Chapter 3: Human Spring Engineering

It should be possible to explain the laws of physics to a barmaid.

—Albert Einstein

How Does This New Model and Approach Apply to Thoracic Outlet Syndrome?

Is your body engineered as a lever mechanism or a spring mechanism?

The human body is engineered as both a lever mechanism and a spring mechanism. Understanding how these two biomechanical systems work together is essential for understanding human movement, thoracic outlet anatomy, thoracic outlet syndrome, and other painful compression disorders.

The engineering of the body’s lever mechanisms has been studied for decades. However, to date, very little information has been presented to the public about how the body functions as an integrated spring mechanism or how human spring biomechanics may help maintain the spaces through which nerves and blood vessels safely pass.

In actuality, the human body functions as a living spring mechanism that allows it to recycle elastic energy, absorb and distribute impact forces, protect joints from repetitive stress, and, most important, maintain spaces and tunnels for the safe passage of blood vessels and nerves. It is vitally important that we understand how this human spring mechanism is engineered, how it works, and how spring weakness may contribute to thoracic outlet compression.

This includes inherent spring strength, spring stiffness, spring compliance, how tension on the spring is controlled, and how the body works in harmony with the established laws of physics and biomechanics. Normal muscle tension is commonly referred to as resting muscle tone, resting tone, or muscle tone.

This chapter is divided into three parts:

1. Part One—How Your Human Spring Is Engineered
2. Part Two—Spring Strength and Spring Weakness
3. Part Three—The Simple Physics of Your Human Spring

Part One—How Your Human Spring Is Engineered

Your human spring is engineered using bones, muscles, tendons, ligaments, fascia, cartilage, vertebral discs, and joints. The Human Spring Model indicates that the body functions as a giant integrated spring with seven interconnected floors, a 9- to 12-pound mass—the head—balanced on top of the spring, and two 10- to 15-pound masses—the arms—suspended from the upper-body spring mechanism.

The Seven Floors of Your Human Spring

1. Spring floor 7—The head, neck, and shoulders
2. Spring floor 6—The spine and chest
3. Spring floor 5—The hips
4. Spring floor 4—The knees
5. Spring floor 3—The ankle mortise
6. Spring floor 2—The subtalar joint
7. Spring floor 1—The foot arch

How does your human spring absorb impacts, recycle energy, preserve joint spaces, and help prevent the compression of blood vessels and nerves associated with thoracic outlet syndrome and other compression syndromes?

It accomplishes these functions through a variety of living biological springs.

Your Living Springs

1. Foot arch = leaf spring
2. Lower limb = torsion spring
3. Menisci, cartilage, and vertebral discs = compression springs
4. Spinal column = torsion spring
5. Tendons = extension springs
6. Human body = integrated torsion spring

Examples of Human Spring Engineering

The Body Is a Human Spring

The human being is a biped, which means we stand, walk, and run on two legs. The advantages of bipedal locomotion include raising the head to provide a greater field of vision for detecting danger and resources, improving communication, and freeing the non-locomotor limbs—the arms—for manipulation, reaching, lifting, carrying, defense, and combat.

Being able to stand and balance on two legs is no easy task. Human beings generally begin standing between 8 and 12 months of age. We take the ability to stand upright for granted, even though standing, walking, and running are learned motor activities developed through practice, sensory feedback, balance training, and neuromuscular coordination. Like learning to ride a bicycle, swing a golf club, or speak a language, upright posture and gait improve through trial and error and eventually become automated by the brain and nervous system.

The foot-arch bridge functions more like a flexible leaf spring that is suspended from above by muscles and tendons resembling elastic bungee cords. These spring-like tendons loop around the sides of the foot like slingshot bands and have strategic attachments to the bones of the foot. Together, they form a slingshot-style spring suspension system that supports the longitudinal and transverse arches from above.

When the tibialis posterior tendon tears or becomes dysfunctional, this spring suspension system can fail, allowing the arch to collapse and contributing to a condition called adult-acquired flatfoot deformity. When this happens, the body loses a significant portion of its lower-extremity spring strength, impact absorption, and elastic energy recycling capacity.

The foot has 26 bones and 33 movable joints that allow it to deform its shape when the body strikes the ground. This spreads impact forces, distributes mechanical stress, and allows the load to dissipate more safely across the entire foot rather than concentrating the force in one joint or tissue.

The three-dimensional foot also changes its shape like a flexible piece of clay, allowing it to adapt to the ground and position the leg more perpendicular to the pull of gravity. This helps maintain equilibrium, postural balance, and healthy tension throughout the lower leg so that no single area becomes excessively stressed, strained, twisted, or compressed.

