effectiveness of wrist extensor strength training with blood flow restriction on lateral elbow tendinopathy

Conditions: Lateral Epicondylitis (Tennis Elbow); Elbow Pain; Lateral Elbow Tendinopathy; Extensor Carpi Radialis Brevis (ECRB)

Summary: repetitive and aggressive injuries to the elbow joint in sports often cause lateral elbow tendinitis (let). in many clinical settings, therapists follow conventional methods according to their treatment protocols; however, complete rehabilitation is not always implemented. without adequate care, elbow tendinitis can lead to chronic and re-injury of the elbow. although many treatments are available, blood flow restriction training (bfr) is a valuable option for exercise in cases where high-intensity training is too painful or contraindicated. in musculoskeletal disorders, it has been shown to induce hypoalgesia, and positive effects, such as improved muscle strength, growth, and tendon adaptations, have been demonstrated in healthy individuals.

lateral epicondylitis is a work-related musculoskeletal disorder and defined as persistent symptomatic degeneration of the wrist extensor muscle tendon that connects to the lateral humeral epicondyle, it associated with pain, at the lateral side of elbow joint, limited range of motion and forearm muscle weakness(vaquero-picado et al., 2016). management of lateral epicondylitis is aimed to reducing pain and discomfort, preserving rom, and enhancing the strength and endurance of the affected limb by using numerous techniques, including electrophysical methods and physical activity(kinandana et al., 2023). blood flow restriction training (bfrt) involves partially restricting arterial blood flow into muscles while occluding venous outflow during exercise. it was first introduced into the literature in 1987 by researchers who used tourniquet ischemia to induce fatigue in muscles, dates back to dr. yoshiaki sato in japan, where it was known as "kaatsu training," meaning "training with added pressure." kaatsu training is now performed all over the world and is more commonly referred to as "bfr training" and achieved using a pneumatic tourniquet system (eiken \& bjurstedt, 1987). in addition to physical rehabilitation, bfrt is used for physical training and performance in healthy individuals. there has been extensive research into its value as a training tool, including elite- and amateur-level athletes, untrained young and older adults, and hypertensive individuals (abe et al., 2010; jenkins et al., 2013; kim et al., 2017; minniti et al., 2020). in addition to reducing arterial blood flow to working muscles, blood flow restriction obstructs venous return. when active muscles are exposed to bfr conditions, they are subjected to ischemia, which increases the metabolic stress on them. in addition to bfr, venous occlusion increases muscle cell swelling, activates intracellular anabolic pathways, and recruits fast-twitch fibers, which are thought to be involved in muscle adaptation(loenneke et al., 2012; tanimoto et al., 2005). there were different factors affecting exercise adaptations with bfr including pressure of occlusion (partial or complete), type of occlusion (continuous or intermittent), intensity of exercise, and volume of exercise with bfr (amani-shalamzari et al., 2019). bfr along with low load resistance training, cardio endurance training, and other activities that are generally recommended to improve muscular mass/strength are also associated with these adaptations in muscles (slysz et al., 2016). the randomized trail done by karanasios et al to assess the effect of low-load resistance training with blood flow restriction (llrt-bfr) versus llrt with sham-bfr in patients with lateral elbow tendinopathy (let), it was found that llrt with blood flow restriction produced significantly better pain ,strength and function improvement in comparison to llrt with sham-bfr for all primary outcomes(karanasios et al., 2022). regarding studying the proximal and distal effect of bfr training, the study done by bowman et al., on lower extremity low-load bfr training resulted in greater increases in muscle strength and limb circumference in healthy participants after completing a standardized 6-week course of bfr training. muscle groups at the proximal and distal ends of the body were similarly strengthened after bfr training(bowman et al., 2019). this study aims to explore the effects of incorporating bfr into wrist extensor strength training for athletes with lateral epicondylitis. by evaluating its impact on strength, function, pain, range of motion (rom), and overall quality of life, this research seeks to determine whether bfr can optimize rehabilitation outcomes and provide a more effective treatment strategy for let.

Eligibility criteria:
inclusion criteria: 1. both male and female, aged between 18 to 45 years old. 2. subjects with a positive test of lateral epicondylitis, which will be determined based on physical therapy assessment procedures. 3. the presence of tenderness over the lateral epicondyle.positive cozen's and mill's tests. 4. pain on grasping. 5. pain on passive flexion of the wrist with elbow extension. 6. pain with resisted wrist extension. 7. show decreased muscle strength and functional ability. exclusion criteria: 1. patients with shoulder tendinopathy, cervical radiculopathy, and rheumatoid arthritis. 2. presences of sensory and motor impairment of the upper extremities 3. history of cardiovascular disease 4. history of trauma and surgery on the elbow 5. having a history of malignancy and peripheral vascular disorders.

Keywords: wrist extensor strength training lateral epicondylitis tennis elbow elbow pain