The effects of blood flow restriction on fatigue and metabolic stress
| ISRCTN | ISRCTN28808565 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN28808565 |
- Submission date
- 20/09/2024
- Registration date
- 23/09/2024
- Last edited
- 23/09/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
This study's purpose is to examine acute responses to low-load resistance exercise while using blood flow restriction (BFR). As a type of training in which resistance or aerobic exercise is performed using an occlusive cuff on a proximal muscle, the intent of occluding venous blood flow (not arterial) is to induce an anabolic response without the requirement of higher loads. There are 3 primary mechanisms through which BFR, when used in conjunction with resistance training, is thought to stimulate anabolic responses: increased cellular swelling, enhanced metabolic stress, and increased muscle fiber recruitment. This technique has primarily been used in performance settings to promote muscle hypertrophy while utilizing lighter loads (30% of 1 repetition maximum) compared to the traditional recommendation of 70% of 1 repetition maximum, often required to induce a hypertrophic response to training. Additionally, BFR is used in clinical settings to aid in muscle recovery following immobilization or injury as a way to stimulate an anabolic response without the requirement of heavy loads. Currently, it is unknown how the physiological response of using BFR during low-load resistance training may compare to high-load resistance training without BFR. The results of this study will indicate how low-load resistance training with BFR compares to high-load resistance training without BFR in regards to the physiological response to exercise. These findings will help guide programming decisions when choosing to incorporate BFR into resistance training programs while also identifying the physiological response to this type of activity.
Who can participate?
Recreationally active male or female healthy volunteers aged between 18 and 27 years old
What does the study involve?
Participants will be randomly assigned to one of two exercise routines:
1. Low weight (30% of their maximum lift) with blood flow restriction (BFR).
2. High weight (65% of their maximum lift) without BFR.
They will be assigned using an online tool. At the start, the researchers will measure how much pressure is needed to restrict blood flow in their limbs using an automated cuff. Then, they will estimate the participants’ maximum squat weight from a test using a Smith machine.
In both routines, participants will do one set of 30 repetitions at the assigned weight, followed by three sets where they can do up to 15 repetitions, with a 2-minute rest between sets. For the BFR routine, the cuff will be inflated to 50% of the pressure needed to restrict blood flow and kept on throughout the exercise and rest periods.
What are the possible benefits and risks of participating?
The potential benefits of participating are strictly for educational purposes and to better understand how blood flow restriction influences short-term physiological responses, lower body power, and perceptions of effort. The risks are physical discomfort from the challenging strength training protocol along with the discomfort of partially occluding blood flow during exercise.
Where is the study run from?
University of Wisconsin–La Crosse
When is the study starting and how long is it expected to run for?
August 2021 and May 2022
Who is funding the study?
University of Wisconsin–La Crosse
Who is the main contact?
Dr Andrew Jagim, jagim.andrew@mayo.edu
Contact information
Public, Scientific, Principal Investigator
Director of Sports Medicine Research (Sports Medicine / Family Medicine)
Mayo Clinic Health System Franciscan Healthcare in La Crosse
800 West Ave. S.
La Crosse
WI 54601
United States of America
 ORCID ID |
0000-0002-6651-5096 |
|---|---|
| Phone | +1 7017304842 |
| jagim.andrew@mayo.edu |
Study information
| Study design | Randomized controlled within-subject cross-over trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised cross over trial |
| Study setting(s) | University/medical school/dental school |
| Study type | Other |
| Scientific title | The physiological response of low-load resistance exercise with blood flow restriction |
| Study objectives | Blood flow restriction will increase metabolic stress and lead to increases in neuromuscular fatigue. |
| Ethics approval(s) |
Approved 29/07/2021, Institutional Review Board (IRB) for the Protection of Human Subjects, University of Wisconsin - La Crosse (1725 State Street, La Crosse, 54601, United States of America; +1 608-785-8044; irb@uwlax.edu), ref: JS-57-21 |
| Health condition(s) or problem(s) studied | Impact of blood flow restriction on metabolic stress neuromuscular fatigue |
| Intervention | Using a randomized, cross-over design, participants completed one of two experimental conditions: Low load (30% of 1 repetition maximum) + Blood flow restriction (BFR; or High load (65% of 1 repetition maximum [1RM]) + non-BFR. Participants were randomized using a free online randomization tool. During baseline testing, participants had limb occlusion pressure (50%) determined using an automated, self-inflating cuff system (SmartCuffs©, Smart Tools Plus, LLC, Strongsville, OH, USA) for each limb. Following limb occlusion determination, 1RM back squat was estimated from a 3RM test using a Smith machine (Plyometric Power System; Norsearch, Australia). In both conditions, participants completed 1 set of 30 repetitions in their respective resistance training protocol, at the assigned load, and then 3 sets with a maximum number of 15 repetitions allowed in sets 2-4, with a 2-minute rest in between sets. During the BFR condition, the cuff was inflated to the determined leg-specific pressure (set at 50% of total limb occlusion pressure) and left on for the duration of the protocol including rest periods. |
| Intervention type | Device |
| Pharmaceutical study type(s) | Not Applicable |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Automated blood flow restriction cuff |
| Primary outcome measure | 1. Blood lactate measured using a Lactate Scout (Sports Resource Group, USA) handheld analysis device at baseline and following the 4th (final) set of back squat exercises 2. Vertical jump height measured using a 27” x 27” jump mat (Just Jump System, Probotics, AL, USA) at baseline and following the 4th (final) set of back squat exercises |
| Secondary outcome measures | 1. Ratings of perceived exertion measured using Borg’s 10-point ratings of perceived exertion (0-10) scale at baseline and immediately following each set of the back squat exercise 2. Hemodynamic responses measured using a mercurial sphygmomanometer (American Diagnostic Corporation, model #AD-720) before and after the back squat exercise, in addition to post-inflation of the BFR cuffs for the BFR condition only |
| Overall study start date | 25/08/2021 |
| Completion date | 15/05/2022 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 27 Years |
| Sex | Both |
| Target number of participants | 15 |
| Total final enrolment | 13 |
| Key inclusion criteria | 1. Recreationally active male or female 2. Aged between 18 and 27 years old |
| Key exclusion criteria | 1. Neuromuscular conditions 2. Risk factors for cardiovascular disease 3. Prior history of stroke or blood clots |
| Date of first enrolment | 01/09/2021 |
| Date of final enrolment | 01/10/2021 |
Locations
Countries of recruitment
- United States of America
Study participating centre
La Crosse
54601
United States of America
Sponsor information
University/education
1725 State Street
La Crosse
54601
United States of America
| Phone | +1 608 785 8044 |
|---|---|
| irb@uwlax.edu | |
| Website | https://www.uwlax.edu/ |
"ROR" |
https://ror.org/00x8ccz20 |
Funders
Funder type
University/education
No information available
Results and Publications
| Intention to publish date | 20/09/2024 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal The manuscript will be submitted to the Journal of Functional Morphology and Kinesiology |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Andrew Jagim, jagim.andrew@mayo.edu. De-identified participant-level data will be available upon request at any time after publication. Written consent was required and obtained before study participation. |
Editorial Notes
23/09/2024: Study's existence confirmed by the Institutional Review Board (IRB) for the Protection of Human Subjects, University of Wisconsin - La Crosse.