At the same time, healthy joint spaces allow impact forces to be absorbed through the lower-body spring mechanism without damaging the cartilage, ligaments, tendons, bones, or joint surfaces.

That same spring elasticity travels through the ankles, knees, hips, sacroiliac joints, spinal joints, and vertebral discs. Impact forces allow the bones to approach and rebound from one another while cartilage functions as a biological compression spring. When cartilage compresses, fluid and metabolic waste products are squeezed out. When the pressure is released, the cartilage draws in oxygen, nutrients, and synovial fluid that help support tissue nourishment and joint health.

• Spring floors 1–3: The foot arch is a spring mechanism composed of 26 bones and 33 joints arranged in a three-arch, three-dimensional design. Stretchy ligaments and flexible joints allow the foot to behave like the leaf spring of a vehicle, helping absorb impact forces and store elastic energy.
• Spring floor 2: The arch leaf spring, or “human slingshot,” is suspended by spring-suspension muscles and tendons, including the tibialis posterior, tibialis anterior, peroneus longus, and peroneus brevis. These structures function like elastic slingshot bands. The tibialis posterior and tibialis anterior support the inner portion of the spring suspension system, while the peroneus longus and peroneus brevis support the outer portion.

Together, these muscles and tendons stretch when the foot lands, storing elastic energy before helping spring the body forward and upward.

The slingshot-style spring suspension muscles help propel the lower leg off the ground when you take a step. The direction and efficiency of movement are influenced by the amount of stretch, resting muscle tone, elastic recoil, and strength of the muscles and tendons. They work together to spring the body away from the ground with less muscular energy expenditure.

• Spring floor 4: The quadriceps, hamstrings, adductors, and abductors help suspend and stabilize the femur over the tibia while controlling knee stiffness, joint alignment, and impact absorption.
• Spring floor 5: The gluteus medius, gluteus maximus, gluteus minimus, external hip rotators, and iliopsoas muscles help suspend and control the pelvis, hips, and legs from above and from the sides.

If there is an imbalance in the strength, endurance, stiffness, or resting tone of the spring-suspension muscles of the lower body, the lower extremity may collapse and lock the spring on that side. This lower-body spring dysfunction can produce compensatory tension on the opposite side of the spine, neck, and shoulder.

Sometimes this lower-body imbalance is missed by the treating doctor as a source of chronic muscle tension that prevents the scalene muscles, pectoralis minor, and other thoracic outlet muscles from releasing. If you want maximum relief from thoracic outlet syndrome symptoms, you may need to restore the strength, balance, and coordination of the entire integrated human spring from the floor upward.

The spine can twist, bend, rotate, and spring through many different configurations to accept mechanical loads, absorb impacts, and rebound from forces occurring at millions of different angles.

Think about how football players, basketball players, hockey players, rugby players, gymnasts, runners, and martial artists twist, move, jump, collide, bounce, and fall without becoming injured during most movements. This protection is partly related to the unique torsion-spring resistance, elasticity, and spring-suspension mechanics of the spine and entire human body.

Your Body Will Collide with Earth Approximately 287,401,000 Times in Your Lifetime

During an average lifetime, it is estimated that your human spring may withstand approximately 287 million ground-impact collisions from walking, running, exercise, work, recreation, and other daily activities.

Torsion Spring

The entire body functions as one large integrated torsion spring. A torsion spring can be understood by imagining a wet towel being twisted to remove the water. The towel stores increasing amounts of elastic energy as it becomes twisted. When you release it, it quickly returns toward its original shape and releases the stored energy.

For example, when you step forward with your right leg, the left foot, ankle, lower leg, thigh, pelvis, and spine must rotate and twist to allow the right leg to advance. This movement loads elastic recoil energy into the body’s torsion spring. That stored elastic energy is then released to improve movement efficiency during the next step.

Compression Spring

The spinal spring is further enhanced by the vertebral discs, which function as biological compression springs. Most doctors refer to these discs as shock absorbers. However, a conventional shock absorber is designed primarily to dissipate energy rather than return it. The spine and vertebral discs can both store and return elastic energy, allowing the human body to function as a more efficient spring-mass system.

The vertebral discs load and unload impact forces during walking, running, jumping, lifting, and collisions. The spaces maintained by healthy spinal spring mechanics also allow the spinal nerve roots to pass safely through the intervertebral foramina between the vertebrae.

This may help explain why many athletes report improvements in mobility, comfort, coordination, and sports performance after chiropractic adjustments or other treatments that restore normal joint movement. These interventions may help when they improve the movement of the integrated spring rather than simply treating the body as a collection of isolated levers.

As a matter of interest, your heart also uses spring-like proteins. Elastic proteins called titin help cardiac muscle cells stretch when the heart fills with blood and recoil when the heart contracts. This elastic recoil reduces the amount of active muscular work needed during each heartbeat.

