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Trial registered on ANZCTR


Registration number
ACTRN12624000488505
Ethics application status
Approved
Date submitted
17/02/2024
Date registered
22/04/2024
Date last updated
22/04/2024
Date data sharing statement initially provided
22/04/2024
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effect of the blood flow restriction during low-load resistance training unit on the knee flexor muscles fatigue in recreational athletes: a randomized double-blinded placebo-controlled pilot study
Scientific title
The effect of the blood flow restriction during low-load resistance training unit on the knee flexor muscles fatigue in recreational athletes: a randomized double-blinded placebo-controlled pilot study
Secondary ID [1] 311560 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
knee injuries 332925 0
Condition category
Condition code
Physical Medicine / Rehabilitation 329637 329637 0 0
Physiotherapy
Injuries and Accidents 329638 329638 0 0
Other injuries and accidents
Musculoskeletal 329639 329639 0 0
Other muscular and skeletal disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Name of the intervention: blood flow restriction
Materials: For blood flow restriction purposes, a wireless lower limb blood flow restriction cuff with a length of 81 cm and a width of 10 cm will be used (AirBands, VALD Health, VALD Pty Ltd., Newstead QLD, Australia). Detailed information concerning the cuffs used in the study is available on the product's website: https://airbandsbfr.com.
Procedures: The cuff will be placed on the thigh of the dominant limb, at the level of the largest circumference, directly under the inguinal fold. Then, the examiner will ensure the module is facing forward, and the AirBands logo can be read the right way up. The examiner will fasten the cuff in the correct position by wrapping the cuff through the metal loop, ensuring enough room under the cuff for two fingers between the skin and the cuff and no residual air in the air bladder. Consecutively, the cuff will be paired with the AirBands App installed on the tablet (Galaxy Tab S7 SM-T870, Samsung Electronics Co., Ltd. 129, Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, Republic of Korea) via Bluetooth. Then, the cuff will be calibrated. The calibration will be carried out supine, with the relaxed knee supported on a half-moon bolster pillow. During calibration, the cuff will be inflated to automatically detect the maximal (100%) limb pressure and consecutively deflated.
The intervention will be applied during low-load resistance training for knee flexors. The unilateral low-load resistance training for dominant limb knee flexors will be performed using the isokinetic dynamometer Biodex System 4 Pro (Biodex Medical Systems, Inc., Shirley, NY, USA. The length of the lever arm will be set at 40 cm. The trunk will be stabilized using belts. The arms of the participant will be crossed on his chest, and his head will be leaning on the chair. The foot of the trained limb will be in a neutral position. Three consecutive series of alternate concentric repetitions will be performed for the extension and flexion of the knee joint; however, the resistance will be applied only for knee flexion. The pre-defined resistance will exceed 30% of the maximal isometric torque measured on a previous occasion. The three series will comprise 30, 15, and 15 repetitions consecutively, with thirty-second-long breaks between consecutive series.
Before baseline primary outcome measurement preceding the low-load resistance training for knee flexors, participants will perform a standardized warm-up on a cycle ergometer (12 minutes with a constant speed of 60 revolutions per minute and a constant load of 50 watts).
Intervention provider: The examiner, a physiotherapist with over a decade of experience in clinical practice and research, is responsible for applying the blood flow restriction and conducting the low-load resistance training for knee flexors. She has extensive experience in applying blood flow restriction using specific cuffs and isokinetic dynamometers.
Mode of delivery: face-to-face, individually.
The number of times the intervention will be delivered: once.
Duration of the intervention: through a single unit of the unilateral low-load resistance training for dominant limb knee flexors described above.
Dose: The blood flow restriction cuff will be inflated to 80% of the maximal pressure detected during the calibration.
Intervention code [1] 328014 0
Treatment: Devices
Comparator / control treatment
Two comparators will be separately provided: precisely inactive intervention (placebo) and no intervention.
a) Inactive intervention (placebo)
In the case of a placebo, a wireless lower limb blood flow restriction cuff with a length of 81 cm and a width of 10 cm will be used (AirBands, VALD Health, VALD Pty Ltd., Newstead QLD, Australia). Detailed information concerning the cuffs used in the study is available on the product's website: https://airbandsbfr.com.
The cuff will be placed on the thigh of the dominant limb, at the level of the largest circumference, directly under the inguinal fold. Then, the examiner will ensure the module is facing forward, and the AirBands logo can be read the right way up. The examiner will fasten the cuff in the correct position by wrapping the band through the metal loop, ensuring enough room under the cuff for two fingers between the skin and the cuff and no residual air in the air bladder. Consecutively, the cuff will be paired with the AirBands App installed on the tablet (Galaxy Tab S7 SM-T870, Samsung Electronics Co., Ltd. 129, Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, Republic of Korea) via Bluetooth. Then, the cuff will be calibrated. The calibration will be carried out supine, with the relaxed knee supported on a half-moon bolster pillow. During calibration, the cuff will be inflated to automatically detect the maximal (100%) limb pressure and consecutively deflated.
The inactive intervention (placebo) will be applied during low-load resistance training for knee flexors. The unilateral low-load resistance training for dominant limb knee flexors will be performed using the isokinetic dynamometer Biodex System 4 Pro (Biodex Medical Systems, Inc., Shirley, NY, USA. The length of the lever arm will be set at 40 cm. The trunk will be stabilized using belts. The arms of the participant will be crossed on his chest, and his head will be leaning on the chair. The foot of the trained limb will be in a neutral position. Three consecutive series of alternate concentric repetitions will be performed for the extension and flexion of the knee joint; however, the resistance will be applied only for knee flexion. The pre-defined resistance will exceed 30% of the maximal isometric torque measured on a previous occasion. The three series will comprise 30, 15, and 15 repetitions consecutively, with thirty-second-long breaks between consecutive series.
Before baseline primary outcome measurement preceding the low-load resistance training for knee flexors, participants will perform a standardized warm-up on a cycle ergometer (12 minutes with a constant speed of 60 revolutions per minute and a constant load of 50 watts).
Inactive intervention provider: The examiner, a physiotherapist with over a decade of experience in clinical practice and research, is responsible for applying the blood flow restriction cuff and conducting low-load resistance training for knee flexors. She has extensive experience using isokinetic dynamometers.
Mode of delivery: face-to-face, individually.
Number of times the inactive intervention will be delivered: once.
Duration of the inactive intervention: through a single unit of the unilateral low-load resistance training for dominant limb knee flexors described above.
Dose: The blood flow restriction cuff will stay uninflated.
b) No intervention
The unilateral low-load resistance training for dominant limb knee flexors will be performed using the isokinetic dynamometer Biodex System 4 Pro (Biodex Medical Systems, Inc., Shirley, NY, USA. The length of the lever arm will be set at 40 cm. The trunk will be stabilized using belts. The arms of the participant will be crossed on his chest, and his head will be leaning on the chair. The foot of the trained limb will be in a neutral position. Three consecutive series of alternate concentric repetitions will be performed for the extension and flexion of the knee joint; however, the resistance will be applied only for knee flexion. The pre-defined resistance will exceed 30% of the maximal isometric torque measured on a previous occasion. The three series will comprise 30, 15, and 15 repetitions consecutively, with thirty-second-long breaks between consecutive series.
Before baseline primary outcome measurement preceding the low-load resistance training for knee flexors, participants will perform a standardized warm-up on a cycle ergometer (12 minutes with a constant speed of 60 revolutions per minute and a constant load of 50 watts).
The examiner, a physiotherapist with over a decade of experience in clinical practice and research, is responsible for conducting low-load resistance training for knee flexors. She has extensive experience using isokinetic dynamometers.
Control group
Placebo

