretching after, or keep static stretching holds to under 60 seconds before exercise.

Ideally, try to do a few stretching sessions per week, including a short warmup beforehand. If you have any musculoskeletal problems or injuries, or experience pain while stretching, speak with your health care provider or physical therapist.

Read the original article on EatingWell