The USA Swimming IMX Challenge is a series of events that challenges swimmers in all strokes, designed to encourage training in all four strokes rather than to specifically specialize on one. Scores are calculated Power Points, determined by a matrix of distances and speed.
There are two parts to this challenge: IM Ready (IMR) and IM Xtreme (IMX). IMR consists of shorter distance events and targets the training foundations of each stroke. Blue Gills and first-year Flying Fish are expected to complete this challenge. IMX consists of longer distance events and aims for proficiency and speed in all four strokes, stemming from a higher level of training. Second-year Flying Fish and up are expected to complete this each year. Once a swimmer swims all of the IMX events at an officiated meet, they are then ranked to other swimmers in their age group in SFAC, AMS, the Eastern Zone, and USA Swimming nationally.