Abstract
PURPOSE: This pilot study aims to explore how skin parameters and body composition impact the tolerance to EMS (Electrical Muscle Stimulation) stimuli in women, particularly focusing on pain tolerance in response to varying intensities of EMS. This research seeks to understand what is essential for optimizing EMS applications. PATIENTS AND METHODS: The study involved 16 females (age 35.9 ± 12.3). Body composition and anthropometric measurements were taken, including BMI (Body Mass Index), weight percentage, WHtR (Waist to Height Ratio), WHR (Waist-Hip Ratio), and Bioelectrical Impedance Analysis. High-frequency ultrasound scans were conducted to assess skin parameters. The EMS stimulation was performed using an Evolvex (InMode, Israel), with applicators placed around the abdomen and intensity adjusted according to patient tolerance, recorded at the pain threshold. RESULTS: The maximum tolerated EMS stimulus varied from 12V to 55V, with a median of 33V. Body weight showed a strong positive correlation (R=0.76, p<0.001) and hip circumference (R=0.66, p<0.001) with EMS intensity. Body fat mass (R=0.61, p=0.012) and visceral fat area (R=0.55, p=0.029) were positively correlated with EMS intensity. However, no significant correlations were observed between EMS tolerance and muscle tissue parameters or total body water content. The study also found that skin structure parameters showed no significant impact on EMS tolerance. CONCLUSION: The study reveals that women's tolerance to EMS stimuli is influenced by various factors. Anthropometric parameters like hip circumference, body weight, skinfold, and BMI are strongly correlated with EMS tolerance. Body composition factors, particularly adipose tissue characteristics such as body fat mass and percentage, also significantly impact EMS intensity requirements, with no notable correlation to muscle tissue or water content. However, variations in skin structure, including thickness and density, do not significantly affect EMS tolerance. These insights are crucial for tailoring personalized EMS therapy to enhance effectiveness and comfort in both aesthetic and rehabilitative applications.