Isokinetic Exercise Combined With Blood Flow Restriction: High-Load Vs Low-Load Training

Official title

Isokinetic Exercise Combined With Blood Flow Restriction: High-Load Vs Low-Load Training : A Randomized Controlled Trial in Post-ACL Reconstruction Populations

Overview

The goal of this clinical trial is to see which type of strengthening exercise with a tight band (blood flow restriction) helps people recover better after ACL reconstruction. The study includes adults after ACL surgery who are doing physiotherapy to rebuild thigh muscle strength and knee function. The main questions are: * Does heavy strengthening with blood flow restriction improve thigh strength, knee function, and daily activities more than light strengthening with blood flow restriction after ACL surgery? * Can light strengthening with blood flow restriction give similar benefits to heavy strengthening while putting less strain on the knee? Researchers will compare a heavy-exercise program plus blood flow restriction to a light-exercise program plus blood flow restriction to see which gives better strength and functional improvements. Participants will: * Come for supervised physiotherapy sessions and do knee exercises on a machine, using either heavy or light loads while a cuff on the thigh gently squeezes to reduce blood flow. * Have their leg strength, and knee questionnaires checked several times during the study.

Detailed description

This clinical trial is testing two different ways of doing strength training with a tight leg cuff (blood flow restriction) during rehabilitation after ACL reconstruction. The aim is to find out which program helps people rebuild thigh muscle strength and knee function more effectively, while still keeping the knee joint safe after surgery.

Study purpose and questions After ACL reconstruction, many people lose muscle size and strength in the front of the thigh, which can slow down recovery and delay return to sport or full activity. Blood flow restriction training allows people to train with lighter weights but still gain strength and muscle, which may be useful when heavy loads are not yet safe.

The main questions are:

* Does a heavy-load isokinetic exercise program with blood flow restriction improve thigh strength, knee function, and patient-reported outcomes more than a low-load isokinetic program with blood flow restriction? * Can low-load isokinetic exercise with blood flow restriction provide similar benefits in strength and function, while placing less stress on the healing knee joint? Who will take part The study will include adults who have had ACL reconstruction and are in the strengthening phase of their rehabilitation. Participants will typically be active people, cleared by their surgeon and physiotherapist to start moderate to high resistance training, with no serious heart, blood vessel, or bleeding problems that would make blood flow restriction unsafe.

What happens in the study Participants will be randomly assigned to one of two groups so that each person has an equal chance of being in either group.

* One group will do heavy-load isokinetic knee exercises with a blood flow restriction cuff on the thigh. * The other group will do low-load isokinetic knee exercises with the same type of cuff and similar exercise schedule.

Both groups will:

* Attend supervised physiotherapy sessions several times per week for around 3-4 months. * Perform knee extension and flexion exercises on an isokinetic machine, where the speed of movement is controlled and resistance adjusts through the range of motion. * Wear a wide cuff around the upper thigh, which is inflated to a set pressure to partially reduce blood flow out of the leg during sets, then deflated during rest periods.

The physiotherapist will adjust the load (heavy or light), cuff pressure, and number of sets and repetitions according to a fixed protocol so that each participant trains safely and progressively over time.

Measurements and outcomes

Participants will be tested at the start of the study and at follow-up visits (for example, after several weeks and at the end of the program). The main outcome is peak quadriceps strength measured on an isokinetic dynamometer. Other outcomes may include:

* Rate of torque development (how quickly the muscle can produce force). * Functional tests such as hop tests, walking or stair tests, and timed tasks. * Patient questionnaires about knee symptoms, daily activities, sports function, and quality of life.

Interventions

• Other High Load Isokinetic Training with Blood Flow Restriction
  High Load strength training that was administered through the use of an isokinetic device, and not conventional strength training equipment, combined with blood flow restriction.
• Other Low Load Isokinetic Training with Blood Flow Restriction
  Low Load strength training that was administered through the use of an isokinetic device, and not conventional strength training equipment, combined with blood flow restriction.

