Achilles Tendon RuptureNCT07498166
Project Tendura: The Impact of Blood Flow Restriction Resistance Training (BFR-RT) in Patients With Achilles Tendon Rupture (ATR) Repair
A study testing Blood Flow Restriction Resistance Training (BFR-RT) and Standard Physical Therapy in people with Achilles Tendon Rupture and Blood Flow Restriction Therapy, run by Massachusetts General Hospital at 1 site in United States.
Trial summary
The goal of this clinical trial is to determine whether blood flow restriction resistance training (BFR-RT) improves postoperative muscle recovery and functional outcomes following primary surgical repair of acute Achilles tendon rupture (ATR) in adults undergoing standard rehabilitation. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Achilles Tendon Rupture, Blood Flow Restriction Therapy, Achilles Tendon Repairs/Reconstructions
- What is being tested?
- Blood Flow Restriction Resistance Training (BFR-RT) and Standard Physical Therapy
- Type of treatment
- Medical device, Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 75 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Feb 2026to 1 Feb 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18 to 75 years
- Acute unilateral midportion Achilles tendon rupture
- Primary surgical repair performed within 2 weeks of injury
- Willingness and ability to comply with the postoperative rehabilitation protocol and follow-up schedule
Who cannot join
- Cognitive impairment or inability to follow study instructions
- Planned postoperative follow-up at another institution
- Use of fluoroquinolone antibiotics or systemic corticosteroids within the past 6 months
- Previous Achilles tendon rupture in either limb
- Simultaneous bilateral Achilles tendon rupture
- History of venous thromboembolism (deep venous thrombosis or pulmonary embolism)
Show all 21Show fewer
- Diabetes mellitus
- Reduced lower extremity function due to conditions other than Achilles tendon rupture
- Uncontrolled hypertension
- Peripheral vascular disease or ankle-brachial index less than 1.0
- Chronic kidney disease or heart failure with lower extremity edema
- Lower extremity dialysis access
- Lower extremity thrombophlebitis
- Active cancer or ongoing chemotherapy treatment
- Prior lymphadenectomy
- Tumor or malignancy affecting the lower extremities
- Hemophilia or other major bleeding disorders
- Factor V Leiden mutation or known thrombophilia
- Sickle cell anemia
- Pregnancy
- Surgery within the previous month
Trial locations and contacts
1 site in 1 country.
United States1 site
Massachusetts General Hospital, Department of Orthopaedics
Boston, Massachusetts, 02114
About this study
The goal of this clinical trial is to determine whether blood flow restriction resistance training (BFR-RT) improves postoperative muscle recovery and functional outcomes following primary surgical repair of acute Achilles tendon rupture (ATR) in adults undergoing standard rehabilitation. The main questions it aims to answer are:
Does patient-specific BFR-RT improve ankle plantarflexion strength recovery compared with sham BFR-RT or standard rehabilitation alone?
Read more
Does BFR-RT improve gastrocnemius-soleus muscle morphology and patient-reported functional outcomes following ATR repair?
Researchers will compare (1) BFR-RT combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, and (3) standard physical therapy alone to determine whether BFR-RT enhances muscle recovery, functional outcomes, and return-to-activity timelines following surgical ATR repair.
Participants will:
Be randomized to BFR-RT + standard physical therapy, sham BFR-RT + standard physical therapy, or standard physical therapy alone
Perform supervised rehabilitation exercises using a personalized tourniquet system calibrated to limb occlusion pressure (LOP) depending on group allocation
Undergo isometric ankle plantarflexion strength testing using the Fysiometer platform
Receive ultrasound imaging of the gastrocnemius-soleus complex to assess muscle cross-sectional area
Complete patient-reported outcome measures assessing pain and physical function
Attend follow-up evaluations at 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Read the detailed description
Achilles tendon rupture (ATR) is a common musculoskeletal injury that frequently results in prolonged functional impairment despite successful surgical repair. Even with modern operative techniques and standardized rehabilitation protocols, many patients demonstrate persistent weakness of the gastrocnemius-soleus complex, deficits in ankle plantarflexion strength, and delayed return to activity. These deficits are thought to arise from a combination of postoperative immobilization, restricted early loading, and muscle atrophy during the early phases of recovery. Conventional postoperative rehabilitation protocols typically emphasize gradual progression of low-load resistance training to protect the healing tendon. While these protocols prioritize tendon safety, they may provide insufficient mechanical and metabolic stimulus to promote optimal muscle hypertrophy and neuromuscular recovery during the early postoperative period.
