The intervention will include home use of Genesis Flex FES device alongside usual rehabilitation care. Participant education in Genesis FES use will be conducted during the baseline assessment session. FES parameters will be initially adjusted at the lowest possible current for patient comfort with the constraint that they should not elicit a tetanic contraction. FES will be provided via two self adhesive electrodes attached across shoulder joint.A shoulder harness adjustable neoprene padding will be provided to enable anatomical contouring for patient comfort and support for positioning of stimulator and electrodes to the affected shoulder.

Participants diagnosed with shoulder adhesive capsulitis and being treated at a local physical and occupational therapy outpatient clinic will be deemed eligible for inclusion in the study.The intervention will include home use of Genesis Flex FES device alongside usual rehabilitation care. Usual care therapy may consist of manual therapy, hot packs, transcutaneous electrical nerve stimulation, ultrasound treatments, daily home-based shoulder exercises, and/or acetaminophen for pain, which will be documented.

Participant-reported satisfaction, comfort, and ease of use assessed using a 5-point Likert scale and open-ended qualitative feedback.A Likert scale is a rating scale used in surveys to measure opinions, attitudes,and perceptions by asking respondents to indicate their level of agreement or disagreement with a statement. It consists of a series of statements with a symmetric range of response options, such as a five-point scale from 0="Strongly Disagree" to 5="Strongly Agree". This method allows for the collection of quantitative data to analyze subjective experiences.

Percentage of participants able to correctly and independently use the portable FES device for ≥80% of prescribed home sessions, as verified by device logs and participant self-report.

The Disabilities of the Arm, Shoulder and Hand (DASH) Questionnaire is a 30-item self-report measure assessing symptoms and functional limitations related to upper-limb musculoskeletal disorders. It also includes two optional 4-item modules (Work and Sports/Performing Arts). Each item is rated on a 5-point scale and converted to a total score ranging from 0 to 100, where 0 indicates no disability and 100 indicates the most severe disability. Changes in DASH total and optional module scores will be compared from baseline to 4 weeks.