Dr. David Wang, Sports Medicine Physician, offers his expertise on the Kinetic Chain.
You may not realize it, but you were learning about the kinetic chain long before you learned your fractions or state capitals. Remember the song, “the shin bone’s connected to the knee bone, the knee bone’s connected to the thigh bone, the thigh bone’s connected to the hip bone?” That favorite childhood song is actually a good way to think about the kinetic chain.
The idea of the kinetic chain was first described in the late 1800s as an engineering concept. It was found that in a system fixed at both ends with a series of overlapping segments connected by joints, an applied force was transferred to adjacent segments in a chain reaction. This concept was adapted to the human body in the 1930s, with the bones acting as the segments linked by joints.
A good example of the kinetic chain at work in the body is the throwing motion. While you may think the arm is responsible for developing the velocity in a throw, it is actually just the last stop in the kinetic chain. The legs and trunk start the chain by generating the majority of the force behind the throw. This force is then transmitted up to position to transfer the force down the arm, and ultimately out to the ball.
Because all segments in the kinetic chain are connected, an injury or insult to one part can affect the entire chain. If one component is not working correctly, the remaining parts must compensate. This places increased stress on areas that are not used to handling them, potentially leading to injury. In the example of the throwing motion, if the legs and trunk do not produce the necessary force, the shoulder and arm must work harder to offset this, placing them at risk for injury. That is why even if your symptoms are localized to one part of your body, you might notice your physician examining everything from your head to your toes as he or she tries to identify any defects along the kinetic chain.
The kinetic chain also plays a large role in the rehab setting because the opposite is true as well. If you rehab one part of the chain, the benefits can be seen elsewhere. An example of this is the rehab for patellofemoral pain syndrome of the knee. Addressing further up the chain by strengthening the thigh, hip, and core, or further down the chain by correcting any abnormalities in foot biomechanics can improve symptoms at the knee.
Dr. David Wang is a sports medicine physician at Hospital for Special Surgery specializing in the treatment of acute and overuse injuries. His main clinical and research interests are overuse injuries, concussions, viscosupplementation injections, and the pre-participation physical exam. As a former collegiate baseball player, he also has a special interest in the care of baseball players.