Review Reports - Assessing Aquatic Readiness as a Health-Enhancing Measure in Young Swimmers with Physical Disabilities: The Revised Aquatic Independence Measure (AIM-2)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Author, please recheck and answer the below items:

In the introduction part:

How does the study account for potential confounding variables, such as previous swimming experience or access to aquatic training facilities, that might influence the participants' progress?

Given that the study assumes male participants will score higher than females, what underlying theoretical or empirical justification supports this hypothesis, and how are potential socio-cultural factors considered?

The study references multiple assessment tools for aquatic competence, but how does AIM-2 specifically address the unique needs of children with physical disabilities in ways that existing scales do not?

While the research claims to be the first to compare aquatic performance across different disability levels, how does it ensure that the measures used are equally valid and reliable across diverse types and severities of physical impairments?

In the Materials and Methods :

How does the retrospective nature of the study affect the reliability and validity of the findings, particularly considering potential inconsistencies in data collection over six years?

Given that the study relies on subjective ratings from swimming instructors, what measures were taken to minimize potential biases and ensure inter-rater reliability beyond the small sample of 22 participants?

How does the study justify the use of walking ability as the primary criterion for defining disability levels, and could this classification overlook other critical factors influencing aquatic performance?

While exploratory factor analysis (EFA) was used to refine the AIM-2 scale, how were potential limitations, such as overfitting or sample size constraints, addressed to ensure the scale’s robustness and generalizability?

In the Discussion:

The study suggests that while adaptation and basic skills improve within a year, advanced skills require a longer training duration. What factors might contribute to the slower progression in advanced skills, and how could training programs be adjusted to accelerate this process?

The findings indicate that while children with more severe disabilities scored lower, their learning trajectory was similar to other groups. Does this suggest that with extended training, they could achieve comparable outcomes? How might individualized training plans help optimize skill acquisition for those with greater physical limitations?

Boys outperformed girls in advanced skills, but no differences were found in adaptation or basic skills. Beyond physical strength, could differences in confidence, exposure to aquatic environments, or motivation play a role in this disparity?

Younger participants showed improvement in advanced skills over time, whereas older participants did not. Could this be due to differences in neuroplasticity, engagement levels, or prior experience with swimming? How might training methods be adapted for different age groups to maximize learning outcomes?

The study acknowledges variability in instructor evaluations and calls for inter-rater reliability assessments. What steps could be implemented in future research to standardize evaluations further?

Given the findings, what additional variables (e.g., cognitive ability, parental involvement, swimming frequency outside of training) might be worth investigating in future studies?

Author Response

Reviewer 1

Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

R: The Introduction and Methods have been significantly revised as reported in the point-by-point responses.

Dear Author, please recheck and answer the below items:

In the introduction part:

[#1] How does the study account for potential confounding variables, such as previous swimming experience or access to aquatic training facilities, that might influence the participants' progress?

R: The following section has been included in the Limitations and Future Research section (4.2.5):
“In this study, we ensured a sufficiently large sample and exercised caution in interpreting the factor structure [60]. Nonetheless, despite the relatively large sample compared to previous assessments of swimming in CAWPD, certain factors may have introduced confounding effects. The broad age range, varying severity of disabilities, and a 15.7% comorbidity rate of learning difficulties among participants may have influenced the findings.”

[#2] Given that the study assumes male participants will score higher than females, what underlying theoretical or empirical justification supports this hypothesis, and how are potential socio-cultural factors considered?

R: The following added to the introduction:
“Based on the more frequent participation of male children and adolescents in sports it was expected that they would score higher than females [41];”

Hutzler, Y.; Tesler, R.; Gilad, A.; Ng, K.; Barak, S. 2022 para report card on physical activity of Israeli children and adolescents with disabilities. Adapt. Phys. Activ. Q. 2023, 40, 513–522, doi:10.1123/apaq.2022-0070.

[#3] The study references multiple assessment tools for aquatic competence, but how does AIM-2 specifically address the unique needs of children with physical disabilities in ways that existing scales do not?

R: The following added to the introduction:
“Gelinas and Reid [21] argue that swimming skill development in typically developing children may not apply to children and adolescents with physical disabilities (CAWPD), who may progress at a different rate and sequence.

In 2000, these researchers developed an adapted test for individuals with developmental disabilities, especially those with limitations to their movement system. However, they have used a fail/pass system, whereas a tiered (e.g., 5=point) grading system is argued to provide more objective information [22] and to motivate students to perform better than a simple pass/fail system [23].”

[#4] While the research claims to be the first to compare aquatic performance across different disability levels, how does it ensure that the measures used are equally valid and reliable across diverse types and severities of physical impairments?