The Chest and Shoulder Spring Design

Your shoulder girdle attaches to the rib cage, spine, and chest primarily through muscles, fascia, and the sternoclavicular joint. The position of the shoulder depends partly on the resting muscle tone, length, strength, stiffness, and endurance of the muscles that suspend and control the shoulder girdle.

Resting tone refers to the low level of continuous muscle activity present when the muscles are not performing a strong voluntary contraction. Balanced resting muscle tone helps maintain posture and the position of the shoulder girdle over the thoracic outlet.

The average shoulder, arm, forearm, and hand may weigh approximately 10 to 15 pounds or more. This upper-extremity mass hangs from the integrated spring mechanism of the chest, spine, neck, and shoulder girdle. The collarbone connects the shoulder complex to the sternum at the sternoclavicular joint, while the remaining upper-extremity weight is suspended over the chest and rib cage by spring-like muscles positioned around the thoracic outlet.

The thoracic outlet is the passageway through which the brachial plexus, subclavian artery, and subclavian vein travel from the neck and chest into the arm. Therefore, the strength and resting tone of the shoulder-suspension muscles may directly influence the amount of space available for the neurovascular bundle.

Your shoulder is held in position by the spring stiffness, natural strength, endurance, and resting tone of several muscles. However, only a small group of muscles provides meaningful upward suspension of the shoulder girdle above the thoracic outlet tunnel. Coincidentally, exercises designed to develop these shoulder-suspension muscles are among the most neglected upper-body exercises. You will learn these exercises in Chapter 14, “Spring Training.”

Several muscles can pull or depress the shoulder girdle downward, potentially narrowing the thoracic outlet and costoclavicular space. In contrast, the upper trapezius and levator scapulae help suspend the shoulder girdle over the thoracic outlet from above.

• Spring floors 6–7, neck-shoulder suspension muscles: The trapezius and levator scapulae muscles contribute to the suspension, positioning, and movement of the shoulder girdle.
• Spring floors 6–7, neck-chest muscles: The anterior scalene, middle scalene, posterior scalene, and anterior cervical muscles influence the neck, first rib, and thoracic outlet region.
• Spring floor 6, shoulder-arm muscles: The subclavius, pectoralis minor, short head of the biceps, coracobrachialis, latissimus dorsi, lower trapezius, serratus anterior, middle scalene, posterior scalene, and pectoralis major help control tension between the chest, shoulder girdle, and arm. This muscular tension may influence compression of the thoracic outlet and thoracic tunnel.

When the pectoralis minor, short head of the biceps, coracobrachialis, latissimus dorsi, and other shoulder-depressing muscles become shortened, overactive, fatigued, or imbalanced, they can pull the shoulder girdle downward toward the rib cage. This may narrow the costoclavicular space between the clavicle and first rib and contribute to compression of the brachial plexus or subclavian blood vessels.

The rib cage is itself spring-like. Place your hands over the front of your chest and feel your ribs. Take a deep breath, then exhale gently. You can feel the rib cage expand and recoil as the chest spring helps move air into and out of the lungs.

Spring Engineering Provides Space for Structures to Pass Safely

• Spinal nerve roots pass safely through the intervertebral foramina between the vertebrae.
• The brachial plexus passes from the neck over the first rib toward the arm.
• The nerves pass safely beneath the clavicle and shoulder girdle.
• The subclavian artery and vein pass safely over the first rib.
• The blood vessels pass safely beneath the clavicle and shoulder girdle through the thoracic outlet.

Your head weighs approximately 9 to 12 pounds, which is about the weight of a bowling ball. Mechanically, you can envision the body as a giant elastic and flexible spring with the head balanced on top and the shoulder girdles suspended from the upper portion of the spring.

How does the thoracic outlet tunnel remain open and resist injury during impacts and collisions?

1. Consider the impacts your body endures when running at full speed. When your foot strikes the ground, your 10- to 15-pound shoulders continue moving downward. When the shoulders reach the bottom of their downward movement, why do they not crush the brachial plexus, subclavian artery, and subclavian vein against the first rib?
2. If you are playing football and tackle someone with your shoulder, you would expect the impact to narrow the space between the clavicle and rib cage. Why do athletes not develop immediate thoracic outlet syndrome symptoms with every collision? A temporary brachial plexus injury during sports is sometimes called a stinger or burner.
3. Why does the thoracic outlet not narrow enough to cut off blood flow or compress the nerves when you carry a heavy purse, backpack, suitcase, or shoulder bag?
4. A forceful football tackle may expose the neck and shoulder to forces similar to those experienced during a car accident. Why is thoracic outlet syndrome commonly associated with whiplash injuries but less commonly produced by every routine impact in contact sports?

