Final answer:
The duration of the electrical current needed to cause a denervated muscle to contract can vary. A sustained electrical current is typically required. A square wave is a commonly used waveform for muscle stimulation.
Step-by-step explanation:
The duration of the electrical current needed to cause a denervated muscle to contract can vary depending on the specific circumstances and individual. In general, a sustained electrical current is needed to continuously stimulate the muscle contraction.
Regarding the waveform, a commonly used waveform for this purpose is a square wave. The square wave is characterized by its rapid rise and fall times, which allow for efficient muscle stimulation.