Background: High-intensity focused electromagnetic waves (HIFEM) can achieve optimal body contours by training muscle mass, strength, and toning, as well as fat reduction.
Objective: This study aimed to define the effect of HIFEM devices on muscle training and subcutaneous fat reduction.
Methods: This is the first-time report of a clinical case series by using a modified protocol. The study was a single-centre evaluation in Hong Kong, China, involving 13 participants, of whom nine were female. Each subject underwent six treatments, 1-2 times a week for 3–6 weeks, and each treatment session lasted for 60 minutes. Body contours were recorded using 2D and 3D high-resolution images. Ultrasonography was performed for standardized areas in each participant. The above assessments were performed at the first and last treatment visits, and then at the 1- and 3-month follow-up visits. Data were quantified and compared. The main outcomes were percentage improvement, satisfaction levels, and adverse events.
Results: A significant improvement in muscle thickness of the rectus abdominis with a corresponding decrease in subcutaneous fat thickness was demonstrated in the subjects. The mean decrease of subcutaneous fat was 0.31 cm (19.9%), 0.40 cm (25.6%), and 0.53 cm (34.0%) at the last visit, 1 month after the treatment, and 3 months after the treatment, respectively (p=0.017, p=0.014, and p<0.001, respectively). The rectus abdominis demonstrated a mean increase of 0.29 cm (27.8%), 0.28 cm (26.2%), and 0.28 cm (26.2%) at the last visit, 1 month after the treatment, and 3 months after the treatment, respectively (p=0.001, p=0.006, and p<0.001, respectively). No significant discomfort was reported by the subjects, and 100% of the subjects were satisfied with their results.
Conclusion: HIFEM is an effective method for training the rectus abdominis and reducing fat in the abdomen, offering participant satisfaction, comfort, and sustainability.

Keywords: body contouring, electromagnetic wave, exercise, fat reduction, high-intensity focused electromagnetic waves, muscle mass training

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