R: The following paragraph was added to the introduction:

“In 1998, Hutzler et al. [7] developed the Water Orientation Scale (WOS) for children and adolescents with disabilities. Later renamed the Aquatic Independence Scale (AIM), it was further validated in an additional study [36, 37]. The revised AIM-2 version, introduced about a decade ago, has since been examined and validated in various contexts.”

In the Materials and Methods :

[#5] How does the retrospective nature of the study affect the reliability and validity of the findings, particularly considering potential inconsistencies in data collection over six years?

R: The following paragraph was added to the Limitations and Future Research Directions (4.2.5): “However, Powell & Sweeting [64] suggest that while retrospective studies rely on previously collected data, patient case notes from past interventions are generally reliable. Our study utilized real-time assessments conducted in the swimming pool, following a strict and comprehensive procedure to minimize inconsistencies.”

[#6] Given that the study relies on subjective ratings from swimming instructors, what measures were taken to minimize potential biases and ensure inter-rater reliability beyond the small sample of 22 participants?

R: The following added to the Recruitment and Data Collection (2.2.1):
“The assessment followed a strict procedure, including instructions on what to do, the instructor's demonstration of the task, and a preliminary trial, if it appeared to the instructor that the child did not understand the task.”
And also:
“All raters were experienced hydrotherapists and aquatic instructors, who were trained to rate the participants' performance in each item under the supervision of the scale developer.”

[#7] How does the study justify the use of walking ability as the primary criterion for defining disability levels, and could this classification overlook other critical factors influencing aquatic performance?

R: The following added to the Recruitment and Data Collection (2.2.1):
“Swimming requires the coordination of legs, trunk, arms and head movements against water drag, and was found to be associated with gross motor function such as walking in children with Cerebral Palsy [37,42].”

[#8] While exploratory factor analysis (EFA) was used to refine the AIM-2 scale, how were potential limitations, such as overfitting or sample size constraints, addressed to ensure the scale’s robustness and generalizability?

R: The following added to the Limitations and Future Research Directions (4.2.5):
“Exploratory factor analysis (EFA) is a fundamental tool for examining the structure of assessment tools and other theoretical constructs [62]. However, it has limitations, particularly regarding sample size and the interpretation of factor solutions. In this study, we ensured a sufficiently large sample and exercised caution in interpreting the factor structure [62].”

In the Discussion:

[#9] The study suggests that while adaptation and basic skills improve within a year, advanced skills require a longer training duration. What factors might contribute to the slower progression in advanced skills, and how could training programs be adjusted to accelerate this process?

R: The following added to the Performance across Disability Levels (4.2.2):
“Participants with severe disabilities who require high levels of support have been reported to take longer to enter and exit the pool compared to non-disabled swimmers [56]. This extended transition time may reduce the actual training duration in each session, potentially limiting the development of advanced skills that require prolonged practice and exposure.”

[#10] The findings indicate that while children with more severe disabilities scored lower, their learning trajectory was similar to other groups. Does this suggest that with extended training, they could achieve comparable outcomes? How might individualized training plans help optimize skill acquisition for those with greater physical limitations?

R: The following added to the Performance across Disability Levels (4.2.2):
“For swimmers with disability and particularly those with severe disability it would probably take longer time to develop the strength needed to increase the propulsive phase. Strategies to support swimmers with disability to develop propulsive strength may include on-land rubber band or resistive pulley training as well as water training such as gloves and tie ropes [52].”

[#11] Boys outperformed girls in advanced skills, but no differences were found in adaptation or basic skills. Beyond physical strength, could differences in confidence, exposure to aquatic environments, or motivation play a role in this disparity?

R: Confidence and motivation can certainly be considered to impact performance in skill learning. However, they are a result of individualized interactions between the participant, his or her environment, and the task difficulty. Gender is only one personal constraint and therefore, we believe it should not be considered a potential factor impacting motivation and performance

The following paragraph was added to the Performance across Genders (4.2.3):

It could, therefore, be suggested that the difference observed in performance may be attributed to physical strength [59], more exposure to physical activity or other background variables attributed to males.

[#12] Younger participants showed improvement in advanced skills over time, whereas older participants did not. Could this be due to differences in neuroplasticity, engagement levels, or prior experience with swimming? How might training methods be adapted for different age groups to maximize learning outcomes?

R: The following added to the Performance across Age (4.2.4):

Research on swimming skill acquisition in non-disabled children reveals mixed findings regarding age and speed. Based on Swimming instructors' testimony it has been suggested that those aged 8-13 years (referring to most of our younger age group) may learn faster than older ones [61]. Nevertheless, individual training planning is necessary to cope with the mixed impact of age, gender and disability.

