Hi Shaka! The support in Trail styles like the Cascadia 16 is different to Support Road styles like the Adrenaline GTS When you're on the roads, the GuideRails deliver a consistent level of support with each stride. But when you're on the trails, your foot is landing differently each time with the varied terrain. We determined that the Ballistic Rock Shield found in the Cascadia series offers a similar level of support, but was more specifically tailored to the unique terrain found on trails. This allows your foot to move naturally with the trail while still being supported during each stride.