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The Effects of Restriction Pressure on Muscle Damage Responses to Blood Flow Restriction Exercise

NCT ID: NCT05037942

Last Updated: 2023-12-26

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

34 participants

Study Classification

INTERVENTIONAL

Study Start Date

2021-11-29

Study Completion Date

2022-06-28

Brief Summary

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Blood flow restriction (BFR) exercise involves the application of a constriction device to the limbs to restrict muscle blood flow during exercise. In recent years, BFR has become increasingly popular due to its additive effects on low-load resistance training, often promoting greater increases in muscle strength and size compared to similar resistance training without BFR. However, like other exercise, it is possible that BFR exercise can cause exercise-induced muscle damage (EIMD) that results in short-term reductions in muscle function and increased muscle soreness and swelling. One major variable that may influence the onset of EIMD is the restriction pressure used to restrict blood flow; however, the influence of restriction pressure on resistance EIMD is unclear.

The purpose of this study is to investigate effects of two different restriction pressures (low and high) on EIMD responses to a bout of low-load BFR resistance exercise in a sample of healthy, active adults. It is hypothesised that a higher restriction pressure will result in increased EIMD compared to a lower restriction pressure. To test this hypothesis, participants will perform a lower-body exercise protocol with and without BFR, and several markers of EIMD will be assessed before and immediately, 24, 48, and 72 hours after the exercise.

Detailed Description

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Following screening for the inclusion and exclusion criteria of the study, eligible participants will be fully informed of the study purposes and procedures and written consent will be acquired. During this study, participants will be randomly allocated into one of two experimental groups, with each group performing blood flow-restricted knee extension exercise with one leg and the same exercise protocol without BFR with the contralateral leg. Experimental groups will be differentiated by the tourniquet pressure used during the BFR condition. Several indirect markers of EIMD will be assessed at baseline and 24, 48, and 72 hours after the exercise bout. Additional neuromuscular assessments will be performed immediately post-exercise to provide insight into the fatiguability of the exercise protocol.

Participants will be required to attend the laboratory on five separate occasions: one visit for screening, assessment of limb occlusion pressure (i.e., the lowest pressure required to occlude blood flow to the limb), and familiarisation of the exercise protocol and neuromuscular assessments, one visit for completion of the exercise protocol and baseline/post-exercise tests, and three follow-up visits. All participants will be asked to refrain from alcohol and exercise from 24 hours prior to the exercise trial up to their final visit. The consumption of any pain-relieving medications (e.g., anti-inflammatory drugs) and undergoing of any muscle damage treatments (e.g., massage) will be prohibited throughout the study. To minimise the effects of pre-exercise feeding on the outcome measures, visits will be scheduled for the morning and participants will attend the lab following an overnight fast of a minimum of 10 hours, although water may be consumed ad libitum. All post-exercise measures will be collected at the same time of day ± 1 hours.

Conditions

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Muscle Damage Muscle Soreness Muscle Strength

Keywords

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Muscle Damage Muscle Soreness Muscle Strength Blood Flow Restriction

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

The study uses a within-between, unilateral design, in which participants will be randomly allocated into one of two experimental groups using a stratified random allocation technique. Each group will perform blood flow-restricted exercise with one leg and the same exercise protocol without BFR with the contralateral leg. Experimental groups will be differentiated by the tourniquet pressure used during the BFR condition: i) tourniquet pressure set to 40% of limb occlusion pressure or ii) tourniquet pressure set to 80% of limb occlusion pressure. Legs will be counterbalanced such that the BFR and control conditions in each study group contain an equal number of dominant and non-dominant legs. This study design allows comparison between the two experimental conditions (i.e., 40% vs. 80% limb occlusion pressure), while allowing participants to serve as their own control condition.
Primary Study Purpose

OTHER

Blinding Strategy

SINGLE

Outcome Assessors
Given the perceptual response that occurs under different occlusion pressures, it is difficult to mask the participant to the experimental conditions. Efforts will be made to minimise detection bias by blinding the outcome assessor to the study conditions and the timepoints from which the data has been collected.

Study Groups

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Blood flow-restricted exercise at 40% limb occlusion pressure (BFR-40)

Participants in BFR-40 will perform a lower-body exercise protocol under BFR set to 40% of the participants' relative limb occlusion pressure.

Group Type EXPERIMENTAL

Blood flow restriction at 40% limb occlusion pressure

Intervention Type OTHER

A 13-cm-wide pneumatic cuff will be applied to the most proximal portion of the chosen thigh (as determined by randomisation), immediately distal to the inguinal fold, prior to a bout of lower-body resistance exercise. The cuff will be inflated to 40% of limb occlusion pressure pressure and will remain inflated throughout the exercise (total occlusion time: \~5 mins).

Blood flow-restricted exercise at 80% limb occlusion pressure (BFR-80)

Participants in BFR-80 will perform the same lower-body BFR exercise protocol as BFR-40; however, the occlusion pressure will be set to 80% of the participants' relative limb occlusion pressure.