Look closely at how the neurovascular bundle passes through the thoracic outlet, which I also refer to as the thoracic tunnel. The brachial plexus and subclavian blood vessels travel from the neck and chest, over the first rib, beneath the clavicle and shoulder complex, and into the arm.

The simplest explanation for thoracic outlet compression is that the rib cage or first rib rises into the thoracic tunnel, the shoulder girdle and clavicle descend into the tunnel, or both changes occur simultaneously. In many patients with thoracic outlet syndrome, both mechanisms may contribute to narrowing of the outlet.

Now think about how professional football, hockey, rugby, and other contact-sport athletes use their shoulders and necks to tackle opponents and absorb extreme impact forces.

According to Timothy Gay, author of Football Physics: The Science of the Game, Marcus Trufant, at 5 feet 11 inches and 199 pounds, was an average-sized National Football League defensive back. Those measurements do not stand out in a league where more than 500 players weighed 300 pounds or more during the 2006 training camps. However, a defensive back’s mass combined with an average 40-yard-dash speed of 4.56 seconds can generate up to 1,600 pounds of tackling force (1).

If this entire 1,600-pound force were absorbed only by the shoulder girdle, it could force the shoulder downward toward the thoracic outlet and potentially compress the nerves and blood vessels. Why does the shoulder not crash into the brachial plexus, subclavian artery, and subclavian vein with every football tackle?

The answer is spring engineering and whole-body force distribution.

The thoracic outlet remains open because the shoulder girdle is supported by a living suspension system. I call this the shoulder-chest spring-suspension system. The impact is not absorbed completely by the shoulder. Instead, the force is distributed across the integrated spring system of the feet, legs, hips, spine, rib cage, neck, and shoulders, reducing the amount of mechanical stress concentrated in the thoracic outlet.

A useful analogy is bungee jumping. A bungee cord functions as an extension spring. It extends downward, stores elastic energy as it stretches, and then recoils upward when it reaches its maximum extension.

• You are the shoulder girdle.
• The bungee cords are the upper trapezius and levator scapulae muscles.
• The river below represents the brachial plexus and subclavian blood vessels.
• The hard ground represents the first rib and rib cage.

If the bungee cord lacks sufficient strength, stiffness, or endurance, you may reach the river or hard ground before the spring recoils. Similarly, if the shoulder-suspension muscles are weak or fatigued, the shoulder girdle may descend toward the first rib and reduce the available space in the thoracic outlet.

The primary muscles that suspend the shoulder girdle over the thoracic outlet and chest include:

• Upper trapezius—helps suspend and position the shoulder girdle over the chest.
• Levator scapulae—helps elevate and suspend the scapula and shoulder girdle.

Now you may better understand why football players often appear to have very short necks. They develop powerful upper trapezius, levator scapulae, and neck muscles that create a strong shoulder-suspension system. Differences in neck and shoulder muscle strength may be one factor contributing to the higher reported prevalence of thoracic outlet syndrome among women.

Your Human Spring Must Be Integrated, Linked, and Coordinated

The word “integrated” means combining and coordinating separate elements into a harmonious and interrelated whole. The body is composed of different types of biological springs that are linked into one integrated spring-mass system. The head functions as a mass balanced on the upper portion of the spring, while the arms function as suspended masses attached to the shoulder girdles.

The Force That Holds Your Spring Linked When Standing or Sitting Is Called Resting Tone

In physiology, medicine, and anatomy, muscle tone—also called residual muscle tension or tonus—is the continuous, passive, partial activation of muscles or their resistance to passive stretch while at rest (2). Normal passive muscle tone helps maintain upright posture with minimal energy expenditure and allows the body to stand or sit for prolonged periods without excessive fatigue.

Your muscles and tendons link your bones together to form the human spring. While sitting or standing, a minimal amount of muscle activation is required to hold the bones and joints in alignment. This helps maintain balanced tension, preserve joint spaces, and prevent excessive strain on individual muscles, ligaments, and tendons. We will refer to this baseline muscular tension as resting muscle tone.

To reduce injury risk, muscular strength, endurance, stiffness, flexibility, and resting tone must be balanced throughout all seven floors of the human spring. If one floor is trained much more heavily than another, a spring imbalance may develop and create abnormal strain or compensation elsewhere in the body.

Resting tone also maintains tension in the upper trapezius and levator scapulae muscles, helping suspend the shoulder girdle high enough to preserve an open thoracic outlet. If these muscles become weak, fatigued, injured, or neurologically inhibited, their resting tone may become insufficient to support the shoulder. The roof of the thoracic outlet may then descend, narrowing the thoracic tunnel and increasing the risk of brachial plexus compression, subclavian vein compression, or subclavian artery compression.