[#13] The study acknowledges variability in instructor evaluations and calls for inter-rater reliability assessments. What steps could be implemented in future research to standardize evaluations further?

R: Since the study demonstrated high inter-rater reliability (See response to comment #32), additional standardization measures may not be necessary.

[#14] Given the findings, what additional variables (e.g., cognitive ability, parental involvement, swimming frequency outside of training) might be worth investigating in future studies?

R: The following added to the Limitations and Future Research Directions (4.2.5):
“Further validation of the revised scale should be pursued in future studies by incorporating additional variables. For example, assessing the correlation between swimming scores and the Gross Motor Function Measure in children with CP, as examined in the original version [37], would be valuable. Moreover, evaluating the test items in children and adolescents with other disabilities, such as intellectual disability and autism, would enhance the scale’s applicability. Investigating its utility and validity in adults with acquired disabilities who are relearning to swim represents another important research direction.

Finally, future studies should explore the impact of innovative skill-learning programs, including strength training interventions [52] and non-linear pedagogical approaches [67], to further enhance skill acquisition and performance outcomes.”

Reviewer 2 Report

Comments and Suggestions for Authors

Your study is scientifically robust, original, and highly relevant. The main areas for improvement involve clarifying practical applications, improving readability, and ensuring that references are fully up to date. This study presents a well-structured and scientifically rigorous validation of the AIM-2 scale for assessing swimming skills in children with physical disabilities. Below are the detailed comments and suggestions to enhance the clarity, impact, and overall quality of your manuscript.

1. Originality and significance

✅ Strengths:

This study provides a novel validation of the AIM-2, addressing an important gap in swimming assessments for children with disabilities.

This is one of the first studies to compare aquatic skill acquisition across disability levels, gender, and age groups.

The use of exploratory factor analysis (EFA), reliability testing, and ANOVA comparisons.

This strengthens the originality of this study.

🔹 Suggestions for Improvement:

Consider expanding the discussion on how AIM-2 differs from or improves upon existing scales (e.g., YMCA, and Canadian Red Cross assessments).

Highlight the broader applicability of AIM-2—could it be adapted for adults with disabilities or non-competitive swimmers?

Clarify why AIM-2 is a better alternative for measuring swimming independence than other scales.

2. Research design and Methods

✅ Strengths:

The study uses a robust methodological framework, including EFA, intra-class correlations, and statistical comparisons to ensure reliability. The participant sample (N=108) is relatively large compared to prior research in this area.

🔹 Suggestions for Improvement:

The study's retrospective nature should be acknowledged as a limitation. Were there any potential biases in the original data collection?

Were the raters (swimming instructors) uniformly trained? If so, providing details on their training process would enhance their reliability.

Specify whether any confounding variables (e.g., previous swimming experience, socioeconomic factors, or instructor variability) were considered.

3. Quality of presentation

✅ Strengths:

The manuscript is well-structured and logically organized.

The tables and figures (e.g., scree plot, ANOVA results) help illustrate the findings clearly.

🔹 Suggestions for Improvement:

Some sentences are long and complex - consider simplifying them for better readability.

Example:

"The findings suggest that the AIM-2 is a valid tool for assessing swimming readiness in young swimmers with disabilities, and coaches may find it useful in tracking the progression towards utilizing the aquatic environment for the health enhancement of children and adolescents with disabilities and adjusting training programs accordingly."

Suggested Revision:

"The findings support AIM-2 as a valid tool for assessing swimming readiness in young swimmers with disabilities. Coaches can use it to track progress, promote aquatic-based health benefits, and adjust training programs."

Ensure consistent formatting of tables and citations (e.g., check the alignment of table headers and ensure that all in-text citations are properly formatted).

4. Scientific soundness

✅ Strengths:

The use of EFA to validate the scale structure strengthens the study’s rigor.

Inter-rater reliability tests confirmed that the AIM-2 scale produces consistent results.

Statistical analysis is well-documented and appropriate for the study’s objectives.

🔹 Suggestions for Improvement:

Effect sizes should be reported where applicable; this would help contextualize the practical significance of the findings. Also, include a short explanation of why certain items were removed during the factor analysis—were they conceptually redundant or statistically weak?

Consider briefly discussing potential biases in instructor-based evaluations–do more experienced instructors rate differently?

5. Interest to readers

✅ Strengths:

This study is highly relevant to sports scientists, rehabilitation specialists, and disability advocates.

