Titin Restores Sarcomere Length and Prevents Overstretching
Definition
Titin
Titin is the largest protein in the human body, spanning from the Z-discs to the myosin filaments in the sarcomere.
- It runs parallel to actin, functioning as a molecular spring that stretches and recoils.
- Its primary roles include:
- Elasticity: Titin stretches during sarcomere elongation and recoils to restore the resting length.
- Prevent Overstretching: It limits excessive extension, reducing the risk of muscle damage.
- Energy Storage: When stretched, titin stores potential energy that aids both contraction and relaxation.
- During muscle relaxation, titin’s recoil action pulls the Z-discs back.
- This process relies on passive force, as titin’s elasticity restores the sarcomere to its resting length without requiring ATP.
Titin’s elasticity is especially important during repetitive movements, such as running or jumping, where muscles are constantly stretched and contracted.
Why Muscles Need Antagonistic Pairs
Definition
Antagonistic muscles
Antagonistic muscles are pairs that work in opposition—when one contracts, the other relaxes.
