Give scientific reasons: Striated muscles get fatigued rapidly.

(N/A) Striated muscles undergo rapid contraction and relaxation.
$\Rightarrow$ During intense activity,glycogen is broken down anaerobically,which leads to the accumulation of lactic acid.
- Due to the accumulation of lactic acid and the depletion of energy reserves,the muscles become unresponsive to further stimulation.
$=$ This state of temporary inability to contract is known as muscle fatigue.