Authors’ response to the Comments on: “Effect of aquatic exercises on pain and functional performance in plantar fasciitis”

Dear Editor,

We thank the author of the Letter to the Editor^[1] for their critical appraisal of our randomized controlled trial titled “Effect of Aquatic Exercises on Pain and Functional Performance in Plantar Fasciitis.”^[2] and for acknowledging the value and relevance of our research. We truly appreciate the constructive comments and thoughtful insights, which will enrich future studies in this area.

We acknowledge that a previous letter highlighted several methodological aspects of our study, including the duration of follow-up, the clinical applicability of the findings, and the extent of blinding.^[3] In response to those remarks, we mentioned that the study used a single-blinded design. A key methodological limitation of the present study relates to participant blinding. Due to the inherently distinguishable nature of aquatic and land-based exercise interventions, complete concealment of group allocation from participants was not feasible. This limitation represents a high risk of performance bias, particularly for subjective outcome measures such as pain intensity and self-reported functional performance.^[4]

Although complete assessor blinding was not feasible given the nature and logistical requirements of aquatic therapy, standardized, uniform assessment procedures were employed to reduce potential evaluator-related bias. These considerations, along with the justification for the defined study timeline and participant selection criteria, were previously addressed in detail. We had also assured that the upcoming research will incorporate extended follow-up periods, the use of objective biomechanical assessment tools, and the inclusion of broader participant profiles to further enhance scientific rigor and generalizability.^[4]

In our study, pain reduction and foot function were the primary clinical outcomes, while the remaining measures served as secondary outcomes to provide a holistic clinical picture of foot function. Although the adjunct interventions were administered equally to both groups, this alone does not fully eliminate the potential for confounding and does not permit complete causal isolation of the exercise intervention. However, the uniform application of co-interventions was intentionally adopted to minimize differential treatment effects and to maintain ethical and standardized clinical care across groups. This approach strengthens internal comparability between groups, while acknowledging that the observed outcomes reflect the combined effect of the exercise program within a controlled therapeutic context rather than the isolated effect of exercise alone. We acknowledge that paraffin wax baths and therapeutic ultrasound have the potential to influence symptomatic relief. However, both interventions were administered equally to both groups as part of standardized treatment to ensure uniform baseline clinical conditions. Thus, we believed this approach minimized bias and helped maintain ethical clinical practice.

The study included multiple outcome measures; however, primary outcomes were not explicitly prespecified, and no statistical adjustment for multiple comparisons was applied. This methodological approach increases the risk of Type I error and limits confidence in the reported statistical significance of the findings. Although the outcomes were selected to provide a comprehensive clinical assessment, the absence of multiplicity correction necessitates cautious interpretation of statistically significant results. This is recognized as a major methodological limitation of the study, and future investigations should incorporate prespecified primary outcomes and appropriate correction methods to enhance statistical rigor and interpretability.

Nevertheless, we agree that future research could consider separating these modalities or eliminating adjunct therapies to isolate the independent effect of exercise. We appreciate the emphasis on reporting clinical relevance through effect size and confidence intervals. Although minimal clinically important difference values and percentage improvements were presented to demonstrate meaningful change, we acknowledge that including effect sizes could enhance interpretability and evidence strength. We value this feedback and will incorporate it in future research submissions. We thank the author for identifying the phrasing concern. We agree that manual muscle testing (MMT) is an assessment tool and not an exercise activity. The term “ankle MMT” in the manuscript referred to resisted ankle strengthening performed in aquatic conditions. We acknowledge that clearer terminology (e.g., “ankle strengthening exercises”) would have improved reproducibility and clarity, and we will refine such terminology in future manuscripts. We acknowledge that true collagen or connective tissue remodeling requires longer-term adaptation and may not be clearly measurable within 6 weeks. The reduction in plantar fascia thickness reported in our study was interpreted as an early, observable change rather than definitive long-term remodeling. We agree that an extended follow-up period would yield stronger evidence and plan to conduct longitudinal studies to address this issue.

We sincerely thank the author for these valuable observations, which will significantly strengthen our ongoing and future work in musculoskeletal rehabilitation research. We deeply appreciate the opportunity to clarify our methodology and reiterate our commitment to scientific transparency, clinically relevant research, and continued contribution to physiotherapy practice.