Muscle activation sequences are the patterns of contraction and opposing relaxation of muscles needed to move joints. If the agonist muscles (the one’s that do the initial work) don’t fire off first and the secondary ones do, then imbalances occur. When muscles fire out of sequence and a secondary muscle contracts first, tightness or pain in other areas is experienced as the secondary muscles then become overused and often become tight. This is as important to the human body as is correct firing sequence of cylinders in the efficient working of a motor engine.
Incorrect sequence of muscle firing often occurs after injury to an agonist muscle which causes a person to compensate by using another muscle as the agonist. Those secondary or back-up muscles that then become overused often become tight, and the error is to simply “stretch whatever is tight”, when really what is needed is to get the primary muscles firing efficiently and to have appropriate strength endurance such that they do not quit during an activity.