According to Gary Gray (2000), a respected physical therapist and trainer, function is the “interaction between muscles, nerves, and joints, working together simultaneously to decelerate, accelerate, and stabilize both external and internal forces.” Simply put, function is the outcome of any activity. Everyday functional movements include running, biking, throwing, walking, carrying a child, tying shoelaces, getting out of bed, and even switching from a sitting to a standing position. Thus, the benefits of functional conditioning are not limited to athletics. Its movements occur in some form in work, home, and sport environments. To perform these tasks, a chain reaction involving muscles, nerves, and joints occurs. If this chain reaction is interrupted because of inadequate flexibility or lack of strength in part of the chain, a breakdown results, leading to a decrease in performance and to possible injury.
Exercises to help condition the body for functional movements must meet all four of these criteria:
1. They must include movements in all three planes (sagittal, frontal, and transverse).
2. They must properly condition the body's nerves and muscles to develop muscle memory and help make movements “automatic.”
3. They must condition for responding to external forces, allowing the body to make best use of outside influences such as gravity, ground reaction forces, and momentum.
4. They must condition biomotor abilities (flexibility, strength, power, endurance, agility, or coordination). A quick look at these four criteria comfirms that functional conditioning works beyond the realm of physical fitness and benefits the body during the activities that most people, athletes and nonathletes alike, do every day.