We will discuss this in greater detail in Chapter 5, “The Cause of Compression,” when we examine the causes of thoracic outlet syndrome.

When a patient has rounded or slouched shoulders that allow the shoulder girdles to descend toward the thoracic outlet, we recommend exercises designed to improve the strength, endurance, and resting tone of the postural and shoulder-suspension muscles. The objective is to reposition the shoulder girdle so it provides maximum space for the brachial plexus and blood vessels to pass safely through the thoracic outlet. You will learn more about these thoracic outlet syndrome exercises in Chapter 14, “Spring Training.”

When you are upright, there is always a degree of internal tension and compression within the spring that helps keep the bones stacked and the joints aligned. Balanced resting tone helps maintain spaces for joints, spinal nerve roots, peripheral nerves, arteries, and veins.

Hooke’s Law of Physics Applied to Your Human Spring

Hooke’s law of elasticity, described by the English scientist Robert Hooke in 1660, states that the deformation of a spring is related to the force or load applied to it within its elastic range. In practical terms, the heavier the load placed on a spring, the more the spring deforms or compresses.

Spring strength and spring stiffness are also important. If your human spring is strong and has an appropriate degree of stiffness and muscle tone, it can tolerate heavier loads during standing, walking, running, lifting, jumping, and sports collisions.

Your body’s control center—the brain and nervous system—is capable of making continuous adjustments to the tension of the human spring. These neuromuscular adjustments are similar to changing the tension of a guitar string or adjusting the suspension of a vehicle. The nervous system modifies muscle activation and tendon tension to help the body absorb and return the forces created by walking, running, jumping, and sports movements.

Your Body Springs Like a Giant Pogo Stick

The nervous system can reduce or increase spring tension depending on the task. A more compliant spring may absorb a landing more gradually, while a stiffer spring may rebound from the ground more rapidly and improve walking or running speed.

In a Japanese study, scientists attached diagnostic ultrasound equipment to the lower leg to observe what happened within the calf muscles and tendons during walking (3).

They found that the calf muscle contracted to a relatively stable length when the foot contacted the ground and remained close to that length while body weight moved across the supporting leg. The muscle appeared to function partly as a stabilizer for the thigh and upper body, helping reduce excessive wobbling during walking and running (3).

Much of the movement was produced by the tendons stretching to absorb the landing force and then recoiling to help spring the body away from the ground. Mechanical work was supplied partly through passive elastic energy storage in the tendons (4 - 5), while the active muscles provided the force needed to support the body and maintain tension on the tendon springs.

This research demonstrated that the body bounces and recoils from the ground through spring-like muscle-tendon behavior rather than relying only on muscles pushing rigid levers across the ground. This supports the concept of the human body functioning as an integrated spring-mass system.

Part Two—Spring Strength and Spring Weakness

Spring Stiffness and Spring Compliance

Hooke’s law and studies of muscle-tendon behavior provide important scientific support for understanding human spring biomechanics, elastic energy storage, spring stiffness, and spring compliance.

The differences in stiffness between various springs are obvious. For example, the springs in a vehicle suspension system must be much stiffer than the spring inside a ballpoint pen.

However, it is a mistake to confuse painful joint stiffness or muscle stiffness from an injury with the mechanical stiffness of a strong, efficient, injury-resistant human spring. Painful stiffness, protective muscle guarding, and muscle spasm are different from healthy spring stiffness.

Spring Compliance

Spring compliance is the opposite of spring stiffness. Making a spring more compliant means reducing its tension so it can deform more easily and absorb impacts over a greater distance.

A compliant landing strategy during walking or running can improve impact absorption on hard surfaces. For example, when running barefoot on a hard surface, the nervous system may reduce tension within parts of the spring to create a softer and more compliant landing.

Another example sometimes discussed involves people who survive high-speed accidents while asleep, unconscious, intoxicated, or otherwise relaxed. In some cases, a more compliant body may move with the impact instead of resisting it with excessive muscular stiffness, although many other variables determine the severity of accident injuries.

Landing with an excessively loose or compliant spring, such as during a slow and fatigued jog, may reduce joint stability. When spring stiffness is insufficient, the lower extremity may wobble during landing because the muscles have not generated enough tension in the tendons to stabilize the stacked bones and joints. This wobbling gait is commonly seen in exhausted runners near the finish of a marathon.

An excessively compliant spring is also less mechanically efficient during standing, walking, and running. More muscular effort may be required to stabilize the joints, which can contribute to earlier fatigue.

Spring Stiffness

The nervous system can increase tension in the muscles and tendons to improve healthy spring stiffness without creating pathological muscle spasm. Increased spring stiffness can allow the body to recoil from the ground with greater speed, efficiency, and elastic energy return.

