From the Research
No, a Transcutaneous Electrical Nerve Stimulation (TENS) machine does not guarantee muscle twitching. TENS units primarily work by delivering low-voltage electrical currents through electrodes placed on the skin to stimulate nerves for pain relief. While muscle twitching can occur when using a TENS unit, especially at higher intensity settings or when electrodes are placed over motor points, it is not a necessary outcome for the device to be effective.
The most recent and highest quality study on this topic is from 2013 1, which investigated the magnitude of the current window and perception of TENS sensation at various frequencies and body sites in healthy human participants. This study found that the current window was larger for areas of muscle and soft tissue, and that TENS was most comfortable and easiest to titrate to a strong nonpainful intensity when applied over these areas.
TENS units typically operate in different modes: conventional TENS uses high-frequency, low-intensity stimulation that primarily activates sensory nerves without causing muscle contractions, while acupuncture-like TENS uses lower frequencies that may produce visible muscle twitching. The intensity and frequency settings on the TENS unit, electrode placement, and individual physiological differences all influence whether muscle twitching occurs.
For optimal pain relief, many practitioners recommend setting the TENS unit to a comfortable level where the stimulation is clearly felt but not painful or causing unwanted muscle contractions. Some studies have also suggested that longer applications of TENS may be useful in treating patients with pain and muscle spasm, although the evidence for this is not yet conclusive 2.
Key factors that influence the occurrence of muscle twitching with TENS use include:
- Intensity and frequency settings on the TENS unit
- Electrode placement
- Individual physiological differences
- Mode of TENS operation (conventional or acupuncture-like)
Overall, while muscle twitching can occur with TENS use, it is not a guaranteed outcome and is influenced by a variety of factors. The primary goal of TENS use should be to achieve optimal pain relief while minimizing unwanted side effects, such as muscle twitching.