What is the Rebound Index?
The Rebound Index (RI) is the third measurement taken in the OPIS lab and indicates energy return from a shoe. The midsole of the shoe is placed under a standard amount of pressure, and a measurement is taken from how the shoe responds to that pressure. As the RI is not indicative of shoe stability, it is not used in calculation of the Shoe Stability Index (SSI). However, there is generally a significant correlation found between the Vertical Compression Index (VCI) and Rebound Index (RI). That is, shoes with a greater VCI (less firm, more cushioned) tend to have a higher RI as well. Shoes with a higher RI may be suitable for runners who do not need much support in their footwear and who are concerned with better athletic performance.