It provides important practical insights for swimming coaches and therapists working with disabled children.

🔹 Suggestions for improvement:

Adding real-world case studies or participant testimonials would make this study more engaging for a broader audience. Discuss whether AIM-2 can be adapted for other populations, such as adults with disabilities or recreational swimmers.

6. References

✅ Strengths:

This paper includes a well-rounded set of references, covering both historical foundations and recent studies.

🔹 Suggestions for improvement:

Ensure that all references are up to date - are there any 2023–2025 studies on swimming assessments for children with disabilities? Some inline citations appear crowded with multiple sources - consider streamlining for readability.

7. Conclusion and future directions

✅ Strengths:

The conclusion effectively summarizes the key findings and reinforces AIM-2’s validity.

🔹 Suggestions for improvement:

The study mentioned that progress in advanced skills was limited. How might training programs be improved to address this? Could AIM-2 be modified for different environments, such as open-water training or disability categories (e.g., sensory impairments vs. physical disabilities)?

Expanding future research directions, such as longitudinal studies tracking swimmers over multiple years, would add depth to the discussion.

Comments on the Quality of English Language

Areas for improvement:

Sentence structure & clarity:

Some sentences are overly long and complex, which may affect readability. Consider breaking them into shorter, more direct sentences.
Example:
"The findings suggest that the AIM-2 is a valid tool for assessing swimming readiness in young swimmers with disabilities, and coaches may find it useful in tracking the progression towards utilizing the aquatic environment for the health enhancement of children and adolescents with disabilities and adjusting training programs accordingly."
Revision Suggestion:
"The findings suggest that AIM-2 is a valid tool for assessing swimming readiness in young swimmers with disabilities. Coaches may use it to track progression and adjust training programs for better health outcomes."

Grammar & word choice:

Minor grammatical errors and awkward phrasing could be refined.
Example:
"Since its emergence, the tool has been widely used by the Israel Sport Center for the Disabled for young individuals with disabilities, including poliomyelitis and cerebral palsy."
Revision Suggestion:
"Since its development, the tool has been widely used by the Israel Sport Center for the Disabled to assess young individuals with conditions such as poliomyelitis and cerebral palsy."

Consistency in terminology:

Ensure consistent use of "participants," "subjects," or "individuals" throughout the paper.
The term "aquatic independence" is sometimes used without clear definition—clarifying it early on would help the reader.

Author Response

Does the introduction provide sufficient background and include all relevant references?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	(x)	( )	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

R: Thank you very much for the general positive evaluation. Pont-by-point responses to your comments follow

Originality and significance

✅ Strengths:

This study provides a novel validation of the AIM-2, addressing an important gap in swimming assessments for children with disabilities.

This is one of the first studies to compare aquatic skill acquisition across disability levels, gender, and age groups.

The use of exploratory factor analysis (EFA), reliability testing, and ANOVA comparisons.

This strengthens the originality of this study.

? Suggestions for Improvement:

[#15A] Consider expanding the discussion on how AIM-2 differs from or improves upon existing scales (e.g., YMCA, and Canadian Red Cross assessments).

[#15B] Highlight the broader applicability of AIM-2—could it be adapted for adults with disabilities or non-competitive swimmers?

R: Thank you for the suggestion. The following section has been included in the Limitations and Future Research section (4.2.5), to address potential adaptations: "Moreover, evaluating the test items in children and adolescents with other disabilities, such as intellectual disability and autism, would enhance the scale’s applicability. Investigating its utility and validity in adults with acquired disabilities who are relearning to swim represents another important research direction."

[#15C] Clarify why AIM-2 is a better alternative for measuring swimming independence than other scales.

R: The following has been added to indicate the difference to Gelinas & Reid's proposal which is based on an insensitive scoring system, similar to previous YMCA and Red Cross scales: "However, they have used a fail/pass system, whereas a tiered (e.g., 5=point) grading system is argued to provide more objective information [22] and to motivate students to perform better than a simple pass/fail system [23]."

Research design and Methods

✅ Strengths:

? Suggestions for Improvement:

[#16] The study's retrospective nature should be acknowledged as a limitation. Were there any potential biases in the original data collection?

R: The study's retrospective nature has now been acknowledged in the Limitations section (4.2.5), together with measures taken to enhance the measurement reliability.

[#17] Were the raters (swimming instructors) uniformly trained? If so, providing details on their training process would enhance their reliability.

R: Additional details have now been reported in the Method section (2.2.1):
“All raters were experienced hydrotherapists and aquatic instructors, who were trained to rate the participants' performance in each item under the supervision of the scale developer.”

