Using Biofeedback for Shoulder Impingement

Shoulder impingement is one of the most frequent diagnoses given to those with shoulder pain. Individuals with shoulder impingement syndrome classically present with poor scapular muscle activation patterns and faulty mechanics when reaching or lifting the arm.⁽¹⁾ Going through a motor re-learning program is often necessary to restore proper movement patterning.⁽²⁾ Given the lack of neuromuscular control that results from shoulder impingement, visual biofeedback is an obvious adjunct training tool to any rehabilitation program.

Literature Review

Numerous researchers and clinicians agree that shoulder impingement is the combined result of:

• Tightness of the muscles in the front of the shoulder along with bad posture
• Faulty movement patterns caused by poor muscle timing/coordination of the scapular muscles^(1–4)

We will mostly focus on the second issue.

A study by Larsen et al. found that using EMG biofeedback allowed participants with shoulder impingement to achieve proper muscle activation patterns.⁽⁵⁾ The use of sEMG closely mimics the activation seen in healthy individuals.

Poor posture and weakness often result in reduced infraspinatus use and increased posterior deltoid activity.⁽⁶⁾ Lim et al. found that sEMG biofeedback can increase infraspinatus activity while decreasing posterior deltoid activity during shoulder external rotation.

Du et al. found immediate improvements in upper and lower trapezius activation patterns after video and EMG biofeedback training for scapular dyskinesis.⁽⁴⁾

Incorporating EMG Treatment

Surface EMG biofeedback provides real-time performance feedback during or immediately after exercises. This is ideal for motor learning and its application in daily movement patterns.⁽²⁾

Here are a few ways to use sEMG biofeedback in the clinic to correct improper shoulder movement patterns:

1. Shoulder Scaption / Elevation (Single Channel)
   • Place electrodes on the lower trap of the affected shoulder (see video for placement).
   • Instruct patient to perform elevation or scaption.
   • Encourage increasing lower trap activation – meter should rise.
2. Shoulder Scaption / Elevation (Dual Channel)
   • Electrodes on upper trap (CH1) and lower trap (CH2).
   • Patient performs elevation/scaption.
   • Keep CH1 (upper trap) low; increase CH2 (lower trap).

   Channel 1: Upper Trap | Channel 2: Lower Trap

3. Shoulder External Rotation (Single Channel)
   • Electrodes on infraspinatus of affected shoulder.
   • Patient performs external rotation.
   • Encourage increasing infraspinatus activation.
4. Shoulder External Rotation (Dual Channel)
   • Electrodes on infraspinatus (CH1) and posterior deltoid (CH2).
   • Keep CH2 (posterior deltoid) low; increase CH1 (infraspinatus).

   Channel 1: Infraspinatus | Channel 2: Posterior Deltoid

Summary

Recovering from shoulder impingement can be improved with mTrigger biofeedback. It provides real-time feedback during and after exercises, making it ideal for learning and reinforcing proper shoulder mechanics. Learn more here.

Webinars on Shoulder Rehab

References

1. Hotta GH, et al. Clin Biomech. 2018;58:7-13. View
2. Antunes A, et al. SciTePress. View
3. Cools AM, et al. Scand J Med Sci Sports. 2007;17(1):25-33. View
4. Du W-Y, et al. J Athl Train. 2020;55(3):265. View
5. Larsen CM, et al. J Electromyogr Kinesiol. 2014;24(1):58-64. View
6. Lim O, et al. J Hum Kinet. 2014;44(1):83. View