Written by Shelby Green, PT, DPT, MTC, CLT-LANA

What is a Pulley?

A shoulder pulley is a commonly used device in the rehab setting to aid in recovery from a shoulder injury or surgery. The pulley itself is a very simple device, which involves a door attachment and a handled rope that attaches to the pulley system. Due to the simplicity of this device, it has been found to be a great tool to use at home as part of a home exercise program; however, the real question remains: why does a shoulder pulley help in recovery?

Shoulder Dysfunctions

To understand why a pulley will assist in the rehab process, it is helpful to know what type of shoulder conditions and dysfunctions are needing help in the first place. Below you will see a list that includes some of the most common shoulder impairments, both surgical and non-surgical:

• Adhesive Capsulitis (a.k.a. Frozen Shoulder)
• Shoulder Impingement
• Shoulder Rotator Cuff or Other Muscle/Tendon Tear
• Shoulder Rotator Cuff Repair
• Shoulder Tendinopathy
• Total Shoulder Arthroplasty
• Reverse Total Shoulder Arthroplasty
• Shoulder Open Reduction Internal Fixation Status Post Fracture
• Shoulder Dysfunction Status Post Mastectomy with or without Reconstruction

As you can see, there are a multitude of shoulder injuries that can occur. Typically, if a surgery has been involved, it is not uncommon to follow a specific protocol established by your surgeon. It is important to follow these protocols, as they have a specific timeline to allow optimal soft tissue healing, and gradually promote return to full functioning without harming the surgical site. If a shoulder injury is non-surgical and has not resulted from a severe trauma, the rehab progression will normally be based on how you present at your initial evaluation with your physical therapist. 

The Importance of Range of Motion

One of the first items a physical therapist will assess during an initial consult is how much range of motion (ROM) is available. It is vital to gain as much functional and pain-free ROM as possible early in the rehab process. ROM exercises are necessary to maintain and promote mobility of the joints and soft tissues. Without this, you will quickly lose tissue flexibility and may develop a contracture.1 

There are three primary types of ROM: passive range of motion (PROM), active-assisted range of motion (AAROM), and active range of motion (AROM).1 A pulley will be helpful in promoting AAROM; however, each ROM type has its proper place in the rehab process. Understanding the specifics of each type of ROM can help in understanding the role of a shoulder pulley and how it helps in recovery. 

PROM:

PROM is created by an outside force. This may occur via a machine or by a person, such as your physical therapist. The goal is to move throughout an unhindered ROM with very little or no active muscle contraction.1 PROM is appropriate if dealing with an acute or inflamed soft tissue, which normally will occur immediately after an injury or surgery. In this phase of healing, an active motion may compromise or delay tissue healing.1

AAROM:

AAROM is a form of AROM, but still requires some assist from an outside force.1 This type of ROM is usually elicited if attempting to promote a slightly larger muscle contraction than PROM, but still refraining from initiating a full muscle contraction. Holding a full muscle contraction, such as in AROM, may be due to pain level, need for further tissue healing, or muscle weakness. It allows assistance so the muscle groups being stimulated can be gradually strengthened.1

AROM:

 AROM produces a full muscle contraction through the available ROM.1 Now tissues have appropriately healed, and an active contraction is desired. AROM can also be encouraged in the areas above and below an immobilized region, in order to maintain functional movement in the unaffected areas.1 

Ultimately, the goals of all types of ROM remain the same:

• Reduce or prevent pain

• Promote movement of synovial fluid to provide nutrients for cartilage
• Promote bone and joint integrity    
• Prevent contracture formation
• Increase circulation
• Promote and sustain soft tissue mobility
• Increase coordination and motor skills1

Amount of Muscle Activation During ROM

As mentioned above, each ROM type will trigger different amounts of muscle activity. Just how much muscle activity is the ultimate question. Various electromyographical (EMG) studies have been performed showing the levels of muscle activity during ROM, as well as functional activities. These guidelines can be extremely helpful to guide the rehab process. 

For example, a study from PM & R: The Journal of injury, function and rehabilitation specifically determined muscle activation levels during PROM, AAROM, and AROM in healthy participants.2 Fine wire electrodes were used in two rotator cuff muscles (supraspinatus and infraspinatus), while surface electrodes were used in the anterior deltoid, upper trapezius, lower trapezius, and serratus anterior muscles. These electrodes recorded activity from the above muscle groups during 12 exercises focused on ROM. Ultimately, PROM was found to create the lowest activity level (<10%) for all muscle groups. AAROM created a small level of muscle activity for supraspinatus and infraspinatus (<10%), but slightly greater than what was created via PROM. AROM, particularly shoulder elevation performed in standing, created the greatest amount of muscle activity (40%). The conclusion of the study implies that most of the exercises used early on in rehab, namely with PROM and AAROM, will use a low maximum voluntary muscle contraction. Even the transition from PROM to AAROM will not create a significant difference in muscle activation; however, because of the significant increase in muscle activity with AROM, those exercises are best used in later rehab phases.2 

Consider an alternative study from the Journal of Orthopaedic & Sports Physical Therapy. This study specifically determined the amount of rotator cuff muscle activity with functional tasks compared to ROM performed while in physical therapy.3 Indwelling EMG activity was tested with all four rotator cuff muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. Surface EMG activity was tested in the upper trapezius, biceps, and mid deltoid. Donning and doffing a shirt or sling were found to stimulate the greatest muscle activity in the rotator cuff. For a shirt specifically, supraspinatus and teres minor demonstrated the greatest muscle activity, followed by infraspinatus then subscapularis. For a sling however, the highest muscle activity was shown in infraspinatus, subscapularis, and the biceps. In comparison to the rehab ROM tasks, use of a pulley created increased rotator cuff activation when compared to the pendulum exercise, PROM, or use of a dowel. Furthermore, practice of the pulley in the scapular versus sagittal plane caused increased EMG activity.3 This information is significantly important to know and understand to properly guide progressive muscle activity and ROM both in the rehab setting and functionally at home. 

