Active Insufficiency: Two Examples

 

Normal hamstrings function at knee

 

 

Active insufficiency of hamstrings at knee

 

 

Active insufficiency of biceps at shoulder

 

 

Normal contraction and range versus active insufficiency of hamstrings

Normal function of hamstrings at the knee - notice:

  1. Contraction of a hip flexor to prevent hip extension by the hamstrings

  2. Hamstrings work only at the knee

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Active insufficiency - notice:

  1. No stabilization is applied at the hip; when the hamstrings contract (to flex the knee) the hip also moves into extension

  2. Hamstrings are functioning across hip and knee and run out of excursion - observe less range of motion at the knee

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Biceps functioning across all of its joints simultaneously: Active Insufficiency

  1. Biceps functions as a

  2.  

  3. Simultaneous action results in the biceps running out of excursion - resulting in incomplete range of motion at one or more of its joints

  4. If any of the following were prevented with contraction of antagonist muscles, range of motion of the two other joints would be complete:

Click on the icon and interact with the problem in the animation. This animation asks for the proximal attachment of the biceps long head. Based on its attachments to the radial tuberosity and supraglenoid tubercle, it crosses (and functions across) three joints.

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