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Trial registered on ANZCTR


Registration number
ACTRN12621000350820
Ethics application status
Approved
Date submitted
27/01/2021
Date registered
26/03/2021
Date last updated
11/10/2023
Date data sharing statement initially provided
26/03/2021
Date results provided
11/10/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Do different ways of applying limb pressure alter blood flow in older adults using blood flow restricted exercise training?
Scientific title
Blood flow restricted exercise: Effect of restriction pressure prescription on peripheral blood flow and tolerability in older adults
Secondary ID [1] 303147 0
None
Universal Trial Number (UTN)
U1111-1263-7114
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cardiorespiratory function 320261 0
Vascular function 321315 0
Condition category
Condition code
Physical Medicine / Rehabilitation 318192 318192 0 0
Physiotherapy
Cardiovascular 319101 319101 0 0
Normal development and function of the cardiovascular system
Respiratory 319102 319102 0 0
Normal development and function of the respiratory system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
In this experimental study, each participant will experience four experimental conditions, randomised over two days (two conditions each day; two 90-minute sessions separated by 48 hours each). In each experimental condition, participants will perform five minutes of low intensity cycling (9-11 on the Borg Rating of Perceived Exertion Scale), using a portable cycling pedal (Dual Exercise Bike, Bodyworx, Australia) while seated in an upright chair. Prior to and during cycling, participants will have an inflatable cuff (Achedway, Australia) placed on the proximal portion of both thighs, which will be inflated to a pre-specified pressure dependant on the experimental protocol. There will be a 10-minute rest interval between each experimental condition conducted on the same day.

Experimental conditions: Four different approaches to lower limb blood flow restriction will be used. For each of the four conditions, prescription of pressure in the inflatable cuffs (Achedway, Australia) placed on the proximal portion of both thighs will differ depending upon the experimental condition where: Approach 1 (Control) = 50% of limb occlusion pressure; Approach 2 = perception of cuff tightness (rating of 7 on a 0-10 scale where 0 means ‘Not tight at all’ and 10 means ‘Unbearable tightness’); Approach 3 = pressure calculated as 1.3 x systolic blood pressure measured at rest on day one; and Approach 4 = standardised pressure of 160 mmHg.

The intervention will be delivered face-to-face in a laboratory at the City East Campus of University of South Australia by a physiotherapist with four years of clinical experience with older individuals, and more than five years of experience with blood flow restricted exercise (BFRE) in the research setting. We will record adherence to intervention using a session attendance checklist.
Intervention code [1] 319455 0
Treatment: Other
Comparator / control treatment
The aim of this study is to evaluate different methodological approaches commonly used in the prescription of restriction pressure for use in the application of BFR during exercise training interventions. Experimental Approach 1 (percentage of limb occlusion pressure) is the currently recommended approach for prescribing BFRE cuff pressure and will be considered the ‘control’ approach. In our statistical analysis, the three other approaches will be compared to Approach 1.
Control group
Active

Outcomes
Primary outcome [1] 326181 0
Change scores in peripheral blood flow (%). To assess this outcome, peripheral blood flow as assessed via sonography of the anterior and posterior tibial arteries (IU22 ultrasound machine, linear array 12-9 MHz transducer, Phillips Healthcare, Bothell, WA, USA).
Timepoint [1] 326181 0
The endpoints are peripheral blood flow change scores from baseline to immediately following exercise with inflated cuff (primary endpoint) and from baseline to immediately following cuff release.
Primary outcome [2] 326679 0
Absolute values of peripheral blood flow (ml/min). To assess this outcome, peripheral blood flow as assessed via sonography of the anterior and posterior tibial arteries (IU22 ultrasound machine, linear array 12-9 MHz transducer, Phillips Healthcare, Bothell, WA, USA).
Timepoint [2] 326679 0
The endpoints are peripheral blood flow absolute values Immediately before exercise (baseline), immediately following exercise with the cuffs inflated (primary endpoint) and immediately after cuff release.
Secondary outcome [1] 390400 0
Breathing discomfort. To assess this outcome the A1 item of the Multidimensional Dyspnea Profile will be used.
Timepoint [1] 390400 0
Immediately before exercise, at the final minute of exercise (fourth minute), immediately following exercise with inflated cuff and immediately after cuff release.
Secondary outcome [2] 390401 0
Peripheral muscle discomfort that will be assessed using a 0-10 numeric scale (0 – ‘No discomfort at all’ and 10 – ‘Unbearable discomfort’).
Timepoint [2] 390401 0
Immediately before exercise, at the final minute of exercise (fourth minute), immediately following exercise with inflated cuff and immediately after cuff release.
Secondary outcome [3] 390402 0
Perceived tightness that will be assessed using a 0-10 numeric scale (0 – ‘No tightness at all’ and 10 – ‘Unbearable tightness’).
Timepoint [3] 390402 0
Immediately before exercise, at the final minute of exercise (fourth minute), immediately following exercise with inflated cuff and immediately after cuff release.

