Effects of Intermittent Versus Continuous Blood Flow Restriction Training on Pain, Functional Ability, Muscle Strength and Exercise Perception Among Female Patients With Grade II Knee Osteoarthritis

This study holds significant clinical, academic, and practical importance in the field of musculoskeletal rehabilitation. Clinically, it addresses a critical need to identify an effective and tolerable strengthening strategy for females with early-stage knee osteoarthritis. By directly comparing intermittent and continuous BFR protocols, the findings will provide physiotherapists with evidence-based guidance for optimizing exercise prescription while minimizing discomfort and improving adherence.Academically, this research contributes to the limited body of literature comparing different BFR application strategies in knee osteoarthritis. The inclusion of exercise perception outcomes adds valuable insight into patient-centered rehabilitation, which is often underrepresented in clinical trials.From a practical and societal perspective, identifying a more tolerable BFR approach may enhance long-term exercise participation, delay disease progression, and reduce healthcare burden associated with knee osteoarthritis. The findings may also support the integration of low-load BFR training into rehabilitation programs in resource-limited clinical settings.

Study Overview

• Status: Completed
• Conditions: Knee Osteoarthristis
• Intervention / Treatment: Other: Intermittent blood flow training (iBFR); Other: Continuous blood flow training (cBFR)

Detailed Description

Knee osteoarthritis (KOA) is a chronic, progressive musculoskeletal disorder characterized by joint degeneration, pain, muscle weakness, and functional limitations, with a higher prevalence among middle-aged women. Quadriceps muscle weakness is a key clinical feature associated with reduced functional capacity and progression of the disease. Although high-load resistance training is considered effective for improving muscle strength, its application is often limited in symptomatic individuals due to increased joint loading and pain, thereby affecting adherence to rehabilitation programs.In recent years, low-load resistance training combined with Blood Flow Restriction (BFR) has gained attention as a viable alternative for enhancing muscle strength while minimizing mechanical stress on the joint. BFR training can be applied using continuous or intermittent protocols. Continuous BFR maintains cuff pressure throughout both exercise and rest periods, whereas intermittent BFR involves periodic deflation during rest intervals. These variations may influence physiological responses, fatigue levels, perceived exertion, and overall exercise tolerance, which are critical factors in clinical rehabilitation.This randomized controlled trial is designed to compare the effects of intermittent and continuous BFR training on pain, functional ability, muscle strength, and exercise perception in females with Grade II knee osteoarthritis. A total of 84 participants will be randomly allocated into two intervention groups and will undergo structured low-load resistance training in conjunction with standard physiotherapy care over a period of 8-12 weeks.Outcome measures will be assessed at baseline, 4 weeks, 8 weeks, and 12 weeks, including pain intensity (Numeric Pain Rating Scale), functional status (WOMAC Index), quadriceps muscle strength, and perceived exertion (Modified Borg Scale). The findings of this study are expected to provide evidence-based insights into the comparative effectiveness and tolerability of BFR application methods, thereby supporting optimized rehabilitation strategies and improving patient-centered outcomes in knee osteoarthritis management.

• Study Type: Interventional
• Enrollment (Actual): 84
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Pakistan
  • Punjab Province
    • Lahore, Punjab Province, Pakistan, 05450
      • Social Security Hospital, Lahore

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female patients aged 40-49 years.
• Diagnosed with Grade II knee osteoarthritis (radiographically confirmed).
• Moderate to severe pain (NPRS 4-7).
• Ability to participate in exercise programs.

Exclusion Criteria:

• Severe cardiovascular disease.
• Uncontrolled hypertension.
• Recent knee surgery or intra-articular injection.
• Active cancer or metastatic disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intermittent blood flow; Participants will perform low-load resistance exercises at 20-30% of one-repetition maximum (1RM) combined with intermittent BFR application. Cuff pressure will be applied during exercise sets and released during rest intervals. Each session will include a 10-minute warm-up , followed by a 30-minute structured exercise program and a 15-minute cool-down. Sessions will be conducted 2-3 times per week for a duration of 8-12 weeks, with progressive overload applied as tolerated.	Other: Intermittent blood flow training (iBFR); Hamstrings stretching, 3 repetitions of 30 s, Bridge with isometric contraction of the transversus abdominis-CORE training, 3 repetitions of 30 s, Hip abduction with weights , 3 sets of 10 repetitions, Calm exercises with an elastic band, 3 sets of 10 repetitions, Calf raises with weights , 3 sets of 10 repetitions, Sensori-motor training at mini-trampoline, 3 repetitions of 30 s, Leg press, 0-60°, 4 sets of 10 repetitions, Seated knee extension , 90-0° of knee flexion, 4 sets of 10 repetitions. In the iBFR group, the cuff is deflated during each set's rest period and is quickly reinflated to the target pressure 20-30 s into the rest, ensuring the entire rest period does not exceed 45 s . Intensity: 20- 30% of 1RM with BFR cuffs, Frequency: 3 sessions per week for 12 weeks. Each session comprises a 10-min warm up with static cycling, a 30-min exercise program, and a 15-min cool down. BFR cuff from Hhccteo company will be used. pressure:130-150 mmHg, cuff width 5-7cm
Experimental: Continuous blood flow training; Participants will perform the same low-load resistance exercise protocol (20-30% 1RM) with continuous BFR application. Cuff pressure will be maintained throughout both exercise and rest periods. Exercise selection, session structure (warm-up, training, cool-down), frequency (2-3 sessions/week), and duration (8-12 weeks) will be identical to Group A to ensure comparability between groups	Other: Continuous blood flow training (cBFR); Hamstrings stretching, 3 repetitions of 30 s, Bridge with isometric contraction of the transversus abdominis-CORE training, 3 repetitions of 30 s, Hip abduction with weights (side lying), 3 sets of 10 repetitions, Calm exercises (side lying) with an elastic band, 3 sets of 10 repetitions, Calf raises with weights (standing), 3 sets of 10 repetitions, Sensori motor training (standing) at mini-trampoline, 3 repetitions of 30 s, Leg press (machine), 0-60°, 4 sets of 10 repetitions, Seated knee extension, 90-0° of knee flexion, 4 sets of 10 repetitions. In the cBFR group, the Intensity of excersise will be 20-30% of 1RM with BFR cuffs ,Frequency: 3 sessions per week for 12 weeks. Each session comprises a 10-min warmup with static cycling, a 30-min exercise program, and a 15-min cool down. BFR cuff from Hhccteo company will be used. The parameters will be pressure: 130-150 mmHg, cuff width 5-7 cm. Progressive overload will be applied by gradually increasing repetitions or load as tolerated

