BRINGING SCIENCE TO TREATMENT

Brace yourself – neck strength in combat sport.

Concussions are nothing new in the world of contact sports, and for those who participate in combat sports, this is no exception. Joe Cassaro explores the role neck strengthening may play in concussion prevention and return to sports rehabilitation.

Boxing – Harlem Eubank in action against Viorel Simion Action Images via Reuters/Andrew Couldridge

Epidemiology

Nearly 1 in 100 Americans sustain a concussion each year, with an incidence rate of 3.8 million per year, of which 20-25% will go on to develop prolonged symptoms with lasting neurological health problems(1,2). Concussion poses a potential neurological health risk which is magnified in combat sports as concussions occur at rates as high as 0.047 concussions per minute for boxers (1.69 concussions per 12-round fight) and 0.085 concussions per minute for MMA fighters (1.28 concussions per 5-round fight)(3). The high incidence rate should alert practitioners to identify strategies to mitigate the risk and facilitate effective return to sports (RTS).

Does neck strength reduce concussions?

The role of neck strength training in concussion prevention and rehabilitation is debatable. In theory, strengthening the neck musculature to protect from concussive blows to the head or subsequent injury to the cervical spine makes sense; however, the research to support its efficacy is ongoing. For example, researchers at the University of Michigan in the USA found that smaller and weaker necks lead to an increased risk of concussions than athletes with stronger necks(2). Furthermore, researchers at the Research Institute at Nationwide Children’s Hospital in the USA indicated that those who sustained a concussion had significantly smaller and weaker necks than uninjured athletes in high school-aged contact sport athletes. In addition, for every one-pound increase in neck strength, athletes have a 5% decrease in concussion risk(4). In addition, professional male rugby players with increased isometric neck strength show lower head and neck injury risk(5).

Although it is evident that recent research supports neck strengthening for reducing concussion risk, clinicians need to consider a multifactorial and nuanced approach when addressing injury risk. For example, players with more significant neck musculature have increased odds of sustaining moderate and severe head impacts. However, those with greater neck stiffness during these anticipated impacts had less head displacement and, therefore, reduced risk of sustaining higher magnitude head impacts(6). Furthermore, faster reaction times assist the anticipation of an impending head impact. Thus, reducing the severity of the effects and risk of injury(7,8). For example, visuospatial training reduces the incidence of concussions in football players as it may allow them to better react to their environment and avoid collisions(9).

What has become clear is that although the strengthening of cervical spine musculature may play a role in reducing injury risk, the likelihood of sustaining a concussion or cervical spine injury is likely multifactorial and may include visuospatial training, reaction time, and neck strengthening(9).

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30/60/90 rule

Typical minimum suspensions in professional combat sports (vary depending on

the commission):

TKO – 30 days

TKO without loss of consciousness (LOC) – 60 days

TKO with LOC – 90 days

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Rehabilitation

Unfortunately, most combat sport jurisdictions do not require a RTS  testing or medical clearance for an athlete to return to the ring. Instead, these jurisdictions often follow a 30/60/90 rule for the athlete to be cleared for competition. However, this may not be optimal concussion symptom management. Therefore, following a concussion, a safe RTS should follow research recommendations (see table 1)(10).

Table 1: Return to fighting protocol(10)

Phase 1: Return to general fitness
Step 1Light aerobic activity.Gradually increase heart rate (HR) and monitor perceived exertion or HR max.
Step 2Moderate aerobic activity.Escalating HR through moderate and high-demand exercise.
Step 3Sport-specific activity.Sprinting.
Walk-through grappling .
Increased training duration.
Athletes may begin resistance training.
Neck strengthening may start here, barring limitations due to cervical spine injury.
Phase 2: Return to non-contact fighting activities
Step 1Bag/mitt work with movement.Testing vestibular and visual systems.
Step 2Shadowboxing/drills.Reintroduce fighters to the sports environment and re-establish footwork.
Step 3One-sided sparring and grappling.The fighter begins to spar without the concern of contact.
Phase 3: return to contact/sparring fighting activities
NB: May only advance to this phase when concussion symptoms have completely resolved.
Step 1Sparring: short duration.The first step of sparring.
Rounds of short duration and long breaks.
Step 2Sparring: longer duration.Lengthen duration and shorten breaks.
Step 3Sparring: normal parameters.Full return to regular training.

Importantly, athletes should not begin phase one for at least one week following a concussion or fight stoppage due to KO or TKO. While progressing through the protocol, athletes should wait a minimum of 24 hours before advancing to the next step. If athletes experience an aggravation of symptoms, they should regress to the previous step. Phase three should only begin once concussion symptoms have resolved and phases one and two have been completed. If symptoms persist for greater than ten days, the treating clinician should refer the athlete to the appropriate healthcare professional for further concussion evaluation(10).

Clinical implications: effective strength training

The practical implementation of an effective training program remains a challenge for practitioners. Researchers in Dublin and the USA studied the effects of neck strengthening in professional rugby union players to determine an effective dosage. Athletes completed a five-week neck strengthening program twice a week, and researchers assessed neck isometric strength using a hand-held dynamometer. Athletes performed cervical musculature isometric holds by lying supine on a bench and maintaining a neutral cervical spine against applied manual resistance from a strength coach. The athletes performed three 10-second holds in each plane of movement. The researchers found no significant between-group difference preintervention;  however, the results demonstrate that a five-week neck strengthening program improves isometric neck strength in rugby union players. In addition, the study results may enhance the pool of evidence that supports injury prevention, screening, and rehabilitation benefit(11).

Conclusion

The efficacy of neck strengthening for reducing concussions in a combat sport is debatable; however, research supports a link between increased neck strength and concussion risk in contact sports. It is best to take a multifactorial approach to mitigate concussion risk as reaction time and vision training may play a role. Following a concussion, it is best to take a careful periodized approach to return to sport, carefully monitoring the athletes’ symptoms at each step. When incorporating neck-strengthening into an athlete’s program, manually resisted isometric exercises performed twice a week for five weeks effectively improves neck strength in contact sport athletes.

References

  1. Pediatr Exerc Sci 2014; 26:33-40.
  2. Am J Sports Med 2014; 42:566-576.
  3. Physician Sports Med 2021; 49: 469-475.
  4. J Prim Prev 2014;35:309-319.
  5. Sports Med 2016;46:1111-1124.
  6. Clin J Sport Med 2011; 21:46-421.
  7. Ann Biomed Eng. 2014; 42:1-10.
  8. Pediatrics 2010; 125:e1394-1401.
  9. J Exerc Rehab 2018; 14(5): 706-712.
  10. Br J Sports Med 2018;0:1–6.
  11. J. Sport Med. 2014;24:502–508.
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