[#18] Specify whether any confounding variables (e.g., previous swimming experience, socioeconomic factors, or instructor variability) were considered.

R: All participants included in the learn to swim program had no previous swimming experience. Instructors' variability is a limitation reported in the limitation section (4.2.5). However, the rating procedure was consistent and included a comprehensive protocol as elaborated in Method section (2.2.1) and in the limitation section (4.2.5).

Quality of presentation

✅ Strengths:

The manuscript is well-structured and logically organized.

The tables and figures (e.g., scree plot, ANOVA results) help illustrate the findings clearly.

? Suggestions for Improvement:

[#19] Some sentences are long and complex - consider simplifying them for better readability.

Example:

Suggested Revision:

R: Thank you for the recommendation. Additional long and complex sentences were reviewed and revised as follows in the table below

R: Thank you for the recommendation. Additional long and complex sentences were reviewed and revised as follows in the table

Line	Original	Rephrased
44	Furthermore, not only does the aquatic environment improve functional performance outside the water, but it also offers an enjoyable, suitable, and adaptive form of physical activity – fostering participation in a form of exercise that promotes both mental and social well-being (12,13).	Furthermore, aquatic exercise enhances functional performance on land while providing an enjoyable, adaptive, and accessible activity that supports mental and social well-being(12,13).
62	Gelinas and Reid (21) claim that the development of swimming skills seen among typically developing children may not be valid or relevant for children and adolescents with physical disabilities (CAWPD), with the latter likely exhibiting a different rate and sequence of progress.	Gelinas and Reid (21) argue that swimming skill development in typically developing children may not apply to children and adolescents with physical disabilities (CAWPD), who may progress at a different rate and sequence.
70	Research on learn-to-swim programs for children and adolescents highlights the importance of formal instruction, especially concerning developing swimming abilities and preventing drowning (24); indeed, formal instruction is associated with higher self-reported swimming skills compared to informal learning (25).	Research highlights the importance of formal instruction in learn-to-swim programs for children and adolescents. Formal training enhances skill development and helps prevent drowning (24). It is also associated with higher self-reported swimming proficiency compared to informal learning (25).
87	In 1998, Hutzler and colleagues (7) developed the Water Orientation Scale (WOS) for children and adolescents with disabilities; this tool, which has since been further validated in an additional study (36) , was later renamed the Aquatic Independence Scale (AIM); since the development of the revised AIM-2 version about a decade ago, this tool has been further examined and validated in various contexts (37) .	In 1998, Hutzler et al. (7) developed the Water Orientation Scale (WOS) for children and adolescents with disabilities. Later renamed the Aquatic Independence Scale (AIM), it was further validated in an additional study (36, 37). The revised AIM-2 version, introduced about a decade ago, has since been examined in various contexts.
98	The aim of the current study was to examine the construct validity of the AIM-2 scale, designed to assess swimming skills among young individuals with physical disabilities and without previous swimming experience, who are enrolled in a beginner learn-to swim program.	This study aimed to examine the construct validity of the AIM-2 scale, which assesses swimming skills in beginners with physical disabilities and no prior swimming experience.
221	The results indicate a significant main effect of both time and disability level – for the total scale and for two of the subscales (basic skills and adaptation) – whereby mean scores in the second year were higher than in the first one, and across all disability levels .	The results show a significant main effect of time and disability level on the total scale and two subscales (basic skills and adaptation). Mean scores improved in the second year across all disability levels.
228	A significant main effect was found for disability level (across time) in both the total scale and all three subscales, whereby lower mean scores were seen in participants with a severe disability while higher scores were seen in those with a mild disability.	A significant main effect of disability level was found across time for the total scale and all three subscales, with lower scores in participants with severe disabilities and higher scores in those with mild disabilities.
255	Mean comparisons by time and age showed a significant main time effect for the total AIM-2 scale and for all subscales, whereby second year means were higher than first year ones across the two age groups (Table 6).	Mean comparisons by time and age showed a significant main effect of time for the total AIM-2 scale and all subscales, with higher scores in the second year across both age groups (Table 6).
