The Kinetic Chain & Human Movement
Human movement occurs directly in part to the “kinetic chain.” Kinetic means force and the chain defined as a system linked together. Throughout DWMA, when we indicate the kinetic chain, we refer to a method of interconnected body segments that allow the body to move in a mobility/stability pattern of human movement.
The anatomical concept of the kinetic chain was developed in 1955 by Dr. Arthur Steindler who adapted the theory from Franz Reuleaux, a nineteenth-century mechanical engineer signified as the father of kinematics. Reuleaux offered that a series of interlocking segments connected via a revolute joint (also called pin joint or hinge joint) would create a linked kinematic system that allows movement of one joint to affect the action of another joint. Similarly, Dr. Steindler regarded the human body as a kinetic chain with overlapping segments connected by a series of joints.
Well-known physical therapist Gray Cook and strength coach Mike Boyle took Dr. Steindler’s principles and enumerated The Mobility/Stability Pattern of Human Movement which states an alternating pattern of mobile joints and stable body segments allow for efficient movement within the kinetic chain. If altered, dysfunction in movement patterns occur, and compensations in these movement patterns result. DWMA refined the mobility/stability pattern to include the lower quarter leg (i.e., big toe, foot, ankle), the cervical joints (i.e., upper and lower), and the shoulder, elbow, and wrist. The figure below is a summary of the DWMA kinetic chain and a joint-by-joint clarification.
Joint mobility gets defined as the optimal range of motion of a joint within the body; therefore, the intended range of motion is dependent upon the structure of the joint. For example, the hip is considered a ball-and-socket joint. This type of joint has a broad range of motion, meaning it can move in multiple planes of motion with vast ranging degrees. On the other hand, the knee has one plane of motion and can primarily flex and extend classifying it as a hinge joint.
The ability of any system to remain constant or aligned in the presence of outside forces is called stability. Regarding the kinetic chain, we reference stability as segmental stability. Segmental stability is the ability of the kinetic chain to maintain specified postural positions and alignment during human movement. Movements occurring within each body segment gets dictated by two things: joint mobility and segmental stability.
Joint mobility gets influenced by both joint structure and flexibility. As stated prior, the joint structure is dependent on the mobility parameters of the joint. However, motions within the kinetic chain get influenced by the flexibility of muscular and ligament structures (i.e., soft tissues) surrounding the joint. Therefore, flexibility means the optimal extensibility of all soft tissues surrounding a joint.
Segmental stability is contingent upon muscular strength and endurance; therefore, the muscular system should efficiently execute and control movement patterns. For instance, let’s use a golf swing as an example because it’s the single sports movement that most, regardless if you play or not, recognize the level of efficiency that must be achieved to hit the ball straight and with accuracy. Therefore, a golf swing requires certain parts of the kinetic chain to be moving while additional segments are stationary. For the kinetic chain to perform this movement patterns efficiently, you need sufficient levels of muscular strength and endurance to maintain postural positions and perform dynamic, athletic actions.
As a result, within the Mobility/Stability Pattern of Human Movement, you can see how the foot can affect the ankle and knees, how the position of the pelvis can affect the hip and low back, or how the thoracic spine can affect the shoulder joint. This kinetic chain model of training and assessment can assist with enhancing performance, lessening the likeliness of injuries, and how to organize it into coaching, training, and programming.
If anatomical limitations in the kinetic chain exist in terms of mobility and segmental stability, then joints that aren’t mobile enough force other segments of the kinetic chain to compensate and make up for the inefficient movement patterning, which can hinder performance and potentially result in injury.
In virtually every sport, the kinetic chain is a ground-based, so if limitations exist in terms of mobility or segmental stability, the goal is to improve these physical dysfunctions via the implementation of corrective exercises. The corrective exercises consist of a series of flexibility and joint mobility exercises to improve range of motion. Also, a series of strength training exercises would be implemented to address segmental stability weaknesses within the kinetic chain. Over time the inclusion of these types of exercises improves the kinetic chain’s mobility and stability parameters, thus allowing for improvement in functional movements to occur.