Efficacy of Heavy Slow Resistance Training in Adults With Frozen Shoulder- a Double Blind Randomised Controlled Trial
Phase: NA
Conditions: Frozen Shoulder
Sponsor: Ministry of Health, Kuwait

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Effect of heavy slow resistance exercise 
in adults with frozen shoulder: 
a randomized controlled 
trial(HSRFSRCT) 
 
 
 
 
DATE: - 04/07/2022 
 
 
 
 
 
 
 
 
 

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Introduction and Background  
Frozen shoulder is characterized by painful limitation of active and passive range of 
motion (ROM) of the shoulder. People describe pain, which can be severe, an inability to 
sleep on the affected side, loss of shoulder function in activities of daily living and limited 
movements that can lead to chronic stiffness.  
 
Physiotherapy is one of the main treatments which aims to reduce pain, and regain mobility, 
muscle strength and optimal daily function. There is global loss of both passive and active 
ROM of the glenohumeral joint, with external rotation usually being the most restricted 
physiologic movement. Although frozen shoulder is frequently described as a self-limiting 
condition with gradual spontaneous recovery ,the condition typically has mean duration of 30 
months. 
 
Individuals with primary frozen shoulder are commonly between 40 and 65 years old, and the 
incidence appears 4 times higher in females than males. The condition generally presents 
unilaterally with the non-dominant shoulder more commonly affected.  
 
Frozen shoulder is “a condition difficult to define, difficult to treat, and difficult to explain 
from the point of view of pathology(Codman 1935) . The term adhesive capsulitis was 
introduced by Nevaiser to describe the inflamed and fibrotic condition of the capsule sticking 
to the humerus. But this term does not appear to appropriately describe the condition and 
arguably term should be abandoned as explained by Lundberg (1979). 
 
The etiological explanation of frozen shoulder was directed toward two theories, contraction 
of the capsule and adhesions of the capsule which were running parallel. Some histological 
findings show that there is contraction of the capsule. In 1969, Lundberg came with the term 
frozen shoulder syndrome. In 2014, Jeremy Lewis came out with the term frozen shoulder 
contraction syndrome. It is likely that limitations in range of motion and the pain associated 
with frozen shoulder are not only related to capsular and ligamentous tightness, but also 
fascial restrictions, muscular tightness, and trigger points within the muscles. Physical 
therapists can address impairments and limitations associated each of these contributors to 
the pathology of frozen shoulder with a variety of treatment methods. 
 
A meta-analysis suggested that glucocorticoid injections combined with exercise and manual 
therapy may provide improvement in range of motion . 
 
Intensive mobilization may be more effective than other methods but mostly for late stages of 
the disease. Rehabilitation programs consisting of exercise, and modalities have been shown 
to improve shoulder ROM in all planes except external and internal rotation . 
 
One study also showed that supervised neglect physical therapy worked better than intensive 
physical therapy . 
 
A 2013 RCT showed short term improvement in function and range of motion in the painful 
phase using intra-articular corticosteroid . A 2016 study showed adding mobilsation to 
stretching patients had a long-term improvement in function and passive range of motion at 
one year follow up .  
 
In a review of 31 studies in 2012, Maund et al concluded that there is limited clinical 
evidence on the effectiveness of treatments for primary frozen shoulder .  

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The UK FROST trial compared early structured physiotherapy, manipulation under 
anesthesia and arthroscopic capsular release. All three treatment options led to 
substantial improvements in pain and function and none of the treatments were superior 
to each other in the long term follow up  
 
A recent study by Hollmann et al (2018) has demonstrated that muscle guarding may be a 
significant contributing factor to shoulder movement deficits in some patients suffering from 
frozen shoulder  In a sample of five patients with an indication for capsulotomy, they found 
that under general anesthesia, the movement of the affected shoulder was less restricted. All 
patients showed a significant increase in their passive range of motion (ROM), especially in 
abduction while under general anesthesia conditions, compared to their ROM while awake.  
 
This finding supports the hypotheses that the fear of pain or the fact that little used tissue can 
be more easily damaged can produce a fear-based brain reaction and generate a muscle 
defense response that could lead to Frozen Shoulder. So, this may be the major contributing 
factor to movement restriction in some of these patients although more research is needed to 
determine the number of patients suffering from this type of Frozen shoulder. 
 
One study by Donatelli et al shows promising results with low load prolonged stretch in 
frozen shoulder but there is no evidence for high load training.  
 
An RCT by Annales et al showed that adding heavy load eccentric training resulted in a 
higher gain of isometric strength at 90 degrees of scapular abduction in subacromial 
impingement. Another study shows that a 12-week-isolated eccentric training program of the 
rotator cuff is beneficial for shoulder function and pain after 26 weeks in patients with rotator 
cuff tendinopathy . A systemic literature review shows that eccentric exercise may provide a 
small but likely not clinically important reduction in pain compared with other types of 
exercise in patients with subacromial impingement syndrome. But the load used on these 
studies were low.  A systemic review by Kieren O sullivan shows eccentric training can 
improve strength and reduce the risk of injury in lower limb and facilitate increased muscle 
flexibility via sarcomerogenesis.  
 
