Some new research looks at the effects of footwear and fatigue on the biomechanics of trail runners. The tests were done using different shoe types on treadmills.
The paper, titled “Effects of Footwear and Fatigue on Running Economy and Biomechanics in Trail Runners” was published in the journal Medicine & Science in Sports & Exercise.
The research concluded:
In the non-fatigued condition, runners exhibited a better RE [running economy] only during level running in MS [minimalist shoes] and MSm [minimalist shoes with added mass] (i.e. combined effects of shoe mass and midsole geometry), in association with significant decreases in foot strike angle (P<0.05). However, no significant difference in RE was observed between shod conditions after TR either during uphill or level running.
In other words, running economy and biomechanics change over time as we get more tired. Unsurprisingly, the researchers also suggested more research was needed.
You can access the full article here.