Developed to Aim for Sub-4, ASICS's Latest Shoe, the "S4"

Named after the four S's: Speed, Stability, Safety, and Sub-4, the S4 is a model developed for runners aiming to complete a full marathon in under 4 hours, commonly referred to as Sub-4.

Incorporating the essence of the "METASPEED" series, the carbon-plated shoe boasts several features. So, what are the differences between this shoe and the "METASPEED" series or the similarly carbon-plated "MAGIC SPEED"?
 
Sub-4 is a challenging target that requires ample preparation time and rigorous training. In racing-oriented Japan, many runners are practicing diligently to aim for Sub-4, and the "S4" is squarely designed to support achieving this goal.

The development of the "S4" began at the request of ASICS President, CEO, and COO Yasuhito Hirota, who is an avid runner himself, asking the development team to "create a shoe for Sub-4." This fact vividly illustrates how dedicated the development was to the “Sub-4” concept.

Equipped with Features Necessary to Achieve Sub-4

To achieve Sub-4, runners must maintain an even pace from start to finish, running each kilometer in approximately 5 minutes and 40 seconds. This requires a considerable speed, which is supported by the carbon plates and the highly responsive foam material.
 
"The upper layer of the two-layered midsole features the lightweight, highly responsive FF BLAST TURBO, which is also used in the METASPEED series.