To generate power, you need mobility. To have mobility, you need stability. Proximal stability feeds distal mobility. Instability signals the brain and nervous system to put the brakes on power output because it feels threatened. A lack of stability is a threat to your nervous system.
When dysfunctional movement patterns exist, the brain will simply choose an easier alternate path to accomplishing a given task.
When the patient complains of pain in neck for long period of time and after doing certain activities e.g pushing an object) when they have poor core muscles, the SCM activate and gradually with the repetition of task the pain triggers.
Lie on your back with your leg straight. Now tie one of your legs to strong elastic band and try to bring your knee towards the chest. If resistance is strong enough to restrict you from pulling knee into your chest, you wil start to lift neck and shoulder off the floor. You are performing the hip flexion but your neck is coming into play.Why this happens because Sternocleidomasoid have a synergistic relationship to hip flexor (read Thomas myers’ anatomy trains superficial front line) for more details).
Now if the hip flexors are not working correctly (whether they are ‘weak’ or ‘inhibited’) then the SCM will have to work extra hard.
A SCM that is working extra hard to do the job for the hip flexors will also become ‘stronger’ which may result in the muscles at the back of the neck becoming inefficient to produce force for neck .
Now if this continues then over time the SCM may develop trigger points Trigger points in the SCM have been found to cause jaw pain, earache, toothache, hearing loss, and migraines. So when hip flexors are not working efficiently, the synergistic SCM has to work more. If this continues over period of time then SCM wil have to over work and neck extensors become inefficient.
Over a period of time SCM will develop active trigger points, which have been found to cause jaw pain, earache, tooth ache, hearing loss, and headache.
So when patient comes to you with headache try to figure out the possibility of hip flexor weakness. Always Think out of box.
the treatment of overactive SCM also requires hip flexor recruitment strategy exercises.
Release SCM and activate semi spenalis and Longus Coli and psoas.
I hope you find this post helpful.