This randomized controlled trial study aims to evaluate the feasibility and preliminary efficacy of a combined inspiratory muscle training (IMT) and blood flow restriction (BFR) intervention in frail older adults. Outcomes of interest include feasibility, physical function, respiratory muscle strength, handgrip strength, five-times sit-to-stand performance, body composition, frailty level, fall efficacy, blood pressure, and adverse events.
This is a parallel randomized controlled trial. 30 participants who are older adults with frailty will be enrolled. Eligible participants who complete the baseline measurements will be randomly allocated to a combined BFR and IMT intervention group (N=15) or in the control group with BFR and sham IMT (N=15). Primary outcomes include feasibility and physical function (i.e., the Short Physical Performance Battery (SPPB), 6-minute walk test (6MWT), and Time Up and Go (TUG) test). Secondary outcomes include respiratory muscle strength, handgrip strength, five-times sit-to-stand performance, body composition, frailty level, fall efficacy, blood pressure, and adverse events. All outcomes will be assessed at baseline (T0) and immediately after the 6-week intervention period (T1) in both groups.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
30
Each session will last approximately 60 minutes and will include three components: (1) an initial 3-minute IMT exercise performed at an intensity corresponding to rating of perceived exertion (RPE) 11-13 on the Borg 6-20 scale, (2) a 50-minute low-intensity exercise program combined with BFR, and (3) a second 3-minute IMT session at the same target intensity. For the IMT, the protocol follows a progressive intensity model, starting with 30% of the maximum inspiratory pressure (MIP) in Week 1 to allow participants to become familiar with the technique. The intensity will gradually increase to a target of 60% MIP by Week 6, based on the participants' tolerance. For the BFR, during weeks 1-2, participants will train at constant loads. From weeks 2-6, training loads will be increased. Cuff pressure will be prescribed relative to the calculated arterial occlusion pressure (AOP): 50% in weeks 1-2, 60% in weeks 3-4, and 70% in weeks 5-6 for both lower- and upper-body exercises.
Participants in the control group will perform the identical BFR exercise protocol as the intervention group. However, IMT will be delivered at 2% of MIP, which is considered a sham condition and has not been shown to improve respiratory muscle function
Taipei Medical University
Taipei, Taiwan
Recruitment rate
The recruitment rate will be calculated by dividing the number of recruited participants by the number of eligible participants
Time frame: T0 = baseline; T1 = immediately after intervention
Attrition rate
Attrition rate is the proportion of randomized participants who withdraw from the study or are lost to follow-up before completing the final assessment.
Time frame: T0 = baseline; T1 = immediately after intervention
Exercise Enjoyment
Enjoyment will be assessed using a single-item Exercise Enjoyment Scale, which asks participants, "How much did you enjoy the exercise session?). Responses are rated on a 7 Likert scale ranging from 1 (not at all) to 7 (extremely)
Time frame: T0 = baseline; T1 = immediately after intervention
Short Physical Performance Battery (SPPB)
The SPPB consists of three components-standing balance, gait speed, and repeated chair stands-each scored from 0 to 4 and summed to a total score ranging from 0 (worst performance) to 12 (best performance). Lower SPPB scores indicate poorer physical function and a higher risk of adverse outcomes, with scores below 10 predictive of all-cause mortality in older adults.
Time frame: T0 = baseline; T1 = immediately after intervention
6-Minute Walk Test (6MWT)
The 6MWT will be used to assess functional exercise capacity. Participants will be instructed to walk as far as possible along a flat, straight course for 6 minutes, and the total distance is recorded.
Time frame: T0 = baseline; T1 = immediately after intervention
Time Up to Go (TUG)
The TUG test is used to assess functional mobility, balance, and fall risk in older adults, incorporating a series of dynamic activities. Participants will be instructed to rise from a chair, walk three meters at a comfortable pace, turn around, walk back to the chair, and sit down. The total time taken to complete the task is recorded, with longer times indicating poorer functional mobility and higher fall risk
Time frame: T0 = baseline; T1 = immediately after intervention
Respiratory Muscle Strength
We will use the S-Index Test to evaluate the respiratory muscle function based on maximum dynamic inspiratory pressure, which is a recommended tool developed by POWERbreathe. Participants will be advised to avoid strenuous exercise for 24h and to rest in a sitting position for 15 minutes before the assessment. Then, they performed eight inspiratory maneuvers in a standing position, divided into three to four series of two to three repetitions.
Time frame: T0 = baseline; T1 = immediately after intervention
Handgrip Strength
Handgrip strength will be evaluated to estimate the maximum upper-limb muscle function in older adults. Participants will be seated with the shoulder adducted, the elbow flexed to 90°, and the forearm and wrist in a neutral position. They will then be instructed to squeeze the dynamometer as forcefully as possible.
Time frame: T0 = baseline; T1 = immediately after intervention
Five-times sit-to-stand
The five-times sit-to-stand test is simple to administer and has been widely applied in both clinical and research settings. Participants will sit with their backs against the chair and be instructed to stand and sit five times as quickly as possible.
Time frame: T0 = baseline; T1 = immediately after intervention
Frailty level
The Clinical Frailty Scale (CFS) is a 9-point global clinical measure ranging from 1 (very fit) to 9 (terminally ill), used to classify frailty severity in older adults. A traditional Chinese version of the CFS has been validated in Taiwanese older adults, demonstrating acceptable inter-rater reliability and good criterion validity against established frailty measures
Time frame: T0 = baseline; T1 = immediately after intervention
Fall Efficacy
The short form of the Falls Efficacy Scale-International (FES-I) includes 7 items rated on a 4-point Likert scale from 1 (not at all concerned) to 4 (very concerned). The total score ranges from 7 to 28, with higher values indicating greater concern about falling
Time frame: T0 = baseline; T1 = immediately after intervention
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Adverse events
The study team will record adverse events during the intervention caused by the exercise, including falls, fractures, exercise-related pain, dizziness, muscle strain, sprains, respiratory and cardiac adverse events, and hospitalization.
Time frame: T0 = baseline; T1 = immediately after intervention
Fat mass
Fat mass will be assessed using a body composition analyzer and recorded in kilograms
Time frame: T0 = baseline; T1 = immediately after intervention
Fat-free mass
Fat-free mass will be assessed using a body composition analyzer and recorded in kilograms.
Time frame: T0 = baseline; T1 = immediately after intervention