Are electronic muscle stimulators (EMS) effective?

From the Guidelines

Electronic muscle stimulators (EMS) are effective for rehabilitation purposes, particularly in preventing muscle atrophy and re-educating muscles after injury, but have limited effectiveness for fitness and weight loss claims. For rehabilitation purposes, EMS can be beneficial when prescribed by healthcare professionals to prevent muscle atrophy, re-educate muscles after injury, or manage certain types of pain, as supported by studies such as 1 and 1. Typical medical EMS treatments might involve 20-30 minute sessions, 3-5 times weekly for several weeks, with electrode placement and intensity determined by a physical therapist. However, for fitness and weight loss claims, EMS devices show minimal effectiveness, as they cannot significantly build muscle strength compared to voluntary exercise, reduce body fat, or create well-defined abs as sometimes advertised, as noted in 1 and 1. This is because EMS causes involuntary muscle contractions that don't replicate the metabolic demands or neuromuscular adaptations of regular exercise. While EMS may complement a rehabilitation program, it should not replace traditional exercise for healthy individuals seeking fitness improvements. Side effects are generally mild but can include skin irritation, muscle soreness, or discomfort during use, as reported in 1. Key considerations for the use of EMS in rehabilitation include:

• Frequency: 3–7 days/week, as recommended in 1
• Objective: To increase peripheral muscle strength in severely deconditioned or bed-bound patients
• Mode: Pulse duration 200–700 ms, duty cycle 2–10 s on/4–50 s off
• Intensity: Increase intensity (mA) until a visible muscle contraction occurs or to the maximum tolerated level
• Duration: One to two sessions per day, total exercise time per day 20–60 min, as outlined in 1

From the Research

Effectiveness of Electronic Muscle Stimulators (EMS)

• Electronic muscle stimulators (EMS) have been found to be effective in improving muscle strength and function in various studies 2, 3, 4, 5, 6.
• A systematic review of 17 studies on the use of electrical stimulation (ES) for rehabilitation after anterior cruciate ligament reconstruction found a statistically significant improvement in quadriceps strength and functional outcomes 2.
• Another study found that EMS implemented during the early rehabilitation stage after ACL reconstruction was effective in maintaining and increasing muscle thickness and strength in the operated limb 3.
• EMS has also been found to be beneficial in preventing muscle atrophy and weakness in patients after ACL reconstruction 3.
• A review of the literature on neuromuscular electrical stimulation (NMES) found that it can be an effective treatment for muscle impairment, particularly in conditions such as stroke, ACL reconstruction, and knee osteoarthritis 5.
• However, the level of evidence for the efficiency of electromyostimulation is still low, and its benefits for strength gains are not significantly higher than those of traditional strengthening methods 6.

Applications of EMS

• EMS can be used in healthy subjects and in several conditions associated with muscle function loss, such as post-traumatic or postsurgery lower-limb immobilizations 6.
• It can also be used to prevent muscle atrophy and weakness in patients after ACL reconstruction 3.
• EMS has been found to be beneficial in maintaining and increasing muscle thickness and strength in the operated limb after ACL reconstruction 3.
• It can be used as a complementary tool for muscle strengthening, particularly in conditions where traditional strengthening methods are not effective 4, 6.

Recommendations for Clinical Practice

• The optimal stimulation parameters and application techniques for EMS vary depending on the condition being treated 5.
• A review of the literature on NMES found that it can be an effective treatment for muscle impairment, particularly in conditions such as stroke, ACL reconstruction, and knee osteoarthritis 5.
• Physiotherapists should use evidence-informed practice when using EMS, and follow recommended guidelines for stimulation parameters and application techniques 5.