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Helmets: How they prevent injury

Sports and recreational activities are important for children’s health and development. They also carry a risk of injury: almost half of children’s injuries treated in emergency departments every year occur during sports and recreation activities. The skull offers some protection to the brain, but serious injuries can still occur without a helmet.

How the skull protects the brain

The skull has evolved features that protect the brain in several ways.

  • The thick bone of the forehead, part of the frontal bone, protects the large masses of brain called the frontal lobes. But to keep the head light, much of the skull is more delicate. For instance, the temporal bone around the temple is quite thin.
  • The skull's nearly-spherical shape efficiently protects the delicate brain against pressure and impact. Since the brain has about the same consistency as jelly, it needs a lot of protection.
  • A nutrient mixture, the cerebrospinal fluid or CSF, bathes the brain and cushions it against collisions with the inside of the skull. A three-layered membrane system called the meninges fits between the CSF and the skull.

Despite this padding, some accidents can cause the brain to shift rapidly and bounce off the inside of the skull with enough force to do damage. A sudden impact can also damage the brain’s tissues or connections between brain cells or cause the blood vessels that feed the brain to rupture. The surface of the head can also be cut or bruised, especially if it hits a sharp object. In certain types of injuries, the skull may be fractured.

How children's brains and skulls differ from those of adults

Children's brains and skulls have a few advantages over those of adults.

  • Children's tissues are more resilient. Their blood vessels are less likely to tear under twisting or squeezing stress.
  • Children's heads and brains are smaller, so the forces acting to deform or stretch the brain are lessened.

However, children, especially young children, fall much more often than adults. They also do not act to protect their heads when falling. This is part of the reason why those under 19 years of age make up nearly a third of all hospitalizations for head injuries. It is also why it is so important for a child to wear a properly-fitted helmet for sports and recreation activities​.

How helmets work to prevent injury

In many cases, a helmet can make all the difference between serious injury and walking away from an accident unharmed.

In general, helmets are designed to:

  • help the head slow down more gradually
  • spread the impact of a knock or a fall over a larger area
  • prevent direct impact to the skull.

The right helmet can protect against head injury in the following sports and activities:

  • bicycling
  • football
  • hockey
  • horseback riding
  • ice skating
  • off-road and all-terrain vehicle (ATV) driving
  • rugby
  • skiing and snowboarding.

These are not the only sports that may benefit from helmet use. Many more activities see far fewer injuries when helmets are worn.

Helmet features that prevent injury

The materials and shape of the helmet are important features in minimizing the risk of injury.

  • Most helmets use foam or another crushable material. When your head hits something, your skull smacks into the foam and then slows down over a distance of a few centimetres. When the impact is over, the foam has deformed, but the skull and brain are much better off.
  • The shape of helmets has changed to improve fit and stability. Without a good fit, helmets do not work. If you or your child tried wearing a helmet previously, only to give it up because the helmet was uncomfortable or would not stay on, try adjusting the straps and padding or using a different helmet.
  • Some helmets use dozens of vents to protect the head. These helmets are more expensive because they use higher quality foam.

Types of helmets

Father putting helmet on son Father putting helmet on son

Most sports have their own helmet design. Children should wear the right helmet for their activity: it is not safe, for example, to wear a bicycle helmet to play hockey or vice versa.

Despite differences in design, there are two broad categories of helmets for non-motorized sports:

  • single-impact helmets
  • multi-impact helmets.

Single-impact helmets

These helmets are designed to absorb the energy of a single serious crash but must then be replaced.

  • Their foam material, expanded polystyrene, crushes on impact and remains crushed.
  • They are suitable for road biking, most types of off-road biking, skiing and snowboarding. They are also good for inline skating, unless your child does tricks or inline hockey or crashes often.

Multi-impact helmets

Multi-impact helmets can absorb the impact of a number of crashes. This category is relatively new. One helmet is often suitable for more than one sport.

