Comparison of the Effectiveness of Blood Flow Restriction Exercise and Eccentric Exercise in Lateral Epicondylitis

Lateral epicondylitis (tennis elbow) is a musculoskeletal disorder affecting approximately 1-3% of the general population. It is characterized by pain and tenderness at the lateral epicondyle of the elbow due to degenerative changes in the extensor carpi radialis brevis (ECRB) tendon caused by repetitive microtrauma. Conservative treatment options include rest, orthotic devices, physical therapy, and exercise programs.

Eccentric exercise has been widely recommended as a first-line conservative treatment for lateral epicondylitis. However, these programs typically require loading at 70% or more of one-repetition maximum (1-RM), which may not be tolerated by patients experiencing significant pain.

Blood flow restriction exercise (BFRE) is a training method in which a pneumatic cuff is applied to the proximal portion of a limb to partially restrict arterial blood flow and completely restrict venous return during low-load resistance exercise. BFRE has been shown to produce muscle strength and hypertrophy gains at loads as low as 20-40% of 1-RM, making it a potential alternative for patients who cannot tolerate heavy loading. Recent studies have demonstrated the effectiveness of BFRE in various musculoskeletal conditions including osteoarthritis, anterior cruciate ligament reconstruction, and patellar tendinopathy. However, evidence for its use in lateral epicondylitis is limited.

STUDY DESIGN:

This was a prospective, randomized controlled trial with three parallel groups. Patients were allocated using block randomization with blocks of nine.

INTERVENTION PROTOCOLS:

BFRE Group (n=9): Arterial occlusion pressure (AOP) was individually determined using a pneumatic cuff and pulse oximetry. Exercise was performed at 30% of AOP and 30% of 1-RM. Protocol: 3 sets of 15 repetitions with 1-minute rest intervals, twice weekly for 6 weeks. Stretching exercises (3 repetitions x 30 seconds) were performed before and after each session. On non-exercise days, home stretching was performed twice daily. A wrist extension orthosis (15-20 degrees) was worn throughout the study.

Eccentric Exercise Group (n=9): Slow eccentric wrist extensor exercises were performed with the elbow in full extension and forearm in pronation. The weight was lowered from wrist extension to flexion over approximately 30 seconds. Protocol: 3 sets of 10 repetitions with 1-minute rest intervals, five times weekly for 6 weeks, at 70% of 1-RM. Stretching and orthosis protocols were identical to the BFRE group.

Orthosis Group (n=9): Participants wore a wrist extension orthosis maintaining 15-20 degrees of extension throughout the day, removing it only during sleep, bathing, and stretching exercises. Stretching exercises were performed twice daily (3 repetitions x 30 seconds).

Exercise protocols were kept constant throughout the 6-week intervention period without progression. All supervised sessions were conducted at Dokuz Eylül University. Patients received illustrated exercise booklets and maintained exercise diaries to monitor home program adherence.

SAMPLE SIZE JUSTIFICATION:

Sample size was calculated using G*Power (version 3.1.9.4) with the following parameters: effect size 1.8, Type I error rate alpha = 0.05, and 95% statistical power, yielding a minimum of 9 participants per group (total N = 27).

STATISTICAL ANALYSIS:

Data were analyzed using SPSS version 20.0. Normality was assessed using the Shapiro-Wilk test. Baseline comparisons used one-way ANOVA. Within-group pre-post comparisons used paired t-tests. Between-group differences and time-by-group interactions were evaluated using mixed model ANOVA with post-hoc analyses. Significance was set at p < 0.05.

Inclusion criteria

• Clinical diagnosis of lateral epicondylitis confirmed by physical examination
• Provision of written informed consent

Exclusion criteria

• Bilateral lateral epicondylitis
• Cervical radiculopathy
• History of elbow, forearm, or wrist pathology (previous elbow surgery, tendon rupture, fracture of the humerus/radius/ulna, osteoporosis, neurological involvement, or nerve paralysis)
• Physiotherapy within the preceding 6 weeks
• Tumor
• Cardiac arrhythmia, pacemaker use, coagulation disorders, anticoagulant therapy, or history of deep vein thrombosis
• Systemic or neurological disease
• Peripheral vascular disease or endothelial dysfunction
• Conditions associated with endothelial dysfunction, including uncontrolled hypertension, cardiovascular disease, systemic inflammation, obesity, diabetes, or atherosclerosis
• Active infection