Neuromuscular Electrical Stimulation for Patellar and Achilles Tendon Loading: A Scoping Review With Practical Recommendations

Abstract

OBJECTIVE: To summarize the effects of neuromuscular electrical stimulation (NMES) interventions for improving strength outcomes after injuries such as tendon ruptures and tendinopathies. DESIGN: Scoping review. LITERATURE SEARCH: A bibliographic database search was performed in PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Physiotherapy Evidence Database (PEDro), and Cochrane Library databases between June and July 2024. STUDY SELECTION CRITERIA: Data on participant demographics, study characteristics, NMES parameters, tendon-related outcomes, and study quality (PEDro scale) were extracted. DATA SYNTHESIS: We performed a scoping review on NMES parameters and dosages used for treating tendon injuries. RESULTS: Of 973 records, 10 studies (5 randomized controlled trials, 3 crossovers, 2 cohorts) involving 166 participants (82.2% male) were included. Most participants were healthy (60%), whereas others had patellar tendinopathy (20%), spinal cord injury (10%), or Achilles tendon rupture (10%). NMES parameters were well detailed; however, only 3 studies reported the dosage. Within-session, NMES alone or superimposed (NMES⁺) altered tendon loading by increasing force, strain, and stress. NMES also changed tendon mechanical properties in both the short and long term. In long-term studies, implementing NMES⁺ reduced tendinopathy symptoms and pain during tendon loading activities. One study compared NMES⁺ to heavy slow resistance training, whereas another compared NMES⁺ to baseline. PEDro scores ranged from 1 to 7. CONCLUSIONS: Studies on NMES for tendon loading were generally well documented. There is room for improvement in detailed reporting of specific dosage and evoked torque to facilitate the clinical implementation of NMES for tendon rehabilitation. J Orthop Sports Phys Ther 2025;55(7):482-494. Epub 16 June 2025. doi:10.2519/jospt.2025.13151.

Keywords: Achilles tendon; electrical stimulation; patellar tendon; physical therapy; rehabilitation.