Strengthening the Neck Is an Effective Defense Against Concussive Forces and Poor Posture

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Hilary Mosley
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1 Strengthening the Neck Is an Effective Defense Against Concussive Forces and Poor Posture How Neck Muscles Move & the Mechanism of Injury Ef fects of Linear & Rotational Force on the Brain Research on Neck Training by Activity Dif ferences Between Male and Female Necks

Connecting the Head and the Body The Missing Link Whether it is from a sudden impact in sports, or from prolonged use of a computer or smart phone, the neck is subjected to high levels and durations

2 Connecting the Head and the Body The Missing Link Whether it is from a sudden impact in sports, or from prolonged use of a computer or smart phone, the neck is subjected to high levels and durations of stress. These forces can lead to injuries like concussion, whiplash associated disorder (WAD), and an array of cervical injuries and chronic pain. The neck naturally serves as the body's built-in shock absorber - it is designed to mitigate these forces. Once we understand how the neck operates, the mechanisms of injuries, and the threats that exist from on-field competition to the work environment and everywhere in between, we can transform the neck from a liability to an asset. Don t neglect the neck. The Stress on the Neck Neck pain has become all too familiar in today s world. Many adults spend eight hours a day sitting at a desk staring at a computer screen in a position the spine is not designed to support. With the proliferation of (and addiction to) smart phones, nearly everyone spends a few hours a day with their heads tilted downward. The average head weighs about 12 pounds. When we are locked in on these screens, 12 pounds can feel more like 60 pounds. That s a tremendous strain on the neck and spine. While improving our behavior and posture would help alleviate much of this force, we often ignore neck strengthening exercises as a proactive solution, and only rely on them as a reaction to symptomatic pain. The role the neck plays is even more critical in sports where the forces from impacts are significant and can result in more serious cervical injuries and concussions. Whether that force is applied directly to the head or the body, the neck is engaged, and has the capability to reduce the amount of force that reaches the brain.

3 The Brain's Shock Absorber Inverse Relationship of Neck Strength and Concussions In 2014, the Journal of Primary Prevention published a study that tracked 6700 high school athletes in boys and girls soccer, basketball, and lacrosse over a 2.5 year period. Researchers captured anthropometric measurements, concussion incidents and athletic exposure data and found for every one pound increased in neck strength, odds of concussion decreased by 5%. Smaller mean neck circumference, smaller mean neck to head circumference ratio, and weaker mean overall neck strength were significantly associated with concussion. (Collins et al 2014) Note: This study did not incorporate neck strengthening to see how increased neck strength impacts concussion risk. Rather, it looked at the neck size and strength of a large group of high school athletes and retrospectively analyzed that data based on the occurrence of concussions. Neck Muscles Need to Contract Quickly To help decrease the effective magnitude of a forceful impact, neck muscles need to rapidly contract at the instant that impact occurs. Isotonic neck strengthening alone is not sufficient to enhance the head-neck dynamic restraint mechanism. (Mansell et el 2005) Stronger muscles are not only capable of generating greater absolute force values, but have a greater cross-sectional area, greater tensile stiffness at a given activation level, and generate torque more rapidly than weaker muscles. Anticipatory cervical muscle activation ( bracing for impact ) can reduce the magnitude of the head s kinetic response. (Eckner, 2014) Anticipatory muscle activation plays a dominant role on impact outcomes. Increased neck strength can decrease the time to compress the neck. (Jin at al 2017) How Neck Muscles Move The muscles of the neck are primarily diagonal fibers, which allows for greater range of motion across all three movement planes: Coronal, Sigittal & Transverse. Working in pairs on the left and right sides of the body, these muscles control the flexion and extension of the head and neck. Working individually, these muscles rotate the head or flex the neck laterally to the left or right. Neck muscles contract to adjust the posture of the head throughout the course of a day and have some of the greatest endurance of any muscles in the body.

Types of Contractions To help decrease the effective magnitude of a forceful impact, neck muscles need to rapidly contract at the instant that impact occurs.

Strengthening the neck muscles along all three planes of movement has direct benefits in reducing head acceleration and mitigating forces before they injure the brain.

neck rotation strength to absorb impacts to the jaw Linear & Rotational Forces Concussion at a physiological level is caused by rotational and angular forces to the brain, and direct impact to the

4 Types of Contractions To help decrease the effective magnitude of a forceful impact, neck muscles need to rapidly contract at the instant that impact occurs. Isotonic contractions activate a muscle by shortening (concentric) and lengthening (eccentric) it (e.g. pressing/pulling against side of head while moving or rotating head). Strengthening the neck muscles along all three planes of movement has direct benefits in reducing head acceleration and mitigating forces before they injure the brain. Coronal Plane: Eccentric lateral flection to absorb impacts to the side of the head Sagittal Plane: Eccentric neck flection to absorb impacts to the front/back of the head Transverse Plane: Eccentric neck rotation strength to absorb impacts to the jaw Linear & Rotational Forces Concussion at a physiological level is caused by rotational and angular forces to the brain, and direct impact to the head is not required. Shear forces disrupt neural membranes, causing fluctuations in the flow of ions and reducing cerebral blood flow. (Giza et al 2014) Linear Force Dynamic loads, especially angular acceleration, have been shown to be the common cause of head injury. Rotation, particularly in the coronal plane, appears to most often precipitate loss of consciousness. (Scorza et al 2012) Rotational Force

Impact on the Brain As the head rocks back and forth, it s also twisting a little on the brain stem, and it s those accelerative

A stronger neck means you re reducing those accelerations and rotational forces.

acceleration or whip-lash like movement.

