Effects of Wushu Programs on Lower-Limb Explosive Power in Preschool Children Aged 5–6 Years: A Cluster-Randomized Controlled Trial

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

A very well designed study and also manuscript. All my feedback is in the attached PDF. 

There are issues noted regarding elaboration on GPower calculation and the need to provide more details. The describption of the assessments used needs to demonstrate that they are valid and reliable with this young age group. 

More detail about the "control group activities" is needed, preferably in a table format. 

Please provide an explanation of the wave like cycle of the sets in the intervention program. I would like to know the science behind this. Traditionally one would follow a periodised flow. 

With regards the limitations, must include that physical activity type and duration was not monitored, hence it could influence results. 

Overall well done! and check the PDF.

Comments for author File: Comments.pdf

Author Response

Reviewer 1

Dear authors,

A very well designed study and also manuscript. All my feedback is in the attached PDF.

Thank you for your encouraging comments and for the time and effort you have devoted to reviewing our manuscript. We have revised the manuscript carefully in line with your suggestions, all of which have substantially improved the quality of the paper. The revisions are highlighted in red.

 

Comment 1：There are issues noted regarding elaboration on GPower calculation and the need to provide more details. The describption of the assessments used needs to demonstrate that they are valid and reliable with this young age group.

Response: We sincerely appreciate this comment. We would like to clarify a typographical error in our previous description: the sample size calculation was not performed using G*Power but was carried out with R. For this two‑arm cluster randomized controlled trial, we assumed an individual‑level Cohen’s d of 0.8, an intraclass correlation coefficient (ICC) of 0.025, a two‑sided α of 0.05, and 80% power. This yielded 15 participants per cluster. To allow for up to 20% attrition, a minimum of 19 participants were recruited for each class (see the revised Methods section).

 

Comment 2：More detail about the "control group activities" is needed, preferably in a table format.

Response: As suggested, we have added Supplement Table 1, which provides a summary of the control group activities and the targeted motor skills of the outdoor materials used in the kindergarten.

 

Comment 3：Please provide an explanation of the wave like cycle of the sets in the intervention program. I would like to know the science behind this. Traditionally one would follow a periodised flow.

Response: Thank you for this comment. In contrast to conventional periodized flow models designed for adults, the "wave-like cycle" was specifically developed for preschoolers. The experimental design entailed the implementation of high-load weeks, which entailed three sets per session, with a focus on familiarization and consolidation. In contrast, low-load weeks were characterized by a single set per session, with an emphasis on enhancing movement quality, rectifying errors, and facilitating active recovery. This nonlinear configuration has been shown to prevent the development of excessive fatigue and boredom, thereby sustaining the motivation of young children. It is noteworthy that the total number of practices sets for each movement remained constant across the entire intervention period, whether measured over four weeks or over ten weeks. The movement difficulty and precision requirements increased incrementally over the course of several weeks. However, since all sessions were led by a coach and children were not permitted to practice independently at home, there was an absence of self-learning obligations. Consequently, the wave‑like load fluctuation primarily functioned to manage fatigue and promote engagement, rather than to facilitate motor skill acquisition.

 

Comment 4：With regards the limitations, must include that physical activity type and duration was not monitored, hence it could influence results.

Response: Thank you for this important point. This limitation has been acknowledged in the Discussion section. Specifically, physical activity outside the designated sessions was not objectively recorded. Despite children and parents being instructed not to practice the movements at home, it is not possible to completely exclude the possibility that some children in the intervention group engaged in additional Wushu-related activities. Future research is needed to employ questionnaires or accelerometers to address this issue.

 

Overall well done! and check the PDF.

Response: We have carefully reviewed all the comments in the PDF and revised the manuscript as follows.

(1) “Capital K” has been corrected in the Abstract.

(2) “Need to elaborate on this calculation for greater transparency.” We have revised the sample size calculation to make it more transparent (please see our response to Comment 1).

(3) “An explanation of why total training load fluctuated from week to week. Going from a high training load to low training load for an exercise would lead to reduced adaptation. For example Week 1 3 sets and then in Week 2 1 set.” We have added the relevant explanation in Section 2.3 (Intervention).

