Validity and Feasibility of the Seated Medicine Ball Throw and Unilateral Shot-Put Tests in Assessing Upper Extremity Function in Rotator-Cuff-Related Shoulder Pain
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors,
thank you for the opportunity to review this manuscript prior to publication. Overall, it is an interesting paper, but the reviewer has her doubts about its clinical relevance due to the complex test setting. Below are the detailed comments:
Introduction:
Please further describe the clinical relevance of these new tests. What do you expect yourself from implementing those test in your daily clinical examination?
What means closed and open kinetic chain positions? How are they charaterized and what distinguishes them from each other?
Methods:
It is quite hard to imagine how the technique of the test worked. A figure demonstrating the different steps would conduct extremely to better understanding.
How was it confirmed that the participants had shoulder pain associated with the rotator cuff? Did they undergo imaging? In the reviewer's experience, most patients present with a combination of symptoms on clinical examination, meaning that several structures can be responsible for the pain (e.g. long biceps tendon, AC joint, rotator cuff). How did you differentiate between these or filter only those with a painful rotator cuff?
Author Response
Reviewer's Comment:
Introduction:
- Please further describe the clinical relevance of these new tests. What do you expect yourself from implementing those test in your daily clinical examination?
Author’s response:
We addressed your comment in the following addition to the Introduction:
Location: Introduction section, after paragraph 3 (after "...evaluating shoulder muscle performance in a functional manner may hold clinical significance [4].")
“The clinical implementation of functional tests that assess shoulder strength and power holds particular relevance in several contexts. First, these tests can provide objective measures of functional capacity that complement traditional clinical examinations. Unlike isolated muscle testing or range of motion assessment, functional tests can evaluate the integrated performance of the upper extremity, offering insights into how RCRSP affects daily activities and occupational tasks. Second, when selecting appropriate interventions and monitoring progress, clinicians need reliable tools that can quantify functional improvements without exacerbating symptoms [4].”
The SMBT and ULSPT may fulfill this need by measuring power output in a controlled, seated position that minimizes lower limb involvement and compensatory movements, and potentially of minimal risk of symptom aggravation.
- What means closed and open kinetic chain positions? How are they charaterized and what distinguishes them from each other?
Author’s response:
For the second point regarding open and closed kinetic chain definitions we added the following text. Location: Introduction section, where these terms are first mentioned (paragraph 3)
“While functional upper extremity tests exist, including push-up, pull-up, Y-Balance Test-Upper Quarter, and the Closed Kinetic Chain Upper Extremity Test, these are performed in closed kinetic chain positions (where the distal segment is fixed and the proximal segment moves, typically with the hand or forearm fixed against a surface)[5,6]. Many daily shoulder activities, however, occur in an open kinetic chain, where the distal segment moves freely through space while the proximal segment remains relatively fixed, such as reaching, lifting, or throwing movements.”
This distinction is crucial as different kinetic chain positions can affect muscle recruitment patterns, joint forces, and functional performance in ways that may influence test results and clinical applicability{Karandikar, 2011 #193}.”
Methods:
- It is quite hard to imagine how the technique of the test worked. A figure demonstrating the different steps would conduct extremely to better understanding.
Author’s response:
We added 2 figures (Figure 1+2) to demonstrate the SMBT and ULSP tests. In addition we also added the testing procedure.
- How was it confirmed that the participants had shoulder pain associated with the rotator cuff? Did they undergo imaging? In the reviewer's experience, most patients present with a combination of symptoms on clinical examination, meaning that several structures can be responsible for the pain (e.g. long biceps tendon, AC joint, rotator cuff). How did you differentiate between these or filter only those with a painful rotator cuff?
Author’s response:
We addressed this important comment in the methods section, under "3.1. Study Design and Participants":
“Diagnosis of RCRSP was established through a clinical examination performed by a shoulder orthopedic specialist. While imaging is not required for diagnosing RCRSP, participants who had undergone imaging (MRI, ultrasound) had findings consistent with RCRSP. “
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript is interesting and has merit, however I have a few comments:
1. The RCRSP group is not homogenous group of patients. Were these patients further stratified based on final radiologic/arthroscopic diagnosis? If not, this is severe limitation of the study, since test could behave differently in each subgroup of patients.
