Z-CoiL is the Original Spring Shoe since 1995. The Z-CoiL spring has over three times the compression distance of any other shoe ever built — 27 mm total compression or just over 1 inch. It averages between 15-25 mm compression with each step. This is significantly more that regular shoes giving your dramatically more impact reduction. Additionally, The spring compensates in all directions for uneven ground. After compression, the spring returns energy into the next step. Z-CoiL springs come in four different strengths, which are rated for different overlapping weight ranges.
Many Z-CoiL fans don’t know the Z-CoiL springs can be rotated. Although the factory setting is the most common position the springs are often rotated to adjust for over pronation (feet that roll inward). The strong side of the spring is factory set on the outside of the foot. By rotating the spring 180 degrees additional resistance is applied to the inside of the foot, correcting more severe cases of pronation. A 90 degree turn can correct moderate pronation. You can identify pronation by watching the heel upon impact with the ground (watch from behind). The heel should go down vertically/straight. If it rolls to the inside, then an adjustment may be necessary.