Blood flow restriction resistance training (BFR-RT) has emerged as a potential strategy to enhance muscular adaptation while using low mechanical loads. By applying controlled external pressure to the proximal limb during exercise, BFR-RT produces localized hypoxia and metabolic stress that can stimulate anabolic signaling pathways associated with muscle hypertrophy and strength gains. Prior studies in orthopedic and sports rehabilitation settings-including anterior cruciate ligament reconstruction and chronic Achilles tendinopathy-have demonstrated that low-load BFR-RT can produce physiologic adaptations comparable to traditional high-load resistance training while minimizing mechanical stress on healing tissues. However, the efficacy and safety of BFR-RT during the early rehabilitation period following primary ATR repair have not been evaluated in a prospective randomized clinical trial.
This study is designed as a prospective, three-arm randomized controlled trial to evaluate whether integrating BFR-RT into postoperative ATR rehabilitation improves early muscle recovery and functional outcomes while maintaining an acceptable safety profile. Participants undergoing primary surgical repair for an acute unilateral mid-portion ATR will be randomized to one of three rehabilitation protocols: BFR-RT combined with standard physical therapy, sham BFR-RT combined with standard physical therapy, or standard physical therapy alone. The BFR intervention will be delivered using a personalized tourniquet system that determines limb occlusion pressure for each participant to standardize vascular restriction and minimize inter-individual variability in occlusion levels.
Participants will undergo standardized postoperative rehabilitation and will be followed longitudinally over a 12-month recovery period. Clinical assessments will be performed at predefined postoperative intervals to evaluate physiologic recovery of the gastrocnemius-soleus complex and patient-centered functional outcomes. Safety monitoring will include systematic documentation of potential adverse events associated with postoperative rehabilitation or vascular restriction techniques.
By evaluating the physiologic and clinical effects of patient-specific BFR-RT following surgical ATR repair, this study aims to generate evidence regarding whether low-load metabolic training can safely accelerate muscle recovery and improve functional rehabilitation outcomes in this population. Findings from this trial may inform future postoperative rehabilitation protocols and help define the role of BFR-RT as an adjunctive strategy in tendon repair recovery pathways.
- Conditions
- Achilles Tendon Rupture, Blood Flow Restriction Therapy, Achilles Tendon Repairs/Reconstructions, Dynamic Blood Flow Restriction
- Being tested
- Blood Flow Restriction Resistance Training (BFR-RT), Sham Blood Flow Restriction, Standard Physical Therapy
- Keywords
- Achilles Tendon, Tendon Injuries, Blood Flow Restriction Training, Achilles Rehabilitation, Postoperative Physical Therapy, Hypoxic Muscle Recovery
- Medical subject headings
- Tendon Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blood Flow Restriction Resistance Training (BFR-RT)Device
Also called Delfi Personalized Tourniquet System
Blood flow restriction resistance training will be performed using the Delfi Personalized Tourniquet System applied to the affected limb during supervised rehabilitation exercises. The device automatically determines limb occlusion pressure (LOP) and applies 80% of LOP during low-load resistance exercises. This controlled vascular restriction produces metabolic stress intended to stimulate muscle hypertrophy and strength recovery while minimizing mechanical load on the healing Achilles tendon. Sessions are conducted under physiotherapist supervision within the standardized postoperative rehabilitation protocol.
Sham Blood Flow RestrictionDevice
Participants assigned to the sham group will wear the Delfi tourniquet cuff during rehabilitation sessions; however, cuff pressure will be inflated only to 20 mmHg, a level insufficient to induce vascular occlusion. This condition mimics the experience of the intervention device while avoiding physiologic blood flow restriction, thereby controlling for potential placebo effects associated with device use.
