The purpose of this study was to investigate if trunk accelerometry measures were influenced by outdoor surface while running. A sample of highly-trained (n=12) and recreational (n=17) ran on three independent surfaces, namely asphalt, synthetic track, and wood-chip. Dependent accelerometry measures were step frequency (S FREQ), step symmetry (S SYM), stride regularity (S REG), axis contribution to total amplitude (RMS RATIO) and sample entropy (S EN). Surface effects on accelerometry measures were consistent for both running groups. Several significant differences existed between wood-chip and either asphalt or synthetic track. The results suggest that surface specific considerations should be made when quantifying trunk accelerometry measures related to running gait symmetry and regularity during running.