Like other contact sports, football involves concussion and head injury risk. Concussion prevention strategies can mitigate these risks. For example, training neck strength can decrease sports-related concussions.

Many risk factors can predispose athletes to concussions. A non-modifiable risk factor is genetic predisposition, whereas a modifiable factor is one’s decision to play a sport. One study suggests that both neck strength and impact anticipation are two potential modifiable risk factors for concussion.¹

This post will focus on training neck strength for concussion prevention, whereas a future post will address training one’s anticipation of impact. The following topics will be discussed:

Head Acceleration Is Necessary to Cause a Concussion

Faster Activation of Strong Neck Muscles Can Decrease Head Movement

Poor Neck Strength Alone Increases Head Acceleration

Increased Neck Strength Decreases Concussion Risk

Neck Training Is Effective for Increasing Neck Strength

Training Neck Strength Can Decrease Head Acceleration

Neck Strengthening Programs Can Reduce Sports-Related Concussions

Implementing a Neck Strengthening Program for Concussion Prevention

Head Acceleration Is Necessary to Cause a Concussion

The head must accelerate—quickly change speeds and/or direction—after an impact for a concussion to occur. For this reason, not every impact to the head will cause a concussion.

The medical community has known this fact about concussions since the 1940s.² If the animal’s head was held in place when a weight was dropped on it, there may have been cuts, broken bones, and even bleeding in the brain, but the animal’s brain seemed to function properly.

Brain dysfunction only occurred after allowing the animal’s head to move freely once impacted. Sometimes this even caused loss of consciousness, which is not necessary with a concussion; however, there should be signs and symptoms of brain dysfunction.

Furthermore, if the head accelerates in a linear direction like jutting one’s chin out or moving one’s ears side to side like on a string, it may not be enough to produce a concussion. Rotational acceleration is more powerful. Think about a boxer taking multiple jabs to the head versus taking one left hook across the chin that rotationally accelerates the head leftward and backwards. The latter is more likely to produce a knockout and subsequent concussion.

I described more concussion pathophysiology in the post, Sports-Related Concussion: What Happens in the Brain?

Because the player cannot hold one’s head during competition, the only way to prevent fast head movement upon head/body contact is to stiffen its only connection to the body—the neck.

Faster Activation of Strong Neck Muscles Can Decrease Head Movement

One study has shown that greater neck strength and anticipatory neck muscle activation (or speed of the brain to brace for impact) can reduce the amount of head movement.¹ The researchers applied an impulsive loading apparatus to a group of 46 male and female contact sport athletes between the ages of 8 and 30.

They found that head peak velocity was decreased in all planes of motion with greater neck isometric strength and anticipatory cervical activation.¹ These two variables were also effective independent of each other.

In other words, the ability to stiffen one’s neck without movement and anticipate the head movement impulse by the apparatus helped the individuals prevent head movement speed. Hence, if a player can see an expected hit and isometrically contract one’s neck muscles fast enough, the head will not accelerate as much, which reduces concussion risk.

Another study measured neck isometric strength, muscle size, and response to quick cervical movement in 49 high school and collegiate football players. The researchers compared these tests to the odds of sustaining higher magnitude head impacts during a season.³

Isometric neck strength and neck muscle size did not affect the magnitude of impacts; however, players with stiffer necks in response to quick cervical movement had decreased odds of sustaining moderate and severe head impacts during the season.³

In total, the speed of neck muscle contraction and greater stiffening are important to decrease higher head impacts and movements.

Poor Neck Strength Alone Increases Head Acceleration

If greater neck strength and activation can decrease head movement, then poor neck strength must be associated with increased head acceleration. This has been identified in soccer players.

In 16 collegiate male and female soccer players, researchers found that an imbalance in muscle strength between the neck flexors and extensors correlated with increased rotational head acceleration when heading a soccer ball.⁴

Next, 17 female high school soccer players were assessed for neck strength (flexion, extension, and lateral flexion) and head acceleration upon heading a ball.⁵ Weaker neck strength was significantly correlated to greater head impact acceleration among the players.

While these studies are small, they show the importance of balanced neck strength in decreasing head acceleration, even when performing low-level head impact activities.

Increased Neck Strength Decreases Concussion Risk

Despite the evidence above, only one large study shows that increased neck strength is directly associated with decreased concussion risk.

Over two sports seasons from 2010-2011, athletic trainers from 51 high schools gathered pre-season data on neck strength for 6,704 athletes in boys’ and girls’ soccer, basketball, and lacrosse.⁶ They measured neck strength in flexion (forwards), extension (backwards), and lateral flexion (side-to-side).

They found that smaller neck circumference and weaker overall strength were highly associated with concussion.⁶ When controlling for gender and sport, overall neck strength was an independent predictor of concussion. Furthermore, the odds of sustaining a concussion decreased by 5% for every one-pound increase in overall neck strength.

Although this study did not include football players, participants from both genders across multiple contact sports demonstrated that poor neck strength is a risk factor for concussion. More importantly, increased neck strength decreases concussion risk.

Neck Training Is Effective for Increasing Neck Strength

Because increasing neck strength can decrease concussion risk, we should train it. And studies show that neck strengthening programs can increase neck strength.

In a review article, healthy non-athletes can effectively increase neck muscle strength by using a variety of neck training programs with different forms of equipment.⁷

Soccer players also benefited from a neck strengthening program, but one group of professional rugby players did not see the same increases in strength.⁷ They may have already had robust neck strength and did not train it long enough to see a notable change.

