Closed chain exercises (CKC) or closed kinetic chain exercises are physical exercises performed where distal part of the body is fixed for example the hand (for upper extremity movement) or foot (for lower extremity movement) is fixed in space and cannot move.
The extremity remains in constant contact with the immobile surface, usually the ground or the base of a machine.
Closed-chain exercises are primarily performed in weight-bearing positions.
Closed chain exercises are complex movements that incur compressive forces in contrast to open-chain exercises which are isolation movements which promote more shearing forces.
In a rehabilitation program, closed-chain exercises can be incorporated in an exercise regimen as soon as partial or full weight bearing is safe
Closed-chain strengthening exercises generate less shear force on knee ligaments as mentioned above particularly anterior tibial translation, than open-chain quadriceps-strengthening activities. Therefore, resistance can be added to closed-chain activities sooner after injury or surgery than to open-chain exercises while still protecting healing structures such as the ACL. Clinically, closed-chain exercises enable a patient to develop strength, endurance, and stability of the lower extremity in functional patterns sooner after knee injury or surgery than do open chain exercises.
Biomechanical and Neurophysiological Factors
Closed kinetic chain exercises techniques emphasize the sequential movement and placement of functionally related joints and therefore require coordinated and sequential muscle activation patterns to control proper joint movement. During a standing squat, for example, the quadriceps and hamstrings are thought to contract concurrently to control the knee and hip, respectively.
In the upper extremity, closed-chain exercises in weight-bearing positions are also thought to cause coactivation of the scapular and glenohumeral stabilizers and, therefore, to improve dynamic stability of the shoulder complex.
The assumption seems reasonable, but evidence of co-contraction of muscles of the shoulder girdle during weight-bearing exercises, such as a prone push-up or a press-up in a chair, is just starting to appear, making it difficult for clinicians to draw conclusions or make evidence-based decisions at present time.
Closed kinetic chain exercises stimulate the proprioceptive system by proprioceptive feedback to initiate and control muscle activation patterns
Theoretically, because multiple muscle groups that cross multiple joints are activated during closed-chain exercise, more sensory receptors in more muscles and intra-articular and extra-articular structures are activated to control motion than during open-chain exercises. The weight-bearing element (axial loading) of closed-chain exercises, which causes joint approximation, is believed to stimulate mechanoreceptors in muscles and in and around joints to enhance sensory input for the control of movement.
Closed Chain Upper-Body Kinetic Exercises
Examples include push-ups and derivatives, pull-ups or chin-ups, and dips. These concentrate on a co-contraction of the triceps brachii, biceps brachii, deltoids, pectoralis major and minor, and lower back for stabilization in various ratios depending upon the angle and leverage.
Closed Chain Lower-Body Kinetic Exercises
Examples include squats, deadlifts, lunges, power cleans, and leg presses. These concentrate on a co-contraction of the quadriceps, hamstrings, hip flexors, soleus, and gastrocnemius muscles. The joints of movement include the knee, hip, and ankle.