Posterior Kinetic Chain or Don’t Look Back in Anger, Look Back with Strength!

Who starts a fitness program and says, “Gee, I’d like to look worse as a result of my exercising.” Young or old the answer is no one! Even my 90+ year-old clients often ask me if there is anything they can do that will help them slim down, lose their tummy or become more toned. Everyone wants to put their best foot forward or, in the case of fitness, their best 6-pack. Often, in our need to look good in a mirror, we forget that there is a whole other side to fitness that we can’t easily see: our back side!

Now, when I say, “back side,” I’m not only referring to your buttocks, (glutes, fanny, butt, rear-end, caboose, assets or whatever you choose to call it) I am referring to all of the muscles in the back side of the body from the neck and shoulders all the way down to the calves. The muscles in the back of the body are known collectively as the “posterior kinetic chain.”

Why Focus on the Back?

The muscles in the back of the body are responsible for deceleration during large functional movements. Basically, these muscles work against gravity to slow down limbs thus minimizing impact on joints. Some examples of deceleration are sitting in a chair from standing, descending stairs or taking something down off of a shelf.

When I’m working with my clients, those with weak PKC muscles may flop down into a chair, or their feet will “thud” upon stairs as they descend (because they are using momentum and not controlling their motions against gravity). Also, those with a weakness in their PKC can exhibit a rounded thoracic spine and shoulders because the muscles in the back body responsible for posture are weaker than those in the front of the body.

A weak PKC can also mean that the muscles in the front of the body are picking up the slack for their weakened counterparts which can cause lead to joint injury. When your foot hits the ground after jumping, walking, or descending stairs the amount of force of that impact can be 2-3x your body weight! So now you’re descending stairs with poor body mechanics and you’re nearly doubling the amount of force on your joints.

My aunt used to take me hiking in New Hampshire’s White Mountains when I was a kid and told me to be careful when going down the mountain because my thighs would “jackhammer.” My quads would twitch and shake because I was using them to absorb the impact of my body descending the mountain. In an ideal world, your glutes and hamstrings would take over as you descend minimizing impact and taking strain out of the knees.

Break It Down, Now.

Now let’s talk about some of the specific muscles and what we can do to not only strengthen them but to also make sure that these muscles are being activated. This means that the prime mover muscle is working throughout the whole movement and the bulk of muscular effort is not being controlled by synergists (other muscles that work together with the prime mover).

Glutes and Hamstrings – The Squat is an exercise that teaches a client how to properly engage the muscles in the back of the upper leg. A squat is a functional movement akin to lowering oneself into a chair. Although a simple-seeming exercise, the squat can be difficult to execute. The client needs to be able to lower themselves into the squat position, rise from that position, keep their torso up, tummy in and they have to maintain balance. A progression I use with my clients is squats with a chair behind them, squats where they are holding onto a bar, wall squats, etc.

Another exercise that I use for hamstrings is called “The Flamingo.” The Flamingo is a standing leg curl where the client either wears ankle weights or a band around the ankles for resistance. This exercise isolates the hamstrings but also challenges the client’s balance and proprioception (body awareness). I actually  love cueing this exercise: “rest your toe on the ground behind you with your heel up. Lift your heel from the ground as if you are trying to kick yourself in the buttocks.”

Actually having a client walk up and down stairs and cueing them to descend heel first, helps to activate the glutes.

Lats, Upper Back – The most effective exercises to work the Upper Back are rowing exercises where the client is activating postural muscles as well as maintaining upper body strength. The big “wing muscles,” Latissimus Dorsi can be targeted by an exercise called a pull down. Pull-downs can be executed with a cable machine, a Lat Pull down machine or therabands. The military press is also effective at targeting lats and shoulders.

Erector Spinae – These muscles are responsible for maintaining an erect spine and can be targeting with back extensions. This can be as simple as asking the client to stand against a wall and pull their tummy in while trying to bring their shoulders and upper back toward the wall. Back extensions can be isometric or dynamic.

The End

Don’t ignore the back of your body! It is important to maintain function and fitness as we age. A healthy back body can encourage proper body mechanics and minimize joint issues. It is especially important for seniors to strengthen their back body as, over time, these muscles can weaken more than those on the front body leading to a rounded upper back and loss of function in the low body.

Sources:

Anatomy and Strength Training for Women by Mark Vella

The Muscle Manual by Dr. Nikita A. Vizniak

NASM Essentials of Personal Fitness Training

http://fixmysportsinjury.com/index.php?p=281273

http://www.oneresult.com/articles/training/training-hamstrings-and-glutes

http://www.muscleimbalancesyndromes.com/janda-syndromes/lower-crossed-syndrome/

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