Instructor Interpersonal Behaviours in Classical Pilates as a Pathway to Improve Blood Pressure Control and Well-being in Hypertensive Adults

A group of people with high blood pressure following a predefined Classical Pilates protocol, with neutral communication from the instructors (a regular class that takes into account safety, corrections and adaptations to the exercises, but without any specific support).

The control group will undergo the same 24-week intervention as the experimental group, with two 50-minute sessions per week, following the same classical Pilates matwork protocol described above. There is no supportive communication in this variant, instead, communication is neutral, as usual in any class. Neutral communication refers to natural communication that includes tips, technical adjustments, answers to queries and safety advice, but without any specific concerns regarding autonomy, competence or relatedness.

A group of people with high blood pressure following a predefined Classical Pilates protocol, with communication designed to support their basic psychological needs, based on Self-Determination Theory.

The intervention will last 24 weeks, and both groups (intervention and control) will follow a classical Pilates matwork programme, twice a week in 50-minute sessions. Lessons for the control and experimental groups will be conducted separately. The programme will consist of 50-minute sessions of classical Pilates matwork sequence, based on the original exercises by Joseph Pilates. In this experimental group, in addition to exercise, supportive communication (autonomy, competence and relatedness) will be introduced.

• Interpersonal behaviours

Resting SBP and diastolic blood pressure (DBP) measured with a validated automatic sphygmomanometer following 2024 ESC guidelines (three measurements, 1-2 min interval; the mean of the last two readings will be used for analysis).

Ambulatory blood pressure monitoring will not be included due to logistical and financial constraints in a small-scale study. Furthermore, as this method is uncomfortable, it may itself constitute a barrier to the study, given that three measurements must be taken within a short period of time (3 months). However, automated office blood pressure measurement, taken at rest, when carried out rigorously and in accordance with the guidelines, may offer a level of accuracy similar to that of ambulatory monitoring.

Attendance records (percent of sessions attended) and study completion rate.

The Portuguese version of the BREQ-3 assesses the regulation of motivation in exercise through 18 items, which are subdivided into six dimensions (amotivation, external regulation, introjected regulation, identified regulation, integrated regulation and intrinsic motivation), with responses given on a 5-point Likert scale, ranging from 0 ("I strongly disagree") to 4 ("I strongly agree").

The SF12v2 is a shortened version of the SF-36 (Short-Form Health Survey-36), which measures physical and mental health in relation to quality of life on a 12-item scale covering eight dimensions (physical functioning, physical role limitations, bodily pain, general health perceptions, energy/vitality, social functioning, emotional role limitations and mental health), which are summarised into two domains: the physical component summary and the mental component summary. Items are scored on a scale of 0 to 100 ("worst health state" to "best health state").

The SWLS is a subjective, self-reported well-being scale that assesses overall life satisfaction, including five short items rated on a 7-point Likert scale ranging from 1 ("strongly disagree") to 7 ("strongly agree").