It’s been said that you’re only as strong as your weakest link, but guess what? When you push your body to the brink of failure, that weakest link becomes one of the single most likely areas for injuries to occur. Sure that sounds pretty simple, but what if I were to tell you that the “weak link” may not be what you think it is?
Here’s how the kinetic chain model of training and assessment can prevent injuries before they rear their ugly heads, and how to incorporate this system into your training, coaching and programming.
The Origins of The Kinetic Chain Model
What is a kinetic chain? It’s a concept or a way of thinking which you need to understand because its how the human body was designed to function. I realize that’s a pretty vague definition, so lets start from the beginning, shall we?
Originally published by orthopedic surgeon Art Steindler in 1955, the basic concept of a kinetic chain is described as individual joints and muscles don’t work individually, but rather they work together as a group for any meaningful motion you’ll ever make. This recognizes the fact that we don’t just have muscles, we have a nervous system that controls muscles.
Isolate one muscle with an exercise and you’ll get stronger at that one exercise and might even get build muscle but you missed out on the opportunity to transfer that training to work in a real world, dare I say functional, scenario.
Isolation movement may yield aesthetic results, hence why bodybuilders isolate for this exact reason, but the truth is that you wont be nearly as strong as you could be for the amount of effort you just gave. Effort and hard work in the gym doesn’t always correlate with positive outcomes.
Strength expert and kettlebell master Pavel Tsatsuline has a term to illustrate the benefit of kinetic chain exercises vs isolation exercises, “Be as STRONG as you LOOK.” Isolation exercises will puff you up but you miss out on training the muscles to work together like they do in a real situation, so you can avoid being all show and no go.
Open Vs Closed Kinetic Chain Mechanics
From an anatomical standpoint, the kinetic chains refer to all the joints and muscles of the limb and the portion of spine they connect to. So the upper kinetic chain would consist of the fingers, wrist, elbows, shoulders, shoulder blades and spinal column. The lower kinetic chain includes the synergy between toes, feet, ankles, knees, hips, the pelvis, and the spine.
Also, the kinetic chain can be broken down into two types: Closed and Open
Closed Kinetic Chain (CKC) refers to a position where the upper body or lower body (mainly hands and feet) are fixed to something solid like the ground, which alters the movement of the joints and surrounding musculature up the chain. An easy example here would be the feet contacting the ground in a CKC during the squat movement.
Open Kinetic Chain (OKC) refers to the extremities not being fixed to the ground or ground based surface. Think of the arms doing biceps curls. The hands, arms and weights move freely in space, which causes a particular joint and muscular pattern representing the OKC.
But lets be clear here, CKC aren’t limited to just legs and OKC aren’t limited to just arms, which is a common misconception about the kinetic chain model.
Putting The Kinetic Chain To Work
Differentiating the OKC from the CKC takes knowledge not only of anatomy and biomechanics, but also an in depth understanding of the goals of training, especially for athletes with a particular physical metric they are training to enhance. Simply put, there are times and places where both types of kinetic chains can be appropriate for an individual client or athlete. It’s your job as a serious athlete or fitness professional to figure out which fits each situation and goal set ideally.
Knowing that one of the most foundational positions in the human movement library is the bipedal position aka standing and walking, why would someone use the notorious seated leg extension machine? If you answer “to train the quads” I’ll come back and ask you, “how often do you use your legs with the feet in the air?” That question usually gets this concept to click in for my athletes pretty quickly.
Grays Anatomy textbook states the quadriceps act as primary extensors of the knee. But remember, Gray was an English anatomist who studied the bodies of dead people. If you pull on the quad of a cadaver, the knee clearly extends, as many of you have had experience with during your days in gross anatomy class.
Those of us still living need to emphasize the use our quads in concert with the rest of our body as part of a closed kinetic chain, mostly to decelerate gravity. Think how your quads feel after lunges on FHT leg day, or the day after you went downhill skiing. The “function” of the CKC is enough to produce a targeted training effect, and yes, it may even carry over into your sport, life or beyond.
The Joint by Joint Theory of Mobility & Stability
The kinetic chain can also be thought of in terms of mobility, and not just strength. If the portions of the kinetic chain that are anatomically designed to be mobile aren’t mobile enough then other portions of the kinetic chain will have to compensate and make up for that. This leads to inefficient movement patterning, which can hinder performance and potentially even lead to injury.
Below are some examples of kinetic chain concepts as they relate to both your mobility and strength in a joint by joint approach to mechanics and movement. While this approach to function and movement is far deeper than the example regions and joints featured, these are the key players I see on a consistent basis with my clients and patients.
The Knee Joint
If you have knee pain there is a common cause that demonstrates the importance of kinetic chain thinking. The first place I look to evaluate is the ankle, and if you have insufficient ankle mobility into the forward direction (dorsiflexion). The norm is to be able to touch knee to wall with toes 4” away while the heel remains flat in a simple positional test. After testing more than my fair share of ankle dorsiflexion mobility issues, it’s safe to say that a majority of people cannot do this.
