Effects of protein supplementation during pilates training on body composition, core muscle endurance, and joint flexibility in trained women: a randomized controlled trial.

Background: Pilates is a popular type of exercise, aimed at improving core muscle strength and endurance, core stability, and joint flexibility through a variety of whole-body exercises. Research has shown that Pilates improves body composition, muscle endurance, and joint flexibility. Adequate protein intake is a key factor in supporting the adaptive response of skeletal muscle to exercise training. However, whether protein supplementation augments the adaptations to Pilates training remains unknown. Thus, the aim of the present study was to investigate the effects of protein supplementation during Pilates training on body composition, core muscle endurance, and joint flexibility in trained women.

Methods: Nineteen Pilates-trained women (31 ± 9 y) performed 10 weeks of Pilates training using the Reformer and Cadillac apparatuses, at least 2 times per week. Participants were randomly allocated to either a placebo ( = 10) or protein supplementation group ( = 9) in a quadruple-blind (participants, intervention providers, investigators, and outcome assessors) design. Participants received 0.6 g of maltodextrin or whey protein per kg body weight daily, respectively. Habitual dietary intake was monitored throughout the study. Before and after the intervention, anthropometric measures (body weight, body mass index, waist and hip circumferences), body composition [through full-scan dual-energy X-ray absorptiometry (DXA) and multifrequency bioelectrical impedance analysis (BIA)], core muscle endurance (through the McGill's torso muscular endurance test battery), and joint flexibility (through the sit-and-reach test) were assessed. Data were analyzed by 2-way ANOVA (supplement × time) with repeated measures on time. Common DXA and BIA variables (whole-body fat and lean mass) were compared through paired Student's t tests and subjected to Pearson's correlation analysis. The level of statistical significance was set at α = 0.05.

Results: Participants received, on average, 1.3 g protein/kg body weight/day from their habitual diet. After 10 weeks of Pilates training and regardless of supplementation, body fat (assessed by BIA) and hip circumference decreased; lean mass, total water, and extracellular water (by BIA) increased; and arm lean mass, trunk bone mineral content, and trunk bone area (by DXA) increased (all  < 0.05). The common BIA and DXA variables were highly correlated ( > 0.78,  < 0.001) and did not differ pre-intervention ( > 0.1), although they differed post-intervention ( < 0.001), with BIA overestimating lean mass compared with DXA. Core muscle endurance and joint flexibility increased with training ( < 0.05), with no effect of supplementation.

Conclusion: Ten weeks of Pilates training improved core muscle endurance, joint flexibility, and aspects of body composition in healthy trained women, but these adaptations were not enhanced by daily supplementation with 0.6 g of protein per kilogram body weight.