Kinetic Chain

Original Editor - Tarina van der Stockt

Top Contributors - Tarina van der Stockt, Evan Thomas, Kim Jackson, Khloud Shreif, Olajumoke Ogunleye, WikiSysop, Rewan Elsayed Elkanafany, Lilian Ashraf, 127.0.0.1, Simisola Ajeyalemi, Rucha Gadgil, Wanda van Niekerk, Lucinda hampton, Kirenga Bamurange Liliane, Naomi O'Reilly and Claire Knott

Introduction

 The kinetic chain is an engineering concept used to describe human movement. It is used in a wide variety of clinical conditions, including musculoskeletal, sports medicine, neuro-rehabilitation as well as prosthetics and orthotics. 

The concept was introduced by Franz Reuleaux, a mechanical engineer, in 1875. He proposed that rigid, overlapping segments were connected via joints and this created a system whereby movement at one joint produced or affected movement at another joint in the kinetic link.

In 1995, Dr. Arthur Steindler adapted Reuleaux’s theory and included the analysis of human movement, sport-specific activity patterns and exercise. He suggested that the extremities should rather be thought of as rigid, overlapping segments in series and he defined the kinetic chain as a “combination of several successively arranged joints constituting a complex motor unit.” This series, or chains can be open or closed. 

Open Kinetic Chain

Steindler defined an open kinetic chain as “a combination of successively arranged joints in which the terminal segments can move freely”.  Thus the distal segment of the extremity is free to move in space. Examples of this are when you wave your hand, moving the foot during the swing phase of gait or doing a seated knee-extension. 

Characteristics of Open Kinetic Chain Exercises:

1. Open kinetic chain exercises are typically characterized by a rotary stress pattern at the joint. For example when doing a seated knee-extension the primary stress to the joint is rotation of the proximal tibia on the distal femur even though other accessory movements like rolling and translation occur. 
2. Open kinetic chain movements occur on one primary axis. During the seated knee-extension exercise the motion primarily occurs in the sagittal plane. 
3. The number of simultaneously moving segments. “One segment of the joint (i.e. femur in the knee extension) remains stationary during the knee-extension exercise, while the other segment that forms the joint (i.e. tibia) is mobile. This adds control to the exercise because of the stability of the stationary segment (i.e. femur). 
4. Allow more isolated muscle activation because less muscle co-contraction is used to do the movement.
   

Closed Kinetic Chain

Steindler’s definition of a closed kinetic chain exercises is a condition where the distal segment meets “considerable” external resistance that prohibits free movement.  (Thus it is a system where neither the proximal nor the distal segments can move.) Movement at one segment in the closed kinetic chain produces movement at all the other joints in a predictable manner. . For example, during a squat the movement at the knee joint accompanies movement at the hip and ankle joints.

In Steindler’s initial definition he did not qualify the term “considerable” and this let to confusion and controversy and thus true closed kinetic chain movement patterns never occur in the extremities except in isometric exercises where no movement occur. 

But in clinical practice the definition of closed kinetic chain is when “resistance is placed through the distal aspect of the extremity and remains fixed to the extremity”. The best example of this is the standing squat because the feet remain fixed to the ground and the surface produces considerable resistance, in response to the athlete’s body weight or added weight. 

For more than 20 years closed kinetic chain exercises has been incorporated more and more into rehabilitation programs because of their inherent functional stimulation.

Characteristics of Closed Kinetic Chain exercises:

Using the standing squat as an example - Linear stress pattern is produced at the tibiofemoral joint due to axial joint loading. Movement occurs at multiple joints and multiple-joint axes at the hip, knee, ankle (talocrural), and subtalar joints. Simultaneous movement of both segments Because of the simultaneous segmental movement and increase in muscular co-contraction is needed to stabilize and control the movements across the joints in the closed kinetic chain.

Standing Squat

  The current Kinetic Chain concept challenged

• Some exercises are more difficult to classify as open or closed kinetic chain. Stair-climbing machines is one example because the feet are fixed to a pedal that is continuously moving during the exercise. The same with riding a bicycle, even though it is a closed system researchers and clinicians do not agree that is a closed kinetic chain exercise. 
• In his blog titled, The Problem with the Kinetic Chain, Mike Reinold challenges the idea of the kinetic chain in two ways. Firstly, not all links in the kinetic chain are equally important also to rather think of a chain reaction than just a chain.  "Take the hip as an example. Any tightness, weakness, or imbalance of the hip is going to have a large influence on the low back and knee, and a much less impact on joints the further away you get from the hip." Secondly, the kinetic chain needs to include what is between each link (this includes muscles, fascia, ligaments, tendons etc).  "A joint doesn’t have to just influence a joint and a muscle influence a muscle. All these structures work and interact together. A great example of this is the upper body cross syndrome."
  
• Butler and Major suggested that there should be a distinction made between joints with active neuromuscular control (for e.g. sitting up straight with no back support and with the thighs and feet supported) and those with control deficiencies (for e.g. sitting with collapse of the lumbar spine). The authors proposed new terminology: Controlled Closed Kinetic Chain (CCKC) and Controlled Open Kinetic Chain (COKC). CCKC = system of links forming a Closed loop, continuously or for a moment where “a maximum of three of the articulations between links needs to be under active control”. COKC = Continuous active control of all the articulations and one part of the chain “may be in contact with a support surface” (but not a requirement). 

Recent Related Research (from Pubmed)

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References

 

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