287	Building upon the results presented above, key aspects of the tool will be addressed, including the scale’s internal structure and its construct validity, reflecting its discriminant capability, and responsiveness to change.	Building on these results, key aspects of the tool will be examined, including its internal structure, construct validity, discriminant capability, and responsiveness to change.
366	Similarly and partially supporting our hypothesis, our findings reveal a nuanced outcome, whereby a significant advantage for male performance was only seen in advanced skills and in the total AIM-2 scale – not in adaptation and basic skills.	The findings show a nuanced result, partially supporting our hypothesis: males performed significantly better only in advanced skills and the total AIM-2 scale, but not in adaptation or basic skills. The findings show a nuanced result, partially supporting our hypothesis: Males performed better only in advanced skills and the total AIM-2 scale, but not in adaptation or basic skills.
406	Despite strong inter-rater agreement, variations in evaluations may have occurred, particularly among less experienced trainers or those prone to expectation bias, such as a tendency for their expectations or overall impression of a participant to influence their judgments (61,62).	Despite strong inter-rater agreement, some variations in evaluations may have occurred. This is particularly true for less experienced trainers or those prone to expectation bias. Such bias can lead to judgments being influenced by prior expectations or overall impressions of a participant (61,62).
3.4.4 title	3.4.4. Inter-rater Reliability and Correlations between First and Second Year Mean Scores	3.4.4. Inter-rater Reliability and Yearly Score Correlations
4.2.5 the whole paragraph has been revised.	While the study was based on a relatively large sample size compared to previous assessments of swimming in CAWPD, the wide range of ages and disability severity among participants may have introduced certain confounding factors that were not taken into account. Moreover, the diversity of instructors who conducted the assessments may have introduced variability in the evaluation process. While very strong iner-rater associations were observed, differences in evaluations across raters may have occurred – especially in trainers with less experience and with less acquaintance with the participants. . Furthermore, investigations utilizing extended training periods are warranted to further substantiate the observed training effect on swimming skill acquisition.	Exploratory factor analysis (EFA) is a fundamental tool for examining the structure of assessment tools and other theoretical constructs [60]. However, it has limitations, particularly regarding sample size and the interpretation of factor solutions. In this study, we ensured a sufficiently large sample and exercised caution in interpreting the factor structure [60]. Nonetheless, despite the relatively large sample compared to previous assessments of swimming in CAWPD, certain factors may have introduced confounding effects. The broad age range, varying severity of disabilities, and a 15.7% comorbidity rate of learning difficulties among participants may have influenced the findings. Additionally, the voluntary nature of participation could have led to selection bias [61], with individuals who have had higher motivation being more likely to enroll. Variability in instructor assessments may also have contributed to inconsistencies in evaluation. Although all evaluations were conducted and reported in real-time, the retrospective design spanning multiple years presents a potential limitation. However, Powell & Sweeting [62] suggest that while retrospective studies rely on previously collected data, patient case notes from past interventions are generally reliable. Our study utilized real-time assessments conducted in the swimming pool, following a strict and comprehensive procedure to minimize inconsistencies. Despite the strong inter-rater agreement, minor variations in evaluations may have occurred, particularly among less experienced trainers or those susceptible to expectation bias. Such bias can result in assessments being influenced by prior expectations or general impressions of participants [63,64]. To mitigate these concerns, future research should incorporate extended training periods to ensure consistency in skill evaluation. Further validation of the revised scale should be pursued in future studies by incorporating additional variables. For example, assessing the correlation between swimming scores and the Gross Motor Function Measure in children with CP, as examined in the original version [37], would be valuable. Moreover, evaluating the test items in children and adolescents with other disabilities, such as intellectual disability and autism, would enhance the scale’s applicability. Investigating its utility and validity in adults with acquired disabilities who are relearning to swim represents another important research direction. Finally, future studies should explore the impact of innovative skill-learning programs, including strength training interventions [52] and non-linear pedagogical approaches [65], to further enhance skill acquisition and performance outcomes.

