Title: Short-term effects of a new resistance exercise approach on physical function during
chemotherapy after radical breast cancer surgery: a randomized controlled trial
Version: 2 Date: 20 Dec 2023
Reviewer's report:
Thank you for the opportunity to review the manuscript entitled: “Short-term effects of a new
resistance exercise approach on physical function during chemotherapy after radical breast
cancer surgery: a randomized controlled trial.”
1. The abstract mentions "short-term effects" but does not provide a specific duration of the
intervention or define what is considered short-term. A clearer timeframe would enhance the
precision of the study's findings.
2. The abstract does not mention any follow-up assessments beyond the post-intervention period.
Information on the sustainability of the observed effects over time would provide a more
comprehensive understanding of the intervention's impact.
3. While the abstract reports post-intervention outcomes, it does not explicitly compare these
results with baseline values.
4. The abstract focuses on shoulder range of motion, pain, grip strength, and supraspinatus
muscle thickness as outcome measures. Additional functional outcomes or patient-reported
outcomes could offer a more comprehensive assessment of the intervention's impact on patients'
daily lives.
5. The abstract does not specify if the study was conducted in a single center. If so, it may limit
the generalizability of the findings to a broader population.
6. The abstract does not mention randomization methods, raising questions about the potential
for bias in group assignment. A clear description of the randomization process would enhance
the study's methodological rigor.
7. The abstract lacks detailed information about the nature of the control group. Describing the
interventions or activities of the control group would provide a clearer context for interpreting
the NJF group's outcomes.
8. While the abstract reports statistical significance, it does not provide information on the
clinical significance of the observed changes. Understanding the practical implications of the
findings is essential for clinicians and researchers.
9. While providing statistics on breast cancer incidence globally and in China, the introduction
lacks a clear connection to the specific focus of the study—the short-term effects of a
new resistance exercise approach. The global context, while informative, may dilute the
introduction's relevance to the study's objectives.
10.  The introduction mentions shoulder joint movement disorders in post-operative cancer
patients but does not elaborate on the nature and extent of these disorders. A more detailed
discussion of the challenges faced by breast cancer patients post-surgery would provide a
stronger rationale for the study.
11.  The introduction briefly mentions shoulder joint dysfunction caused by breast cancer
treatment but does not cite specific studies or evidence supporting this claim. Incorporating
references to relevant literature would enhance the credibility of the stated problems and the
need for further research.
12.  The introduction introduces the idea that shoulder joint dysfunction may be related to the
pathological development of the rotator cuff but lacks elaboration on the specific pathology
involved. Providing more details on the rotator cuff's role and its post-treatment changes would
add depth to the introduction.
13. While the introduction hints at post-operative changes, such as increased shoulder pain and
decreased shoulder function, it does not provide specific details on the temporal progression
of these changes. A clearer timeline would contribute to understanding the evolving challenges
faced by patients.
14.  The introduction mentions the benefits of active exercise and physical therapy without
specifying the details or outcomes of these interventions. A more comprehensive discussion of
previous therapeutic approaches would help contextualize the new resistance exercise approach
introduced in the study.
15. The hypothesis regarding the improvement in rotator cuff muscle contraction through
proximal shoulder joint resistance is presented, but the connection between this hypothesis and
the specific NJF intervention is not clearly established. Further clarification on the rationale
behind the chosen intervention is needed.
16.  While introducing NJF, the description lacks clarity on how this method differs from
existing therapies and why it is considered a suitable intervention for the study. A more detailed
explanation of NJF and its theoretical basis would enhance the introduction.
17. The introduction briefly mentions previous studies demonstrating the positive effects of NJF
but does not provide specific details or references. Citing and summarizing these studies would
strengthen the foundation for using NJF in the current research.
18. The introduction introduces the study's focus on patients with shoulder dysfunction during
chemotherapy but does not clearly explain the relevance of chemotherapy to shoulder issues or
how the proposed intervention addresses these challenges specific to the chemotherapy context.
19. The study was conducted at Beijing Chaoyang Sanhuan Cancer Hospital, which may limit
the generalizability of the findings. Results from a single center might not be representative of a
broader population, and variations in patient demographics and healthcare practices could affect
external validity.
20. The study duration is mentioned as November 2020 to March 2022, but the specific
intervention period or the length of follow-up after the intervention is not provided.
21. While patients were randomly divided into three groups, the method of randomization is
not detailed. A lack of information on the randomization process may introduce bias or raise
questions about the allocation concealment and randomness of the assignment.
22.  Although age, body mass index (BMI), and surgical side information were collected, the
method lacks a comprehensive description of other potentially relevant patient characteristics,
such as comorbidities or baseline physical activity levels. These factors could influence the
outcomes but are not adequately addressed.
23.  It appears that both the patients and the physical therapists were aware of the assigned
interventions. The absence of blinding introduces the possibility of bias, especially in subjective
outcomes like pain assessment, where patients may unintentionally provide responses aligning
with the perceived effectiveness of their assigned intervention.
24.  The study's sample size calculation is mentioned, but specific details about the literature
and case analyses used for this calculation are not provided. A more transparent explanation
of the sources and methods used for sample size determination would enhance methodological
transparency.