Lacking this specific range of motion causes the body to literally go out and find mobility from elsewhere in the kinetic chain. The more approximate anatomical link in the kinetic chain to the ankle complex is the knee. Lacking ankle dorsiflexion commonly causes the knees to fall in towards each other with running, squatting, hiking etc. We call this position a valgus dynamic instability.
This mal-position is inefficient and often causes knee cap pain at least or a ligament tear at worst. With traumatic knee injuries such as non-contact ACL tears on the rise, this is often times the most pivotal position to be monitoring and improving in rehab, training and beyond.
The Shoulder Complex
By now, everyone has heard of the rotator cuff, rotor cup, rotary club or whatever that muscle group is called that’s important for the shoulder. I like to think of the rotator cuff like quarterbacks of a football team. They receive far too much credit when things go well, but also get quickly thrown under the bus when things make a turn for the worse.
The rotator cuff is a group of muscles that function together to keep the ball of the shoulder joint, referred to as the humeral head, in the center of the shoulder socket, called the glenoid fossa, which is essentially a portion of the scapula. The ball is much larger than the socket so the relationship between these two structures can be compared to a golf ball on a tee, but unlike the golf tee the socket can move in all directions. So a better analogy might be a ball balancing on the end of a seals nose.
Since we can all imagine a trip to Sea World to see the seal’s circus tricks, in this example the seal is the shoulder blade or scapula. No matter how strong the rotator cuff is, if the scapula isn’t positioned properly, the ball still won’t be centered in the socket so pain, decreased performance or both will occur. This is why the practice and mastery of shoulder centration is so pivotal.
It is very common when someone presents with pain or even a tear in the rotator cuff that the cuff is more of an innocent bystander than a culprit. Usually the origin of pain and dysfunction is located somewhere else in the kinetic chain.
If the scapular muscles aren’t working properly, the ball and socket relationship will be faulty, and the shoulder will lose it’s centrated position. If the spine isn’t positioned well secondary to poor posture for instance, then the scapula (socket) which rests on the spine cannot be positioned well either so the ball and socket relationship suffers as well.
The rotator cuff is usually the weakest (and smallest, for that matter) link in the chain so suffers first and loudest. Not even the best cuff in the world can do meaningful work without a well functioning spine and scapula. Another way of thinking of this is to throw a ball sitting down, then throw it standing up. Which was better? Easy answer right? Use your whole kinetic chain and things just work better.
The Lumbar Spine & Pelvis
Low back pain is common. So common that most people in their lifetime will seek medical help or miss a day of work because of it. In my practice, most patients complain of back pain for “no reason” and when I evaluate these people the reason is commonly a lack of hip mobility. Insidious lower back pain is usually not insidious.
Taking the kinetic chain concept into account, if the hips don’t move as well as they should, where will that motion come from? The next link in the kinetic chain is the spine, and yes, it usually compensates for poor hip mobility and control until pain and injury occurs.
If you golf without enough hip rotation, your swing and back will both suffer, and hell, your knees might even flare up as well.
If you squat ass-to-grass like the cool kids on social media without enough hip flexion you’ll compensate by flexing your spine or collapsing your knees to get the depth you seek. Knee and back pain are likely, and decreased performance will be essentially assured.
Want to stay healthy and perform at your highest physical limit? Understanding the kinetic chain can help you improve your performance and decrease injuries over your training and performing lifetime.
Integrating The Kinetic Chain Model Into Training
In general, try to utilize the kinetic chain concept to meet your goals or the goals of your clients. Want better flexibility in your hamstrings? Think downward dog to get feet, calves, hamstrings, gluts and lower back rather than isolate it by putting a foot on a box.
Want greater leg strength and muscle? Think squats and deadlifts both double and single leg versions, kettlebell swings, lunges and step ups because that’s how your lower body works, in a closed kinetic chain and usually one leg at a time.
Want stronger arms? Prioritize something that challenges your grip pulling with the whole kinetic chain, like pull ups, chin ups, seated and bent over rows. Then incorporate pushing with the whole chain vertically and horizontally. Pushups, bench presses, shoulder presses, push presses rather than preacher curls and triceps kick backs.
Some exercises become whole body. What are kettlebell swings good for? Upper body, lower body or core? Yes, yes and yes! Same with farmers carries, deadlifts, suitcase carries, ball slams, etc. That’s what makes these staples in training.
Get away from the isolationist mindset and utilize the whole kinetic chain. Then you can be like Pavel and be as strong as you look and feel better too.
About The Author
Dan Swinscoe, MPT, CSCS is a physical therapist and strength and conditioning coach with Peak Sports and Spine Physical Therapy located in Issaquah, Washington.
He employs SFMA/FMS principles to his patients and athletes, while specializing in treating baseball players and golfers. Dan holds certifications through Titleist Performance Institute (TPI), USA Weightlifting (USA!), StrongFirst and HKC.