Everybody wants to be fit. A fit person is considered healthy and can use his body for athletic as well as daily activities. A fit person is flexible. Within this article we lay the groundwork for a deeper understanding of human anatomy so you enter the wild field of the current state of science and learn why the 4 selected stretching techniques work wonder.


There are plenty of good reasons why it´s important to make sure that your lifestyle or training is not messing up with your mobility. Science showed that mobility is one essential aspect of injury prevention, that elastic muscles are less likely to cramp (1), that stretching can reduce post-exercise muscle soreness, and increase power (2), as well as running economy (17). But the idea of being able to tie your shoestrings your whole life, all by yourself, is also pretty nice.

“I’ve never enjoyed my running more. I also do 200 sit-ups a day, 60 push-ups, and a lot of stretching. I’ve had some back issues. I think the stretching helps with that.”

Running Legend Alberto Salazar (3)

In this first chapter, we will refresh your anatomy knowledge and explain 4 basic types of stretching, as well as an application-oriented perspective. To get the best results out of the time you hang in a really uncomfortable position, acquiring some meta-knowledge will help you to choose the best stretching technique and understand the importance of alignment, contraction, and relaxation. Inhale.

Now put your reading glasses on. And exhale.

Stretching anatomy

A muscle is a part of a complex organ system that consists of muscle cells, blood vessels, nerves, tendons, and fascia. On a microscopical scale you have actin and myosin filaments, stick-shaped proteins, that slide closer to each other when the muscle-fiber gets the order to contract – For visualization interlace your fingers and slide your hands closer together. If you zoom away you see that a muscle consists of hundreds or thousands of these filaments that form cylindrical muscle cells that are bundled together and wrapped in different connective tissue coverings, also called fascia.

The order for this shortening of the muscle aka contraction is transmitted by nerve cells. But nerve cells are not only the transmitter of orders but they also report information about the muscle length, position, and power back to the central nervous system (brain & spinal cord).

One example of how these structures are working together is the stretch reflex. The one where the doctor smashes down the hammer on the tendon below your knee cap. The impact causes an extremely fast lengthening of your front thigh muscle. This alarms the receiving nerve cells, the proprioceptors, and they immediately transmit a signal to those nerve cells that give the order for contraction. Your front thigh muscle shortens and your lower leg kicks front. As this front kick requires your back thigh muscles to shut up, there is not only a transfer of information towards the front thigh muscle but also to the antagonist muscle.

In this case, the nerve cells that would contract your hamstring muscles are inhibited. This allows the back of the thigh to lengthen. The stretch reflex, or myotatic reflex, prevent injuries that occur while overstretching and is useful when you stumble over your shoestrings. (4)

Remember the following points in order to understand the different stretching techniques:

  • Muscles are made of rows and lines of protein filaments, that are wrapped in connective tissue
  • Some nerve cells report the state of the muscle (length, power, and position) to the central nervous system
  • Other nerve cells are transferring the signal for contraction when they are active
  • There´s some communication going on between opposing muscle groups (agonist and antagonist), during the stretch reflex, when the agonist contracts the antagonist likes to chill

So, what does that mean for stretching?

There is no active process inside a muscle for stretching – more a relaxing process. A muscle is stretched because it gets into a position where it lengthens. Through alignment, you determine what you stretch. Sitting on the ground with highly bent legs will not stretch your hamstrings.


Why is stretching so painful?

Sometimes a muscle just forgets to relax again. The relaxing process requires ATP (a molecule that is the engine for lots of physiological processes). So if you crunch and crUNCH and CRUNCH your biceps, it might be more convenient for your lazy muscle to stay contracted, than to “waste” energy to loosen it all up again. The same happens after death when there’s no ATP the muscles stay tensed. But also connective tissue adapts to not moving by losing some of its elasticity, when, for example, elastin (a highly elastic protein) begins to fray or the collagen increases in stiffness and density.

When, in this worst-case scenario, everything is shorter than it is normally, the nerve cells report the higher tension and warn you by sending pain signals. As you would feel after unwarranted parental advice, be grateful for the message, it stops you from ripping your muscles. (5) So your body really changes, for good or bad, depending on how much you move and stretch each muscle. Mobility training is not a one night stand, it is more a serious long-term relationship.

These changes occur when you become more flexible:

While doing a proper stretching program, several changes occur within the muscle fibers and surrounding and adherent tissue: the filaments slide apart, back to the maximum resting length of the muscle.(5,6,7) It was found, that by regular stretching over time also the numbers of filaments increase, like it happens after eccentric strength training. (7,8) But also the fascia stay smoother. One function of fascia is to protect your muscles creating a sheath and allowing muscles to slide easily within your body. Stiffened fascia -BAD- No sliding or even compression of nerves and muscles. Smooth fascia -GOOD- As the fascial system is continuous throughout the body, also the integrity of muscle relies on the happy fascia. (9,10)

Stretching is like lubing your bike chain. Once you’ve done it you can do some serious pedaling.

These 4 stretching techniques will change your hamstring-game:

Let’s continue with a short intro to 4 basic types of stretching (2):

  • Dynamic stretching
  • Active Stretching
  • Static stretching
  • PNF stretching

1. Dynamic stretching

Take a standing forward fold. Grab your elbows and slowly move your upper body from side to side. Work on keeping the legs straight. In this technique, you use soft and controlled bouncing and swinging movements. It’s similar to ballistic stretching but not as aggressive. You never go past the joint’s normal range of motion. Still, it has the effect of keeping your body mobile and stimulating the production of synovial fluids.

