Effects of an Eight-Week Reformer Pilates Intervention on Fat Percentage, Visceral Fat, and Lean Mass in Sedentary Women

Background Reformer Pilates is widely used to improve functional capacity and body composition, yet its physiological mechanisms in sedentary women remain underexplored. The spring-based resistance of the Reformer apparatus increases neuromuscular demand, enhances core activation, and elevates metabolic workload, suggesting that even short-term training may induce meaningful physiological adaptations. Methods A quasi-experimental design utilizing a single-group pretest-posttest methodology was implemented. Twenty-five inactive women aged 20 to 40 years engaged in supervised Reformer Pilates classes three times weekly for a duration of eight weeks. Body weight, body mass index (BMI), fat percentage, visceral fat score, muscle mass, and anthropometric circumferences were evaluated at baseline and post-intervention utilizing bioelectrical impedance analysis (Tanita BC-418) and standardized tape measurements. Data were examined utilizing paired-samples t-tests, with significance established at p < .05, and effect sizes computed using Cohen’s d. Results The eight-week Reformer Pilates program resulted in significant reductions in body weight, BMI, fat percentage, visceral fat, waist circumference, and arm circumference, alongside a significant increase in muscle mass (p < .05). Effect size analysis indicated small-to-moderate magnitudes of change across most parameters, supporting the practical and physiological relevance of the intervention. Conclusions A duration of eight weeks in a Reformer Pilates program resulted in significant enhancements in body composition in inactive women, decreasing fat percentage and visceral adiposity while augmenting lean mass. These findings endorse Reformer Pilates as a low-risk, accessible, and clinically pertinent exercise modality for enhancing metabolic health in sedentary female populations. Extended and regulated investigations are advised to better investigate its preventative and therapeutic efficacy.