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Manual Muscle Testing (MMT)	Quadriceps strength will be assessed using standardized isometric testing procedure. It grades muscle strength on a 0-5 scale based on the ability to move a joint against gravity and external resistance. A grade of 0 indicates no visible or palpable muscle contraction, while 1 (Trace) represents a slight contraction without actual movement. Grade 2 (Poor) describes the ability to move the joint through its full range only when gravity is eliminated, whereas Grade 3 (Fair) allows movement through the full range against gravity but without resistance. Grade 4 (Good) indicates movement against moderate resistance, and Grade 5 (Normal) reflects full range of motion against maximal resistance, representing normal muscle strength	baseline, 6 weeks (post intervention), 12 weeks (follow up)
Numeric Pain Rating Scale (NPRS)	The NPRS is a10-point scale (0-10) used to quantify pain intensity. Pain severity will be interpreted as no pain (0), mild pain (1-3), moderate pain (4-6), and severe pain (7-10).	baseline, 6 weeks (post intervention), 12 weeks( followup)
Modified Borg Scale	It is used to assess ratings of exercise-related perceived exertion. The scale ranges from (0 to 10), where 0 means no breathlessness at all and 10 means maximium breathlessness. According to this, 0-2 for Minimal exertion, 3-4 for Moderate (often target for rehab), 5-6 for Hard and 7-10 is for Very hard to maximal	baseline, 6 weeks( post intervention), 12 weeks (follow up)

Collaborators and Investigators

• Sponsor: Lahore University of Biological and Applied Sciences

Publications and helpful links

General Publications

• Hughes 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.
• Centner C, Wiegel P, Gollhofer A, Konig D. Effects of Blood Flow Restriction Training on Muscular Strength and Hypertrophy in Older Individuals: A Systematic Review and Meta-Analysis. Sports Med. 2019 Jan;49(1):95-108. doi: 10.1007/s40279-018-0994-1.
• Sorensen B, Aagaard P, Hjortshoj MH, Hansen SK, Suetta C, Couppe C, Magnusson SP, Johannsen FE. Physiological and clinical effects of low-intensity blood-flow restricted resistance exercise compared to standard rehabilitation in adults with knee osteoarthritis-Protocol for a randomized controlled trial. PLoS One. 2023 Dec 14;18(12):e0295666. doi: 10.1371/journal.pone.0295666. eCollection 2023.
• Harper SA, Roberts LM, Layne AS, Jaeger BC, Gardner AK, Sibille KT, Wu SS, Vincent KR, Fillingim RB, Manini TM, Buford TW. Blood-Flow Restriction Resistance Exercise for Older Adults with Knee Osteoarthritis: A Pilot Randomized Clinical Trial. J Clin Med. 2019 Feb 21;8(2):265. doi: 10.3390/jcm8020265.
• Freitas EDS, Miller RM, Heishman AD, Aniceto RR, Silva JGC, Bemben MG. Perceptual responses to continuous versus intermittent blood flow restriction exercise: A randomized controlled trial. Physiol Behav. 2019 Dec 1;212:112717. doi: 10.1016/j.physbeh.2019.112717. Epub 2019 Oct 17.

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2026
• Primary Completion (Actual): July 10, 2026
• Study Completion (Actual): July 20, 2026

Study Registration Dates

• First Submitted: July 20, 2026
• First Submitted That Met QC Criteria: July 20, 2026
• First Posted (Actual): July 23, 2026

Study Record Updates

• Last Update Posted (Actual): July 23, 2026
• Last Update Submitted That Met QC Criteria: July 20, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Functional Ability; Blood Flow Restriction (BFR); Intermittent BFR; Continuous BFR; Exercise Perception
• Other Study ID Numbers: UBAS/ERB/26/04/012

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No