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Trial registered on ANZCTR


Registration number
ACTRN12620001009909
Ethics application status
Approved
Date submitted
12/08/2020
Date registered
7/10/2020
Date last updated
7/10/2020
Date data sharing statement initially provided
7/10/2020
Type of registration
Prospectively registered

Titles & IDs
Public title
The impact of individualised post-exercise blood flow restriction on exercise performance and perceived recovery following strenuous resistance exercise in trained adults.
Scientific title
The effect of individualised post-exercise blood flow restriction on peak isokinetic torque, jump height, and perceived recovery after strenuous resistance exercise in a group of trained adults: A randomised controlled trial
Secondary ID [1] 301991 0
None
Universal Trial Number (UTN)
U1111-1256-6423
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Exercise performance 318553 0
Perceptual recovery status 318554 0
Condition category
Condition code
Physical Medicine / Rehabilitation 316564 316564 0 0
Other physical medicine / rehabilitation

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study will explore the effects of individualised post exercise blood flow restriction on physical performance and perceived recovery following heavy resistance exercise.

A three-armed parallel group randomised trial will be used to compare the effects of three interventions on exercise recovery: a post-exercise blood flow restriction group (PE-BFR), an active recovery group (AR), and a passive recovery group (CON). Participants will be randomised into one of the three groups with a 1:1:1 ratio. Reporting will be conducted in accordance with the CONSORT statement. The study will be approved by the University of South Australia Human Research Ethics Committee.

All participants will undergo a testing battery to obtain of isometric peak knee extension torque, time to peak torque, and countermovement jump (CMJ) height. To obtain peak isometric force and time to peak force, participants will perform three trials of isokinetic unilateral knee extensions per leg, at a speed of 60 degrees per second, with 60s breaks between trials. All trials will be using a HUMAC norm isokinetic dynamometer. During testing, hip angle will be set at 95° (85° backrest angle), with the dynamometer axis of rotation aligned with the most prominent point of the lateral femoral condyle. Participants will be asked to cross their arms on their chest and told to extend their knee as hard and fast as possible with an instructor's verbal encouragement. Isometric peak torque will be defined as the highest torque (nm) produced either leg across the six total trials. Time to peak torque will be defined as the time taken to reach maximal torque from the onset of muscular contraction (measured in ms). CMJ height will be obtained using the jump and reach method (Vertec, Sports Imports, Hilliard, OH).

Following the testing protocol proposed, all participants will undergo an isokinetic fatigue protocol, consisting of 5 sets of 10 maximal intensity concentric and eccentric knee extension and flexion repetitions set to a speed of 60 degrees per second on the Humac NORM dynamometer. Participants will be verbally encouraged to complete their repetitions ‘as hard and as fast as possible.’ All participants will get 90 seconds rest between sets.

After performing post exercise outcome measures, participants will undertake 1 of 3 recovery strategies, in accordance with their random group allocation (PE-BFR, AR, or CON). PE-BFR will lay supine in a comfortable position with occlusion cuffs (smart tools USA) fitted to the proximal thigh and inflated to a pressure corresponding with 80% of their individual limb occlusion pressure. The cuffs will remain inflated for 5 minutes, before being deflated for 5 minutes to allow for reperfusion. This will be performed three times each leg, for a total of 15 minutes occlusion per leg. Participants in PE-BFR will remain supine for a total of 30 minutes. AR will undertake 30 minutes of low intensity cycling exercise at self-regulated at an RPE of 12 in accordance to the Borgs 6-20 scale. CON will lay supine for 30 minutes with occlusion cuffs will placed on the proximal thigh, but the cuffs will not be inflated.

All participants will undergo a total of 4 sessions. The baseline testing session (baseline measures, fatigue protocol, and recovery protocol), and three follow up performance testing sessions. All sessions will be conducted by an exercise scientist. It is expected that the initial testing session will take 90 minutes. The following testing sessions will take approximately 30 minutes, as they do not include the recovery or fatigue protocols. Session attendance will be recorded by the exercise scientist to monitor testing adherence.
Intervention code [1] 318278 0
Other interventions
Comparator / control treatment
The Control group will lay supine for 30 minutes with occlusion cuffs will placed on the proximal thigh, but the cuffs will not be inflated.
Control group
Active

Outcomes
Primary outcome [1] 324691 0
Peak isokinetic torque (assessed using a HUMAC Norm Isokentic Dynamometer)
Timepoint [1] 324691 0
immediately post exercise, 1 hour post exercise (immediately after the recovery protocol), 24 hours post exercise, 48 hours post exercise, and 72 hours post exercise
Primary outcome [2] 324692 0
Time to peak torque (assessed using a HUMAC Norm Isokentic Dynamometer)
Timepoint [2] 324692 0
immediately post exercise, 1 hour post exercise (immediately after the recovery protocol), 24 hours post exercise, 48 hours post exercise, and 72 hours post exercise
Primary outcome [3] 324693 0
Countermovement jump height (assessed using a Vertec vertical jump system)
Timepoint [3] 324693 0
immediately post exercise, 1 hour post exercise (immediately after the recovery protocol), 24 hours post exercise, 48 hours post exercise, and 72 hours post exercise.
Secondary outcome [1] 385410 0
The perceived recovery status (PRS) scale measures the participants' perceived recovery (0 = very poorly recovered, 10 = very well recovered)
Timepoint [1] 385410 0
Immediately post exercise, 1 hour post exercise (immediately after the recovery protocol), 24 hours post exercise, 48 hours post exercise, and 72 hours post exercise
Secondary outcome [2] 385411 0
Measures of muscle soreness will be obtained using an adapted Visual analog scale (VAS) (0 = nothing at all, 10 = extremely high)
Timepoint [2] 385411 0
Immediately post exercise, 1 hour post exercise (immediately after the recovery protocol), 24 hours post exercise, 48 hours post exercise, and 72 hours post exercise

