EDITOR'S NOTE: Due to the current fitness industry debate about the validity of the Open and Closed chain training model, we at PTontheNET.com have tried to offer multiple perspectives so that trainers can assess all the facts and make informed decisions to suit their needs. The following article by Suzi Nevell, an accomplished physiotherapist and sports injury rehabilitation expert, provides an interesting counterpoint to the physiological exploration of the same topic by esteemed author Mel Siff in his PTontheNET.com article titled "Closed Versus Open Kinetic Chain Exercise?" Enjoy both reads and let us know what you think!
The continuum that exists between open and closed chain activities in the sports, work and ADL environment, certainly makes us aware of the deficiencies in the definitions and the system of classification of when a kinetic chain is open or closed. We should not however, be so quick to discard a system that certainly does have a role in enhancing sports performance, exercise rehabilitation and activities of daily living. We all know that definitions pose problems, however, contrary to the opinion of some fitness professionals, a deficient system may be better than no system at all. We have gyms and rehabilitation centers filled with injured people and professionals trying to improve sports performance with a lack of knowledge of a system that needs to be better understood. Do we just go ahead and throw the baby out with the bath water, or do we try to obtain a better understanding of how to apply the kinetic chain systems to rehabilitation and improving sports performance?
What is important when considering open and closed chain exercise is that people need to learn to use this system while thinking about force generation in open and closed chain situations. A body builder who works in a warehouse and is unable to efficiently lift 60lb packages but can do a knee extension with every weight plate on the machine, or can only free-squat a fraction of what he can leg press are examples of a dysfunction that exists where you have open chain muscle strength, yet weakness in the closed chain – and thus a true functional deficit. A similar situation exists when you use your legs to ride a bicycle and no matter how fast or strong you are on the bike, it does not mean you can get off the bike and have an equal performance in a 10km run. One is open chain dominant and one is closed chain dominant. If you want to be a good runner, you need to spend time training to generate force in the running gait pattern and use closed chain exercises with a functional carry over to running.
In the Physical Therapy realm, and from a rehabilitation perspective, kinetic chain exercises were developed when studies involving knee rehabilitation following Anterior Cruciate ligament (ACL) reconstruction showed that the joint stress and stress on the new ligament graft was significantly reduced in closed chain training compared to training predominantly in the open chain. It was found that the quadriceps could be safely exercised without jeopardizing the ACL graft using closed kinetic chain exercises (Figure 1). The hamstring and quadriceps co-contraction in the closed chain exercises prevented the anterior tibial translation that was creating significant elongation force in the ACL graft during open chain exercises such as knee extensions.
Research found that knee extension exercises caused anterior tibial translation (Palmiter et al 1991). The closed kinetic chain exercises provided a functional stress on the limb giving joint compression to improve stability and *inner unit (IU) activation of the knee joint. With the ACL rehabilitation protocols described by Shelbourne and Nitz (1992), closed kinetic chain exercises have been emphasized and open chain quadriceps exercises are avoided. Howell et al (1990) stated that closed kinetic chain exercise controls anterior tibial translation in the pre-loaded knee by the interactive effects of compressive forces and the congruent articular surfaces. In cases of decreased shoulder stability, there is a need for increased stability, which is afforded by both compression and inner unit (i.e. rotator cuff) recruitment; the I.U. is stimulated by joint compression exercises for example, a push up. Again a predominantly closed chain activity where this compressive approach was found to aid functional stability in a more effective way than open chain type exercises.
The point here is that there are many specific client applications for the principles of open and closed chain exercise - more than enough to prevent us from disregarding the system all together as some fitness professionals currently suggest. Like most things in life, the usefulness of the model is proportionate to our understanding of it.
OPEN AND CLOSED CHAIN KINEMATICS - are they the same?
This issue is explored in detail in an article by Randal A. Palmitier et al, Kinetic Chain Exercise in Knee Rehabilitation, Sports medicine 11(6) 402-413 1991.
There is a very significant correlation between weakness in a closed chain and injury or dysfunction in the open chain. Steindler speaks of the difficulty “to speak of purely open or closed kinetic chains in ordinary locomotor performances or even in sports events” but he then speaks of a theoretical distinction between the systems with movement “combinations in which speed and force are developed at ratios varying with the specific motor act”. This is where we can establish and recognize differences in the kinetic systems. In the same incidences, we as exercise and rehabilitation specialists need to think about the loading on the body and the force generation of the extremities i.e. the arms and the legs.
Understand that in order to have an extremity move in the open chain, it must have a working anchor that is fixated in the closed chain. Rare exceptions exist in activities such as gymnastics, serving in volleyball with the feet off the ground, and in trampoline where conceptually, the chain closes itself around the center of gravity. Commonly open chain activities are almost always dependent upon a relatively closed or fixed segment of the chain to generate force from (i.e. the foot, the fixed anchor in squatting). In activities like kicking or running, if you are closed chain deficient, you’ll eventually become open chain deficient. Most likely you will already be open chain deficient because, for example, you cannot accelerate the leg without the foundation created by the opposite foot. It is easy to feel the loss in the open chain power when trying to kick while standing on a balance board. All you have to do is stand on an unstable surface to feel how diminished the closed chain is and see how much of a detriment it creates to the working open chain extremity.
