Energy Cost and Metabolic Intensity of Pilates Exercises in Older Adults

This is a randomized crossover acute intervention trial conducted at the Human Movement Biodynamics Laboratory, Center for Health Sciences, Universidade Estadual do Norte do Paraná (UENP), Jacarezinho, Paraná, Brazil.

Twenty older adults (men and women; aged ≥ 60 years) with at least 6 months of uninterrupted Pilates practice will be recruited. Participants will complete three experimental sessions in a randomized order (randomization.com): (1) mat Pilates, (2) equipment-based Pilates, and (3) treadmill walking at 4.8 km/h. A minimum washout of 48 hours will be observed between sessions.

Before experimental sessions, participants will undergo anthropometric assessment, body composition by dual-energy X-ray absorptiometry (DXA; Lunar Prodigy Advance), and a maximal graded treadmill test (modified Balke protocol) to determine peak VO2. Familiarization sessions will be held one week prior to data collection.

Each Pilates session will include 9 exercises: 1 stretching exercise as warm-up, 7 strengthening exercises as the main portion of the session (~50 min), and 1 stretching exercise as cool-down. Strengthening exercises will be performed in 3 sets of 10 repetitions with 1-minute rest intervals. Mat Pilates will use body weight and accessories (Swiss ball, elastic bands, foam roller, magic circle). Equipment-based Pilates will use Reformer, Cadillac, Ladder Barrel and Step Chair. The treadmill walking session will consist of 50 minutes at 4.8 km/h (1% incline), preceded by a 5-minute warm-up and followed by a 5-minute cool-down (warm-up and cool-down periods excluded from analysis).

Energy cost and metabolic intensity will be measured using the Cosmed K5 portable indirect calorimetry system (breath-by-breath). Resting metabolic rate will be estimated from the final 5 minutes of a 20-minute supine rest period before each session. Metabolic intensity will be expressed in METs using the older adult reference value (1 MET₆₀ = 2.7 mL/kg/min). Rating of perceived exertion (Borg CR-10) will be assessed after each exercise set (Pilates) or every 5 minutes (walking); session RPE will be recorded 30 minutes after session completion.

All sessions will be held between 9:00-10:00 AM in a temperature-controlled room (22°C; 40-60% relative humidity). Participants will receive a standardized pre-exercise meal (28 g carbohydrate, 12 g protein, 1.2 g fat; 174 kcal) 30 minutes before each session, following an 8-hour overnight fast.

Statistical analysis: Data normality will be assessed using the Shapiro-Wilk test. Descriptive statistics will be expressed as mean ± SD. A two-way repeated-measures ANOVA (protocol × time) will be used to compare conditions across time points. Mauchly's test will assess sphericity; Greenhouse-Geisser correction will be applied if violated. Post-hoc pairwise comparisons will use Bonferroni correction. Effect sizes will be reported as partial eta-squared (η²p). Cohen's d will be calculated for pairwise comparisons. Significance level: p < 0.05. Analyses will be performed using SPSS 25.0.