Equal-Volume Pilates Frequency in Women With Overweight and Obesity

This randomized clinical trial was designed to examine whether the weekly frequency of supervised Pilates exercise influences functional, musculoskeletal, and quality of life outcomes in women with overweight and obesity when total exercise volume is held constant.

Participants were allocated to one of two intervention groups using computer-generated randomization. One group completed a higher-frequency, shorter-duration program consisting of three supervised Pilates sessions per week over twelve weeks, while the other group completed a lower-frequency, longer-duration program consisting of two supervised sessions per week over eighteen weeks. Both groups completed an identical total of thirty-six supervised mat-based Pilates sessions, allowing exercise frequency and temporal distribution to be examined independently of total training dose.

All Pilates sessions were delivered in a supervised group setting and followed a standardized and progressive protocol. Prior to the intervention, participants attended a familiarization session during which fundamental Pilates principles, including breathing control, core activation, postural alignment, and safe execution of exercises in different positions, were introduced. Each exercise session consisted of a warm-up period, a main Pilates exercise component, and a cool-down period. The program progressed in planned phases by gradually increasing exercise complexity and challenge through changes in body position, repetition number, holding time, and stability demands, while maintaining participant safety.

Exercise intensity during sessions was monitored using the Borg Rating of Perceived Exertion (RPE) scale, with participants encouraged to remain within a moderate to moderately high perceived intensity range. Individual modifications and support were provided when necessary to accommodate physical limitations or discomfort and to ensure correct movement execution.

In addition to the supervised Pilates sessions, participants in both groups were advised to engage in walking activity on at least two non-Pilates days per week. Adherence to both Pilates sessions and walking recommendations was monitored using an exercise diary, in which attendance, perceived exertion, and any exercise-related complaints were recorded.

Outcome assessments were conducted at baseline and after completion of the intervention period by the same physiotherapist to ensure consistency. Assessments focused on functional performance, balance, anthropometric measures, physical activity level, musculoskeletal symptoms, and obesity-specific quality of life, using validated performance tests and self-reported questionnaires.

The rationale for this study was based on evidence suggesting that total training volume is a primary determinant of exercise adaptation, while the independent contribution of weekly frequency remains unclear, particularly for low-impact, neuromuscular-focused exercise modalities such as Pilates. Individuals with overweight and obesity may also experience altered recovery capacity and musculoskeletal burden, making the optimal distribution of exercise sessions clinically relevant. By equating total supervised exercise volume, this study aimed to clarify whether distributing the same exercise dose across different weekly schedules results in distinct functional or quality-of-life outcomes.

This study was conducted in accordance with ethical principles for research involving human participants, and all participants provided written informed consent prior to participation.

Inclusion criteria

• Female participants aged 18-65 years.
• Body mass index (BMI) ≥27 kg/m².
• Waist circumference >88 cm.
• Ability to ambulate independently.
• Sufficient cognitive ability to understand instructions and cooperate with assessments.
• Willingness to participate and provide written informed consent.

Exclusion criteria

• Musculoskeletal surgery within the previous six months.
• Severe cardiopulmonary disease (e.g., recent myocardial infarction or unstable angina).
• Musculoskeletal, neuromuscular, or cognitive conditions interfering with safe participation.
• Use of medications known to affect bone metabolism.
• Pregnancy.
• Presence of metallic implants or electronic devices (e.g., pacemakers).