2. Figures demonstrating each test would help the readers to appreciate how these tests are performed.
3. The use of questionnaires QuickDASH and FABQ and also VAS are subjective measures. Why were patients not examined for physical function?
4. Since the sample size was small Shapiro-Wilk test would be more appropriate for normality testing.
5. Were ROC analysis to determine potential cut-off values performed?
6. Can you discuss further whether the tests would be feasible with all pathologies causing RCRSP or better for some and not appropriate for other?
7. The mean age of studied population was quite low (40), since most of the people with RCRSP are older than 60, do you think this would change the results somehow?
8. For correlation results some scatterplots would be beneficial, at least for most important results, so the readers could easier see the significance of correlations.
Author Response
Reviewer 2's comments:
The manuscript is interesting and has merit, however I have a few comments:
- The RCRSP group is not homogenous group of patients. Were these patients further stratified based on final radiologic/arthroscopic diagnosis? If not, this is severe limitation of the study, since test could behave differently in each subgroup of patients.
Author’s response:
Addressed and added to Discussion section, under "5.5. Limitations"
“This study has potential heterogeneity within the RCRSP group. While all participants met the clinical diagnostic criteria for RCRSP, this diagnosis is a wide umbrella term. We did not further stratify participants based on specific pathological findings (e.g., tendinopathy, partial-thickness tears, or bursitis) through imaging or arthroscopic diagnosis. Future studies should consider subgroup analysis based on specific pathological diagnoses to determine if these tests perform differently across various RCRSP presentations. However, this limitation reflects the clinical reality where RCRSP often presents as a complex, multifaceted condition rather than a homogeneous pathology.”
- Figures demonstrating each test would help the readers to appreciate how these tests are performed.
Author’s response:
Addressed. Figures 1 & 2 were added to demonstrate the throwing tests.
- The use of questionnaires QuickDASH and FABQ and also VAS are subjective measures. Why were patients not examined for physical function?
Author’s response:
We added the following text to address this comment.
Location: Add to Methods section, under "experimental procedure"
“While self-reported measures (QuickDASH, FABQ, VAS) formed a significant component of our assessment, these were complemented by objective physical measures including grip strength and active range of motion. Grip strength serves as a validated strength measure for upper extremity function and has shown strong correlations with shoulder strength in previous research [24,25]. Active range of motion provides an objective measure of functional mobility that directly impacts daily activities.”
The combination of subjective and objective measures aligns with current recommendations for comprehensive shoulder assessment (Doiron-Cadrin, Lafrance et al. 2020).
Additional physical function tests were considered but not included to avoid excessive fatigue or symptom aggravation that might affect the primary outcome measures (SMBT and ULSPT). Future studies might consider incorporating additional physical function measures such as the Simple Shoulder Test or Performance Activity Test, provided adequate rest periods are included between assessments.
- Since the sample size was small Shapiro-Wilk test would be more appropriate for normality testing.
Author’s response:
Thank you for the correction, the Shapiro-Wilk test was found of superior power for smaller sample sizes compared to other normality tests (Razali and Wah 2011). This was addressed. Location: Methods section, under "Statistical Analysis"
"Data normality was assessed using the Shapiro-Wilk test.”
- Were ROC analysis to determine potential cut-off values performed?
Author’s response:
We did not include ROC analysis in our study. This was added to the limitations.
Location: Add to Discussion section, under "5.5. Limitations"
“Another limitation is the absence of receiver operating characteristic (ROC) analysis to determine optimal cut-off values for discriminating between individuals with and without RCRSP. Such analysis would enhance the clinical utility of these tests by providing clinicians with specific thresholds for identifying functional deficits and monitoring progress. Future research should focus on establishing these cut-off values across different age groups and activity levels, which would facilitate more precise clinical decision-making and outcome assessment.”
- Can you discuss further whether the tests would be feasible with all pathologies causing RCRSP or better for some and not appropriate for other?
Author’s response:
Thank you for the important point, which was added to the discussion. Location: Discussion section, after paragraph discussing clinical implications.
