Tag Archives: soccer

Why is heading the ball so dangerous for youth soccer players?

young girl attempting to head an incoming soccer ball
Photo by Carson Ganci on THE42

I received my first concussion while playing soccer at 15 when I was knocked out by a ball that was “accidentally” punted directly into the side of the head. It seemed to me like this was one of the few, rare ways to get a concussion from the sport – an unlikely occurrence combined with an unusually aggressive impact. I was proven wrong, however, after I received two more concussions just from heading the ball – a frequently used technique involving seemingly mild impact forces. I have since come to discover that concussions, particularly due to heading the ball, are a huge problem for youth soccer players: currently, in the United States, youth soccer players aren’t allowed to start heading the ball until age 11 in an effort to reduce the risk of concussions. But how do headers cause so many youth concussions, especially when the speed of play is so much lower than for adults?

Physical vulnerability to concussion mechanics

illustration showing a head impacting a an object with arrows decribing the movement of the skull and the brain towards the object just before impact
Illustration of the movement of the skull and brain just before impact with an object. Upon impact, the movement of the skull decreases rapidly while the movement of the brain has a delayed response. Original image created for Wikipedia

In most sports, concussions are commonly caused by rapid acceleration/deceleration of the head that causes the exterior of the brain to crash into the interior wall of the skull, which is suddenly accelerating in a different direction. When headers are performed in soccer, this rapid acceleration is caused by impact with the ball, and the risk of concussion depends on both the acceleration of the head and the duration of the impact. The acceleration of the brain can be modeled by Newton’s Second Law (F = ma) for a given impact force F, and the resulting acceleration depends on the effective mass of the players head m, which depends on both the strength and weight of the players head and neck as well as their relative movement compared to the ball (which boils down to technique). This means that a major portion of the risk of concussion relies on the size, strength, and technical ability of the player, all of which have an inverse relationship with player age. So while the relative speed of play and impact forces may seem lower for youth players that can’t run as fast or strike the ball as hard as their adult counterparts, these factors are offset by their relative physical vulnerability.

Issues with injury recognition and response

Another factor contributing to the threat of concussions for youth players is their relatively low ability to recognise and respond appropriately to a brain injury when one occurs. Between 2008 and 2012, researchers observing elite female players aged 11 to 14 for 414 player-seasons (288 athletes were observed for a single season and 63 were observed for two seasons) discovered that 59 concussions occurred, with headers being the most frequent cause at 30.5%. In addition to this injury frequency, it was found that over half of these middle-school-aged athletes continued to play with symptoms after receiving a concussion. This is an additional a logistical problem for youth players, for as age decreases, athletes on average have less access to on-hand, qualified medical personnel and less of an ability to self-diagnose and respond appropriately to injury, putting them at increased risk for long term damage.

Artificial Turf: Game Changer or Game Ender?

Woman plays soccer on artificial turf field
Soccer player on artificial turf field
From Pixabay

Artificial turf fields were first introduced in the late 1960s and have grown tremendously in popularity since. Today, artificial turf fields can be found at all levels of sport, from youth league to professional, and across many different sporting disciplines. A major reason they are so popular is because they offer a consistent, low-maintenance, year-round green playing field in all weather conditions and climates. However, despite the benefits they provide, artificial turf fields are not without controversy. Even though artificial turf mimics grass in appearance, its properties are much different.

Of these properties, two are especially relevant to injuries sustained while playing sports, especially concussions and injuries to the knee and ankle. The first of these two is the field’s ability to absorb shock. Older artificial turf fields are often much harder than natural grass fields, which leads to greater impacts on athletes, which can then result in higher rates of concussions and other injuries. As artificial turf technology has developed, however, installation procedures and field composition have improved and greatly reduced the risk of injury.

The second of the two properties is the friction of the field, or how well an athlete’s cleats grip the turf. Because of their greater consistency and density, artificial turf fields can generate more friction than natural grass fields, allowing greater force to be generated at the contact point between an athlete’s foot and the ground. This is both a positive and a negative. Positively, the greater friction generated by athletic moves on artificial turf surfaces enable an athlete to perform at a higher level by enabling quicker changes in direction and more explosive movements. However, these greater forces can overload weaker parts of the anatomy, especially the ligaments in the knee, and cause injury. Numerous studies have found that rates of serious knee injuries, such as ACL (anterior cruciate ligament) tears, are found to be increased on artificial turf fields.

A major reason for this is because the knee is a hinge joint, meaning that it only allows straightening and bending motion while resisting rotation. Within the knee, tendons attach muscles to the tibia/fibula and the femur so that the knee can be bent voluntarily, four major ligaments attach the femur to the tibia/fibula to stabilize and restrict the knee’s motion, and a variety of cartilage and fluid sac structures ensure smooth and consistent motion. While robust together, each individual component in the knee is susceptible to injury if it is subjected to a force in an unusual or extreme way, which could happen while changing direction rapidly, incorrectly landing a jump, or during a collision. On an artificial turf field, the risk of damaging ligaments, cartilage, or other structures in the knee is increased because greater forces can be generated from the ground and because the foot may stick in the turf while changing direction and cause inadvertent rotation in the knee.

Nevertheless, even these risks can be somewhat mitigated by taking steps to avoid injury like the one recommended by The Polyclinic.