Standard Physical TherapyBehavioural
Also called Standard Postoperative Achilles Rehabilitation Protocol
Participants will undergo the standardized postoperative Achilles tendon rehabilitation program used at Massachusetts General Hospital. The protocol includes progressive weight-bearing, range-of-motion exercises, strengthening maneuvers, and return-to-sport progression phases supervised by trained physiotherapists.
| Study group | Role | What they receive |
|---|---|---|
| Blood Flow Restriction Resistance Training + Standard Physical Therapy | Experimental | Participants receive standard postoperative Achilles tendon rehabilitation combined with blood flow restriction resistance training using the Delfi Personalized Tourniquet System. Cuffs are calibrated to 80% limb occlusion pressure to induce controlled vascular restriction during low-load resistance exercises. All sessions are supervised by trained physiotherapists following the standardized Massachusetts General Hospital Achilles rehabilitation protocol. Receives: Device: Blood Flow Restriction Resistance Training (BFR-RT); Behavioral: Standard Physical Therapy |
| Sham Blood Flow Restriction + Standard Physical Therapy | Sham comparator | Participants receive the same standardized postoperative rehabilitation protocol while wearing Delfi tourniquet cuffs inflated to 20 mmHg, a pressure insufficient to induce blood flow restriction. This sham condition controls for potential placebo effects associated with the device while maintaining identical exercise protocols and therapist supervision. Receives: Device: Sham Blood Flow Restriction; Behavioral: Standard Physical Therapy |
| Standard Physical Therapy Alone | Active comparator | Participants undergo the standardized Massachusetts General Hospital postoperative Achilles tendon rehabilitation program including range-of-motion exercises, progressive strengthening, and return-to-sport phases. No blood flow restriction device is used during rehabilitation sessions. Receives: Behavioral: Standard Physical Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Achilles Tendon Total Rupture Score (ATRS)
The Achilles Tendon Total Rupture Score (ATRS) is a validated patient-reported outcome instrument used to assess symptoms and physical function following Achilles tendon rupture. The score ranges from 0 to 100, with higher scores indicating better function and fewer symptoms.
Measured: 12 months postoperatively
Secondary outcomes (12)
Ankle Plantarflexion Isometric Strength (Limb Symmetry Index)
Isometric ankle plantarflexion strength will be measured using the Fysiometer platform. Results will be expressed as limb symmetry index (LSI), calculated as the ratio of injured limb strength to contralateral limb strength expressed as a percentage.
Measured: 3 months, 4.5 months, 6 months, and 12 months postoperatively
Gastrocsoleus Muscle Cross-Sectional Area
Cross-sectional area of the gastrocnemius-soleus muscle complex measured using portable ultrasound imaging to quantify muscle morphology and recovery following Achilles tendon repair.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Visual Analog Scale (VAS) Pain Score
Pain intensity will be measured using a 10-point Visual Analog Scale (VAS), where 0 represents no pain and 10 represents the worst possible pain. Higher scores indicate greater pain severity.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference Score
Pain interference will be measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference questionnaire. Scores are reported as T-scores with a mean of 50 and standard deviation of 10 in the general population; scores range from approximately 41 to 77, with higher scores indicating greater pain interference with daily activities.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Score
Physical function will be assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function questionnaire, which evaluates the participant's ability to perform physical activities. Scores are reported as T-scores with a mean of 50 and standard deviation of 10 in the general population; higher scores indicate better physical function.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Foot and Ankle Ability Measure (FAAM)
The Foot and Ankle Ability Measure (FAAM) is a validated patient-reported outcome instrument assessing functional limitations related to foot and ankle conditions. Scores range from 0 to 100, with higher scores indicating greater functional ability.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Single-Leg Heel Rise Test
Functional calf endurance will be evaluated using the single-leg heel rise test measuring the number of heel raises completed on the affected limb.
Measured: 3 months, 4.5 months, 6 months, and 12 months postoperatively
Single-Leg Heel Rise Height
Heel rise height will be measured during the single-leg heel rise test to assess plantarflexion strength and functional calf performance.
Measured: 3 months, 4.5 months, 6 months, and 12 months postoperatively
International Physical Activity Questionnaire - Short Form (IPAQ-SF)
Physical activity levels will be assessed using the International Physical Activity Questionnaire - Short Form (IPAQ-SF), which evaluates participant activity levels across multiple domains.