[#20] Ensure consistent formatting of tables and citations (e.g., check the alignment of table headers and ensure that all in-text citations are properly formatted).

R: Tables and citations have now been further aligned and properly formatted. In addition, notes have been added to indicate acronyms utilized in the Tables

Scientific soundness

✅ Strengths:

The use of EFA to validate the scale structure strengthens the study’s rigor.

Inter-rater reliability tests confirmed that the AIM-2 scale produces consistent results.

Statistical analysis is well-documented and appropriate for the study’s objectives.

? Suggestions for Improvement:

[#21] Effect sizes should be reported where applicable; this would help contextualize the practical significance of the findings. [#22] Also, include a short explanation of why certain items were removed during the factor analysis—were they conceptually redundant or statistically weak?

R: Effect sizes have now been added to tables and their strength reported in the Discussion section to help contextualize the practical significance of the findings. Regarding the Items removed during the factor analysis, this was performed when found statistically weak: Below 0.4 loading in the relevant factor or cross-loaded above 0.4 in two factors or more. Additionally, the removal of items was discussed and ratified based on the authors' decision.

[#23] Consider briefly discussing potential biases in instructor-based evaluations–do more experienced instructors rate differently?

R: A section in this regard has been added to the limitations:

“Additionally, the voluntary nature of participation could have led to selection bias [63], with individuals who have had higher motivation being more likely to enroll.”

Interest to readers

✅ Strengths:

This study is highly relevant to sports scientists, rehabilitation specialists, and disability advocates.

It provides important practical insights for swimming coaches and therapists working with disabled children.

? Suggestions for improvement:

[#24] Adding real-world case studies or participant testimonials would make this study more engaging for a broader audience.

R: The authors agree that adding real-world case studies or participant testimonials would make the study more engaging, but this would apply when discussing program effectiveness or content validity. The purpose of the current study was to examine the construct validity of the AIM-2 assessment procedure, and the authors do not see how such information could have supported this aim.

[#25] Discuss whether AIM-2 can be adapted for other populations, such as adults with disabilities or recreational swimmers.

R: In the Limitations and Future Research Directions (4.2.5.) section the following paragraph has been added: "Moreover, evaluating the test items in children and adolescents with other disabilities, such as intellectual disability and autism, would enhance the scale’s applicability. Investigating its utility and validity in adults with acquired disabilities who are relearning to swim represents another important research direction."

References

✅ Strengths:

This paper includes a well-rounded set of references, covering both historical foundations and recent studies.

? Suggestions for improvement:

[#26] Ensure that all references are up to date - are there any 2023–2025 studies on swimming assessments for children with disabilities?

R: An exploration of the literature did not reveal any up-to-date references from 2023-2025.

[#27] Some inline citations appear crowded with multiple sources - consider streamlining for readability.

We double checked our references and streamlined it.

Conclusion and future directions

✅ Strengths:

The conclusion effectively summarizes the key findings and reinforces AIM-2’s validity.

? Suggestions for improvement:

[#28] The study mentioned that progress in advanced skills was limited. How might training programs be improved to address this? Could AIM-2 be modified for different environments, such as open-water training or disability categories (e.g., sensory impairments vs. physical disabilities)?

R: The following paragraph was added to the Performance across Time section (4.2.1)
“It has been suggested that advanced swimmers spend more time in the propulsive phase and show greater consistency in relative timing [51]. For swimmers with disability and particularly those with severe disability it would probably take longer time to develop the strength needed to increase the propulsive phase. Strategies to support swimmers with disability to develop propulsive strength may include on-land rubber band or resistive pulley training as well as water training such as gloves and tie ropes [52].”

[#29] Expanding future research directions, such as longitudinal studies tracking swimmers over multiple years, would add depth to the discussion.

R: The following paragraph was added to the Performance across Disability Levels section (4.2.2): “These results suggest that the journey to achieving swimming independence in CAWPD may be a prolonged process, extending beyond a single year or even two subsequent years. Participants with severe disabilities who require high levels of support have been reported to take longer to enter and exit the pool compared to non-disabled swimmers [56]. This extended transition time may reduce the actual training duration in each session, potentially limiting the development of advanced skills that require prolonged practice and exposure.”

Comments on the Quality of English Language

Areas for improvement:

Sentence structure & clarity:

Some sentences are overly long and complex, which may affect readability. Consider breaking them into shorter, more direct sentences.
Example:
"The findings suggest that the AIM-2 is a valid tool for assessing swimming readiness in young swimmers with disabilities, and coaches may find it useful in tracking the progression towards utilizing the aquatic environment for the health enhancement of children and adolescents with disabilities and adjusting training programs accordingly."
Revision Suggestion:
"The findings suggest that AIM-2 is a valid tool for assessing swimming readiness in young swimmers with disabilities. Coaches may use it to track progression and adjust training programs for better health outcomes."

Grammar & word choice:

Minor grammatical errors and awkward phrasing could be refined.
Example:
"Since its emergence, the tool has been widely used by the Israel Sport Center for the Disabled for young individuals with disabilities, including poliomyelitis and cerebral palsy."
Revision Suggestion:
"Since its development, the tool has been widely used by the Israel Sport Center for the Disabled to assess young individuals with conditions such as poliomyelitis and cerebral palsy."

R: Thank you for the recommendations. Minor grammatical errors and awkward phrasing have been refined throughout the manuscript.

Consistency in terminology:

[#35] Ensure consistent use of "participants," "subjects," or "individuals"throughout the paper.

R: Thank you for this comment. We have edited the text to ensure that the use of these terms is consistent and clear.

[#36] The term "aquatic independence"is sometimes used without clear definition—clarifying it early on would help the reader.

