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NCT Number: NCT07213726

Quantification of Progenitor Cell Circulation Following Vascular Resistance Exercise Using Delfi Tourniquet System

The purpose of this observational study is to examine how slowing down blood flow to the legs- a practice called blood flow restriction (BFR)- during exercise by applying compression to the legs affects the way stem cells are released into the blood stream. This will be determined by drawing 6 cubic centimeters (ccs) of blood immediately post-exercise after the Delfi Personalized Tourniquet System (PTS) has been removed. 6 ccs of blood will also be taken prior to exercise and at the 20-, 40-, and 60-minute marks after exercise. The main question of this study is:

• Will the levels of stem cells extracted before and after exercise be the same if blood flow is restricted during exercise?

In this study, participants will undergo the following:

* 6 ccs of blood extracted from the forearm prior to exercise to establish a baseline * 3 exercises- seated leg extension, semi-reclined leg press, and seated hamstring curl- consisting of 4 sets of 30-15-15-15 repetitions per exercise; resistance will be set to 30% of one-rep maximum (1-RM) * Additional 6 cc blood draws will be performed immediately post-exercise and after 20, 40, and 60 minutes have elapsed

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This study is active but is not currently recruiting participants.

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Key information

Conditions

Blood Flow Restriction (BFR) Training Effects

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Andrews Institute for Orthopaedics & Sports Medicine

Gulf Breeze, Florida, 32561, United States

About this study

The proposed study is a prospective, quasi-experiment, dual-center (exercise facility and laboratory) study involving 15 healthy, male and female volunteers. A potential subject must clear the screening, consent to the procedures of this study, and complete the medical interview before proceeding with the familiarization session. The familiarization process will include an introduction to the Delfi BFR Tourniquet System (Delfi Medical Innovations Inc., Vancouver, BC) and the exercises (seated leg extension, semi-reclined leg press, seated hamstring curl) that the subject will complete. The weight each subject will use for each exercise will be determined during this time. All familiarization procedures must be completed prior to the scheduling and execution of the first of twelve experimental testing sessions.

The experimental testing sessions will occur twice a week for six weeks (12 sessions) and will involve the BFR training utilizing the Delfi BFR Tourniquet System, as further described in the Experimental Testing Session section of the treatment plan (6.2). At the beginning of the first, the sixth, and the twelfth testing sessions there will be a blood draw requiring 6 cc of blood to be taken prior to exercise. Post-exercise, at each testing session, additional 6cc blood draws will be conducted immediately post exercise (time point 0), as well as 20- , 40- , and 60 minutes after the conclusion of the workout. Following every testing session workout, finger-prick blood samples for lactate testing will be taken. These blood samples are to be taken at Time point 0- (T 0), 10-, 20-, 30-, 40-, 50-, and 60-minutes following exercise. Once the twelfth experimental testing session has been completed, the subjects will have one final session that is to take place no more than five days following the twelfth testing session. This final session will include one final blood draw of 6 cc. Throughout the duration of the study, the blood drawn will be used for obtaining a complete blood count (CBC) and for cellular analysis to quantify peripheral hematopoietic progenitor cell concentration. The blood samples collected from subject's fingers throughout the study will be used for analysis using a portable lactate analyzer. Lactate analysis will allow researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Volunteer population of healthy males and females aged 18-45.
  • Subjects consent to attending a total of 14 visits over a time span of seven to nine weeks. The breakdown of the 14 visits is as follows: 1 familiarization session, 12 experimental testing sessions, 1 final session.

Exclusion criteria

Volunteers who have medical history involving one or more of the following medical conditions:

  • Diabetes
  • Uncontrolled hypertension
  • Autoimmune disorders
  • Blood disorders
  • Ongoing infectious disease
  • Cancer
  • Any disorder requiring immunosuppression treatment
  • Steroid usage
  • Significant cardiovascular, pulmonary, hepatic, or renal disease.
  • Volunteers where 20 minutes of intense exercise is contra-indicated will also be excluded from the study.
  • Positive pregnancy test

Treatment and study plan

Delfi Personalized Tourniquet System

Device

Bilateral proximal thigh bands that will be applied and inflated to a pressure of 80% of occlusive pressure as determined by the automated tourniquet before exercise. A standard exercise session would not include any blood occlusion.

Primary outcomes

  1. Concentration of Blood Lactate

    Time frame: 1 week after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  2. Concentration of Blood Lactate

    Time frame: 2 weeks after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  3. Concentration of Blood Lactate

    Time frame: 3 weeks after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  4. Concentration of Blood Lactate

    Time frame: 4 weeks after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  5. Concentration of Blood Lactate

    Time frame: 5 weeks after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  6. Concentration of Blood Lactate

    Time frame: 6 weeks after enrollment

    Allows researchers insight into each subject's exertion level reflected by the amount of lactate found within the samples collected.

  7. Prevalence of Hematopoietic Stem Cells

    Time frame: 1 week after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

  8. Prevalence of Hematopoietic Stem Cells

    Time frame: 2 weeks after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

  9. Prevalence of Hematopoietic Stem Cells

    Time frame: 3 weeks after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

  10. Prevalence of Hematopoietic Stem Cells

    Time frame: 4 weeks after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

  11. Prevalence of Hematopoietic Stem Cells

    Time frame: 5 weeks after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

  12. Prevalence of Hematopoietic Stem Cells

    Time frame: 6 weeks after enrollment

    Technique completed using special machine that utilizes lasers to separate and quantify various content of cell samples; used in this study to determine complete blood cell count (CBC) and peripheral hematopoietic progenitor cell concentration

Sponsors and collaborators

Lead sponsor

Andrews Research & Education Foundation

Other

Collaborators

  • Florida

Registry information

Official study title

Quantification of Peripheral Hematopoietic Progenitor Cell Circulation Following Repeated Acute, Vascular Restriction Resistance Exercise Using the Delfi Tourniquet System

Important dates

Study start
2022
Primary completion
2023
Study completion
2026
First posted
Oct 9, 2025
Registry last updated
Dec 8, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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