When comparing sensory stimulation to motor stimulation in TENS, which characteristic does sensory stimulation require?

Sensory stimulation in transcutaneous electrical nerve stimulation (TENS) is designed to activate the sensory nerves without producing muscle contractions. This is primarily achieved through the application of a higher frequency of electrical stimulation. Higher frequencies in sensory stimulation (typically in the range of 50-100 Hz or more) are effective in providing pain relief through the activation of the gate control theory of pain modulation, which suggests that stimulating sensory pathways can inhibit the perception of pain.

In contrast, motor stimulation, which targets motor nerves to induce muscle contractions for therapeutic benefits, often uses lower frequencies (around 1-10 Hz) to ensure effective muscular contractions while minimizing discomfort. Therefore, the requirement for greater frequency in sensory stimulation is what differentiates it from motor stimulation. This approach helps in maximizing the effectiveness of the sensory stimulation modality, leading to improved analgesic effects without engaging motor pathways, thereby making it suitable for conditions where muscle activation may not be desired.