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DISTRICT Seminar Series #1: Modern Methods of Flexibility Training with Yiannis Christoulas

Human Performance Specialist, Yiannis Christoulas, MSc, of Greece visits the DISTRICT to teach the science of flexibility.

"You should stretch." We've all been told this, and yet there are still people with tight hamstrings and athletes who pull muscles when they go beyond their current range of motion. The words mobility and flexibility are carelessly tossed around interchangeably and we are fed a reactive approach from many in the fitness industry that says "If it's tight, stretch it." Unfortunately, there's more to the range of motion of a muscle than just reaching for your toes or holding a specific position. We brought Yiannis in to dive into the details and bring our clients and coaches a neuroscience approach to improving functional range of motion.

Yiannis Christoulas is a modern sports scientist and coach from Greece, who has focused his studies on improving human performance and health, with a specialty in flexibility training. He has amassed over 50,000 subscribers on his youtube channel where he teaches the neuroscience approach to flexibility while providing solutions to many common questions in the fitness industry. His seminar focuses on science and theory before diving in to a hands on component where everyone in attendance left improved. In case you missed the event, check out below:


Part I: Yiannis defines flexibility as "the range of motion (ROM) around a joint or group of joints (that) reflects the ability of the muscle-tendon unit to elongate." He discusses that the range of motion we feel is not truly the maximum length of that muscle but actually the nervous system guarding our end range to prevent injury where it feels "unsafe." To further illustrate this, he points out that if you were under general anesthesia/sedation, you would have greater range of motion than when you are awake and alert. This shows that there are other systems in play here beside just the physical length or tension of a muscle. Instead, we are working with complex systems of neurology and reflexes that must be specifically targeted in our training to improve flexibility.


Active ROM: Unassisted - the range of motion your muscles are capable of pulling you through. Example: Active Straight Leg Raise

Passive ROM: Assisted - The range of motion you can be moved to by an outside force/practitioner. Example: Practitioner putting you through a hamstring stretch.

Mobility vs. Flexibility: Mobility implies active ROM, Flexibility implies passive ROM

Agonist: The primary muscle contracting with a certain movement.

Antagonist: The muscle that is relaxing during a certain movement.

Examples: When the knee is flexion, the hamstrings are the agonist muscle group and the quadriceps are the antagonists.

"Being flexible means: "to be able to move through the desired range of

motion of each joint and movement’’

Part II: Practical Applications

Yiannis discusses 4 types of stretching before running our group through a flexibility assessment before using these stretching strategies to improve range of motion right away within a given training session.

4 Types of Stretching:

Dynamic: Stretching with movement

Static: Sustained stretching holds

Proprioceptive Neuromuscular Facilitation (PNF): Stretching patterns involving various or alternating contractions of agonist and antagonist muscles to enable the nervous system to reduce tension in the desired muscle group.

Antagonist Contraction Relax - Contract the opposite muscle group for 6-7s to reduce "tone" in the agonist muscle group.

Contract Relax - Contract the agonist muscle group for 6-7s to "fatigue out" the muscle and allow it to relax further.

Contract Relax Antagonist Contraction - Combine these 2 methods by contracting the agonist muscle for 6s before alternating and contracting the antagonist (opposite) muscle for 6s with the goal of reducing resting tension in the agonist muscle.

Static + PNF: Using sustained holds at end-range immediately after a PNF strategy to take advantage of the inhibiting response of the desired muscle group.


Where there's muscle, there's the nervous system. In order to improve both mobility and flexibility, we need to understand why our muscles feel tight or tense in the first place. If we appreciate this relationship between the muscles and nervous system, we can use effective strategies to create lasting improvements in ROM without sacrificing stability.

The tension we feel in our muscles is often related to our body's natural "stress response" that is designed to protect us. When we are less recovered, our brain reads this as higher injury risk and we become more tense to add stability to our system. This overall recovery factors in nutrition, hydrations, sleep, mental and physical stress in addition to other factors, but the further these are from optimal, the more we are driven into tension. Consider addressing these areas prior to flexibility training for improved results.

Furthermore, consider the environment you are training in. If you are standing at the edge of a building 20 stories high, you can bet your hamstrings will be tighter than if you are standing in the sand on a relaxing beach. The key here is relaxing. When we are relaxed, our body is more in a parasympathetic (rest and digest) state as compared to a sympathetic (fight or flight) state that we are in when stressed or experiencing high levels of stimulation. With this, your muscle tone will be more relaxed in a parasympathetic state vs. a sympathetic state, so you can improve your ROM results by reducing the immediate stressful inputs in the environment you are training in.

Try this at the end of your routine in a relaxing environment for improved hamstring flexibility:

Static + PNF using Contract Relax Antagonist Contraction Method for hamstring flexibility:

Stand with one heel on a bench elevated to an end range stretch and lean forward to push into a hamstring stretch for approximately 20s.

  1. Repeat 3x: Contract your hamstring for 6s, "pulling" your heel towards you, while in end range.

  2. Repeat 3x: Relax the hamstring and follow this with a sustained 6s contraction of your quadriceps.

  3. Gently release without losing the end range stretch and push further into a static hamstring stretch for approximately 20s.

  4. Come out of the stretch to "Reset" and repeat entire process 2-3 times.


Thank you to all in attendance! For those who want to see rapid improvement in their side split, Yiannis is offering 20% off his flexibility program using code: DISTRICT

(Click below to learn more about this program)

Connect with Yiannis:

Instagram: yiannis_christoulas

Youtube: Yiannis Christoulas

As animal lovers and owners, we are happy to announce that all proceeds for this event were donated to the Mount Pleasant Animal Shelter in East Hanover, NJ. For those looking to contribute further to the cause, visit them at: to learn how you can help!

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