Outcomes
Primary outcome [1] 337428 0
The primary outcome will be the change of the surface electromyography-based knee flexor muscles fatigue index.
Timepoint [1] 337428 0
The change will be determined by comparing the results obtained at baseline (first assessment) and after the intervention (second assessment). Precisely, the first assessment will be performed at baseline, just before the low-load resistance training unit, and the second assessment will be carried out immediately after the training unit.
Secondary outcome [1] 431823 0
Occurrence of adverse events.
Timepoint [1] 431823 0
The interview will be conducted face-to-face just after the training and by phone the next day after the training.

Eligibility
Key inclusion criteria
The inclusion criteria will be as follows: male; dominant right lower limb; age 20-30 years; lack of a history of injuries or diseases in lower limbs or lower back; no pain in lower limbs or lower back; no diagnosed systematic illnesses; sports activity on a recreational level; general good health; lack of any contraindications for blood flow restriction training, precisely any heart or vessels disorders, venous thromboembolism, antiphospholipid syndrome, family history of venous thromboembolism, thrombophilia, limb infection, diabetes mellitus, cancer, history of vascular transplantation, lymphoedema, antithrombin deficiency; Body Mass Index between 18.50 and 24.99; the bilateral full range of knee active motion; bilateral knee muscles strength exceeding grade 5 in Medical Research Council Scale; bilaterally negative results of all performed special tests; the between-limb differences in knee joint and thigh circumferences less than 2 cm.
Minimum age
20 Years
Maximum age
30 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
The exclusion criteria will be as follows: female; dominant left lower limb; younger than 20 years or older than 30 years old; history of injuries or diseases in lower limbs or lower back; the presence of pain in lower limbs or lower back; diagnosed systematic illnesses; sports activity on other than recreational level; presence of any contraindications for blood flow restriction training, precisely any heart or vessels disorders, venous thromboembolism, antiphospholipid syndrome, family history of venous thromboembolism, thrombophilia, limb infection, diabetes mellitus, cancer, history of vascular transplantation, lymphoedema, antithrombin deficiency; Body Mass Index lower than 18.50 or higher than 24.99; deficiency in knee active range of motion; deficiency in knee muscles strength according to Medical Research Council Scale; positive results of all performed special tests; the between-limb differences in knee joint and thigh circumferences larger than 2 cm.

