Answer:
When an axon (nerve) damage or destruction occurs due to injury, it will increase the sensitivity to neurotransmitter by post-synaptic muscle membrane and this process is called the denervation super-sensitivity.
Step-by-step explanation:
Basically, motor neurons releases and regulates a neurotransmitter acetylcholine at neuormuscular junction for sensitivity of the muscles. But when a nerve injured it will increase the sensitivity of muscle fiber to neurotransmitter acetylcholine. Means, after injury of nerve the muscle fiber become supersensitive to acetylcholine.