The Kinetic Chain

You’ve probably heard that a baseball pitcher’s power comes from his legs, right? But you might not have understood exactly how or why that is. It’s hardly obvious...unless you understand how the body works, in which case, it makes perfect sense. And whether you care about baseball or not, you definitely should care about this explanation because even though your activities might be different, your body works in the exact same way.

The Kinetic Chain

What I’m alluding to is a basic functional concept known as the Kinetic Chain. It’s a useful, illustrative term that accurately conveys how your body works, mechanically (kinetic means pertaining to movement). Specifically, it likens the various parts of the body (e.g. shoulder, abdomen, hips) to single links strung together to function as a contiguous chain.

The analogy helps explain how most major movements (throwing, walking, bending, lifting, etc) are--contrary to what they may seem--actually not the action of any one body part, or  “link,” e.g. the shoulder or the spine. They’re not even the action of a few links. Rather, such movements, if performed properly, are the culmination of multiple links, or areas of the body, working together.

Take the aforementioned pitcher. Even the best major league pitcher’s arm couldn’t create a 100 MPH fast ball on its own.  That kind of power can only arise from the cumulative effort of many body parts. That pitch reflects the energy generated by the sequential winding and then explosive release of all his joints from his toes up through his ankles, knees, hips, abdomen, spine, shoulder, elbow, wrist, and fingers. That big wind up on the mound isn’t just for show. Every one of his body’s “links” has to contribute for him to get the best possible function out of his kinetic chain, and the more links he can coordinate together, the more power he’ll summon. When that ball leaves his hand, it’s being propelled by the total forces created by all of the joints that participated in that wind up. Given the relatively large size of leg muscles, it should come as no surprise that those contribute the largest share of the power.

Now, that same pitcher could throw the ball from a complete stand still using just his upper body; it just wouldn’t come close to being as forceful (and his lower body would still need to engage just to keep him standing and balanced. There’s no escaping the need for the whole chain!) He could even throw the ball if he were sitting down strapped into a chair such that only his shoulder and arm were free to move. But you can just imagine how weak that pitch would be!

Put simply, the body is designed to function as a whole unit, and that’s how it functions best.

More = Better

Since your body is designed no differently than the pitcher’s, the kinetic chain concept applies just as much to you. And its functional implications are just as significant. Indeed, a basic understanding of the chain will allow you to perform your desired activities better, easier, and more safely with less injury and/or pain.

Athlete or not, optimal physical performance generally requires that you engage your whole body. Ever wonder why you’re never supposed to lift something, especially something heavy, just by bending down from your waist? Well, one of the main reasons is that such form demands that a single link (your lumbar spine) do essentially all of the work. Lifting from the recommended position of a squat, however, recruits much more of the kinetic chain--everything from your toes to your arms. This lets you harness the combined power of, and spread the stress across, your entire body. Why wouldn’t you do it that way? After all, more (not to mention bigger) muscles on the job makes the task easier to accomplish and allows the work load to be divided over multiple joints and muscles, sparing any one joint from being overburdened.

So one of the main advantages of the kinetic chain design is that it compounds the smaller forces of individual “links” to create a much greater force in the end. It’s a very efficient mechanism, giving you a sum that is greater than the parts, much to your functional benefit.

Bottom line: the more of the kinetic chain you can use for an activity, the better.

Live by the Chain, Die by the Chain...

Of course, there’s rarely an upside without a downside, and the kinetic chain is no exception. While the linkages improve our function immensely, they also link the bad stuff...injuries. An injury anywhere in the chain will often cause problems elsewhere along the chain. So while the body functions as one large unit, unfortunately, it often gets injured as a unit too.

Any part that becomes injured immediately becomes the weak link in the chain. In an effort to maintain ultimate function, your body will try to compensate for that weak link by squeezing more out of another link (or links). This includes having muscles to do more than they’re safely capable of, making a joint extend beyond its safe range of motion, etc.-- all in an attempt to make up for what’s lost somewhere else. It’s no coincidence that pitchers with shoulder limitations commonly develop subsequent elbow injuries. After all, when the shoulder can’t contribute its fair share, the body naturally pushes the elbow to pick up the slack by contributing more than its fair share. Injury is all but guaranteed in such circumstances.

And quite often, the association between injuries isn’t as direct as shoulder and elbow injuries on the same arm. The extensive connections along the chain mean that an ankle problem can even lead to an elbow injury in the opposite side arm.

So this kinetic chain design is genius, but it has its drawbacks.

Rehab the Chain, Not the Injury

An understanding of the kinetic chain design is an advantage not only for achieving better function, but also for better healing.

Clearly, a seemingly focal injury can be a set-up for disaster if not handled properly. It is insufficient simply to rehab the injured part without addressing the rest of the kinetic chain, and it’s unrealistic to expect full function unless you do. Incorporating the entire kinetic chain when recovering from an injury will give you the absolute best possible outcome.          Less recognized but just as critical is the fact that the kinetic chain frequently holds the answer to why an injury isn’t getting better or why it recurs despite “proper” treatment. Take the case of the pitcher that has an elbow injury as a consequence of the shoulder not working right (described above). Ultimately the elbow isn’t the real issue, it is simply the manifestation of a shoulder problem. In such a scenario, you can treat the elbow until you’re blue in the face, but it will never completely resolve until you correct the real cause of the problem, the shoulder. But you have to know about the kinetic chain design to realize that.

So a general understanding of the kinetic chain not only can be used for functional advantages but can save you a lot of time, money, pain, and aggravation!