Benefits of Home and Professional Rehab

If you are experiencing any type of shoulder pain (e.g., surgical or non-surgical), it is highly recommended to consult with a rehab specialist. If a surgery has been involved, your surgeon will give specific guidelines for when to begin your rehab journey. A rehab professional with knowledge of rehabilitating shoulder injuries (a physical or occupational therapist) can provide an incredible wealth of information and hands-on assistance that will allow for a smooth recovery. Part of your home program provided by your therapist will always involve a home exercise regimen. 

An article in the Singapore Medical Journal discusses the typical treatment options specifically for a frozen shoulder.4 While anti-inflammatories and injections are commonly prescribed by medical practitioners to initially treat painful symptoms, this article highlights how and why physical therapy and a home exercise program should be included in the initial management phase. Physical therapy will provide a direct source of education regarding the shoulder diagnosis, pain relief, and sooner return to an individual’s prior level of function. Anti-inflammatories have even been found to work more effectively for pain relief in conjunction with rehab.4 To say the least, the importance of therapy and your home program cannot be overstated. 

As ROM progression is one of the first priorities, this is where an at-home pulley can further move along your recovery. Once it is appropriate to initiate the amount of muscle activity found with AAROM, try to begin self-assisted ROM as soon as able. This will promote controlled and assisted movement, while protecting healing soft tissues.1 It is not uncommon during AAROM performed by an outside force (e.g., your therapist or a machine/object), that you may be nervous to elicit a painful response, and therefore begin muscle guarding. Unfortunately, this guarding can worsen pain and will prevent you from gaining the most optimal ROM. For this reason, self-assisted ROM, such as with pulleys, can be very helpful as you are in control of the movement. Additionally, if you’re trying to intentionally create greater muscle activity, this will usually occur with a tool, such as a pulley, versus manual assist from a therapist or machine.1 

Another factor to consider is that not everyone will have access to a rehab professional. This may be due to location or finances and lack of insurance. In cases such as these, a home exercise program is incredibly vital. While the combination of in-person therapy and a home program is preferrable, you can still achieve success with an independent home program; however, your recovery may take a little longer. Normally manual therapy is a primary part of shoulder recovery, but studies have shown that use of pulleys for AAROM show similar results as manual joint mobilizations performed by a therapist in certain conditions, such as frozen shoulder. This indicates that AAROM is an effective method for both increasing ROM and reducing pain levels.5 

Conclusion

The role of a pulley in the rehab process should always be addressed in the clinic and at home. Once a patient has reached an appropriate time frame of tissue healing, and a certain amount of muscle activity is warranted, the pulley is a great tool to aid in recovery. After guidance from a rehab professional as to how to properly use a pulley to progress functional ROM, consider acquiring this tool for your home program. It will allow you to gently advance a greater pain-free range, while also re-training your shoulder musculature. This will allow you to recover more efficiently and move on to the more advanced phases of the rehab process in a timely manner. 

References:

1. Kisner C, Lynn Allen Colby, Borstad J. Therapeutic Exercise: Foundations and   Techniques. 7th ed. F. A. Davis Company, Cop; 2018.
2. Uhl TL, Muir TA, Lawson L. Electromyographical Assessment of Passive, Active Assistive, and Active Shoulder Rehabilitation Exercises. PM&R. 2010;2(2):132-141. doi:10.1016/j.pmrj.2010.01.002.
3. Gurney AB, Mermier C, LaPlante M, et al. Shoulder Electromyography Measurements During Activities of Daily Living and Routine Rehabilitation Exercises. Journal of Orthopaedic & Sports Physical Therapy. 2016;46(5):375-383. doi:10.2519/jospt.2016.6090.
4. Chan HBY, Pua PY, How CH. Physical therapy in the management of frozen shoulder. Singapore Med J. 2017;58(12):685-689. doi:10.11622/smedj.2017107.
5. Aziz A, Muhammad Asim H, Dilshad Ali H. Comparison of Outcome of Passive Joint Mobilization Techniques with Active Assisted Pulley Exercises in Patients with Frozen Shoulder in Improving Range of Motion. International Journal of Science and Research. 2015;4(4):255-259. Accessed June 2, 2022. https://www.researchgate.net/profile/Hira-Ali-4/publication/274709741_Comparison_of_Outcome_of_Passive_Joint_Mobilization_Techniques_with_Active_Assisted_Pulley_Exercises_in_Patients_with_Frozen_Shoulder_in_Improving_Range_of_Motion/links/5526b65e0cf2e486ae40929c/Comparison-of-Outcome-of-Passive-Joint-Mobilization-Techniques-with-Active-Assisted-Pulley-Exercises-in-Patients-with-Frozen-Shoulder-in-Improving-Range-of-Motion.pdf.