Appropriate muscular and tendon stiffness also improves joint stability and may help prevent injury during sudden changes in direction, landing, running, and sports collisions. Insufficient stiffness may destabilize joint motion and increase the risk of soft-tissue injury (11) (10) (9) (8) (7) (6).

In practical terms, healthy spring stiffness reduces excessive wobbling during walking and running. When we apply this concept to the neck, shoulders, and thoracic outlet, the objective is to prevent the head and shoulder girdles from wobbling or collapsing excessively during walking, running, working, or sitting at a desk.

The exercises in Chapter 14 are designed to improve the strength, endurance, and mechanical stiffness of the neck, upper back, shoulder, and thoracic outlet suspension system.

A stiffer spring can also generate greater impact forces. During running, the spring should not become excessively stiff because adequate deformation is still needed to absorb impacts. This is especially important at higher running speeds.

Coaches and athletes continually search for the ideal combination of spring compliance and spring stiffness to achieve safe, fast, efficient, and powerful performance.

What Determines Human Spring Strength?

• Overall body stiffness
• Single-joint stiffness, including foot, ankle, knee, hip, spine, neck, and shoulder stiffness
• Muscle-tendon unit stiffness, such as the medial gastrocnemius and Achilles tendon working together
• Individual tissue stiffness, such as Achilles tendon stiffness
• Individual muscle-fiber stiffness
• Cellular stiffness, because even individual cells possess measurable mechanical properties

A Weak Human Spring

• Not strong enough to absorb and distribute impacts, increasing vulnerability to injury
• Not strong enough to create sufficient stiffness for efficient movement, contributing to chronic fatigue
• Not strong enough to resist fatigue, allowing the spring to collapse, drop, and lock
• More vulnerable to chronic pain, degenerative changes, joint compression, nerve compression, and blood-vessel compression
• Less capable of maintaining open anatomical spaces, including the thoracic outlet, intervertebral foramina, and other nerve tunnels

A Strong Human Spring

• Capable of improving spring compliance to protect the body from steps, falls, sports collisions, automobile accidents, and occupational injuries
• Capable of increasing spring stiffness to improve speed, power, balance, and movement efficiency
• Capable of maintaining spring integrity under heavy lifting loads
• Capable of maintaining posture and spring alignment during prolonged sitting, standing, walking, or working
• Capable of maintaining adequate spaces for peripheral nerves, spinal nerve roots, arteries, and veins

Most important, the upper-body spring must have enough strength and endurance to maintain a wide thoracic outlet so that the brachial plexus, subclavian artery, and subclavian vein can pass safely.

Improving the strength of the muscles that support the human spring is an example of muscle tuning or spring tuning. Lever-based strengthening exercises can be used to improve muscle strength and create stronger spring tension. Strengthening the upper trapezius and levator scapulae may help suspend the shoulder girdle higher and preserve the thoracic outlet space.

However, exercises that isolate muscles and joints train only individual lever components. To develop a stronger, coordinated, integrated full-body spring, you must also perform exercises such as plyometrics and dynamic spring-training drills that challenge elastic recoil, balance, stiffness, and whole-body coordination.

I have included more than 30 thoracic outlet syndrome stretches and strengthening exercises, along with five important spring-training drills, in Chapter 14, “Spring Training.” These exercises are designed to increase the strength of the human spring suspension system and specifically improve the support of the thoracic outlet and shoulder girdle.

Remember, muscle stiffness is not the same as spring stiffness. Painful muscle stiffness often develops after injury or when the brain senses strain and activates protective muscle guarding. We will discuss muscle spasm, protective tension, and thoracic outlet compression more extensively in Chapter 5, “The Cause of Compression.”

Part Three—The Simple Physics of Your Human Spring

As mentioned previously, much of the medical world has not yet learned to evaluate the body as a living, integrated spring. Traditional examinations, treatment methods, and explanations of musculoskeletal injuries are often based primarily on a lever model of biomechanics.

Consequently, it is my view that doctors may be missing important aspects of how the human body moves, absorbs impacts, stores and recycles elastic energy, preserves joint spaces, and maintains tunnels for nerves and blood vessels in a world governed by the laws of physics, nature, engineering, and biomechanics.

Science already contains laws that help explain how materials and springs respond to force. Established principles can help predict how the human body may respond to collisions, compression, tension, twisting, bending, loading, and repetitive mechanical stress.

Materials science incorporates principles of physics, chemistry, biology, and engineering. We can apply concepts from materials science to the human spring to better predict and understand what happens when the body is subjected to mechanical stress and force.