Group Type EXPERIMENTAL

Blood flow restriction at 80% limb occlusion pressure

Intervention Type OTHER

A 13-cm-wide pneumatic cuff will be applied to the most proximal portion of the chosen thigh (as determined by randomisation), immediately distal to the inguinal fold, prior to a bout of lower-body resistance exercise. The cuff will be inflated to 80% of limb occlusion pressure pressure and will remain inflated throughout the exercise (total occlusion time: \~5 mins).

Control for BFR-40

Participants randomised to BFR-40 will perform the same exercise protocol without BFR with the contralateral leg.

Group Type NO_INTERVENTION

No interventions assigned to this group

Control for BFR-80

Participants randomised to BFR-80 will perform the same exercise protocol without BFR with the contralateral leg.

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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Blood flow restriction at 40% limb occlusion pressure

A 13-cm-wide pneumatic cuff will be applied to the most proximal portion of the chosen thigh (as determined by randomisation), immediately distal to the inguinal fold, prior to a bout of lower-body resistance exercise. The cuff will be inflated to 40% of limb occlusion pressure pressure and will remain inflated throughout the exercise (total occlusion time: \~5 mins).

Intervention Type OTHER

Blood flow restriction at 80% limb occlusion pressure

A 13-cm-wide pneumatic cuff will be applied to the most proximal portion of the chosen thigh (as determined by randomisation), immediately distal to the inguinal fold, prior to a bout of lower-body resistance exercise. The cuff will be inflated to 80% of limb occlusion pressure pressure and will remain inflated throughout the exercise (total occlusion time: \~5 mins).

Intervention Type OTHER

Other Intervention Names

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Vascular restriction Vascular occlusion Venous restriction Vascular restriction Vascular occlusion Venous restriction

Eligibility Criteria

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Inclusion Criteria

* Recreationally active (defined as performing ≥ 150 minutes of moderate-intensity or ≥ 75 minutes of vigorous-intensity exercise per week for the past 6 months)
* Resistance-untrained (defined as performing less than 2 resistance exercise sessions per week for the past 6 months)

Exclusion Criteria

* Any history of cardiovascular (including hypertension \[diastolic \> 90 and/or systolic blood pressure \> 140 mmHg\] and peripheral arterial vascular disease), metabolic, respiratory (including severe asthma), haematological (including deep vein thrombosis and pulmonary embolism), neurological, gastrointestinal, kidney, liver, or musculoskeletal disease
* Current or previous musculoskeletal injury that may be aggravated by exercise
* Current smoker
* Recently used prescribed anti-inflammatory medication within the previous 1 month
* Self-reported or diagnosed menstrual irregularities within ≥ 3 months prior to recruitment
* Currently pregnant
Minimum Eligible Age

18 Years

Maximum Eligible Age

45 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Surrey

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Kyle Gapper

Role: PRINCIPAL_INVESTIGATOR

University of Surrey

Locations

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University of Surrey

Guildford, Surrey, United Kingdom

Site Status

Countries

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United Kingdom

References

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Patterson SD, Hughes L, Warmington S, Burr J, Scott BR, Owens J, Abe T, Nielsen JL, Libardi CA, Laurentino G, Neto GR, Brandner C, Martin-Hernandez J, Loenneke J. Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Front Physiol. 2019 May 15;10:533. doi: 10.3389/fphys.2019.00533. eCollection 2019.

Reference Type BACKGROUND
PMID: 31156448 (View on PubMed)

Lixandrao ME, Ugrinowitsch C, Berton R, Vechin FC, Conceicao MS, Damas F, Libardi CA, Roschel H. Magnitude of Muscle Strength and Mass Adaptations Between High-Load Resistance Training Versus Low-Load Resistance Training Associated with Blood-Flow Restriction: A Systematic Review and Meta-Analysis. Sports Med. 2018 Feb;48(2):361-378. doi: 10.1007/s40279-017-0795-y.

Reference Type BACKGROUND
PMID: 29043659 (View on PubMed)

de Queiros VS, Dos Santos IK, Almeida-Neto PF, Dantas M, de Franca IM, Vieira WHB, Neto GR, Dantas PMS, Cabral BGAT. Effect of resistance training with blood flow restriction on muscle damage markers in adults: A systematic review. PLoS One. 2021 Jun 18;16(6):e0253521. doi: 10.1371/journal.pone.0253521. eCollection 2021.

Reference Type BACKGROUND
PMID: 34143837 (View on PubMed)

Hyldahl RD, Hubal MJ. Lengthening our perspective: morphological, cellular, and molecular responses to eccentric exercise. Muscle Nerve. 2014 Feb;49(2):155-70. doi: 10.1002/mus.24077. Epub 2013 Dec 3.

Reference Type BACKGROUND
PMID: 24030935 (View on PubMed)

Other Identifiers

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FHMS 20-21 151 EGA

Identifier Type: -

Identifier Source: org_study_id