Eligibility
Key inclusion criteria
45 healthy adults aged 18-35 will be recruited into the study via poster advertisements placed within the Adelaide CBD. To be eligible for the study, participants must be considered low risk in accordance with the Exercise and Sports Science Australia (ESSA) adult pre-exercise screening instrument for apparently healthy adults and have a minimum of one year’s resistance training experience.
Minimum age
18 Years
Maximum age
35 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants will be excluded if they had any barriers restricting their ability to perform vigorous physical activity, such as pre-existing injury, or contraindications to exercise in accordance to ESSA pre-exercise screening instrument for apparently healthy adults

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 occur via a method of randomisation using minimisation, and be performed by a separate member of the research team who is not conducting statistical analysis.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be randomised to an intervention group (PE-BFR, AR, or CON) using a method of minimisation, with gender, age, years resistance training experience as minimisation variables.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Descriptive statistics will be computed to compare the intervention groups on background variables and baseline measures. Linear mixed models with random effects will be used to compare interventions. For participants who are lost to follow-up, missing data will be handled with multiple imputation, with subsequent sensitivity analyses to evaluate the effect of potential non-random attrition. Baseline measures and changes in outcome variables will be presented as means ± SD or 95% confidence intervals.. Effect sizes (Cohen’s d) for the outcomes will also be presented. Effect sizes will be interpreted as 0.2 (small), 0.21–0.5(medium), 0.51–0.8 (large) and 0.81–0.93 (very large). The level of significance for analyses will be set at p <0.05. All analyses will be conducted in SPSS (v25, IBM, USA).

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
19/10/2020
Actual
Date of last participant enrolment
Anticipated
1/07/2021
Actual
Date of last data collection
Anticipated
12/07/2021
Actual
Sample size
Target
45
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA
Recruitment postcode(s) [1] 30933 0
5000 - Adelaide
Recruitment postcode(s) [2] 30934 0
5001 - Adelaide

Funding & Sponsors
Funding source category [1] 306414 0
University
Name [1] 306414 0
University of South Australia
Country [1] 306414 0
Australia
Primary sponsor type
Individual
Name
Dr. Hunter Bennett
Address
University of South Australia, City East Campus, 108 North Terrace, Adelaide, South Australia, 5001.
Country
Australia
Secondary sponsor category [1] 306923 0
None
Name [1] 306923 0
None
Address [1] 306923 0
Country [1] 306923 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 306611 0
University of South Australia Human Research Ethics
Ethics committee address [1] 306611 0
108 North terrace, Adelaide, South Australia, 5001.
Ethics committee country [1] 306611 0
Australia
Date submitted for ethics approval [1] 306611 0
24/06/2020
Approval date [1] 306611 0
07/08/2020
Ethics approval number [1] 306611 0
203196

Summary
Brief summary
Post exercise blood flow restriction (PE-BFR) appears to offer a novel, ecologically viable, and practical method of enhancing recovery that is becoming increasingly common in athletic settings. In brief, PE-BFR consists of repeated brief alternating periods of blood flow restriction and reperfusion on targeted limbs, most commonly applied via an inflatable pneumatic cuff placed on the proximal most portion of the limb.

However, the effect of PE-BFR on recovery have been conflicting. In certain settings, PE-BFR has been shown to attenuate decrements in physical performance, measures of muscle damage, and perceptual measures of recovery between 24 and 72 hours after exercise. Conversely, in others, no positive effects on recovery have been observed. Irrespective of outcomes, it is important to highlight that methodological differences exist between previous studies regarding the implementation of BFR. For example, all previous methods of application used either standardised arbitrary pressures, pressures based on thigh girth, or pressures based on a percentage of systolic blood pressure – none of which align with the current recommendations of restricting blood flow using a percentage of limb occlusion pressure (LOP)

As such, this study aims to explore the effects of individualised post exercise blood flow restriction, based upon a percentage of LOP, on measures of physical performance and perceived recovery following heavy resistance training exercise.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 104458 0
Dr Hunter Bennett
Address 104458 0
University of South Australia, City East Campus, 108 North Terrace, Adelaide SA 5001
Country 104458 0
Australia
Phone 104458 0
+61 433377222
Fax 104458 0
Email 104458 0
hunter.bennett@unisa.edu.au
Contact person for public queries
Name 104459 0
Hunter Bennett
Address 104459 0
University of South Australia, City East Campus, 108 North Terrace, Adelaide SA 5001
Country 104459 0
Australia
Phone 104459 0
+61 433377222
Fax 104459 0
Email 104459 0
hunter.bennett@unisa.edu.au
Contact person for scientific queries
Name 104460 0
Hunter Bennett
Address 104460 0
University of South Australia, City East Campus, 108 North Terrace, Adelaide SA 5001
Country 104460 0
Australia
Phone 104460 0
+61 433377222
Fax 104460 0
Email 104460 0
hunter.bennett@unisa.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
8751Informed consent form    380350-(Uploaded-10-08-2020-10-19-19)-Study-related document.docx



Results publications and other study-related documents

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No documents have been uploaded by study researchers.

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