The purpose of this study was twofold: first, to examine the effects of specific cut-off scoring points (on the estimated prevalence of meeting health-related guidelines for physical activity in youth) and, second, to document the differences in gender physical activity patterns according to two different cut-off points. The sample comprised 62 children (boys n = 23; girls n = 39) aged 8-16 years old. Children wore accelerometers for three consecutive weekdays. The daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated using an equation regression developed for youth according to different cut-points. The data analysis from Freedson's cut points showed that both sexes engaged in significantly (p [less than or equal to] 0.01) more MVPA when compared with Puyau's cut points. Boys engaged in significantly (p [less than or equal to] 0.01) more MVPA activities than girls regardless of the cut-off point used. Our data also showed that the percentage of students that reach the physical activity/health related guidelines was significantly higher in both boys (77.3 vs 6.9 percent; p less than 0.001) and girls (60 vs 2.3 percent; p less than 0.001) when Freedson's cut-off point was used. Our data showed that for preventive strategies youth specific cut-off points still need to be refined and, as a result, health-related criteria for young people need to be based on further research evidence. (Contains 4 tables and 1 figure.)