The Body Deforms Its Shape During Everyday Movement

The human spring, like all springs, must deform or change its shape to absorb impacts and adapt to different positions. Without flexibility, elasticity, and controlled deformation, the body would become vulnerable to tissue damage and structural failure.

In materials science, deformation refers to a change in the shape or size of an object. This concept also applies to the human body.

Healthy deformation occurs when the foot changes shape during a step. The flexible foot arch bends and deforms to absorb the landing impact while adapting to the ground and helping the body remain balanced against gravity. This is healthy elastic deformation when the foot returns to its original shape after leaving the ground.

Unhealthy deformation occurs when a body structure changes shape and does not fully return to its original form. Examples may include permanent joint changes, ligament damage, cartilage injury, or a disc that remains chronically displaced or bulged after an injury.

Spring Deformation

A deforming force may be applied to the human spring through stretching, compression, squeezing, bending, shearing, rotation, or twisting.

Two important forms of deformation can occur in the body:

• Elastic deformation is temporary and generally protective.
• Plastic deformation is persistent or permanent and may be damaging.

Elastic Spring Deformation

Elastic spring deformation occurs when a structure changes shape, stores energy during the deformation, and then returns to its original shape while releasing the stored energy.

The return to the original shape is important. Elastic deformation allows the human spring to absorb force, recycle energy, and avoid permanent structural damage.

This is an example of elastic deformation in the human body:

1. You walk on uneven ground, and your foot deforms to match the shape of the terrain.
2. The foot changes shape by flattening the arch and loading energy into the arch like the string of a bow. The tendons that suspend the arch stretch like the elastic bands of a slingshot.
3. Elastic energy is stored in the arch, plantar tissues, muscles, and tendons.
4. You spring away from the ground as the tendons recoil and the foot returns toward its original shape.

Elastic deformation is one way the body recycles energy, absorbs impact forces, and preserves the joints over a lifetime.

If your human spring is mobile, balanced, strong, and free from excessive muscle tension or joint restriction, it may withstand repetitive impact forces without permanently deforming.

Three objectives can then be achieved:

1. The body can tolerate millions of repetitive deformations without permanently damaging the spring.
2. Appropriate mechanical stress can stimulate the living spring to become stronger.
3. Healthy movement mechanics may help preserve mobility and reduce accelerated musculoskeletal aging.

Muscles and tendons behave partly like biological elastic bands. When they contract or stretch, they deform and store energy. When released, they recoil and return toward their original shape while releasing energy.

You want the spring system of your neck, spine, and shoulders to be strong and capable of elastic deformation during a car accident or sports collision. Ideally, the tissues absorb and distribute the force and then return to their pre-impact alignment without permanent injury.

For example, I was involved in a serious car accident in California several years ago. A truck struck my friend’s compact car and forced it into a concrete wall. She sustained several herniated discs and experienced chronic pain for months. I did not feel a single ache. I believe this was partly because I had trained my human spring with exercises and drills designed to strengthen the spring-support system and improve injury resistance.

The vertebral discs provide another example. Every time you step, jump, or land, the discs act partly like compression springs. They load the force of the impact, deform slightly, and then return toward their original shape as the force is released.

When athletes tackle with their shoulders, the shoulder spring-suspension system allows controlled deformation of the shoulder girdle and surrounding elastic tissues. These structures help absorb and distribute the impact before allowing the shoulder to return toward its original position.

Mechanical examples of elastic deformation include a rubber band, metal spring, bungee cord, or pogo stick.

Plastic Deformation Is Harmful

Plastic deformation occurs when a structure is compressed, stretched, bent, or twisted beyond its elastic range and does not return to its original shape. The deformation becomes persistent or permanent.

This can happen instantaneously through a traumatic injury, such as a fracture, ligament tear, or severe disc injury. It can also develop gradually through millions of repetitive impacts performed with abnormal biomechanics.

For example, repeated abnormal loading of the big toe may gradually contribute to a permanently altered joint position known as a bunion or hallux valgus.

If you walk for approximately 78.74 years, your body may experience about 287,401,000 ground-impact deformations. Ideally, each step should involve controlled elastic deformation and a return toward normal alignment.

With approximately 287 million lifetime collisions with the ground, even subtle biomechanical abnormalities can produce significant cumulative stress and permanent structural change. According to the Human Spring Model, repeated plastic deformation may contribute to accelerated musculoskeletal aging.

To follow an effective anti-aging and injury-prevention lifestyle, the goal is to help the body deform elastically during steps, exercise, work, and daily movements and then return toward its original alignment rather than remaining permanently deformed.

Spring Yield

Every human spring and individual body structure has a maximum load or yield point. When the applied load exceeds this capacity, the structure may begin to deform permanently.

Everyone should theoretically come with a warning label similar to the label on a pogo stick:

“Caution: Do not exceed this amount of force or weight, or permanent deformation may occur.”

