Movement scientists refer to body coordination as motor coordination, a term that describes the interactions between your muscular, skeletal and nervous systems. Clear communication between these systems creates coordinated movements. Injury, disease, alcohol, drugs and faulty postural alignment might cause communication roadblocks, which interfere with your body's ability to coordinate your movements.
The word "kinetic" means force and "chain," when used in reference to anatomy, describes an interconnected system. Your kinetic chain is an interconnected system that produces, absorbs and distributes forces throughout your body. Your brain controls the interactions that take place along the entirety of the chain. The phrase "you are only as strong as your weakest link" describes how one abnormality along the chain confuses your brain and triggers a different, often inappropriate movement pattern.
The Spinal Cord Keyboard
The late neuro-physicist Irvin Korr compared the human spinal cord to a keyboard, on which your brain plays when it desires a particular type of movement. Unlike a traditional piano keyboard -- where each key designates a specific note -- each of the "keys" on your spinal cord corresponds to a complex, harmonious and fully orchestrated pattern of notes. Korr's vivid analogy illustrates what movement scientists call the dynamic pattern theory of motor learning. When your brain wants to perform a specific movement, it "strokes a key" that produces an organized pattern of movements. It does not isolate a specific muscle group.
Nervous System Functions
Your brain uses three of the nervous system's functions to select the most appropriate movement pattern. Your sensory system identifies changes in your overall environment, such as cracks on the sidewalk. This system uses your propriceptors and extroceptors. Proprioceptors determine your body's internal awareness of its position in space. Extroceptors, such as your eyes and ears, provide external positional awareness, which helps you maintain equilibrium. The integrative system analyzes the sensory system's input. The motor system relies on your mechanoreceptors to determine the position of your joints. After analyzing the integrative system's input, it creates the most functionally appropriate movement response.
Coordination requires your muscles to fire in the most functional kinetic chain sequence. The research studies of physical therapist Paul Hodges illustrate this theory. Hodges discovered that people without lower back pain habitually activate their deep core muscles -- specifically the transverse abdominal muscle --, a fraction of a second before performing any type of movement. Since the transverse abdominal muscle is a spinal stabilizer, their lumbar area remained stable throughout the movement. In contrast, people with chronic back pain had a delayed transverse abdominal muscle response, which destabilized their spine during movement. Any deviation from correct alignment and proper strength ratios between muscle groups confuses your brain and creates dysfunctional movement sequencing.