The incorrect statement is: The more neurons involved, the more powerful the contraction.
The motor neuron cell is connected to muscle cell via synaptic cleft, where neurotransmitter is released. A motor neuron and that skeletal muscle cell form a motor unit. The muscle side of this synapse is called motor end plate. Released neurotransmitter is acetylcholine and it binds to its receptor (ACh receptor) on the motor end plate. As it binds, ion channels open, and Na+ gets into the muscle cell. This event reduces the voltage difference between the inside and outside of the cell and causes depolarization which creates a wave through the entire muscle cell (its membrane-sarcolema). As a consequence, Ca2+ is released from the sarcoplasmic reticulum which will cause the contraction of the muscle cell.
Muscles that have more motor units are capable to control force output more finely. The number of motor units determinate the force of a muscle contraction.