(4) “Provide a table that outlines the activities.”  We have provided Supplement Table 1, which outlines the outdoor free play materials and the associated lower‑limb muscular fitness activities.

(5) “Must explain if these tests are valid and reliable with the participant age group and if so cite references.” We have included references that confirm the validity and reliability of these tests for the participant age group.

(6) “A limitation that needs to be included is that there was no monitoring of physical activity outside the research study and there was no account of the possibility that children performed the activities of the intervention group outside the study.” We have added this important limitation to the Discussion.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for the opportunity to review this interesting manuscript examining the effects of Wushu programs on lower-limb explosive power in preschool children. The study addresses a relevant topic in pediatric exercise science and provides valuable data regarding martial arts-based interventions in early childhood. The inclusion of both field-based and force plate assessments is a notable strength, and the manuscript is generally well organized. However, there are several methodological and interpretative aspects that should be clarified before publication.

The most important issue relates to the interpretation of the comparison between the 4-week and 10-week interventions. Although the manuscript repeatedly suggests a dose–response effect or “additional benefits” from the longer intervention, the two experiments were conducted in separate cohorts recruited in different years. Since participants were not randomized between intervention durations within the same study population, direct comparisons between Experiment 1 and Experiment 2 should be interpreted with caution. At present, the design only allows independent interpretation of each experiment rather than a true causal comparison of intervention duration. I strongly recommend softening the language throughout the manuscript and clearly acknowledging this limitation in both the Discussion and Conclusions.

Another important methodological concern involves the cluster-randomized design. Participants were randomized by classes, but the statistical analyses were conducted primarily using ANCOVA with class included as a covariate. This approach may not fully account for the lack of independence between participants within clusters. The manuscript would be strengthened by reporting the intraclass correlation coefficient (ICC) and discussing the potential impact of clustering on statistical precision. Ideally, mixed-effects models with class as a random effect would be more appropriate. At minimum, this limitation should be acknowledged more explicitly.

The interpretation of the neuromuscular findings also requires refinement. In Experiment 2, CMJ improved significantly whereas SJ and EUR did not. The manuscript interprets this pattern as evidence of improved stretch-shortening cycle efficiency; however, if SSC efficiency had meaningfully improved, one would also expect changes in EUR. This apparent inconsistency should be discussed more carefully, especially considering the relatively small effect size observed for CMJ. The current mechanistic interpretation appears somewhat stronger than the data support.

Regarding the control condition, although heart rate monitoring suggests comparable exercise intensity between groups, the free-play activities were not sufficiently standardized or quantified. Consequently, it remains difficult to determine whether the observed benefits are attributable specifically to Wushu-related motor patterns or simply to differences between structured and unstructured physical activity exposure. This limitation should also be acknowledged.

There are additionally several smaller issues that should be corrected. The statistical analysis section contains an incomplete sentence (“Correlation analyses were performed to examine…”). The abstract repeats the sentence describing the standing long jump as the primary outcome. Table numbering and group labels should be carefully revised because there are inconsistencies between Experiment 1 and Experiment 2 tables (e.g., CON-1/INT-1 appearing in Experiment 2 tables). The notation in Figure 2 (“*** p < 0.005”) should also be verified, as the conventional threshold is usually p < 0.001. Finally, the Discussion section related to flexibility outcomes could be shortened, as this finding is secondary and currently overemphasized relative to the main outcomes.

Overall, this manuscript has merit and contributes relevant information regarding martial arts interventions in preschool children. Addressing the points above would substantially improve the methodological rigor and interpretation of the findings.

Author Response

Reviewer 2

 

Dear Authors,

Thank you for the opportunity to review this interesting manuscript examining the effects of Wushu programs on lower-limb explosive power in preschool children. The study addresses a relevant topic in pediatric exercise science and provides valuable data regarding martial arts-based interventions in early childhood. The inclusion of both field-based and force plate assessments is a notable strength, and the manuscript is generally well organized. However, there are several methodological and interpretative aspects that should be clarified before publication.