R: The following sentence was added to the introduction section:

“These aquatic interventions are typically designed to promote autonomous functioning (i.e. aquatic independence) in the water and acquiring swimming patterns.”

Reviewer 3 Report

Comments and Suggestions for Authors

First of all, thank you for the opportunity to review this article! It is a useful paper for practitioners who will have an objective tool in the evaluation and recording of the progress made by students with physical disabilities who practice swimming.

The article is developed respecting the methodological standards for validating an instrument. Also, the presentation of the results is correct.

There are a few observations on the present form on which the authors could revise, bringing details that can remove the confusion of the reader.

- although some sources are older, they constitute an irreplaceable scientific basis. It is not clear whether this tool has been the subject of any study through which validation on the target group could be pursued. Hence, if they are identified, some results of the study can be compared with the conclusions of these previous studies.

- in the presentation of the characteristics of the subjects, it might be useful to specify if they are only physically disabled, possibly, of what nature, or if they also have associated disabilities. It is known that the nature of physical disabilities is diverse and, hence, a broader picture of the limitations of these individuals.

- information is presented on the number of 108 subjects for whom measurements were performed. In the abstract, information is presented according to which, for all subjects, test-retest type measurements were performed. However, in the presentation of the results, these details are not captured either in the values obtained or in the descriptive explanations.

Moreover, there are clarifications on the data obtained from testing only on 22 subjects.

Thus, a more precise and clearer expression, doubled with statistical data can eliminate confusion and bring added value to the article.

- to be checked and changed, as is correct:

source [17] refers to the work of Gladish Gladish, K. Swimming programs for infants and toddlers. Pediatrics 2002. In the text, in lines 55 and 119 it refers to the YMCA.
in the Discussions, the explanations in the text refer to something other than the content of the cited source. Look at the sources [23] and [33] and the explanations in lines 267-270; 277-280!

Author Response

Does the introduction provide sufficient background and include all relevant references?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	(x)	( )	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

R: Thank you for the positive evaluation of the general structure and content of the manuscript. Pont-by-point responses to your comments follow

Comments and Suggestions for Authors

The article is developed respecting the methodological standards for validating an instrument. Also, the presentation of the results is correct.

There are a few observations on the present form on which the authors could revise, bringing details that can remove the confusion of the reader.

[#30] - although some sources are older, they constitute an irreplaceable scientific basis. It is not clear whether this tool has been the subject of any study through which validation on the target group could be pursued. Hence, if they are identified, some results of the study can be compared with the conclusions of these previous studies.

R: The following paragraph was added to introduction section:

In 1998, Hutzler et al. [7] developed the Water Orientation Scale (WOS) for children and adolescents with disabilities. Later renamed the Aquatic Independence Scale (AIM), it was further validated in an additional study [36, 37]. The revised AIM-2 version, introduced about a decade ago, has since been examined in various contexts.

[#31] - in the presentation of the characteristics of the subjects, it might be useful to specify if they are only physically disabled, possibly, of what nature, or if they also have associated disabilities. It is known that the nature of physical disabilities is diverse and, hence, a broader picture of the limitations of these individuals.

[#32] - information is presented on the number of 108 subjects for whom measurements were performed. In the abstract, information is presented according to which, for all subjects, test-retest type measurements were performed. However, in the presentation of the results, these details are not captured either in the values obtained or in the descriptive explanations.

R: Thank you very much for this comment. The original procedure of the test-retest measurements, which was reported in the Results section 3.4.4. was incorrect. The actual procedure was reported in the Methods section 2.2.2.2. The inter-rater agreement scores in the Results section have been changed accordingly. In addition, the section in the Discussion on internal structure 4.1. was also changed to interpret the actual outcome. Furthermore, the sentence referring to inter-rater reliability assessments in future studies was deleted in Limitations and Future Research Directions section (4.2.5).

[#33] Moreover, there are clarifications on the data obtained from testing only on 22 subjects.

Thus, a more precise and clearer expression, doubled with statistical data can eliminate confusion and bring added value to the article.

R: We believe that the explanation provided to #32 and the statistical data, which appears in section 3.4.4. clarifies the inter-rater reliability outcome and thereby eliminates confusion.

[#34]- to be checked and changed, as is correct:

source [17] refers to the work of Gladish Gladish, K. Swimming programs for infants and toddlers. Pediatrics 2002. In the text, in lines 55 and 119 it refers to the YMCA.
in the Discussions, the explanations in the text refer to something other than the content of the cited source. Look at the sources [23] and [33] and the explanations in lines 267-270; 277-280!

R: Again thank you for this comment. The references were checked and rearranged.