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The purpose of this study was to assess the influence of step width on load carriage economy. Fifteen healthy volunteers (age = 25 ± 3 years; stature = 1.78 ± 0.07 m; body mass = 73.6 ± 10.1 kg) completed three trials in a randomised order. Each trial differed by load carriage method and involved walking on a force-instrumented at 3km.h-1 with 0, 3, 12 and 20 kg. This protocol was then repeated with step width controlled to each participant’s preferred unloaded width. Relative load carriage economy was measured using the Extra Load Index (ELI). Load carriage economy was significantly worse in the head loading method compared to the other two method with step width uncontrolled (p = 0.02) and controlled (p = 0.02). For the trials where step width was uncontrolled, there was a significant difference in step width from unloaded walking between the different loading methods (p = 0.01) but no significant difference between load mass (p = 0.39). There was no difference in ELI between preferred and controlled step widths. Based on the data presented here, moderate alterations in step width caused by load carriage do not appear to influence load carriage economy.