  • They use expanded polypropylene or polyurethane foam that can crush, absorbing an impact, and then bounce back to recover its shape.
  • They spread the impact across a larger area, thanks to their rigid surface.
  • They are suitable for BMX biking, free-riding, trials riding, skateboarding, trick inline skating, parkour, ice skating, hockey and rock climbing.
  • These are not suitable for skiing, water skiing, horse jumping or other equestrian sports, any team sports or any motorized activity such as driving an all-terrain vehicle.

Setting standards for helmet use and design

Many countries have introduced regulations to cover helmet use and helmet design.

Helmet laws

Most Canadian provinces and territories have laws requiring that children under 18 wear a helmet when riding a bicycle on a public road. This usually includes bicycle passengers, for example children riding behind a parent. Individual cities and towns may also have their own helmet laws.

In general, parents of children under 16 must make sure that their child wears a helmet. They may face a fine if the law is not obeyed. Children who are 16 and 17 years old are responsible for their own helmets.

Depending on the laws of their province or territory, children may also have to wear a helmet when riding:

  • scooters, skateboards, in-line skates or roller skates
  • horses
  • off-road and all-terrain vehicles
  • snowmobiles and sleds towed by snowmobiles
  • motorcycles and mopeds.

Even where no law specifies helmet use, always make sure your child wears a helmet.

Helmet safety standards

Several organizations create standards that helmets should meet for different types of activities. They then test them to make sure they are up to the challenge. When choosing a helmet, look for one that has been certified by a national safety organization.

While it is generally better to wear different helmets for different activities, some helmets are certified for more than one activity. Check the helmet certification sticker on top of the helmet to see which activities the helmet is suited for.

Helmets have limits

It is important for everyone, especially children, to understand that helmets do not make them invincible. Here are some situations where helmets fail.

  • The impact on the head may exceed what the helmet was designed to handle. Typically, a helmet can protect the brain in a fall, but it cannot prevent serious harm if, for example, a child rides head-first into a tree. Collisions between a cyclist and a car will also often be more than a helmet can handle.
  • A helmet only protects what it covers. Downhill mountain bike racers and bicycle motocross riders often add chin and jaw protection by wearing full-face helmets, but a rider covering a long distance or climbing hills will probably find these helmets trap too much heat.
  • A helmet must fit properly to have a chance to be effective. A child must wear and secure the helmet correctly. Most helmets come with fitting instructions.
  • A helmet that has been dropped or has been worn while a child had an accident may not be effective, even if it does not look damaged. In these cases, it is better to get a new helmet.

How you can help your child

Head injury can result in life-long disability. Helmets are a simple, proven way to prevent possible tragedies and provide peace of mind.

Clearly, no helmet can protect against all possible injuries. It is important to teach children safety skills as well. In contact sports, rules to protect the head and neck are another important part of preventing injury.

If your child loses consciousness or may have lost consciousness after a head injury, see a doctor, even if your child was wearing a helmet when injured. The doctor can check if your child has a concussion.

If a head injury is serious enough that concussion could be a concern, you will also need to replace the helmet.

Key points

  • In case of an accident, helmets are designed to spread the impact over a larger area and prevent direct impact to the skull.
  • A helmet can make all the difference between serious injury and walking away from an accident unharmed.
  • Most sports have their own helmet design. Children should wear the right helmet for their activity. You can check the suitability of a helmet by looking at its certification sticker.
  • Most countries have regulations covering helmet use and helmet design. Even when no laws exist always make sure your child wears a helmet.
Shawna Silver, MD, FRCPC, FAAP, PEng


Injury Prevention Committee, Canadian Paediatric Society. Preventing injuries from all-terrain vehicles. Paediatrics & Child Health 2012;17(9):513-515.

Injury Prevention Committee, Canadian Paediatric Society. Skiing and snowboarding injury prevention. Paediatrics & Child Health 2012;17(1):35-6.

Injury Prevention Committee, Canadian Paediatric Society. Bicycle helmet use in Canada: The need for legislation to reduce the risk of head injury. Paediatrics & Child Health 2013; 18(9); 475-80.

Parachute. Helmet FAQ​.​

Parachute. The cost and leading causes of preventable injury.