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It’s a Stretch

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Can you touch your toes without bending your knees? Can you scratch that itch in the center of your back? How about doing the splits the way you could when you were on the Cheer team in high school?

The science of stretching has been expanding over the past couple of decades or so and flexibility is beginning to be understood in a new light. It was once thought that long static holds of lengthened muscle tissue was all that was needed to attain superior flexibility, but recent studies have shown that any gains in length achieved through passive stretching, while it may feel good, do not have lasting effects.

Any gains in length achieved through passive stretching, while it may feel good, do not have lasting effects

The reason? How bendy you are is determined by the central nervous system (CNS), not the muscle tissue itself. The stop signs the CNS puts up are its way of protecting muscle from damage through over-stretching. When you reach down to try to touch your toes, the CNS says, “wait a minute, that is the end of the road,” at some point because it believes that to go further would damage the tissue being stretched. This is known as the stretch reflex and can be very limiting to lasting gains in range of motion.

The stretch reflex always gets its way with passive stretching, allowing temporary gains in tissue length, and then the tissue returns to its former length not long after the stretching effort. The sensory signal caused by the stretch only travels to the spinal cord and not all the way to the brain as it is a primitive alarm system for protection of tissue.

However, recent studies have shown that stretching methods involving “tricking” the CNS into not perceiving a threat of damage can lead to more lasting lengthening of the tissue.

A muscle that is working cannot be overstretched. So an engaged muscle overrides the stretch reflex. Furthermore, when you engage the muscle while you are stretching it, the brain itself is involved, not just the spinal cord, and a more complex understanding of the stretch occurs. Over time, the brain begins to develop confidence in that new, greater range of motion, allowing for a more lasting change in tissue length. When the brain feels strong at the end of the range rather than vulnerable, it will extend the range.

The law of reciprocal inhibition is another technique for achieving increased range of motion by fooling your CNS. It says that when a muscle is engaged, its opposite lengthens more easily. So, when you contract your biceps (front of the upper arm), the CNS tells the triceps (back of the upper arm) to relax and allows it to lengthen more.

Another commonly used technique to lengthen muscle tissue is called proprioceptive neuromuscular facilitation (PNF). PNF includes a wide variety of techniques all involving some sort of initial contraction of the muscle to be lengthened which seems to fool the CNS into thinking the tissue does not need protection, and so it lengthens.

Before trying any of these techniques, it is important to account for the ligaments, joints and bones involved in range of motion. Every human body has its own unique combination of factors determining one’s “flexibility”.

Every human body has its own unique combination of factors determining one’s “flexibility”

Each joint in the body is held together by ligaments linking the bones to each other. Ligaments are not elastic like muscle tissue and if they become overstretched through injury or aggressive stretching efforts, they retain a laxity, like an expired rubber band, that can increase wear and tear in the joint, as well as instability. Taking care to protect the ligaments is important when stretching. Always avoid joint discomfort when stretching.

In more weight-bearing joints there are supportive structures, such as the labrums of the shoulder and hip, designed to cushion the bones where they meet, and overly aggressive attempts to stretch muscle tissue can instead cause damage to these structures sometimes causing severe pain. It is an alarming fact that many longtime yoga teachers are having hip replacements.

Bone size and shape can also be limiting factors, and when bone meets bone in a stretching effort, you are at the end of the line.

A thorough stretching routine can be a great addition to any fitness plan. Even passive stretching can help alleviate stiffness from sitting too long or other periods of inertia. If done with techniques that encourage the brain and CNS as a whole to change the perception of what is safe for your body, you may find those toes getting closer.

Stretching tips

Here are a few stretching tips to help you achieve more lasting increases in muscle length:

  1. Always make sure you are feeling the stretch in the belly of the muscle itself, and not in the joints.
  2. Slightly contract the muscle that you are stretching. This will feel counter-intuitive at first and may be hard to do, but keep trying. It will happen eventually, and then it will feel like you are wrestling with yourself, but give it time, and you will notice results within a few weeks.
  3. For PNF stretching, strongly contract the muscle you are stretching for 5-6 seconds, while holding it at its natural, resting length, and then release the contraction and passively stretch the muscle. You will notice an instant increase in range.
  4. For reciprocal inhibition, steadily contract the opposite muscle of the one you intend to lengthen. For example, when bending down to touch those toes, fire your quadriceps (the front of your thighs) to get your hamstrings (the back of your thighs) to lengthen and let you bend a little deeper.
  5. Use passive stretching for relaxation and only after exercise, not before. Lengthening muscles passively before an active workout can make muscle tissue vulnerable to injury. (Dynamic range of motion movements mimicking the activities about to be undertaken are a much more effective way to prepare the body for a workout.) Passive stretches may be held as long as you like, but avoid sensation in the joints and keep your activities gentle after passive stretching.
  6. Be well hydrated and comfortably warm to encourage easy movement.

There are zillions of stretching routines available online. Look for one that includes these methods and that you enjoy and will return to a couple times a week. Soon those toes will not seem so far away.

Ann Constantino, submitted on behalf of the SoHum Health’s Outreach department.