GAIT AND THE KINETIC SYSTEMS
When we walk, up to 85% of the time is spent on one leg. The swing leg acts as a pendulum hanging out of the hip joint and swings with the greatest of ease. To create swing in gait, you have to accelerate the swing leg, which weighs 20% of your body weight, and it has an inertial (momentum) energy that has to be counterbalanced by the other leg / pelvic unit. Here the stance leg is the closed chain anchor. So what happens if you have pain or dysfunction in the stance leg? You have a force generator that is deficient in the closed chain and now you try to accelerate the leg and put force through a system that is commonly collapsing into pronation due to pain inhibition or stabilizer deficiency. The interesting thing is that people often turn up to the clinic with lateral hip pain, hip flexor or tensor fascia lata problems on the swing side, all from trying to pull the leg through an exaggerated amount to compensate for lack of force generation from the closed chain foundation. Lacking the stability and strength on the swing side, these people also may create pain and dysfunction around the sacroiliac joint, because they are unable to stabilize the joint with the accelerated swing phase (Figure 2).
For example, if I have an Achilles Tendonitis or a painful heel and I attempt to run, I will try to get off the painful side quickly in the stance phase of gait, thus diminishing the power output on the closed chain injured leg, which serves as the foundation for force generation. To compensate, I may try to pull the other leg through faster. This can result in an injury in the open chain side. I may then go to a therapist who treats the side of pain because of a lack of understanding of the kinematics and the working relationships of the movement pattern. If therapists don’t understand open and closed chain, and don’t fully understand the nature of human movement, they are left with only one option – treat the spot that hurts, with variable results.
Another example to illustrate how an injury can occur when someone is not strong in the closed and open chain is the situation of a flight attendant pushing a cart down an isle who runs into a passenger’s foot that is resting in the isle. The attendant gets thrown into lumbar extension because her reflexes are slow and core stability is weak (not helped by wearing high heels). Suddenly what was an open chain activity (pushing the rolling cart) becomes closed chain (the abrupt stop) and the nervous system can’t make the switch due to the lack of structural integrity. A few days or a few weeks later (therapist or trainer respectively) the flight attendant comes to you. Here it is vital to avoid exclusively using open chain exercises to treat a closed chain deficit. Their corrective exercise program must have task specific carryover to provide correction, and prevention of re-injury via newly acquired functional strength and development of an optimal motor control strategy.
The critical point in sports and work performance training is to ask, “Where is the performance deficit?” Find out through your knowledge of when the chain is opened or closed in the movement pattern to discover if your client’s problem is because of an open or closed chain deficit. Ask the client “ Where do you have the hardest time in your sports or work environment?” Then observe the client during movement to see where the challenge is.
For example, cycling on straight-aways can usually be considered open chain, steep hills requiring that you get out of the saddle and pull into the peddles with the arms, can often momentary pose closed chain challenges. So if you’re dealing with a cyclist, ask where the challenge is. If it is on the hills, make sure you provide the right training environment (i.e. closed chain exercises) to enable your client to benefit maximally from the training.
It is also important to remember that all your clients are adapting to the exercises you give them - the Specific Adaptation to Imposed Demands, or S.A.I.D. principle. You need to learn to prescribe exercise with the same precision that a good surgeon uses a scalpel. Understanding the difference between the open and closed chain systems will help with your prescription. Palmitier states that “strengthening the thigh with isolation exercises has no practical application for most patients”. Kicking is the likely to be the only activity that requires powerful isolated quadriceps contraction in a function sports environment, but even in this situation the stationary leg needs to be strong in the closed chain to produce the anchor to generate force from. If we are to be masters in strength and conditioning – and develop the appropriate ‘software’ to use newly acquired strength in sport and life – specific exercises need to be selected that will have direct correlation to the task at hand.
When examining the knee extension (as opposed to the squat) in training to jump higher, does any relevant ankle, hip and/or trunk flexion occur while performing the knee extension? The simple answer is No. It is an isolated movement of the knee so the brain learns to do exactly that, and you will find virtually no functional carryover from doing a knee extension into the vertical jump (or any activity requiring closed chain force generation from the lower extremities). Similarly, in a leg press, the rate and relative timing at which the ankle, knee and hip flexion occurs is too different to the rate and relative timing of correlating movements during a jump, to provide any real relevance to the client who wants to increase vertical jump? As Thomas D. Fahey emphasizes, “The further removed from the kinetic chain sequence, the less effective your exercise routine will be”.
A prime example of open and closed chain differentiation in the upper body can be found in the lat pull vs. chin-ups. Anyone with experience in the gym will know that no matter how strong you become using lat pull downs, it has little effect on your chin-up performance. Although these are similar looking movement patterns, the kinematics and the muscle recruitment differ. In a lat pull down, the muscle recruitment is sequenced to pull the bar toward the trunk, which serves as the functional anchor. During a chin or a pull-up the hand on the bar is the functional anchor. Therefore while all the same muscles and joints are involved, the muscle recruitment and joint motions (arthrokinematics) are inverted, or 180° out of phase with each other.
The key is to not give up on the concepts of open and closed chain kinematics due to deficiencies in the definitions. Ultimately, you need to be aware of open and closed chain applications within the task of different activities and apply this knowledge when assessing the movement patterns. If you do not utilize the open and closed chain technology to identify where the problem is, then you’re giving up a massive problem solving tool. Whether you decide to call it a foot on the ground phase or a foot swinging phase, hand fixed or hand moving phase, the name is not relevant, the challenge we all have is being willing to expand on Steindler’s genius and apply the Open and Closed chain principles in a problem-solving model!
- Fahey T.D. The Kinetic Chain And The Powerlifter. In “Power- Research” 34-35
- Palmitier R.A, An K. , Scott S.G, and Chao E. Y.S. Kinetic Chain Exercise In Knee Rehabilitation. Sports medicine 11 (6) 402-413 1991
- Panariello R. A. The Closed Kinetic Chain in Strength Training. National Strength and Conditioning Association Journal. 13 (1) 29-33.1991
- Steindler A. Kinesiology of the Human Body Under Normal and Pathologic Conditions. Charles C. Thomas, Springfield IL, 1973
- Zuluaga M. Sports physiotherapy- applied science and practice. Churchill Livingstone, 1995