Barriers to enrollment have been identified, including a lack of insurance coverage for occupational therapy. This study is being temporarily closed until funding can be secured to offset these costs for participants.

Lateral epicondylitis (LE), often referred to as "tennis elbow" is a common and debilitating overuse injury affecting 1-3% of adults annually. LE is most often defined as a syndrome of pain near the area of the lateral epicondyle of the elbow commonly effecting the origin of the extensor carpi radialis brevis with associated weakness; it most commonly effects the dominant arm. The best treatment for LE is unknown and research to support current treatment methods are insufficient. A common limitation in functional recovery experienced by this population is pain at the lateral aspect of the elbow. As such, innovative therapeutic interventions directed at quickly reducing pain may address this unmet need and allow for improved outcomes, as well as earlier return to function.

Inclusion Criteria:

1. Ages 18-65 years of age
2. Diagnosis of lateral epicondylitis confirmed by the treating orthopaedic surgeon and ultrasound
3. Must be able to read and write in English
4. Able to provide own written consent

Exclusion Criteria:

1. Patients over 65 years of age
2. Contralateral upper extremity involvement resulting in less than normal range of motion, muscle strength or daily pain greater than 1/10
3. History of prior injection for treatment of lateral epicondylitis
4. Pregnancy
5. Recent history of deep venous thrombosis (within the past 12 months)
6. Active treatment with anticoagulants
7. History of upper quadrant lymph node dissection
8. History of endothelial dysfunction
9. Patient history of easy bruising
10. Active infection in the injured arm
11. Cancer
12. Uncontrolled peripheral vascular disease
13. Uncontrolled diabetes mellitus

For patients enrolled in the control group, the participants will undergo calibration of the Delfi Personalized Tourniquet System to measure limb occlusion pressure and will wear the cuff during completion of the exercises with minimal inflation (approximately 5%), to hold the cuff in place during treatment. This will act as a sham.