Measured: 6 months and 12 months postoperatively
EQ-5D-5L Quality of Life Score
Health-related quality of life will be assessed using the EQ-5D-5L (EuroQol 5-Dimension 5-Level) questionnaire. The EQ-5D-5L index score ranges from 0 to 1, with higher scores indicating better health-related quality of life. A visual analogue scale (VAS) component ranges from 0 to 100, with higher scores indicating better self-rated health.
Measured: 6 months and 12 months postoperatively
Ankle Range of Motion
Active and passive ankle plantarflexion and dorsiflexion range of motion will be measured bilaterally using a goniometer.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Calf Circumference
Bilateral calf circumference measurements will be obtained to assess muscle atrophy and recovery following Achilles tendon repair.
Measured: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Mar 2026
- Study start1 Feb 2026
- Primary completion31 Dec 2026 (estimated)
- Study completion1 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (11)Papers the sponsor has linked to this study.
- Other trials for Achilles Tendon RuptureStudies of the same condition, open and under way.
- More trials run by Massachusetts General HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study is a prospective, three-arm, parallel-group randomized controlled trial with a 1:1:1 allocation ratio. Participants undergoing primary surgical repair of an acute unilateral midportion Achilles tendon rupture will be randomly assigned to one of three groups: (1) blood flow restriction resistance training (BFR-RT) combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, or (3) standard physical therapy alone. The intervention and sham groups will use a Delfi Personalized Tourniquet System calibrated to 80% limb occlusion pressure and 20 mmHg, respectively. All participants will follow an identical postoperative rehabilitation protocol and will be assessed longitudinally at predefined postoperative time points over a 12-month follow-up period. Outcomes will be compared between groups to evaluate the efficacy and safety of BFR-RT in postoperative Achilles tendon rupture rehabilitation.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 75 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Massachusetts General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Diana L. Bejarano Pineda, Massachusetts General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07498166
- Sponsor's protocol ID
- IRB#2026P000071
- Status last verified
- Mar 2026
- First submitted
- 23 Mar 2026
- Last updated
- 1 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No: There are no current plans to share individual participant data. Data generated in this investigator-initiated study are subject to institutional data governance and participant privacy protections, and the study team has elected not to make IPD publicly available at this time.
Publications
O'Neill S, Weeks A, Norgaard JE, Jorgensen MG. Validity and intrarater reliability of a novel device for assessing Plantar flexor strength. PLoS One. 2023 Mar 31;18(3):e0282395. doi: 10.1371/journal.pone.0282395. eCollection 2023.
PubMed 37000780Callanan MC, Plummer HA, Chapman GL, Opitz TJ, Rendos NK, Anz AW. Blood Flow Restriction Training Using the Delfi System Is Associated With a Cellular Systemic Response. Arthrosc Sports Med Rehabil. 2020 Dec 27;3(1):e189-e198. doi: 10.1016/j.asmr.2020.09.009. eCollection 2021 Feb.
PubMed 33615264Rolnick N, Licameli N, Moghaddam M, Marquette L, Walter J, Fedorko B, Werner T. Autoregulated and Non-Autoregulated Blood Flow Restriction on Acute Arterial Stiffness. Int J Sports Med. 2024 Jan;45(1):23-32. doi: 10.1055/a-2152-0015. Epub 2023 Aug 10.
PubMed 37562444Hwang PS, Willoughby DS. Mechanisms Behind Blood Flow-Restricted Training and its Effect Toward Muscle Growth. J Strength Cond Res. 2019 Jul;33 Suppl 1:S167-S179. doi: 10.1519/JSC.0000000000002384.
PubMed 30011262Centner C, Jerger S, Lauber B, Seynnes O, Friedrich T, Lolli D, Gollhofer A, Konig D. Similar patterns of tendon regional hypertrophy after low-load blood flow restriction and high-load resistance training. Scand J Med Sci Sports. 2023 Jun;33(6):848-856. doi: 10.1111/sms.14321. Epub 2023 Feb 3.
PubMed 36703264Centner C, Lauber B, Seynnes OR, Jerger S, Sohnius T, Gollhofer A, Konig D. Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training. J Appl Physiol (1985). 2019 Dec 1;127(6):1660-1667. doi: 10.1152/japplphysiol.00602.2019. Epub 2019 Nov 14.
