Functional movements improve everyday life for many of my clients, from those recovering from hip and knee replacement to collegiate athletes and everyone in between. I’ve also seen powerlifters, pre- and post-natal populations, and the average everyday working stiff benefit from such exercises. When I first began using functional training in my own workouts ten or so years ago, I found that my squat, bench, dead lifts etc. improved in terms of range of motion as well as strength. I’ve never looked back.
As several others have said, ‘functional training’ is a very broad term, but I’ll assume you’re refering to exercises using little or no weights. I include those exercises using unorthodox equipment like ropes, bands, med balls & yoga balls in the ‘functional’ category as well. I agree that cardiovascular fitness and weight bearing exercises as well as flexibility training are the foundation of any great workout program, but they don’t necessarily prepare us for real life. Most clients that I’ve trained post-injury were hurt during lateral, diagonal, or rotational movements (which are difficult to replicate using traditional weight room training). By teaching them to maintain their body alignment through some of these less popular planes of motion, many can prevent re-injury. I’ve also heard of functional training refered to as “Prehab”. That is, by incorporating movements like these the risk of injury is reduced, as is the “Rehab” that said injury would require.