AK Question

Scott, can define and elaborate a little on the concept of "active insufficiency"? I must be dense, I still don't get it. Thanks.


"Active insufficiency is the diminished ability of a muscle to produce or maintain active tension."

"At the sarcomere level, this state may occur either when a msuscle is elongated to a point at which there is no overlap between the myofilaments or when the muscle is excessively shortened. Usually, this state occurs when a muscle has shortened to a point at which no further sliding of the filaments can take place."

"In many instances, muscles are arranged around a joint so that the muscle can be neither excessively elongated nor excessively shortened relative to its resting length. This arrangement is most effective for muscles that cross only one joint (one-joint muscles). Muscles that cross more than one joint (two- or multijointed muscles) may reach maximum elongation or shortening prior to the attainment of full ROM at all of the joints crossed by the muscle. Active insufficiency is most commonly encountered when the full ROM is attempted simultaneously at all joints crossed by a two- or multijointed muscle. Therefore, during active shortening a two-joint muscle will become actively insufficient at a point prior to the end of a joint range, when full ROM at all joints occurs simultaneously. Actively insufficiency may occur in one-joint muscles, but is not as common."

Norkin & Levangie, "Joint Structure & Function"

Let me know how this helps.



Yep, Scott that is exactly what I was after. Worked some of the AK principles in class last night. They worked almost too well, my training partner was REALLY squirming!