Most studies in this review used isometric neck strength as the marker for improvement over 6-12 weeks of neck training. The individual studies used varying pieces of equipment.

Training Neck Strength Can Decrease Head Acceleration

Neck strengthening programs not only can improve neck strength, but they also help decrease head acceleration in athletes. Currently, these studies have only been performed on soccer players while heading a ball following neck training.

A recent study showed beneficial effects of a 5-week neck training program in 12-17-year-old boy and girl soccer players.⁸ They completed soccer-specific, neuromuscular neck exercises called the Versteegh Roll and Tuck. These exercises involve an isometric contraction in multiple planes while rolling and only take about 90 seconds.

The players who completed the neck exercises three times per week demonstrated an increase in isometric neck strength and decreased head impact magnitude during heading the ball.⁸

This study shows the importance of training all planes of neck muscle control for preventing excessive head movement upon heading. However, does neck strength training also decrease sports-related concussion risk?

Neck Strengthening Programs Can Reduce Sports-Related Concussions

Evidence shows that neck strengthening programs can reduce sports-related concussions (SRC) and overall head and neck injuries.

One study with 364 male and female soccer players aged 12-18 years compared two schools using the Versteegh Roll and Tuck neuromuscular neck exercise program with four schools not training neck strength.⁹ The players with neck training were less likely to report a concussion, pain with heading a ball, and had significantly lower incidence of potentially concussive events.

Also, a neck strengthening program significantly decreased the number of match injuries and reduced cervical spine injuries in professional rugby players compared with the previous season.¹⁰

Next, the following studies show clear benefits of a comprehensive exercise program that includes neck exercises in reducing SRC risk.

Two studies compared rugby players utilizing balance/perturbation training, resistance training (including neck strengthening), plyometric exercises, and rugby-specific landing and cutting maneuvers versus traditional dynamic warm-up, stretching, controlled wrestling, and speed drills.^11,12

If completed at least three times per week, this preventative exercise program significantly reduced match injuries and concussion incidence among 3,188 rugby players aged 14-18 years old.¹¹ Similarly, this program showed a 40% reduction in lower-limb injuries and 60% reduction in concussion incidence among 81 men rugby players.¹²

Lastly, one high school in Johnstown, Pennsylvania used 20-minute training sessions with exercises in the following areas: mobility, agility, stability, strength, and flexibility (MASSf) that included neck strengthening.¹³ All football, soccer, and female volleyball players completed the pre-season ten-week training program with sport-specific training.

In the four previous years, an average of 126 student-athletes played these sports with 13.75 concussions per year, mostly in football.¹³ With 119 athletes participating in 2014, the researchers expected 11 concussions; however, with the MASSf program, there were only 2 concussions, both in soccer. They repeated the program in 2015 and only had 2 concussions per 121 athletes.

While these studies involve more exercises than just neck training, they show a great benefit in reducing the incidence of SRCs.

Implementing a Neck Strengthening Program for Concussion Prevention

When implementing a neck strengthening program, the following components must be considered: time, direction, muscle contraction, and equipment.

Time

First, the most successful studies used at least eight weeks of training that involved at least three training sessions per week. This would be a minimum of 24 training sessions prior to the athlete’s season. Neck training sessions could be as short as 3-5 minutes and included in other training.

Direction

Second, successful studies involved neck training direction in all planes of motion. This includes flexion/extension (forward/backward like nodding), lateral flexion (side-to-side like ear to shoulder), and rotation (turning like shaking head ‘no’). Rotational acceleration of the head that causes the brain to excessively move within the skull can occur within each plane. Hence, neck strengthening programs should involve all these movements.

Muscle Contraction

Third, muscle contraction type and speed of contraction are important when choosing exercises. If the purpose of neck strengthening is to prevent head acceleration, then athletes need to generate a maximum amount of neck tension in the shortest amount of time to help them better able to resist external forces.

Because the goal is to decrease head movement, isometric neck strength—when the muscle does not change length—is ideal. Other contraction types (concentric and eccentric) can still be included in the program. Additionally, the exercise should not be a long endurance test, but rather one that requires high output of neck muscles.

At the same time, to prevent head acceleration upon contact, the athlete must quickly generate a high amount of neck muscle contraction. Hence, one should use exercises that involve powerful neck movements in all planes.

Equipment

Lastly, there are many pieces of equipment that can be used in neck training. Large machines are beneficial for increasing the resistance to produce maximal strength and speed of the muscles. However, these are not necessary if one is aware of the concepts above.

An exercise ball and resistance bands may be the only necessary equipment to achieve results. Doing a wall plank with one’s head on an exercise ball improves isometric strength. Moving one’s head quickly and forcefully into an exercise ball builds power. Completing walkouts and head turns with different resistance bands around one’s head increases neck strength.

A recent study did not need any equipment, but rather, self-resisted neck exercises were effective at increasing neck strength in 16-17 years old.¹⁴ Half of the 28 rugby players completed 15-second self-resisted, maximal neck contractions against their own hands in flexion, extension, and side flexion at a frequency of three times per week for eight weeks. These players had significant improvements in neck strength.

Conclusion

Neck strength is a modifiable risk factor for concussion. Greater neck strength is associated with less head movement upon contact and decreased incidence of SRC.

Neck strength training should be a school and organizational requirement for all athletes playing contact sports. The training program should use exercises in all planes of movement with powerful isometric contraction.

Neck strengthening is one tool to prevent concussions in sports.

References

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