Flashcards for:
Lecture on Muscle Insufficiency

Passive muscle insufficiency occurs because myosin and actin filaments are stretched too far apart, limiting cross-bridge formation, and it acts as a protective mechanism to prevent muscle damage.

Exercises such as rows, lat pull-downs, and reverse flyes can help strengthen back muscles that have been stretched due to poor posture.

Active muscle insufficiency is caused by insufficient cross-bridge formation, where myosin and actin are too close.

Poor posture can lead to muscle imbalances, with back muscles being stretched and chest muscles shortened, which can contribute to discomfort and inefficiency in movement.

To correct muscle imbalances, it is recommended to strengthen the stretched back muscles through exercises and to stretch the shortened chest muscles, such as the PEC minor and major.

In cases like spinal cord injury, passive muscle insufficiency can be utilized to enhance wrist and finger movements, such as using gravity to aid wrist flexion and extension to assist with grasping.

It is easier to touch your toes with slightly bent knees because this reduces the stretch on the hamstrings, which otherwise may limit your movement due to passive muscle insufficiency.

The hamstrings, which function to extend the hip and flex the knee, experience active muscle insufficiency because they cannot perform both movements simultaneously to their full range.

In active insufficiency, the hamstrings cannot fully extend the hip and flex the knee simultaneously. In passive insufficiency, they limit the ability to bend forward with straight knees due to being overly stretched.

A C6 spinal injury is mentioned, which leads to limited wrist flexion and finger movement issues.

Passive muscle insufficiency occurs when a muscle acts as an antagonist and is stretched, limiting its ability to produce force because myosin and actin are too far apart.

Tenodesis is the exploitation of passive insufficiency in finger extensors to assist spinal cord injury patients. For instance, gravity-induced wrist flexion stretches the finger extensors, helping to open the hand, while wrist extension creates passive insufficiency, aiding in grasping.

An example of passive muscle insufficiency is the difficulty in bending to touch toes with knees extended, which is easier when the knees are slightly bent. This happens due to the hamstrings being stretched to a point where myosin and actin filaments are too far apart.

Wrist flexion (aided by gravity) stretches finger extensors to open the hand, while wrist extension induces passive insufficiency in finger extensors to aid in grasping.

Active muscle insufficiency occurs when muscles crossing multiple joints are unable to perform both movements simultaneously to their full range due to insufficient cross-bridge formation (myosin and actin are too close).