San Diego Corrective Exercise and Personal Training Specialists | Function First Function First specializes in corrective exercise and individual performance enhancement. Through understanding the science of human movement we can correct, improve, and maintain a more efficient you Function First specializes in corrective exercise and individual performance enhancement. Through understanding the science of human movement we can correct, improve, and maintain a more efficient you. A body that moves better feels better. You are given the tools to optimize your physical output without pain - be that for everyday living or competitive sports. Your body responds quickly to a strategic corrective exercise program designed specifically for you.