Functional training was first introduced by physiotherapist Gary Gray in his Kinetic Chain Reaction courses in the 1990s.

Functional training was developed by strength and conditioning coaches to increase the speed, strength and power characteristics of athletes, as well as their athletic performance and reduce the risk of injury. Functional training combines the use of balance skills and proprioceptive perception by deliberately using unilateral exercises. Functional training programs train movements, not muscles. The emphasis is not on excessive development of strength on a particular movement, but rather on the gain of balance between the strength in pushing and pulling movements and the knee-dominant hip extension and hip-dominant hip extension movements.