PubMed 31725362Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, Ferris G, Dawes J, Paton B, Patterson SD. Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial. Sports Med. 2019 Nov;49(11):1787-1805. doi: 10.1007/s40279-019-01137-2.
PubMed 31301034Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. Br J Sports Med. 2017 Jul;51(13):1003-1011. doi: 10.1136/bjsports-2016-097071. Epub 2017 Mar 4.
PubMed 28259850Eliasson P, Agergaard AS, Couppe C, Svensson R, Hoeffner R, Warming S, Warming N, Holm C, Jensen MH, Krogsgaard M, Kjaer M, Magnusson SP. The Ruptured Achilles Tendon Elongates for 6 Months After Surgical Repair Regardless of Early or Late Weightbearing in Combination With Ankle Mobilization: A Randomized Clinical Trial. Am J Sports Med. 2018 Aug;46(10):2492-2502. doi: 10.1177/0363546518781826. Epub 2018 Jul 2.
PubMed 29965789Heikkinen J, Lantto I, Piilonen J, Flinkkila T, Ohtonen P, Siira P, Laine V, Niinimaki J, Pajala A, Leppilahti J. Tendon Length, Calf Muscle Atrophy, and Strength Deficit After Acute Achilles Tendon Rupture: Long-Term Follow-up of Patients in a Previous Study. J Bone Joint Surg Am. 2017 Sep 20;99(18):1509-1515. doi: 10.2106/JBJS.16.01491.
PubMed 28926379Mashimo S, Nozaki T, Amaha K, Tanaka K, Kubota J, Sato H, Kitamura N. Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study. Am J Sports Med. 2023 Dec;51(14):3781-3789. doi: 10.1177/03635465231206391. Epub 2023 Nov 13.
PubMed 37960840
Study at a glance
From the registry record, last updated by the sponsor on 1 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Project Tendura: The Impact of Blood Flow Restriction Resistance Training (BFR-RT) in Patients With Achilles Tendon Rupture (ATR) Repair
- ClinicalTrials.gov ID
- NCT07498166
- Acronym / sponsor ID
- IRB#2026P000071
- Conditions
- Achilles Tendon Rupture, Blood Flow Restriction Therapy, Achilles Tendon Repairs/Reconstructions, Dynamic Blood Flow Restriction
- Keywords
- Achilles Tendon, Tendon Injuries, Blood Flow Restriction Training, Achilles Rehabilitation, Postoperative Physical Therapy, Hypoxic Muscle Recovery
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 75 participants (estimated)
- Lead sponsor
- Massachusetts General HospitalUniversity, hospital or other
- Study start
- 1 Feb 2026 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 1 Feb 2027 (estimated)
- First posted
- 27 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to determine whether blood flow restriction resistance training (BFR-RT) improves postoperative muscle recovery and functional outcomes following primary surgical repair of acute Achilles tendon rupture (ATR) in adults undergoing standard rehabilitation. The main questions it aims to answer are:
Does patient-specific BFR-RT improve ankle plantarflexion strength recovery compared with sham BFR-RT or standard rehabilitation alone?
Does BFR-RT improve gastrocnemius-soleus muscle morphology and patient-reported functional outcomes following ATR repair?
Researchers will compare (1) BFR-RT combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, and (3) standard physical therapy alone to determine whether BFR-RT enhances muscle recovery, functional outcomes, and return-to-activity timelines following surgical ATR repair.
Participants will:
Be randomized to BFR-RT + standard physical therapy, sham BFR-RT + standard physical therapy, or standard physical therapy alone
Perform supervised rehabilitation exercises using a personalized tourniquet system calibrated to limb occlusion pressure (LOP) depending on group allocation
Undergo isometric ankle plantarflexion strength testing using the Fysiometer platform
Receive ultrasound imaging of the gastrocnemius-soleus complex to assess muscle cross-sectional area
Complete patient-reported outcome measures assessing pain and physical function
Attend follow-up evaluations at 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Detailed description
Achilles tendon rupture (ATR) is a common musculoskeletal injury that frequently results in prolonged functional impairment despite successful surgical repair. Even with modern operative techniques and standardized rehabilitation protocols, many patients demonstrate persistent weakness of the gastrocnemius-soleus complex, deficits in ankle plantarflexion strength, and delayed return to activity. These deficits are thought to arise from a combination of postoperative immobilization, restricted early loading, and muscle atrophy during the early phases of recovery. Conventional postoperative rehabilitation protocols typically emphasize gradual progression of low-load resistance training to protect the healing tendon. While these protocols prioritize tendon safety, they may provide insufficient mechanical and metabolic stimulus to promote optimal muscle hypertrophy and neuromuscular recovery during the early postoperative period.