“We believe the applicability of these tests should not vary significantly across different RCRSP presentations. Based on our findings and theoretical considerations, the ULSPT and SMBT may be appropriate for patients with mild to moderate shoulder symptoms who can maintain appropriate positioning and generate sufficient force for the throwing action. These tests might be less suitable for acute and severe cases, or significant shoulder stiffness which could limit the throwing position.”
- The mean age of studied population was quite low (40), since most of the people with RCRSP are older than 60, do you think this would change the results somehow?
Author’s response:
Thank you for the valuable comment. RCRSP is most common in people over 40 years old, with the prevalence increasing significantly in people aged 60 and above. This is largely due to age-related degeneration of the tendons combined with years of repetitive use. However, it's worth noting that younger people can also experience rotator cuff problems, as did the population in our study.
We added the following text addressing the age group limitation to Discussion section, under "5.5. Limitations"
“The relatively young age of our study population (40 years) represents a generalization limitation, given that RCRSP is most prevalent in individuals over 60 years of age. The performance characteristics and feasibility of these tests might differ in older populations due to age-related changes in muscle strength, power generation, and overall shoulder function. Future validation studies are needed in older populations to establish age-specific normative values and assess test feasibility in this demographic.”
- For correlation results some scatterplots would be beneficial, at least for most important results, so the readers could easier see the significance of correlations.
Author’s response:
Thank you for the suggestion to add visualization to the correlation results.
We added Figure 3: Key Correlations in RCRSP and control Groups. Location: Results section, add new figure after Table 4.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors porpose an interesting application, that could be the first step to have a new support on management of shoulder pain related deseases.
The manuscript is well written and it could be seen as preliminary study, even that limit are presented in a objective way.
For sure it should be replicated in a more ample and comprensive sample.
It should be better highltighted physical activity level of participants.
It should be set a protocol to be applied, better id differentiated in pathological states
Author Response
Reviewer 3's Comments:
The authors porpose an interesting application, that could be the first step to have a new support on management of shoulder pain related deseases.
The manuscript is well written and it could be seen as preliminary study, even that limit are presented in a objective way.
For sure it should be replicated in a more ample and comprensive sample.
It should be better highltighted physical activity level of participants.
It should be set a protocol to be applied, better id differentiated in pathological states
Author’s response:
Thank you reviewer 3, for your positive feedback, and suggestions for improvement which we have addressed.
- Preliminary nature:
Location: Beginning of Discussion section:
" This preliminary investigation into the measurement properties of the SMBT and ULSPT provides initial evidence supporting their potential utility, particularly the ULSPT, in RCRSP assessment. While the findings are promising, they should be considered as a foundation for further research rather than definitive validation."
Conclusion:
"This study provides encouraging evidence for the clinical utility of these tests, particularly the ULSPT. However, larger-scale validation studies across diverse populations and clinical settings are needed to establish these tests as standard clinical tools."
- Physical activity level:
We added to the Methods section, under participant characteristics:
"Physical activity levels were collected through a single self-report of weekly PA hours, documenting the type and duration of physical activity per week.”
PA was not an outcome measure in this study, and therefore we did not use a complete PA evaluation tool such as the International Physical Activity Questionnaire (IPAQ) as it served as an additional descriptive parameter (population descriptive is presented in Table 1).
- protocol:
We added the throwing testing protocol as an appendix, for clinician’s use, and added the following text to the discussion, limitations, regarding the heterogenic presentations in RCRSP.
“This study has potential heterogeneity within the RCRSP group. While all partici-pants met the clinical diagnostic criteria for RCRSP, this diagnosis is a wide umbrella term. We did not further stratify participants based on specific pathological findings (e.g., tendinopathy, partial-thickness tears, or bursitis) through imaging or arthroscopic diagnosis. Future studies should consider subgroup analysis based on specific patho-logical diagnoses to determine if these tests perform differently across various RCRSP presentations. However, this limitation reflects the clinical reality where RCRSP often presents as a complex, multifaceted condition rather than a homogeneous pathology.”
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors satisfactorily addressed my comments. However, I cannot find new figures, so I cannot comment on them.
