According to Rush University Medical Center, helmets protect the head by absorbing most of the impact energy during a fall or collision, thereby reducing the risk of a serious brain injury or death. The Alaska Center for Resource Families explains that the foam of a helmet crushes when a person’s head hits the road; this cushions the blow and often saves the brain.
The ACRF further expounds that the shell of a helmet keeps the foam in one piece and makes it skid on the street so a person’s neck does not get jerked. It is important for people to wear the strap correctly, so the helmet does not slip to the side or back. Moreover, the helmet must fit the head snugly to prevent it from flying through the air during a fall or collision, according to the ACRF.
The Bicycle Helmet Safety Institute states that helmets have a layer of crushable foam designed to handle major crash energy. When a person crashes and hits a hard surface, the helmet’s foam crushes and controls the crash energy. This extends the head’s stopping time by approximately six milliseconds to reduce the peak impact to the brain. The crushing of the foam reduces internal strains and rotational forces. Thicker foam gives the head more space and more milliseconds to stop. The Bicycle Helmet Safety Institute explains that helmets must not be overly thick, as helmets that are too thick may not skid on the crash surface, causing more strain on the neck and potentially more rotational forces on the brain.