Blood flow restriction resistance training (BFR-RT) has emerged as a potential strategy to enhance muscular adaptation while using low mechanical loads. By applying controlled external pressure to the proximal limb during exercise, BFR-RT produces localized hypoxia and metabolic stress that can stimulate anabolic signaling pathways associated with muscle hypertrophy and strength gains. Prior studies in orthopedic and sports rehabilitation settings-including anterior cruciate ligament reconstruction and chronic Achilles tendinopathy-have demonstrated that low-load BFR-RT can produce physiologic adaptations comparable to traditional high-load resistance training while minimizing mechanical stress on healing tissues. However, the efficacy and safety of BFR-RT during the early rehabilitation period following primary ATR repair have not been evaluated in a prospective randomized clinical trial.
This study is designed as a prospective, three-arm randomized controlled trial to evaluate whether integrating BFR-RT into postoperative ATR rehabilitation improves early muscle recovery and functional outcomes while maintaining an acceptable safety profile. Participants undergoing primary surgical repair for an acute unilateral mid-portion ATR will be randomized to one of three rehabilitation protocols: BFR-RT combined with standard physical therapy, sham BFR-RT combined with standard physical therapy, or standard physical therapy alone. The BFR intervention will be delivered using a personalized tourniquet system that determines limb occlusion pressure for each participant to standardize vascular restriction and minimize inter-individual variability in occlusion levels.
Participants will undergo standardized postoperative rehabilitation and will be followed longitudinally over a 12-month recovery period. Clinical assessments will be performed at predefined postoperative intervals to evaluate physiologic recovery of the gastrocnemius-soleus complex and patient-centered functional outcomes. Safety monitoring will include systematic documentation of potential adverse events associated with postoperative rehabilitation or vascular restriction techniques.
By evaluating the physiologic and clinical effects of patient-specific BFR-RT following surgical ATR repair, this study aims to generate evidence regarding whether low-load metabolic training can safely accelerate muscle recovery and improve functional rehabilitation outcomes in this population. Findings from this trial may inform future postoperative rehabilitation protocols and help define the role of BFR-RT as an adjunctive strategy in tendon repair recovery pathways.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- Model description
- This study is a prospective, three-arm, parallel-group randomized controlled trial with a 1:1:1 allocation ratio. Participants undergoing primary surgical repair of an acute unilateral midportion Achilles tendon rupture will be randomly assigned to one of three groups: (1) blood flow restriction resistance training (BFR-RT) combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, or (3) standard physical therapy alone. The intervention and sham groups will use a Delfi Personalized Tourniquet System calibrated to 80% limb occlusion pressure and 20 mmHg, respectively. All participants will follow an identical postoperative rehabilitation protocol and will be assessed longitudinally at predefined postoperative time points over a 12-month follow-up period. Outcomes will be compared between groups to evaluate the efficacy and safety of BFR-RT in postoperative Achilles tendon rupture rehabilitation.