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 concealed using sealed opaque envelopes.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomization using a randomization table from a statistic book will be used.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
SPSS Statistics Version 28.0.1.0 (142) (IBM® SPSS® Statistics, Armonk, NY, USA) and Microsoft Office Excel 365 (Microsoft Corporation, Redmond, WA, USA) will be used for the statistical analysis. The arithmetic means, and standard deviations for the studied features will be calculated.
The parameter of interest will be the surface electromyography-based (sEMG-based) local fatigue index separately for the semitendinosus and biceps femoris muscles. Initially, a within-group comparison of the index obtained during the first and second assessments will be conducted. The results of the Shapiro-Wilk test will guide the choice between parametric or non-parametric tests for dependent samples.
The between-group comparison will be based on the change in the index, calculated by subtracting the value obtained during the first assessment from the value obtained during the second assessment. Following the Shapiro-Wilk test, a comparison of the change between groups will be carried out using parametric or non-parametric tests for independent samples.
The statistical significance will be set at p < 0.050.
Cohen's d will be used to indicate the size of the difference between the first and second assessment in terms of sEMG-based local fatigue index separately for the semitendinosus and biceps femoris muscles in each study group. Cohen’s d effect size will also be employed for the between-group comparisons regarding the change in the semitendinosus and biceps femoris muscle sEMG-based local fatigue index. Effect sizes of 0.2 will be considered small, 0.5, medium, and 0.8, large.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
29/03/2023
Date of last participant enrolment
Anticipated
Actual
12/04/2023
Date of last data collection
Anticipated
Actual
12/04/2023
Sample size
Target
15
Accrual to date
Final
15
Recruitment outside Australia
Country [1] 26152 0
Poland
State/province [1] 26152 0

Funding & Sponsors
Funding source category [1] 315858 0
University
Name [1] 315858 0
Funds of the Wroclaw Medical University subsidy with internal number SIMPLE: SUBZ.A470.24.075SIMPLE: SUBZ.A470.24.075.
Country [1] 315858 0
Poland
Primary sponsor type
University
Name
Wroclaw Medical University
Address
Country
Poland
Secondary sponsor category [1] 318256 0
None
Name [1] 318256 0
Address [1] 318256 0
Country [1] 318256 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 314710 0
Bioethics Committee at the Medical University of Wroclaw
Ethics committee address [1] 314710 0
J. Mikulicza-Radeckiego 4a, 50367 Wroclaw, Poland
Ethics committee country [1] 314710 0
Poland
Date submitted for ethics approval [1] 314710 0
10/02/2023
Approval date [1] 314710 0
09/03/2023
Ethics approval number [1] 314710 0
KB-192/2023

Summary
Brief summary
The present pilot study aims to explore the effects of blood flow restriction (BFR) during low-load resistance training on knee flexor muscle fatigue in recreational athletes. As a pilot investigation, our specific objectives include assessing the feasibility of the study protocol, refining methodological approaches, and obtaining preliminary data on the potential impact of BFR on knee flexor muscle fatigue index and adverse events. Also, the pilot study serves as an initial step to assess the practicality of the research protocol, identify potential challenges, and estimate effect sizes for sample size calculations in future studies.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 132478 0
Prof Aleksandra Królikowska
Address 132478 0
Ergonomics and Biomedical Monitoring Laboratory, Department of Physiotherapy, Wroclaw Medical University, Tytusa Chalubinskiego 3, 50372 Wroclaw
Country 132478 0
Poland
Phone 132478 0
+48733981189
Fax 132478 0
Email 132478 0
[email protected]
Contact person for public queries
Name 132479 0
Aleksandra Królikowska
Address 132479 0
Ergonomics and Biomedical Monitoring Laboratory, Department of Physiotherapy, Wroclaw Medical University, Tytusa Chalubinskiego 3, 50372 Wroclaw
Country 132479 0
Poland
Phone 132479 0
+48733981189
Fax 132479 0
Email 132479 0
[email protected]
Contact person for scientific queries
Name 132480 0
Aleksandra Królikowska
Address 132480 0
Ergonomics and Biomedical Monitoring Laboratory, Department of Physiotherapy, Wroclaw Medical University, Tytusa Chalubinskiego 3, 50372 Wroclaw
Country 132480 0
Poland
Phone 132480 0
+48733981189
Fax 132480 0
Email 132480 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
All data collected during the study in an anonymous form will be available from the contact person for public queries.
When will data be available (start and end dates)?
The data will be available for one year starting from 01.01.2024 until 31.12.2024. After the first year, the data will be archived.
Available to whom?
The data collected during the study in an anonymous form will be available from the contact person to any concerned party upon reasonable request.
Available for what types of analyses?
The data will be available for any analysis except for for-profit or market research purposes.
How or where can data be obtained?
[email protected]


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.