Potential Effects of Soccer Ball Characteristics on Ball-to-Head Contact: A Systematic Review

Background: The aim of this study was to systematically review research on the effect of soccer ball characteristics on ball-to-head contact. Methods: This systematic review was conducted using electronic databases, which included PubMed, Cochrane, and Web of Science. The search strategy combined keywords related to soccer, the ball and its characteristics, heading, and kinematics variables. Studies analyzing the impact of soccer ball characteristics on heading biomechanics were included. The review included studies using mathematical models, simulations, and human subjects. Results: A total of nine studies were included, highlighting the lack of evidence on this topic. The following ball characteristics were investigated: inflation pressure (n = 7), mass (n = 4), structure/material properties (n = 3), size/diameter (n = 3), and stiffness (n = 3). Most studies used non-human subjects, such as mathematical, simulated, or head-form models. Key findings were as follows: (a) reducing inflation pressure may decrease impact magnitude; (b) ball size may not directly relate to impact magnitude, but one study found that a smaller size resulted in a shorter impact time; (c) lower impact observed with decreasing ball mass; (d) lowering stiffness showed a tendency to lower impact; (e) two studies on water absorption found that wet balls were heavier and had greater impact forces than dry balls; and (f) ball structure and cover material directly influenced impulsive forces. Conclusions: Modifying soccer ball characteristics may reduce heading forces, but the available research has limitations. More controlled studies are needed to determine optimal ball properties for mitigating injury risk during soccer heading. Standardized testing methods can further clarify the biomechanics of heading, supporting ongoing innovations to enhance player experience.