25. While the study introduces NJF (neuromuscular joint facilitation) as a novel resistance
exercise approach, the detailed protocols and parameters of NJF are not thoroughly explained.
A clear description of the intervention is essential for reproducibility and understanding the
intervention's mechanisms.
26. The training period for patients in the NJF group is not specified. The lack of information on
the duration and intensity of the NJF intervention may impact the interpretation of results and
the reproducibility of the intervention in future studies.
27. Patients in the control group were provided with a self-training manual, but the content and
specificity of the manual were not detailed. This lack of information makes it challenging to
assess the extent to which patients in the control group engaged in any form of self-directed
exercises.
28. The study mainly focuses on pre- and post-intervention assessments, providing a snapshot
of outcomes. Longitudinal data would be valuable in understanding how outcomes evolve,
especially during chemotherapy and post-surgery recovery.
29. The study mentions that patients practiced operating the ultrasound machine under the
guidance of a clinical laboratory technician, but details regarding the training of physical
therapists for NJF interventions are not provided. The consistency and quality of the intervention
may depend on the proficiency of the therapists.
30. The study does not mention monitoring patient adherence to the prescribed interventions,
especially in the control group with a self-training manual. Adherence rates can impact the
validity of study results, and their absence introduces a potential confounding factor.
31. The method does not explicitly address potential confounding variables, such as concurrent
treatments or medications that participants may be undergoing during the study period.
Unaccounted variables could influence the observed outcomes.
32. The study uses bivariate ANOVA for statistical analysis, but it doesn't provide a clear
rationale for choosing this method over others. An explanation of why this specific statistical
approach was deemed most appropriate would enhance methodological transparency.
33. There is a notable imbalance in the types of surgeries performed, with 54.3% undergoing
modified radical mastectomy (MRM) and 45.7% undergoing breast-conserving surgery (BCS).
This imbalance might impact the generalizability of the findings, especially if certain surgical
procedures influence outcomes differently.
34. The study reports short-term effects, but the absence of long-term follow-up data limits the
understanding of the sustainability of the observed improvements.
35. While objective measures such as range of motion and muscle thickness are reported, the
study lacks patient-reported outcomes related to the overall quality of life, satisfaction with
interventions, or perceived improvements in daily activities. Including patient perspectives
would provide a more holistic view of the intervention's impact.
36. The study does not explicitly mention controlling for potential confounding variables, such
as concurrent treatments or medications. The influence of these variables on the observed
outcomes is unclear, and their omission limits the ability to draw causal relationships.
37.  While the tables present mean values before and after interventions, statistical significance
is not consistently reported in the text. Clear statements on the significance of changes would
enhance the interpretation of the results.
38.  Subgroup analyses, such as those comparing different surgical procedures, may be limited
by the relatively small sample size in each subgroup. Small sample sizes can lead to insufficient
statistical power and affect the reliability of subgroup-specific findings.
39. The improvements in outcomes, especially in the control group, might be influenced
by a learning effect or increased familiarity with the assessment procedures rather than the
interventions themselves. This potential bias should be acknowledged and discussed.
40. The results for the supraspinatus contraction rate are inconsistent in reporting, and the
meaning of changes at different abduction angles is not clearly explained. Providing a more
detailed interpretation of these results would aid in understanding their clinical implications.
41. The discussion lacks a comprehensive comparison of the study's findings with existing
literature. While the study mentions previous research briefly, it does not critically analyze how
its results align with or differ from prior studies, limiting the context for understanding the
significance of the current findings.
42. While the study asserts that NJF demonstrated a facilitative effect on external rotation
muscles, it falls short in providing an in-depth exploration of the underlying mechanisms. A
more detailed discussion on how NJF specifically influences muscle activation, joint stability,
and intracapsular motion would enhance the theoretical basis of the intervention.
43. The discussion primarily focuses on objective measures, such as range of motion, pain
scores, and muscle thickness, but lacks a thorough exploration of patient-reported outcomes.
Considering the subjective nature of pain and functional improvements, a more detailed analysis
of patients' experiences and perceptions would contribute to a more holistic interpretation.
44. The discussion mentions improvements in shoulder joint mobility disorders and external
rotation but does not provide a clear elaboration on the functional implications of these
improvements.
45. While the study introduces supraspinatus muscle contraction rate as a new index, the
discussion fails to thoroughly explore the clinical significance of changes in this parameter.
46. The study acknowledges the lack of an untreated control group due to ethical considerations
but does not thoroughly discuss how this limitation might impact the interpretation of the study
results.
47. Overemphasis on Short-Term Effects: The study explicitly labels itself as a short-term
observation, but the discussion lacks a robust exploration of the implications of short-term
improvements for long-term outcomes. A more thorough discussion on the necessity for and the
design of future long-term studies would provide a clearer roadmap for advancing the research.
48. The discussion does not touch upon the cost-effectiveness of the NJF intervention.
Considering the importance of resource allocation in healthcare, a brief exploration of the
economic implications and feasibility of implementing NJF on a larger scale would add depth
to the discussion.