What is the difference between a TENS  and an EMS?

T.E.N.S. stands for Transcutaneous Electrical Nerve Stimulation.

The key here is the NERVE part. TENS is a “pain blocker.”

TENS relieves pain in two ways. Electrical pulses pass from the machine through electrodes placed over the nerve centres. Benefit is felt firstly by blocking the pain signals normally sent to the brain through the nerve fibres, thereby interrupting the brain's awareness of pain. Secondly, the body is stimulated to increase it's own production of natural painkillers known as endorphins and enkephalins.

TENS may be able to help reduce pain and muscle spasms caused by a wide range of conditions including:

  • arthritis
  • period pain
  • knee pain
  • neck pain
  • back pain
  • sports injuries
  • osteoarthritis
  • fibromyalia

TENS machines are also widely used as a method of pain relief during labour.

E.M.S stands for Electrical Muscle Stimulation. (also known as Neuromuscular Electrical Stimulation NMES)

The key here is the waveform that it outputs is different than that of a T.E.N.S and it affects MUSCLE. A muscle stim targets muscle and stimulates them to alternately contract and relax.

In addition to having a different waveform, it also has what is called “Timing Options” including Ramp ON/OFF times, “ON/OFF” times and sometimes a “Delay.”

The ramp times are the amount of time that the unit takes in each cycle to ramp up to the maximum intensity. The ON TIME is the time that the intensity is on in each cycle and the OFF Time is the amount of time the unit is off in each cycle. The cycle repeats. This causes a muscle to slowly reach contraction (RAMP ON), stay contracted for a short period of time (ON TIME), slowly release the contraction (RAMP OFF) and then rest before the cycle repeats (OFF TIME). The timing options make it possible for the muscle stimulator to do a “pseudo exercise” for the weak muscle.

What are they used for?

  • Recovery – increase blood flow and remove lactic acid
  • Training – power, endurance, strength, size, etc.
  • Rehabilitation – building and strengthening muscle
  • Prevention – warm up before exercise
  • Appearance – muscle toning

Muscle Stimulators can be used for conditions that may result in:

  • disuse atrophy (tissue wasting)
  • restricted range of motion such as sprains
  • joint and ligament repair or reconstruction
  • knee cartilage injury (chrondomalacia patella)
  • stroke and spinal damage.
  • the re-education of partial nerve damaged muscle groups,
  • for relaxation of spastic muscles,
  • post-operative care to improve blood flow in selected muscles,
  • the maintenance of range of motion
  • a complimentary way to perform muscular training

According to research patients who benefit from NMS include those with the following conditions:

  • strokes
  • head injuries
  • neurological disorders such as multiple sclerosis, and Guillain-Barre syndrome
  • spinal injuries
  • cerebral palsy
  • joint replacements
  • tendon repairs
  • urinary and rectal incontinence
  • arthritis


In conclusion T.E.N.S. units affect NERVE endings and are used for PAIN RELIEF.

Muscle stimulators affect MUSCLE and are used to rehabilitate muscle.

Ask your doctor which modality is right for you!