The forces applied during inferior glenohumeral mobilizations may vary between 3 to 14 kg 
(Witt 2016). A Japanese researcher Eiji Itoi (1993) found that 683 kg/cm2 of force is required 
to stretch the posterior glenohumeral joint capsule. The heaviest dead lift is 472 kg (2018 
world record) is still not enough to stretch the capsule. Most of the frozen shoulder 
contraction syndrome may be due to muscle inhibition, as the capsule cannot be stretched. 
So, exercise, stretching, mobilization procedures are suggested to decrease the muscle 
guarding.  
 
This study focuses on the hypothesis that a heavy slow resistance exercises may have a role 
on muscle guarding in these cases. As there is evidence that frozen shoulder could be further 
complicated with muscle guarding which could further complicate the capsular adhesion, and 
hence a heavy slow resistance exercise is an effective therapeutic intervention which could 
control the muscle guarding status around the shoulder.  
 
 
 
 

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Objective  
The objective of this study is to compare the effect of heavy slow resistance exercises with 
conventional physical therapy alone for the management of frozen shoulder using double-
blind randomized controlled trial design.   
 
Methods 
The study will employ a double-blind randomized controlled study design. Ethical approval 
has been obtained from Kuwait Ministry of Health, Ethics committee. Written informed 
consent will be completed. Seventy patients both Kuwaitis and non-Kuwaitis with frozen 
shoulder attending the outpatient department of the Al Farwaniya hospital and PM& R 
hospital will be randomly assigned to the heavy slow resistance exercises group and the 
control group. 
 
Sample size 
Shoulder external rotation range of motion is considered as the primary outcome measure for 
the proposed study. A study by Celik (2010) [24] was used to inform the sample size 
calculation, where the shoulder external rotation was measured at baseline and at 12-week 
post intervention for the glenohumeral range of motion exercise group. Using the means and 
standard deviations of 22 (12.5) degrees and 33 (14.9) degrees for external rotation range of 
motion changes resulted in an effect size of -0.799. With a two tailed hypothesis, the 
minimum required sample size is 30 patients per group at () 0.05 and a power (1- ß) of 85%. 
35 participants per group will be recruited to account for attrition. 
 
Randomization/Blinding 
Participants will be randomly assigned following simple envelope randomization procedures 
to one of the two treatment groups. Patients will be blinded from the treatment group, and the 
examinations will be performed by a blinded examiner. 
 
Intervention 
Both groups will receive conventional therapy sessions which include active ROM exercise, 
strengthening and stretching exercises, end-range mobilization and hot packs (if indicated). 
Exercises will be given within the pain threshold limit twice a week for 12 weeks. In 
addition, the experimental group will receive heavy slow resistance exercise program using a  
a theratube. The exact management approach will be standardized between the two groups in 
terms of intensity and frequency and the experimental group will only receive additional 
heavy slow resistance exercise. 
 
Subjects will be assessed at baseline and at 3, 6, and 12 months. Shoulder external rotation 
and abduction ROM will be measured and compared within and between groups and will be 
analyzed using a One-way ANOVA. 
 
Inclusion Criteria 
Inclusion criteria are males and females, Kuwaiti and non-Kuwaiti between 40 and 65 years 
with unilateral painful, restricted active and passive range of motion of the shoulder, with 
loss of passive external rotation of at least 50% compared to opposite side at 0 degrees of 
abduction and with normal X ray findings ]. Patients will be included if symptoms present for 
at least 3 months (Cyriax, 1993; Griggs et al., 2000).  
 
 
 

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Exclusion Criteria  
Severe degeneration, or trauma involving the shoulder (ie, rheumatoid arthritis, osteoarthritis, 
history of injury to the labrum or articular cartilage or malignancies in the shoulder region, 
etc.). 
Neurologic diseases such as stroke or peripheral nerve neuropathy. 
Pain or disorders of the cervical spine, elbow, wrist, or hand. 
Pregnancy, cardiac, respiratory, kidney, or circulatory problems pregnancy. 
History of fractures, treatment, or surgery to the lumbar spine, thoracic spine, cervical spine, 
and upper limbs  
 
Injection with corticosteroids in the affected shoulder in the preceding 4 weeks. 
Subjects with diabetes mellitus will be accepted. 
Inflammatory joint disease affecting the shoulder. 
Bilateral frozen shoulder due to possible underlying systemic cause. 
 
Outcome Measures 
The primary outcome measure is shoulder range of motion (active and passive shoulder 
abduction, and active and passive shoulder external rotation) measured by smartphone 
inclinometer (clinometer plaincode). The secondary outcome measures will be functional 
outcome measures [measured by the quick Disabilities of the Arm, Shoulder and Hand 
(Quick DASH) questionnaire and pain [measured using a visual analogue scale (VAS)] and 
SF-12 and Oxford Shoulder Score (OSS). 
 
Data analysis 
SPSS will be used for statistical analysis. All outcome measures will be analyzed using one-
way ANOVA.