The posterior kinetic chain is the web of interconnected muscles, ligaments and tendons that run along the backside of the body. When speaking of the posterior chain, most people are referring to the calves, hamstrings, glutes and erector spinae muscles, although some also include the muscles of the mid and upper back.
A common problem seen both among athletes and the general public is posterior chain weakness. Muscles in the front of the body – the anterior kinetic chain – tend to be stronger, tighter and shorter than muscles in the back of the body. Everyday actions or poor athletic training can cause these muscle imbalances.
Understanding muscle imbalances requires an awareness of reciprocal inhibition and opposing muscle groups. Every muscle in the body has an opposing muscle, one that performs the opposite function and is located in front, in back or to the side of it. When a signal to fire is sent to a muscle from the nervous system, a signal is also sent to deactivate the opposing muscle. This allows the first muscle to contract while the muscle that would oppose this contraction relaxes. This is called reciprocal inhibition. If one muscle is chronically tense, then, its opposite muscle will be chronically weak.
The hip flexors and glutes are opposing muscle groups. Hip flexor tightness is very common, as is gluteal weakness. Hip flexors become shortened and tight due to prolonged periods of sitting or harmful workouts like sit-ups. Gluteal weakness is proliferated by sitting as well, since the muscles are compressed in this state. The hamstrings and quadriceps form another commonly imbalanced opposing group. In everyday life as well as in popular weightlifting exercises that bulk up the legs, the quads are used more than the hamstrings.
Muscle imbalances have a number of consequences. Joints along the lower body risk injury due to the instability caused by unequal support from the front and back sides of the body. The anterior muscles exert a pull on the pelvis without a counterbalancing pull from the posterior chain, leading to pelvic tilt and increased lordosis. The resulting changes in muscle tension, vertebral joint angles and spinal disc compression make posterior chain weakness a lower back pain cause.
While a strong posterior chain is important for everyone, a couple of concerns are specific to athletes. One is maximizing power. The posterior chain contains a larger amount of fast twitch muscle fibers than anterior chain muscles; these fibers cause muscles to fire quickly and create a burst of power. Having access to this resource is important for any athlete that values speed and strength. Another concern is injury. While posterior weakness can lead to joint and lower back injuries for anyone, those who push their bodies and tax their joints to a greater degree are more at risk.
Strengthening the Posterior Chain
If you have a severe muscle imbalance, you’ll need to find a myofascial release specialist or practice self-myofascial release (SMR) to force the chronically tight muscles to relax; otherwise, they won’t allow their opposing muscles to fire and strengthen. See more on this technique at ezinearticles.com. If you wish to prevent muscle imbalances or correct minor ones, you can introduce posterior strengthening and anterior flexibility exercises into your routine.
One simple exercise to engage the glutes and hamstrings is the lunge. You can perform this exercise with weights for added challenge if desired. Doing bridges in conjunction with partial crunches will help build a solid, balanced core. Bridges engage the hamstring, gluteal and lower back muscles.
A more advanced exercise for the posterior chain is the glute-ham raise. You can see a slideshow of this exercise at www.kvusa.com. Note: If your hamstrings are weak when you attempt to do this exercise, you may end up with a pulled muscle. This is not an exercise for beginners, so work up to it.
It is important to frequently stretch your hip flexors and quadriceps to prevent them from getting and staying tight. Doing a lunge while placing the shin of the back leg on the ground and leaning forward will give you a good hip flexor stretch. The classic quadricep stretch – standing on one leg and bringing the opposite heel up to the buttocks – works well, but be careful not to pull up or outward on the raised foot; rather, press the foot into your buttocks to ensure you’re getting a proper stretch.
Balancing the strength and flexibility of your body will help you prevent injury and move more efficiently. Chronic back pain can often be resolved by correcting muscle imbalances.
This book references athletes multiple times. However, it is for anyone who wants to move better, stop pain and move on with life PAIN FREE. Dr. Kelly Starrett has this book and I believe it will be of great benefit…in fact there are SMR techniques you can use taught in his book that you can use right now.