This randomized controlled trial compares blood flow restriction (BFR) resistance training (leg press and seated knee extension at 30% 1RM) versus BFR cycling (stationary cycling at low resistance) in 60 athletes (aged 18-40 years) diagnosed with patellofemoral pain syndrome. Both interventions are delivered over 8 weeks (3 sessions/week) with a pneumatic cuff set at 80% limb occlusion pressure. Primary outcomes include pain intensity (NPRS), quadriceps strength (handheld dynamometer), and functional ability (Kujala Anterior Knee Pain Scale), assessed at baseline and post-intervention.
Patellofemoral pain (PFP) is among the most prevalent musculoskeletal conditions in athletes, with reported prevalence of 30-40% in sports populations. High-load resistance training is the conventional rehabilitation approach but often exacerbates joint stress and reduces adherence. Blood flow restriction (BFR) training enables strength gains at low loads by applying a pneumatic cuff at 80% LOP on the proximal thigh. This trial compares two BFR modalities: * Group A (BFR-RT): Leg press and seated knee extension, 1x30 + 3x15 reps at 30% 1RM, 3x/week for 8 weeks. * Group B (BFR-CYC): Stationary cycling at low resistance, 4x5-minute intervals at 70-80 RPM (RPE 11-13), 3x/week for 8 weeks. All sessions are supervised one-on-one by a physiotherapist. Assessments are conducted at baseline and week 8. The study is single-blinded (outcome assessor blinded). Randomization via computer-generated sequence. Statistical analysis via SPSS v27 (paired t-test / Wilcoxon for within-group; independent t-test / Mann-Whitney for between-group, alpha=0.05).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
48
Participants will undergo blood flow restriction (BFR) resistance training using a pneumatic cuff applied to the proximal thigh at 80% limb occlusion pressure. Exercises include leg press and seated knee extension performed at 30% of one-repetition maximum (1RM). Training will be conducted for 8 weeks, with supervised sessions 3 times per week. Cuff pressure will be monitored and adjusted using BP cuff. The aim is to improve quadriceps strength and reduce pain in patients with patellofemoral pain.
Participants will perform stationary cycling combined with blood flow restriction (BFR) applied to the proximal thigh at 80% limb occlusion pressure. Cycling will be performed at low resistance with controlled cadence for 8 weeks, 3 sessions per week under physiotherapist supervision. The protocol includes structured cycling intervals with rest periods and continuous monitoring of pain and perceived exertion. The intervention aims to improve quadriceps strength, reduce pain, and enhance functional outcomes in patients with patellofemoral pain.
Ibadat International University, Islamabad (Iiui)
Islamabad, Pakistan
Quadriceps Strength - Handheld Dynamometer
Isometric quadriceps muscle strength measured in Newtons using a calibrated handheld dynamometer (ICC \> 0.90). Measurement taken in a standardized seated position at 60° knee flexion.
Time frame: Baseline (Week 0) and Post-intervention (Week 8)
Pain Intensity - Numeric Pain Rating Scale (NPRS)
Self-reported pain intensity rated on a 0-10 scale (0 = no pain, 10 = worst imaginable pain). The NPRS has excellent test-retest reliability (ICC 0.95).
Time frame: Baseline (Week 0) and Post-intervention (Week 8)
Functional Outcomes - Kujala Anterior Knee Pain Scale (AKPS)
13-item patient-reported outcome measure assessing functional limitations due to anterior knee pain. Scored 0-100 (higher = better function). High internal consistency (α = 0.83-0.91).
Time frame: Baseline (Week 0) and Post-intervention (Week 8)
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