Introduction: There is little evidence that details the behavior of each spatial-temporal variable of the running pattern using different surfaces.
Objective: To compare the spatial-temporal variables of the running pattern over two surfaces in adolescent soccer players. Method: A cross-sectional study involving 18 male soccer players was conducted (median [Me] age = 12 years; Interquartile range [IQR] 12-13). Speed, acceleration, contact time (Ct), flight time (Ft), contact phase, support phase, propulsion, stride, and cadence were evaluated through a 5-meter long optical measurement system. The assessments were initially carried out on Artificial Surface (AS) and, 24 hours later, on Natural Surface (NS). The Wilcoxon signed-rank test for paired data and the Spearman correlation coefficients were used.
Results: The support phase was greater in AS than NS (NS: Me = 0.05 IQR: 0.03; 0.06; AS: Me = 0.09 IQR 0.08; 0.10; p <0.001). The Ft (NS: Me = 0.16 IQR: 0.14; 0.19; AS: Me = 0.04 IQR: 0.04; 0.05; p <0.001), the contact phase (NS: Me = 0.02 IQR: 0.02; 0.03; AS: Me = 0.02 IQR: 0.01; 0.02; p = 0.040) and propulsion (NS: Me = 0.14 IQR: 0.09; 0.17; AS: Me = 0.07 IQR: 0.06; 0.09; p = <0.001) were greater in NS than AS. An indirect relationship between speed and contact phase in NS was found. The Ft and the stride were indirectly associated with acceleration in AS.
Conclusion: The running pattern varies according to the surface used. The contact phase can explain the speed in the NS; while the Ft and the stride can explain the acceleration in AS.
Keywords: Soccer, running, locomotion, acceleration, kinetics