This is a chapter 2 summary of the book “Movement” by Gray Cook. Funky Muscles There are anatomically two basic types of muscles; shunt and spurt. Shunt muscles compress and produce structural integrity because the distal attachment is far from the moving joint. Spurt muscles produce movement because the distal attachment is close to the axis of rotation. While these two muscle types are present, they can vary depending on the function performed. For example, if we perform a movement in the closed chain, the spurt and shunt roles become reversed. Focusing on a single muscle group causes us to lack understanding of the supporting matrix behind superficial muscle action. Muscle function depends on body position and joint in action. We can see this point illustrated in Lombard’s paradox, which involves the coactivation of hamstrings and quadriceps when performing a sit to stand. These muscles are antagonistic to one another at their respective joints, yet movement is produced. The resultant effect is the quads and hamstrings becoming global stabilizers. Muscle activity is task specific, therefore Gray purports four types of muscles: 1) Global Stabilizers: Multi-joint muscles contracting to produce stability and static proprioceptive feedback. 2) Global Movers: Multi-joint muscles that produce movement and dynamic proprioceptive feedback. 3) Local Stabilizers: Deep segmental muscles (1-3 segments) that produce stability and static proprioceptive feedback. 4) Local Movers: Single joint muscle that produce movement and dynamic proprioception. These different muscle types require different training modalities. The example given is stabilizer muscles. These muscles cannot
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Explain Pain Section 4: Altered Central Nervous System Alarms
This is a summary of section 4 of “Explain Pain” by David Butler and Lorimer Moseley. CNS Alarms While much of talk in rehab deals with tissue injury and tissue pain, realize that the brain always makes the final decision as to whether or not you should feel pain. No brain, no pain. This sentiment does not mean that pain is not real. All pain is real. However, pain is a construct that the brain creates in order to ensure your survival. Spinal Cord Alarms When an injury occurs and the DRG receives impulses from peripheral structures or the brain, the spinal cord neurons must adapt to better uptake all these signals. In essence, the DRG becomes better at sending danger messages up to the brain. This change leads to short term increases in sensitivity to excitatory chemicals. Those stimuli that didn’t hurt before now do (allodynia) and those that used to hurt now hurt more (hyperalgesia). In persistent pain, this change continues occurring to the point where neurons that do not carry danger messages start growing into space where danger messages are taking place. Now innocuous stimuli such as grazing the skin begin hurting. The pain may be normal, but the underlying processes become abnormal. When these spinal cord alarm systems become unhealthy, the brain no longer receives an accurate message of what is going on. The alarms become magnified and distorted. The brain is told there is more damage in the tissues than is actually present. What is good is
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