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

NCT07213726 | Active Not Recruiting FDA Device

• 1 other identifier: Extended Delfi
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

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

Conditions

Blood Flow Restriction (BFR) Training Effects

Outcome Measures

Primary Outcomes (12)

• Concentration of Blood Lactate

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

  1 week after enrollment

• Concentration of Blood Lactate

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

  2 weeks after enrollment

• Concentration of Blood Lactate

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

  3 weeks after enrollment

• Concentration of Blood Lactate

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

  4 weeks after enrollment

• Concentration of Blood Lactate

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

  5 weeks after enrollment

• Concentration of Blood Lactate

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

  6 weeks after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  1 week after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  2 weeks after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  3 weeks after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  4 weeks after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  5 weeks after enrollment

• Prevalence of Hematopoietic Stem Cells

  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

  6 weeks after enrollment

Study Arms (1)

Healthy

EXPERIMENTAL

This group consists of all participants in this study. Subjects must be healthy, and gender is not a factor for enrollment.

Device: Delfi Personalized Tourniquet System

Interventions

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.

Healthy

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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

Sponsors & Collaborators

• Florida: collaborator
• Andrews Research & Education Foundation: lead

Study Sites (1)

Andrews Institute for Orthopaedics & Sports Medicine

Gulf Breeze, Florida, 32561, United States

Location

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Study Officials

• Tyler Opitz, DPT, SCS, CSCS

  Physical Therapist

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 28, 2022
• First Posted: October 9, 2025
• Study Start: August 16, 2022
• Primary Completion: November 20, 2023
• Study Completion (Estimated): November 20, 2026
• Last Updated: December 8, 2025

Record last verified: 2025-12

Locations

US (1)