Danielle Salmon, Otago University, New Zealand Ice Hockey Neck muscle tension can reduce head acceleration and enhance the ability

tremendous value in building endurance and reducing pain as cyclists must hold a protective position for stretches of several hours.

Due to the high (4-6Gs) when accelerating, decelerating or cornering, the neck has to support nearly 80 lbs.

There is significant negative correlation between isometric neck strength and resultant head impact.

5 Impact on the Brain As the head rocks back and forth, it s also twisting a little on the brain stem, and it s those accelerative and rotational forces as the brain is impacting inside the skull that are really what s causing these concussions. A stronger neck means you re reducing those accelerations and rotational forces. Dawn Comstock, Colorado School of Public Health Neck Training by Activity Rugby We found players with stronger necks had lower acceleration or whip-lash like movement. The stronger you can make the neck the less the head acceleration it controls the brain s movement against the skull. Dr. Danielle Salmon, Otago University, New Zealand Ice Hockey Neck muscle tension can reduce head acceleration and enhance the ability of the neck muscles to absorb forces which could minimize the risk and severity of concussion and whiplash injuries common to ice hockey. (Schmidt et al 2014/Tierney et al 2005) Cycling While cycling has a relatively high occurrence of concussions, neck training has tremendous value in building endurance and reducing pain as cyclists must hold a protective position for stretches of several hours. Flying/Racing The head and helmet for motorsports athletes and Air Force pilots weighs about 17 lbs. Due to the high (4-6Gs) when accelerating, decelerating or cornering, the neck has to support nearly 80 lbs. Soccer Neck strength has been shown to improve outcomes from head impacts sustained during heading in soccer. There is significant negative correlation between isometric neck strength and resultant head impact. Neck strength imbalance (variance between strength in the left and right sides of neck) is also related to increased impact during soccer heading. (Guitierrez 2014/Dezman 2013) Boxing/MMA Over 50% of all KO s studied were shown to be done to direct blows to the mandible (the jaw). Furthermore, and rather intuitively, there was a correlation between the heavyweight class and an increased risk of sustaining a KO. More force generating ability, when applied correctly, equals more opponents stretched out on the canvas. (Hutchinson et al 2014)

6 All Necks Are Not Created Equal Anatomically, females have longer, thinner necks. Research shows that weaker necks are more prone to whiplash and is believed to be a primary cause of higher rates of concussion in female athletes. (Schallmo et al 2017) The Michigan High School Athletic Association (MHSAA) study of head injury reports from 750 (99%) of its member schools revealed a disparity in the number of reported head injuries suffered by girls and boys playing the same sport. Soccer, basketball and baseball/softball are played under nearly identical rules, and in those sports females suffer significantly more concussions than males playing the same or similar sport. MHSAA Head Injury Summary Sports Football - 11 player Head Injuries per 1,000 Participants 49 Ice Hockey 38 Football - 8 player 34 Girl Soccer 30 Girl Basketball 29 Wrestling 26 Boys Soccer 18 Competitive Cheer 17 Boys Lacrosse 17 Boys Basketball 13 Volleyball 11 Football - 11 player 11 Girls Lacrosse 11 Softball 11 Baseball 4 Girls as a group have far weaker necks. That same force delivered to a girl s head spins the had much more because of the weak neck than it does to the guys Girls working to strengthen their necks should remember that they don t produce enough testosterone to build big, bulging necks, but they are going to be stronger and that will help protect them. Dr. Robert Cantu M.D. Clinical Professor of Neurology and Neurosurgery and Co-Founder CTE Center at the Boston Out of the various neck motions, humans are strongest in neck extension, followed by neck lateral bending, followed by neck flexion, followed by neck rotation. (Vasavada et al 2001) Male Isometric Neck Strength Twice that of Women Neck Action Extension Torque Men (Nm) 49 Torque Women (Nm) 49 Lateral Flexion Flexion Rotation info@iron-neck.com W 5th St, Austin, TX 78703

WHY IS YOUR NECK SO IMPORTANT

DOCUMENT PROVIDED BY MOVE WELL PHYSIOTHERAPY WHY IS YOUR NECK SO IMPORTANT 1. A Strong Neck Is Less Prone to Whiplash Injuries 2. Effective defense against concussive forces 3.Poor posture weighs on neck