The investigators purpose of this study is to determine patients-reported outcomes (VAS pain scores) in patients with Scapular Dyskinesis or Posterior Shoulder Instability who undergo rehabilitation with a shoulder pacemaker.

The scapula plays a key role in nearly every aspect of normal shoulder function. Shoulder dyskinesia or scapula winging effects patients as a result of nerve injury or muscle detachment or abnormal muscle recruitment. Patients with abnormal muscle recruitment often are helped the most by therapy but restoring normal firing can be difficult. Abnormal muscle recruitment is due to pain or weakness or instability of the glenohumeral joint and the muscles around the scapula attempt to compensate for the lack of normal firing patterns. In many patients, physical therapy and surgery have proven to be unsuccessful treatment options.

The Shoulder Pacemaker is a device that specifically aims at resolving functional issues that surgery and physical therapy are unable. It's a wearable electro stimulator created for patients suffering from unbalanced muscle activation in the shoulder, such as Scapular Dyskinesis. The Shoulder Pacemaker delivers "smart stimulation" through a dynamic interaction between the patient and the device. The motion technology recognizes muscle movement and automatically sets the appropriate stimulation intensity according to the movement. This process helps to restore normal muscle activation patterns and equilibrium. The pacemaker will hopefully assist in restoring normal muscle recruitment.

Inclusion Criteria:

• Scapular Dyskinesis
• Posterior Shoulder Instability

Exclusion Criteria:

• Rotator Cuff Tearing
• Shoulder Arthritis
• Patients with implantable electrical/electronic devices
• If participants are using wearable electrical medical devices, such as glucose sensors or infusion pumps, these devices will be turned off or the participants will be excluded from the study.