Causes and Risk Factors of Concussions

Causes of Sports and Non-Sports Concussions

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A concussion occurs when a traumatic brain injury results in a temporary change in brain functioning. It is usually caused by a direct blow to the head.

concussion causes
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Common Causes

A concussion can occur due to:

  • Direct force to the head
  • Twisting or rapid turning of the head
  • The brain striking the inside of the skull during acceleration or deceleration

Certain types of activities have a high incidence of concussion.

Concussion causes can be divided into two categories: sports-related concussions and non-sports concussions. Between the two, there is little difference in the actual damage to the brain.

Focused medical care and concussion diagnosis in sports is sometimes mandatorily reported, which affects the recorded incidence rates.

Sports-Related Causes

Virtually every sport can potentially cause a concussion in some way. Volleyball, cheerleading, softball, baseball, basketball, and lacrosse can all lead to player concussions. Youth sports, amateur sports, and professional sports can cause concussions—but some are more likely to do so than others.

According to most reports, football and ice hockey have the highest incidence of concussions in youth sports.

  • Football: Football has the largest overall participation in a single sport. Knowing that football causes concussions has led to increased medical support for players on the field and in the doctor's office. All the attention might have increased the detection and reporting of concussions, which in turn adds to the statistics.
  • Boxing: Of all sports, boxing is the king of concussions. Indeed, the only guaranteed way to win a bout is to cause a concussion in your opponent (knock them out). Research on amateur boxers shows that a knockout isn't the only cause of a concussion though. Repetitive blows to the head may cause concussions, even if they don't result in an acute loss of consciousness. Whether knocked out or not, it takes nearly the same amount of time for a boxer to fully recover after a match. In fact, if a boxer is not knocked out, it often means they spent more time getting pummeled.
  • Soccer: Women's soccer is the female team sport with the highest rate of concussion, typically due to head-to-head collisions while heading the ball.
  • Wrestling: In scholastic competition, wrestling is the individual (non-team) sport with the highest rate of concussions. Takedowns cause the most concussions.

Non-Sports Concussion Causes

Any person can have a non-sports-related concussion for a number of reasons—such as after being hit in the head, after a car accident (which can cause your head to jerk suddenly), after a motorcycle or bicycle accident, or after a fall.

Outside of the gridiron or the ring, the most common causes of concussion happen on the battlefield. Military or combat-related concussions aren't reported by the same process as sports-related concussions, so there is no way to do a direct comparison. However, the concussion causes in combat are well documented and tend to be most often related to explosions.

Combatants often have access to medical personnel before and after ​a concussion, which allows for in-depth assessments, as well as pre-concussion baseline assessments. Those assessments help with concussion diagnosis after an injury.

Treating a Concussion

Verywell / Emily Roberts

Other than explosions, other causes of a concussion during military duty are similar to occupational injuries in non-military industries: vehicle collisions, falls, accidental head strikes, etc.


Only since the turn of the 21st Century has the seriousness of concussion really come to light, with the development of clear definitions and emerging research.

Women may have a lower threshold for concussion injury than men in both sports and military data. Research also suggests that there may be some genetic factors that could influence susceptibility to concussions and differences in recovery.

Risk Factors

The biggest risk factors for developing symptoms of a concussion are having had a previous concussion or experiencing repetitive blows to the head. Boxing, for example, is associated with a high risk of long-term concussive damage due to the high number of direct head strikes.

Avoiding direct, repetitive injury is the single most important factor in lowering personal risk for complications of concussion.

That being said, sometimes it isn't possible to completely avoid the risk. A football player or career soldier is going to be exposed to potential injury.

One study identified that there are potential ways to mitigate the damage potential incurred during a blow to the head. For example, increasing neck muscle strength showed a statistically significant reduction in damage, especially when coupled with anticipating and bracing for impact. When possible, wearing well-constructed safety helmets also reduces risk, as well as replacing helmets when needed.

Frequently Asked Questions

  • How hard do you need to hit your head to get a concussion?

    Not very hard. In fact, you can get a concussion without a blow to the head at all. This is because the damage done to the brain occurs when the head is jarred enough to cause the brain to bang against the hard shell of the skull. Any sudden movement of the head can cause this acceleration of the brain, which can even happen when an athlete takes a blow to the chest.

  • What happens to the brain in a concussion?

    When the brain jerks around inside the skull, a collection of things happen that can temporarily affect how the brain functions, leading to concussion symptoms:

    • Depolarization of neurons (nerve cells) known as ionic flux
    • Changes in how glucose (the main source of fuel for the brain) is metabolized
    • Stretching and damage to nerve cells
    • Impairment of transmission of brain chemicals
    • Changes in certain enzymes and proteins

    These changes can cause pain, cognitive changes, emotional responses, and may increase vulnerability to future brain damage.

  • What is post-concussion syndrome?

    Post-concussion syndrome (PCS) refers to persistent concussion symptoms. It typically is diagnosed when symptoms linger beyond a month or two after the injury and can include dizziness, headaches, fogginess, and irritability. PCS symptoms tend to occur with physical or mental activity, but can also occur when someone is resting. The syndrome can interfere with a person's relationships, work, and overall quality of life.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.