  • When: In your Warm-Up
  • How long: As long as it feels good. 30-60 seconds sounds good though.
  • Intensity: Slowly increase your range of motion without being aggressive. You will feel more space after a few bounces.
  • Example: Standing Forward Fold, grab your elbows and swing from side to side

2. Active Stretching

If you stand upright and lift one leg to the front as high as you can, you might notice that this is hard and painful. In this form, you only use the strength and contraction of the opposite muscle. Remember: The contraction helps the relaxation of the target muscle. Active stretching is a great way to play with different engagements and to work out at the same time. If you are already on your Yoga Path, did you notice that all the challenging poses like the scale (Warrior 3) or the triangle are actually stretches?

  • When: During your session
  • How long: At least 15 seconds repeated 2-4 times
  • Intensity: As deep as you feel the stretched muscle lengthening, no need to put load on joints or tendons.
  • Example: Warrior 3, or standing and lifting one leg up

3. Static stretching.

Bring the body into a position where the target muscle is under tension, a seated forward fold. Then slowly increase the tension by leaning front, placing the hamstring muscles at their greatest length.

Holding a static stretch for at least 15 seconds is considered to be effective. What athletes often forget is that by applying a calm breathing here, it tells the nervous system to relax and helps to deepen stretch (11,12) Static stretching gives you the time for an optimal positioning and turning inwards, noticing how your pain-receptors stop firing after a while and how your muscles and tissues adapt.

Summing it up:

  • When: At the end of the session. More effective, when you are already warm.
  • How long: At least 15 seconds repeated 2-4 times
  • Intensity: Target the muscle you wanna stretch, slowly intensify the stretch, feel the point where you can make your muscle relax even more
  • Example: Holding a lizard Lunge, or a seated forward fold

Flexibility is crucial to my fitness. Incorporating a good warm-up and cool-down into every session decreases my chances of injury. I use both dynamic and static stretching in my training. I’ve started doing a few yoga sessions which incorporate muscle strength and flexibility.

Samantha Stosur, Top Tennis Player (18)

4. PNF Stretching

Proprioceptive Neuromuscular Facilitation – excuse me. PNF stretching is considered to be great for athletes if they aim to increase the range of motion and build strength at the same time. There are different variations of PNF stretching: the trick is to fool your nervous system because the method uses natural muscle reflexes to further the stretching response.

A PNF hamstring stretch can be executed by laying on your back and bringing up one leg as close as you can. Now get a hold of this leg. No need to scream yet. Try to first isometrically contract (= don´t change the shape) the quadriceps. The nerve cells will report that there’s a shortening going on and that there’s still more room for shortening. At the same time, they call their friends the “hamstring contractors” to take a break. And once your quadriceps finishes contracting your hamstring is more relaxed than before and you can pull your leg closer than before. In the PNF method, you can also add a pre-contraction phase of the targeted muscle, which is assumed to increase the stretch tolerance. (13,14,15) This might be helping you out because some of your activation nerve cells are already tired. (10)

  • When: After the session, you should be warm.
  • How long: (if you do CRAC = Contract-Relax-Antagonist-Contract)
    • Hold the contraction of the antagonist for 5-8 seconds
    • Stretch the target muscle for 20-30 seconds
    • When you feel tension is building up again, contract the target muscle for 5-8 seconds
    • And then again stretch the target muscle for 20-30 seconds
    • Repeat 2-4 times
  • Intensity: It´s not necessary to go maximum force. Gentle stretching is effective. The smaller the muscle group, the less force. (19)
  • Example: Lizard Lunge or laying on your back and getting hold of one leg

Note that there are many other brilliant stretching techniques, like resistance stretching (=using a strap), loaded stretching (=using weights) or passive stretching (=using a friend).

By now you learned about how to apply stretching beneficially to your training. As our Yoga Training follows these guidelines, you don’t have to remember all the numbers, you will develop a feeling for all this. Remember that you are individual, in your constitution and training discipline. Don’t expect the split after 2 weeks. But expect improvement!

Adding more days of stretching results in better improvements. Life is hard. But the cool thing is that 6 days a week shows no difference to 7 days. (20)

The important facts:

If stretching is not as exhausting as running a marathon or climbing a mountain, why do most people fail when it comes to stretching? Because most people fail doing it at all. We are conditioned to stick to habits, even if they are unhealthy.

Take your time and attention for each stretch. By being attentive you can start applying techniques to trick your brain, and you will learn all by yourself how to align. Remember that muscles lengthen when they are relaxed, but that not only muscle length counts but also the properties of tendons, fascia, and other tissue matter. The good news is, that you can address them all with stretching and you can change their structures to good or bad.

You might have noticed, that all the exemplary stretches form part of a Yoga Program. The goal of the physical Yoga practice is a balanced training. If there are imbalances because of your sport, with Yoga you actively take your time to work on these. Yoga is not a relaxing Netflix program it´s more a mental and physical challenge. So take this challenge like NBA players Myles Turner (check out his video 16) or Lebron James are doing.

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