| Arm | Type | Receives |
|---|---|---|
| Blood Flow Restriction Resistance Training + Standard Physical Therapy | Experimental | Device: Blood Flow Restriction Resistance Training (BFR-RT), Behavioral: Standard Physical TherapyParticipants receive standard postoperative Achilles tendon rehabilitation combined with blood flow restriction resistance training using the Delfi Personalized Tourniquet System. Cuffs are calibrated to 80% limb occlusion pressure to induce controlled vascular restriction during low-load resistance exercises. All sessions are supervised by trained physiotherapists following the standardized Massachusetts General Hospital Achilles rehabilitation protocol. |
| Sham Blood Flow Restriction + Standard Physical Therapy | Sham comparator | Device: Sham Blood Flow Restriction, Behavioral: Standard Physical TherapyParticipants receive the same standardized postoperative rehabilitation protocol while wearing Delfi tourniquet cuffs inflated to 20 mmHg, a pressure insufficient to induce blood flow restriction. This sham condition controls for potential placebo effects associated with the device while maintaining identical exercise protocols and therapist supervision. |
| Standard Physical Therapy Alone | Active comparator | Behavioral: Standard Physical TherapyParticipants undergo the standardized Massachusetts General Hospital postoperative Achilles tendon rehabilitation program including range-of-motion exercises, progressive strengthening, and return-to-sport phases. No blood flow restriction device is used during rehabilitation sessions. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adults aged 18 to 75 years
- Acute unilateral midportion Achilles tendon rupture
- Primary surgical repair performed within 2 weeks of injury
- Willingness and ability to comply with the postoperative rehabilitation protocol and follow-up schedule
Key exclusion criteria (21 listed)
- Cognitive impairment or inability to follow study instructions
- Planned postoperative follow-up at another institution
- Use of fluoroquinolone antibiotics or systemic corticosteroids within the past 6 months
- Previous Achilles tendon rupture in either limb
- Simultaneous bilateral Achilles tendon rupture
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Blood Flow Restriction Resistance Training (BFR-RT)Also: Delfi Personalized Tourniquet SystemBlood flow restriction resistance training will be performed using the Delfi Personalized Tourniquet System applied to the affected limb during supervised rehabilitation exercises. The device automatically determines limb occlusion pressure (LOP) and applies 80% of LOP during low-load resistance exercises. This controlled vascular restriction produces metabolic stress intended to stimulate muscle hypertrophy and strength recovery while minimizing mechanical load on the healing Achilles tendon. Sessions are conducted under physiotherapist supervision within the standardized postoperative rehabilitation protocol. | Device | Blood Flow Restriction Resistance Training + Standard Physical Therapy |
| Sham Blood Flow RestrictionParticipants assigned to the sham group will wear the Delfi tourniquet cuff during rehabilitation sessions; however, cuff pressure will be inflated only to 20 mmHg, a level insufficient to induce vascular occlusion. This condition mimics the experience of the intervention device while avoiding physiologic blood flow restriction, thereby controlling for potential placebo effects associated with device use. | Device | Sham Blood Flow Restriction + Standard Physical Therapy |
| Standard Physical TherapyAlso: Standard Postoperative Achilles Rehabilitation ProtocolParticipants will undergo the standardized postoperative Achilles tendon rehabilitation program used at Massachusetts General Hospital. The protocol includes progressive weight-bearing, range-of-motion exercises, strengthening maneuvers, and return-to-sport progression phases supervised by trained physiotherapists. | Behavioural | Blood Flow Restriction Resistance Training + Standard Physical Therapy, Sham Blood Flow Restriction + Standard Physical Therapy, Standard Physical Therapy Alone |
Primary outcome
Achilles Tendon Total Rupture Score (ATRS)
Time frame: 12 months postoperatively
The Achilles Tendon Total Rupture Score (ATRS) is a validated patient-reported outcome instrument used to assess symptoms and physical function following Achilles tendon rupture. The score ranges from 0 to 100, with higher scores indicating better function and fewer symptoms.
12 secondary outcomes
Ankle Plantarflexion Isometric Strength (Limb Symmetry Index)
Time frame: 3 months, 4.5 months, 6 months, and 12 months postoperatively
Gastrocsoleus Muscle Cross-Sectional Area
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Visual Analog Scale (VAS) Pain Score
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference Score
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Score
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Foot and Ankle Ability Measure (FAAM)
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Single-Leg Heel Rise Test
Time frame: 3 months, 4.5 months, 6 months, and 12 months postoperatively
Single-Leg Heel Rise Height
Time frame: 3 months, 4.5 months, 6 months, and 12 months postoperatively
International Physical Activity Questionnaire - Short Form (IPAQ-SF)
Time frame: 6 months and 12 months postoperatively
EQ-5D-5L Quality of Life Score
Time frame: 6 months and 12 months postoperatively
Ankle Range of Motion
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Calf Circumference
Time frame: 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Apr 2026.
- Background: PubMed 37000780O'Neill S, Weeks A, Norgaard JE, Jorgensen MG. Validity and intrarater reliability of a novel device for assessing Plantar flexor strength. PLoS One. 2023 Mar 31;18(3):e0282395. doi: 10.1371/journal.pone.0282395. eCollection 2023.