Eligibility
Key inclusion criteria
Participants will be eligible for inclusion in this study if they are 50 years of age or greater.
Minimum age
50 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants will be excluded from the sample if have an ankle-brachial index (ABI) <0.9 or >1.4 or body-mass index (BMI) >30 Kg/m (assessed at the first visit) or self-report mobility issues limiting exercise performance or known contraindications or precautions to BFRE including major surgery within six months, use of oral contraception, family history of coagulation disorders, pulmonary embolism or deep vein thrombosis, a prior diagnosis of peripheral vascular disease, uncontrolled hypertension, Crohn’s disease, past fracture of the hip, pelvis, or femur.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be performed by contacting the holder of the allocation schedule who will br "off-site" or at central administration site.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A computerised sequence generation will be performed to define the randomisation schedule of order of approaches.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety
Statistical methods / analysis
Using a moderate effect size of 0.5, based on previous similar study (Mouser et al., 2017), and level of significance of p equal to or smaller than 0.05, a sample of 34 participants is estimated to provide 80% power. Anticipating up to 20% of participants may not complete the protocol (dropout) we aim to recruit at least 41 participants.

Data will be analysed using SPSS 23.0 software (SPSS, INC., Chicago, IL, USA) using both intention-to-treat (ITT) and per protocol (PP) approaches. All participants consenting to participate will be included in ITT analysis, irrespective of whether they complete all testing/assessment sessions. Per protocol analysis will be conducted where participants have completed the session for Approach 1 and at least one other approach. Descriptive statistics including mean, standard deviation, median and range to characterise the demographic, anthropometric (age, sex, BMI, ABI) and outcome data from each of the four methods. Shapiro-wilk test will be conducted to verify normality of data. For the primary outcome (peripheral blood flow), if data is considered normal, dependent t test will be performed to assess whether peripheral blood flow differs significantly between Approaches 2, 3 and 4 compared to Approach 1 (Wilcoxon test, if data not normally distributed). For the secondary outcomes (tolerability measures), linear regression models for each tolerability measure are planned to investigate associations between cuff pressure and tolerability measures. Level of significance will be set as p equal to or smaller than 0.05 for all analysis.

Recruitment
Recruitment status
Stopped early
Data analysis
Data analysis is complete
Reason for early stopping/withdrawal
Other reasons/comments
Other reasons
Lockdowns and restrictions due to the Coronavirus Disease 2019 (COVID-19) in South Australia disrupted the data collection.
Date of first participant enrolment
Anticipated
6/04/2021
Actual
6/04/2021
Date of last participant enrolment
Anticipated
30/07/2021
Actual
24/08/2021
Date of last data collection
Anticipated
6/08/2021
Actual
8/09/2021
Sample size
Target
41
Accrual to date
Final
25
Recruitment in Australia
Recruitment state(s)
SA
Recruitment postcode(s) [1] 32491 0
5000 - Adelaide

Funding & Sponsors
Funding source category [1] 307550 0
University
Name [1] 307550 0
University of South Australia
Country [1] 307550 0
Australia
Primary sponsor type
University
Name
University of South Australia
Address
Corner of North Terrace and, Frome Rd, Adelaide SA 5001
Country
Australia
Secondary sponsor category [1] 308705 0
None
Name [1] 308705 0
Address [1] 308705 0
Country [1] 308705 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 307616 0
Human Research Ethics Committee - University of South Australia
Ethics committee address [1] 307616 0
Ethics committee country [1] 307616 0
Australia
Date submitted for ethics approval [1] 307616 0
05/11/2019
Approval date [1] 307616 0
06/02/2020
Ethics approval number [1] 307616 0
202735

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 107874 0
Dr Elisio Pereira-Neto
Address 107874 0
University of South Australia, City East Campus, Corner of North Terrace and, Frome Rd, Adelaide SA 5001
Country 107874 0
Australia
Phone 107874 0
+61 8301 22868
Fax 107874 0
Email 107874 0
elisio.pereira_neto@mymail.unisa.edu.au
Contact person for public queries
Name 107875 0
Elisio Pereira-Neto
Address 107875 0
University of South Australia, City East Campus, Corner of North Terrace and, Frome Rd, Adelaide SA 5001
Country 107875 0
Australia
Phone 107875 0
+61 8301 22868
Fax 107875 0
Email 107875 0
elisio.pereira_neto@mymail.unisa.edu.au
Contact person for scientific queries
Name 107876 0
Elisio Pereira-Neto
Address 107876 0
University of South Australia, City East Campus, Corner of North Terrace and, Frome Rd, Adelaide SA 5001
Country 107876 0
Australia
Phone 107876 0
+61 8301 22868
Fax 107876 0
Email 107876 0
elisio.pereira_neto@mymail.unisa.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
De-identified data-set including age, gender, primary and secondary outcomes for each intervention protocol.
When will data be available (start and end dates)?
Data will be available from the last day of data collection (6th August 2021) and since this is a research for a PhD program and does not involve SA government department, the information will be stored and available for 5 years (6th August 2026).
Available to whom?
Available upon request to researchers who provide a methodologically sound proposal.
Available for what types of analyses?
For IPD meta-analysis .
How or where can data be obtained?
Data can be obtained by contacting the principal investigator and dataset will be provided by email.

Investigator: Elisio Pereira-Neto
Email: elisio.pereira_neto@mymail.unisa.edu.au


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.