The effect of foam padding on the head response in soccer heading

Abstract

Background: Soccer is regarded as the most popular sports in the world, with millions of people are actively involved in the game. Being a contact sports in nature, soccer players are susceptible to various kinds of injuries such as lower extremities muscle injury. In addition to those familiar injuries that soccer players sustain during the game, traumatic brain injury is also a possibility. Head impacts in soccer could be a result of head-to-head impact with an opponent player, head-to-elbow impact, an impact with the goal post, impact with the ground, as well as an impact with the soccer ball, which occurs during a heading manoeuvre. Soccer allows the players to use their head to hit the ball to pass it to a teammate, or even perform heading to score goal. Although soccer heading is perceived as less harmful as compared to head impacts with other hard objects, many studies have shown compelling evidence that this repetitive heading might harm the brain, thereby leading to traumatic brain injury. Protective headgears designed, especially for soccer players have been commercially available in the market for some years. Objective: This article investigates the effectiveness of two padding foams by means of heading experiment. Methodology: An anthropometric test device known as Hybrid III head and neck dummy instrumented with an inertial sensor that consists of a triaxial accelerometer and gyroscope installed at the centre of gravity of the head was used in the experiment. A soccer ball launching machine was used to propel the ball at several inbound velocities. Peak linear acceleration and peak rotational acceleration (PRA) were recorded, and the head injury criterion (HIC) and the rotational injury criterion (RIC) were calculated. Results: Poron X-ray diffraction (XRD) foam was found to provide the best protection in both linear and rotational components. However, for protection against HIC, it is evident from the findings that both foams were very effective at lower inbound ball velocity and became drastically ineffective as the inbound velocity increases up to 22 m/s (i.e. equal to 79.2 km/h). This could be attributed to the foam being completely compressed by the high-velocity ball impacting it. The same situation is seen for RIC, however with less significant decline in protective performance. Conclusion: Overall, it can be concluded that the Poron XRD foam could be a better foam to be used in soccer headgear as compared to the yoga mat foam.