The goal of this clinical trial is to explore how walking combined with different levels of partial blood flow restriction (BFR) affects cardiovascular, neuromuscular, and movement (kinematic) variables in older adults. The main questions it aims to answer are: Does walking with BFR increase internal effort, as shown by cardiovascular changes, and is this effect proportional to the level of restriction? Does walking with BFR temporarily reduce neuromuscular control, and is this reduction greater at higher restriction levels? Does walking with BFR change gait movement patterns? This study uses a crossover design, meaning that each participant will complete all four conditions and serve as their own control. Participants will: Take part in walking sessions under four conditions with different levels of restriction: BFR40%, BFR80%, SHAM (0% BFR), and CON (without BFR). Have their cardiovascular responses, muscle performance, and gait movement patterns measured. Report their perceptions of the sessions, including Rate of Perceived Exertion (RPE), satisfaction, and possible side effects.
This innovative research project aims to explore the effect of the novel BFR technique, combined with walking, as a non-pharmacological strategy to prevent or reverse sarcopenia and thereby improve the quality of life in sedentary older adults. BFR involves the use of a specialized pneumatic cuff to restrict venous blood flow to a muscle while partially inhibiting arterial flow, and it can be applied either at rest or in combination with exercise. The application of BFR combined with exercise has shown promise as a tool to induce favorable physiological effects at lower training doses, that is, at lower intensities (e.g., lower intensities or slower walking or running speeds), compared to active control groups. However, despite the promising benefits reported in some studies, comprehensive investigation of the cardiovascular and neuromuscular responses during BFR combined with walking remains a largely unexplored area, both in healthy participants and special populations. This knowledge gap is particularly relevant when considering the substantial benefits that older adults and individuals with mobility limitations could gain from BFR combined with walking, especially given their potential difficulty in adhering to the minimum exercise dosage requirements recommended by the World Health Organization
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
20
Participants will perform two continuous 10-minute walking bouts, separated by a 3-minute seated recovery period to allow reperfusion following BFR or pause, along a rectangular 40-meter walking circuit (15×5 m). Walking cadence will be standardized at 112 steps per minute.
Faculty of Sport of University of Porto
Porto, Porto District, Portugal
Faculty of Education of University of La Laguna
San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain
Blood pressure
Systolic, diastolic and mean blood pressure will be obtained by a photoplethysmography sensor. Units: mmHg
Time frame: 25 minutes
Heart rate
The average and maximum values will be obtained using a chest-worn heart rate sensor. Unit: beats per minute (bpm)
Time frame: 60 minutes
RR-Interval Time-Domain Metrics
Standard time-domain HRV metrics-including mean RR intervals (meanRR), the standard deviation of normal-to-normal intervals (SDNN), and the root mean square of successive differences (RMSSD)-will be derived from inter-beat interval data exported from a chest-worn heart rate sensor (epochs of 5 min). Units: milliseconds (ms).
Time frame: 60 minutes
RR-Interval Nonlinear Metric
Short-term fractal scaling (DFA α1) will be calculated from inter-beat interval data exported from a chest-worn heart rate sensor (epochs of 5 min). Units: dimensionless.
Time frame: 60 minutes
Maximum isometric strength
Maximum voluntary isometric contraction (MVIC) force during a knee-extension task will be recorded using a force-gauge device. Unit: Newtons (N)
Time frame: 10 minutes
Force steadiness
Force steadiness will be evaluated from the RMSSD of the coefficient of variation (CV) during a 30-s submaximal isometric knee-extension contraction at 30% MVIC, using a force-gauge device with data-analysis software. Unit: Percentage (%)
Time frame: 10 minutes
Arterial stiffness
It will be assessed by finger-toe pulse wave velocity (PWV) method. Units: m/s
Time frame: 25 minutes
Temporal Gait Parameters
Mean temporal gait parameters-including stride time, step time, and stance time-will be derived from IMU-based measurements. Units: milliseconds (ms).
Time frame: 20 minutes
Temporal Gait Variability
Stride-to-stride temporal variability (stride time, step time, stance time) will be computed from walking recordings collected using a wearable inertial measurement unit (IMU) equipped with a triaxial accelerometer and gyroscope. Variability will be expressed as the coefficient of variation (CV) for each temporal metric. Units: Percentage (%)
Time frame: 20 minutes
Postural Stability
Postural stability in mediolateral (ML) and anterior-posterior (AP) directions will be assessed during quiet standing under four conditions (eyes open/closed × firm/foam surface). A wearable IMU will record triaxial centre-of-mass acceleration. Stability metrics will be computed as -ln\[m/s²\], where higher values reflect lower acceleration and therefore better postural control. Units: -ln\[m/s²\]
Time frame: 10 minutes
Internal subjective load
Perceived exertion during walking will be quantified every 5 minutes using the OMNI-RES scale. Units: Points (0-10).
Time frame: 20 minutes
Adverse effects
Severity of adverse sensations (e.g., tingling, burning, numbness, fatigue, discomfort, petechiae) potentially associated with BFR will be recorded. Units: Points (0-5).
Time frame: 20 minutes
Affective Responses
Affective valence during the exercise bout will be assessed using the Visual Analogue Feeling Scale. Units: Points (-5 to +5).
Time frame: 20 minutes
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