Primary outcome measures

• Muscle Strength [Time frame: Outcome measures will be measured at baseline(week 0), mid-intervention(week 3) and post-intervention(week 6)]
• Muscle Girth [Time frame: Outcome measures will be measured at baseline(week 0), mid-intervention(week 3) and post-intervention(week 6)]

Secondary outcome measures (3)

• Pain Reduction [Time frame: Outcome measures will be measured at baseline(week 0), mid-intervention(week 3) and post-intervention(week 6)]
• Blood Flow [Time frame: Outcome measures will be measured at baseline(week 0), mid-intervention(week 3) and post-intervention(week 6)]
• Tolerability and Perception of the Intervention(s) [Time frame: Outcome measures will be measured at baseline(week 0), mid-intervention(week 3) and post-intervention(week 6)]

Eligibility criteria

Inclusion criteria

For ACLR group:

•Isolated unilateral ACL reconstruction 8-16 weeks post-surgery with medical clearance for moderate to high resistance training.

For control group(healthy population):

• Healthy adults with no musculoskeletal pathology.

Exclusion criteria

• History of cardiovascular or metabolic diseases
• Deep vein thrombosis
• Coagulopathy
• Hypertension
• Skin lesions or infections at the site of BFR cuff administration
• Neuromuscular disorders
• Non-clearance from the surgeon or physiotherapist or resistance training.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• McNair PJ, Colvin M, Reid D. Predicting maximal strength of quadriceps from submaximal performance in individuals with knee joint osteoarthritis. Arthritis Care Res (Hoboken). 2011 Feb;63(2):216-22. doi: 10.1002/acr.20368. PMID 20890972
• de Deus Passos M, da Rocha AF. Evaluation of infrared thermography with a portable camera as a diagnostic tool for peripheral arterial disease of the lower limbs compared with color Doppler ultrasonography. Arch Med Sci Atheroscler Dis. 2022 Aug 8;7:e66-e72. doi: 10.5114/amsad/150716. eCollection 2022. PMID 36158072
• Corte AC, Pedrinelli A, Marttos A, Souza IFG, Grava J, Jose Hernandez A. Infrared thermography study as a complementary method of screening and prevention of muscle injuries: pilot study. BMJ Open Sport Exerc Med. 2019 Jan 3;5(1):e000431. doi: 10.1136/bmjsem-2018-000431. eCollection 2019. PMID 30687515
• Alghadir AH, Anwer S, Iqbal A, Iqbal ZA. Test-retest reliability, validity, and minimum detectable change of visual analog, numerical rating, and verbal rating scales for measurement of osteoarthritic knee pain. J Pain Res. 2018 Apr 26;11:851-856. doi: 10.2147/JPR.S158847. eCollection 2018. PMID 29731662
• Cvjetkovic DD, Bijeljac S, Palija S, Talic G, Radulovic TN, Kosanovic MG, Manojlovic S. Isokinetic Testing in Evaluation Rehabilitation Outcome After ACL Reconstruction. Med Arch. 2015 Feb;69(1):21-3. doi: 10.5455/medarh.2015.69.21-23. Epub 2015 Feb 21. PMID 25870471
• Gopinatth V, Garcia JR, Reid IK, Knapik DM, Verma NN, Chahla J. Blood Flow Restriction Enhances Recovery After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Arthroscopy. 2025 Apr;41(4):1048-1060. doi: 10.1016/j.arthro.2024.05.032. Epub 2024 Jun 16. PMID 38889851
• Lin Q, Zhang Y, Qin J, Wu F. Effects of Low-Load Blood Flow Restriction Training on Muscle Volume After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis. Orthop J Sports Med. 2024 Dec 13;12(12):23259671241301731. doi: 10.1177/23259671241301731. eCollection 2024 Dec. PMID 39678440
• Koc B, Jansen E, de Jong O, Ehlen T, van Rijn L, de Bie R, Schotanus M. Qualitative Evaluation of Patient Experiences with Low-Load Blood Flow Restriction and Heavy-Load Resistance Training Post-ACL Reconstruction. Int J Sports Phys Ther. 2025 Oct 1;20(10):1479-1488. doi: 10.26603/001c.143781. eCollection 2025. PMID 41048413

Identifiers

NCT: NCT07384780 · GulfMU

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