Episode #8: Kinetic Chains (Principles of Movement Series)

Welcome, everyone, to Episode #8 of the More to Movement podcast, and our focus: Kinetic Chains. 

I’d like you to visualize a carbon steel chain if you can.  You know, the chains you use for hauling or hanging things.  Swings at playgrounds are usually attached to it.

So, you have the visual now.  Look at the chain and notice how each segment is linked together.  Also, notice how each link in the chain is dependent upon the ones connected to it for strength and integrity.  

The chain imagery is great to start the discussion on force transfer through the body because, like the chain, the body is linked together.  And like the chain, the links in the body depend on each other for proper force transfer.

When we talk about “links” in the body, we are talking about bones and their articulation at the joints.  These links are bound together by soft tissue, which helps transfer and mitigate force through the link structures.

When we talk about kinetics chains, that is what we are talking about- a system of linked, rigid structures (i.e., bones) subject to force application.  Or simply put, joints affect each other during movement.  As we’ve already discussed, muscles produce a variety of actions to effectively manipulate gravity, ground reaction forces, momentum, and external resistance.

Force

I’ve used the term force a lot, and I want to take a second to discuss and define it.  Force is something with the capability to cause a change in motion of a system, meaning that force doesn’t always have to cause a change in motion.  Further, force is the interaction within the system that results in acceleration or deceleration of something.  Force is determined by two primary factors:  the magnitude, meaning how strong it is, and the direction, meaning the way the force is moving. 

Why is force so important?  Simply, it’s how we move.  We manipulate and transfer forces from a multitude of directions to effectively produce movement, so understanding its potential impact on movement outcomes is vitally important.  Kinetic chains reinforce the idea that the body is a functionally connected and interdependent system. If we want to optimize our development, we need to exploit force pathways that will optimize our movement for our specific goals.

Kinetic Chains: Simple vs Complex

Let’s chat about the different types of kinetics chains. First, we need to differentiate between the two major types: simple and complex.

Simple Kinetic Chains

Simple kinetic chains describe a chain where each segment participates in no more than two linkages.  This typically is referring to the single-joint movements.  An example would be biceps curl, or elbow flexion.  Assume the wrist and hand are static, the only movement occurring is at the elbow, which is the articulation of two links: the upper arm bone (the humerus), and the forearm bones (the ulna and radius).

Complex Kinetic Chains

Complex kinetic chains involve more than two segments that participate in the linkage, and this commonly refers to multi-joint movements.  Think of the up leg during a step-up exercise.  You push through the foot and plantarflex your ankle, extend your knee, and extend your hip as you stand up onto the box.  This movement includes the ankle (talus, tibia, and fibula), the knee (tibia and femur), and hip (the femur and the pelvis), along with all the musculature that connects the whole system.

Kinetic Chains: Open vs Closed vs Functional

After identifying if the movement is simple or complex, the next step is to classify it as either open or closed.

Open Kinetic Chains

Open kinetic chains are unconstrained, and the distal segment of the movement is free.  This typically means the hands or feet are free to move.  Some examples would be dumbbell chest flyes, knee extension or knee flexion, or lat pulldowns.  All of those are examples of open kinetic chain exercises because the hands and feet are free to move.

Closed Kinetic Chains

Closed kinetic chains are the opposite, where the distal segment (hand or foot) is stationary and constrained and meets considerable external resistance.  Since closed kinetic chains are constrained, movement is dependent on the contribution from adjacent body segments. Each segment of the body receives force from and transfers force to another connected part.  Typically, these are your ground-based exercises, like push-ups or deadlifts.

If you try a push-up, you’ll notice that as hard as you push, the ground doesn’t move.  Your hands are constrained.  Since you cannot push the ground, forces are redirected into your hands and continue through your arms and into your shoulder and chest. 

This is an excellent example of a closed kinetic chain at work because the movement is dependent on contributions from the adjacent body segments.  Because of that, greater emphasis is put the mobility and stability of a joint to achieve optimal movement.   

Functional Kinetic Chains

Finally, there are functional kinetic chains, which are a combination of open and closed kinetic chains.  These kinetic chains pertain to multiplanar and multi-joint activities and movements.  These can be challenging to address because open and closed chains are occurring simultaneously, and these movements require coordination, balance, and synchronized neural input to be efficient. Walking is an excellent example because during the gait cycle, one leg is on the ground (closed kinetic chain) while the other is stepping forward (open kinetic chain).    

Putting it Together

Alright, so we defined the kinetic chains, but what does it mean?  Let me put it into context for you, and let me give you an example to illustrate that all movement is not the same, and why this concept is so crucial.

Think of your ankles, and if you’re in a seated position, I want you to point your foot away then pull it up continuously, like you are pressing on and off the gas pedal in the car.  For most of you, it’s easy.  It’s unconstrained, and you probably really only feel your calf contract as you point your foot.  This is a simple, open kinetic chain.  Movement is exclusively dependent on the muscles at the ankle. 

Now, if you can, stand up, and do a squat, and try to focus on your ankles.  Do your ankles move as well as they did earlier?  Probably not.  You may notice more restrictions at the ankle, and this is due to the type of kinetic chain at work- a complex and closed chain.  

The Difference Explained

The squat movement is noticed more in the hips and upper legs, but the ankles contribute significantly to the movement.  Ankle movement is influenced by the chain of linked muscles through the entire movement, including muscles at the knees, hips, and trunk.  Force transfer demands skyrocket due to all the muscles and joints contributing to the movement, and now, mobility is significantly challenged. 

Function at the ankle now depends on the interaction with the rest of the leg.  A couple of examples include your center of mass, where the load is centered relative to the ankle joint, the efficacy of force transfer, muscle engagement, and stability of the joints. If you have sufficient mobility and stability at the ankle under these conditions, your movement is probably optimal.  If not, it will affect the efficiency of your movement in a big way. 

Let me put it to you this way- out of all the squat patterns I assess, approximately 90% of issues have to do with poor mobility at the ankle.  Seriously- a majority of the valgus effect at the knee, hips dropping, and excessive trunk flexion can be attributed to poor ankle mobility.  You see why developing appropriate kinetic chains is vital.

The Takeaway

So, here’s the takeaway: make sure you utilize appropriate kinetic chains for your desired outcomes by defining the goal of training, then adjusting exercises to meet the needs of the goal.

Most programs will have a mix of simple and complex, open and closed kinetic chain exercises, but you can determine the best course of action based on what you want to develop.

So you have an understanding- great. Now you need to use it to maximize your efforts.  Here’s the other part of today’s takeaway.  I’ve provided a breakdown of what each chain will primarily develop so you can choose what types of exercises work best for your goal.  There is a nice graphic that sums all of this up of this below.

Hopefully, that helps take your exercise selection and training regiments to the next level!

Thanks for tuning into the show today, everyone.  I appreciate you taking the time, and I appreciate you!

I’d love to hear from you.  If you like the show, or if you don’t like the show, take a few minutes to review or rate it for me.  I want to continue to provide you with quality, useful information and your feedback is essential.  You can also reach out through social media.  I’d love to connect with you, and you can find me on Instagram- my handle is: pete.rohleder.

If you could take a few moments to help me out, I’d really appreciate it!

Thanks again, everyone! Take care of yourselves, and remember, wherever you are- keep moving.