Low back pain and quadriceps compensation. A study.

“Neuromuscular changes in the lower extremity occur while resisting knee and hip joint moments following isolated lumbar paraspinal exercise. Persons with a history of LBP seem to rely more heavily on quadriceps activity while jogging.“- Hart et al.

Recently I discussed a paper (link below) about how soleus  motoneuron pool excitability increased following lumbar paraspinal fatigue and how it may indicate a postural response to preserve lower extremity function.
Today I bring you an article of a similar sort.  This paper discusses the plausibility that a relationship exists between lumbar paraspinal muscle fatigue and quadriceps muscle activation and the subsequent changes in hip and knee function when running fatigue ensued. 

"Reduced external knee flexion, knee adduction, knee internal rotation and hip external rotation moments and increased external knee extension moments resulted from repetitive lumbar paraspinal fatiguing exercise. Persons with a self-reported history of LBP had larger knee flexion moments than controls during jogging. Neuromuscular changes in the lower extremity occur while resisting knee and hip joint moments following isolated lumbar paraspinal exercise. Persons with a history of LBP seem to rely more heavily on quadriceps activity while jogging.”- Hart et al.

Whether this or any study was perfectly performed or has validity does not matter in my discussion here today. What does matter pertaining to my dialogue here today is understanding and respecting the value of the clinical examination (and not depending on a gait analysis to determine your corrective exercise prescription and treatment). When an area fatigues and cannot stabilize itself adequately, compensation must occur to adapt. Protective postural control strategies must be attempted and deployed to stay safely upright during locomotion. The system must adapt or pain or injury may ensue, sometimes this may take months or years and the cause is not clear until clinical examination is performed. Your exam must include mobility and stability assessments, motor pattern evaluation, and certainly skill, coordination, ENDURANCE and strength assessments if you are to get a clear picture of what is driving your clients compensation and pain. 

So, if your client comes in with knee, hip or ankle pain and a history of low back pain, you might want to pull out these articles and bash them and other similar ones into your brain. Remember what I mentioned when i reviewed the soleus article ? I mentioned that the reduced ankle dorsiflexion range may be from a soleus muscle postural compensation reaction to low back pain. In today’s discussion, impairment of the hip ranges of motion or control of the knee (from quadriceps adaptive compensation) may also be related to low back pain, in this case, paraspinal fatigue.  

Sometimes the problem is from the bottom up, sometimes it is from the top down. It is what makes this game so challenging and mind numbing at times. If only it were as simple as, “you need to work on abdominal breathing”, or “you need to strengthen your core”.  If only it were that simple. 

Dr. Shawn Allen, one of the gait guys

References:
J Electromyogr Kinesiol. 2011 Jun;21(3):466-70. doi: 10.1016/j.jelekin.2011.02.002. Epub 2011 Mar 8.
Effects of paraspinal fatigue on lower extremity motoneuron excitability in individuals with a history of low back pain. Bunn EA1, Grindstaff TL, Hart JM, Hertel J, Ingersoll CD.

J Electromyogr Kinesiol. 2009 Dec;19(6):e458-64. doi: 10.1016/j.jelekin.2008.09.003. Epub 2008 Dec 16. Jogging gait kinetics following fatiguing lumbar paraspinal exercise.
Hart JM1, Kerrigan DC, Fritz JM, Saliba EN, Gansneder B, Ingersoll CD