At 10,000 steps per day multiplied by 365 days per year, the body experiences approximately 3,650,000 ground contacts each year.

When you buy a pogo stick, the instructions provide a maximum weight capacity. Suppose the maximum loading capacity is 300 pounds, but the user weighs 310 pounds. Each jump may exceed the spring’s intended capacity, gradually bending or damaging the pogo stick.

Similarly, every human body has a maximum load capacity before tissues become injured, bent, torn, or broken. This concept is reflected in the expression, “the straw that broke the camel’s back.”

Athletes and coaches attempt to estimate the amount of force and deformation that can be applied to the human spring while remaining below the yield point. The goal is to create enough stress to stimulate adaptation and strengthening without causing injury.

Understanding and applying this principle is one reason certain coaches consistently produce national and world champions, while others struggle to develop elite athletes.

At Team Doctors®, we have managed strength, conditioning, biomechanics, and recovery programs for athletes. During the past 20 years, we have helped at least 20 local athletes become national or world champions, even though our gym is only 800 square feet.

Failure Strength

Failure strength is the amount of mechanical stress the body can tolerate before structural damage occurs. Examples of spring failure include:

• Bone fractures
• Herniated or ruptured discs
• Meniscus tears
• Ankle sprains
• Muscle tears
• Tendon avulsions
• Ligament tears
• Joint dislocations
• Peripheral nerve injury
• Vascular injury

The human spring may also be considered to have failed when the shoulder-suspension muscles can no longer prevent the shoulder girdle from falling toward the thoracic outlet and compressing the structures within the thoracic tunnel.

For some individuals, the spring-suspension muscles and tendons are not strong enough to manage the impact forces created during ordinary walking. Some people cannot stand with equal weight on both feet without the foot collapsing into an unstable position between excessive pronation and supination because their spring-suspension muscles are extremely weak.

A herniated, bulging, or slipped disc can be described as a plastic deformation of a compression spring within the spinal torsion-spring system. The disc changes shape during loading and does not fully return to its original form.

Continued mechanical compression may maintain the disc in a deformed position. Reducing compression on the spinal spring may reduce pressure on the bulging disc and relieve radiating pain, numbness, tingling, or other nerve-compression symptoms.

If you want to learn more about the Human Spring Approach to herniated discs, watch my lecture, “The Earliest Detection, Intervention and Prevention of Compression Syndromes, Thoracic Outlet Syndrome, Herniated Discs and Degenerative Joint Disease,” presented at the World Congress on Anti-Aging Medicine in Mexico City, Mexico, in 2016.

Permanent structural deformity is rarely the primary cause of thoracic outlet syndrome in the patients I have examined. In my experience, most cases involve reversible muscular tension, postural collapse, first-rib elevation, shoulder depression, or other forms of functional thoracic outlet compression.

The most significant permanent deformities I have observed have sometimes resulted from surgery. Surgically removing scalene muscles or the first rib, or fusing sections of the spine with plates, screws, or rods, permanently alters the body’s original spring engineering.

If you have already undergone thoracic outlet decompression surgery, first-rib resection, scalenectomy, cervical fusion, or another procedure, do not become discouraged. I have helped patients who previously underwent spinal fusion or extensive thoracic outlet surgery. Following the recommendations in this book may help you restore your remaining human spring as close to its optimal function as possible and may reduce pain and other symptoms.

A strong, well-conditioned human spring can protect the body from mechanical failure and injury, improve movement efficiency, and maintain wide spaces for nerves and blood vessels.

A weak or deconditioned human spring is less capable of protecting the body from injury. It is mechanically inefficient, contributes to earlier fatigue, and may allow the suspension systems that maintain the body’s openings and tunnels to collapse.

This weakness may increase the risk of compression syndromes, including thoracic outlet syndrome, cervical radiculopathy, nerve entrapment, and herniated discs.

Conclusion—You Must Have a Strong Human Spring

I have delivered scientific presentations on biomechanics and human movement for more than 15 years. Whether I am giving a small workshop to 50 doctors in Kuala Lumpur, Malaysia, or a keynote presentation to thousands of doctors and scientists at a medical conference in the United States, the reaction to the explanation of the body as an integrated human spring is often the same.

They say, “It’s about time someone explained how the body works and breaks down in a way that makes sense,” and, “Don’t all doctors think this way?”

I hope you enjoyed learning about your amazing human spring, the Integrated Spring-Mass Model, and how human spring biomechanics apply to thoracic outlet syndrome.

Now it is time to learn how the brain and nervous system control the tension on your human spring—and how abnormal tension may contribute to thoracic outlet compression.

Let’s spring ahead to the next chapter.