4-on-4 is a fun game often used in training to recreate match conditions from a technical, tactical, athletic, and mental perspective. Martin Lenoir and Mathis Vannier, fitness coaches for CF Montréal's U16 team, wanted to know if changing one variable: the presence of a goalkeeper or not, could increase the risk of contact injuries (traumatic injuries) among their young players. The result? "In goalkeeper formats, there is more contact, and the attackers are most exposed. On the other hand, in the stop-ball format, defenders play fewer duels and have a similar number of contacts to other positions," the Montrealers indicate, observing a risk of increased exposure to injuries and, in some cases, potential seriousness. "Coaches must be informed about the impact of each parameter of reduced sized games: number of players, duration, dimensions of the field, type of goal, because all these elements influence the risk of injury. In our study, playing with the goalkeeper induces more contact, so, in periods of high load, it would be relevant to favour other formats, such as the stop ball, which seems less risky." The two physical preparations and their research director, Alexandre Dellal, will soon be working with Ricard Pruna, doctor at FC Barcelona, in writing a scientific article on this subject.