- Background: PubMed 33615264Callanan MC, Plummer HA, Chapman GL, Opitz TJ, Rendos NK, Anz AW. Blood Flow Restriction Training Using the Delfi System Is Associated With a Cellular Systemic Response. Arthrosc Sports Med Rehabil. 2020 Dec 27;3(1):e189-e198. doi: 10.1016/j.asmr.2020.09.009. eCollection 2021 Feb.
- Background: PubMed 37562444Rolnick N, Licameli N, Moghaddam M, Marquette L, Walter J, Fedorko B, Werner T. Autoregulated and Non-Autoregulated Blood Flow Restriction on Acute Arterial Stiffness. Int J Sports Med. 2024 Jan;45(1):23-32. doi: 10.1055/a-2152-0015. Epub 2023 Aug 10.
- Background: PubMed 30011262Hwang PS, Willoughby DS. Mechanisms Behind Blood Flow-Restricted Training and its Effect Toward Muscle Growth. J Strength Cond Res. 2019 Jul;33 Suppl 1:S167-S179. doi: 10.1519/JSC.0000000000002384.
- Background: PubMed 36703264Centner C, Jerger S, Lauber B, Seynnes O, Friedrich T, Lolli D, Gollhofer A, Konig D. Similar patterns of tendon regional hypertrophy after low-load blood flow restriction and high-load resistance training. Scand J Med Sci Sports. 2023 Jun;33(6):848-856. doi: 10.1111/sms.14321. Epub 2023 Feb 3.
- Background: PubMed 31725362Centner C, Lauber B, Seynnes OR, Jerger S, Sohnius T, Gollhofer A, Konig D. Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training. J Appl Physiol (1985). 2019 Dec 1;127(6):1660-1667. doi: 10.1152/japplphysiol.00602.2019. Epub 2019 Nov 14.
- Background: PubMed 31301034Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, Ferris G, Dawes J, Paton B, Patterson SD. Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial. Sports Med. 2019 Nov;49(11):1787-1805. doi: 10.1007/s40279-019-01137-2.
- Background: PubMed 28259850Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. Br J Sports Med. 2017 Jul;51(13):1003-1011. doi: 10.1136/bjsports-2016-097071. Epub 2017 Mar 4.
- Background: PubMed 29965789Eliasson P, Agergaard AS, Couppe C, Svensson R, Hoeffner R, Warming S, Warming N, Holm C, Jensen MH, Krogsgaard M, Kjaer M, Magnusson SP. The Ruptured Achilles Tendon Elongates for 6 Months After Surgical Repair Regardless of Early or Late Weightbearing in Combination With Ankle Mobilization: A Randomized Clinical Trial. Am J Sports Med. 2018 Aug;46(10):2492-2502. doi: 10.1177/0363546518781826. Epub 2018 Jul 2.
- Background: PubMed 28926379Heikkinen J, Lantto I, Piilonen J, Flinkkila T, Ohtonen P, Siira P, Laine V, Niinimaki J, Pajala A, Leppilahti J. Tendon Length, Calf Muscle Atrophy, and Strength Deficit After Acute Achilles Tendon Rupture: Long-Term Follow-up of Patients in a Previous Study. J Bone Joint Surg Am. 2017 Sep 20;99(18):1509-1515. doi: 10.2106/JBJS.16.01491.
- Background: PubMed 37960840Mashimo S, Nozaki T, Amaha K, Tanaka K, Kubota J, Sato H, Kitamura N. Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study. Am J Sports Med. 2023 Dec;51(14):3781-3789. doi: 10.1177/03635465231206391. Epub 2023 Nov 13.
- Individual participant dataSharing planned: No. There are no current plans to share individual participant data. Data generated in this investigator-initiated study are subject to institutional data governance and participant privacy protections, and the study team has elected not to make IPD publicly available at this time.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Blood Flow Restriction Resistance Training (BFR-RT) and Standard Physical Therapy in people with Achilles Tendon Rupture and Blood Flow Restriction Therapy, run by Massachusetts General Hospital at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 1 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Achilles Tendon Total Rupture Score (ATRS) (time frame: 12 months postoperatively). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07498166, which also lists 11 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Apr 2026.