Thank you for your encouraging comments and for the time and effort you have devoted to reviewing our manuscript. We have revised the manuscript carefully in line with your suggestions, all of which have substantially improved the quality of the paper. The revisions are highlighted in red.

 

Comment 1：The most important issue relates to the interpretation of the comparison between the 4-week and 10-week interventions. Although the manuscript repeatedly suggests a dose–response effect or “additional benefits” from the longer intervention, the two experiments were conducted in separate cohorts recruited in different years. Since participants were not randomized between intervention durations within the same study population, direct comparisons between Experiment 1 and Experiment 2 should be interpreted with caution. At present, the design only allows independent interpretation of each experiment rather than a true causal comparison of intervention duration. I strongly recommend softening the language throughout the manuscript and clearly acknowledging this limitation in both the Discussion and Conclusions.

Response: We fully agree with this concern and have carefully revised the manuscript. Although both experiments were cluster-randomized trials, the two intervention durations were tested in separate trials with separate cohorts and time periods, resulting in participants not being randomized between durations. Consequently, all cross-experiment languages have been softened, and the implication of a dose-response relationship has been removed. The primary revisions were made to the final paragraph of the Introduction, the first paragraph of the Discussion, and the Conclusions. This was incorporated into the limitation paragraph in the discussion. Thank you for helping us improve the accuracy of our interpretation.

 

Comment 2：Another important methodological concern involves the cluster-randomized design. Participants were randomized by classes, but the statistical analyses were conducted primarily using ANCOVA with class included as a covariate. This approach may not fully account for the lack of independence between participants within clusters. The manuscript would be strengthened by reporting the intraclass correlation coefficient (ICC) and discussing the potential impact of clustering on statistical precision. Ideally, mixed-effects models with class as a random effect would be more appropriate. At minimum, this limitation should be acknowledged more explicitly.

Response: Thank you for this important methodological suggestion. We have now reanalyzed all data using linear mixed-effects models with the baseline value, treatment group, age, and sex as fixed effects, and a random intercept for each cluster to account for within-cluster correlations. The reanalysis fully confirms the original findings for all outcomes except for CMJ. The Methods and Discussion have been revised accordingly. ICCs have also been estimated for all outcomes and are presented in Supplemental Table 2. The ICCs of majority outcomes were low, 71.1% were below 0.05. However, non-negligible ICCs were observed for several measures (e.g., BMI and 15 m zigzag run in Experiment 1; EUR, SJ, and grip strength in Experiment 2).

 

Comment 3：The interpretation of the neuromuscular findings also requires refinement. In Experiment 2, CMJ improved significantly whereas SJ and EUR did not. The manuscript interprets this pattern as evidence of improved stretch-shortening cycle efficiency; however, if SSC efficiency had meaningfully improved, one would also expect changes in EUR. This apparent inconsistency should be discussed more carefully, especially considering the relatively small effect size observed for CMJ. The current mechanistic interpretation appears somewhat stronger than the data support.

Response: Thank you for this careful and constructive comment. Following the suggestion in Comment 2, we re‑analyzed the Experiment 2 data from the 10‑week intervention using linear mixed-effects models. The previous significant improvement in CMJ was no longer statistically significant and its effect size remained small. The results for the other variables did not change. SJ, CMJ, and EUR did not change significantly, and only SLJ showed a robust improvement. We therefore rewrote the relevant Discussion. We removed claims of enhanced SSC efficiency, we acknowledged the inconsistency between the non-significant EUR findings and the prior CMJ trend, and we offered a more cautious interpretation that is closely tied to the data. We sincerely appreciate your guidance, which has substantially strengthened the rigor and appropriateness of our discussion.

 

Comment 4：Regarding the control condition, although heart rate monitoring suggests comparable exercise intensity between groups, the free-play activities were not sufficiently standardized or quantified. Consequently, it remains difficult to determine whether the observed benefits are attributable specifically to Wushu-related motor patterns or simply to differences between structured and unstructured physical activity exposure. This limitation should also be acknowledged.

Response: We appreciate this constructive suggestion and have incorporated this limitation into the Discussion. Children in the control group engaged in free play. We provided materials to encourage activities that focused mainly on lower-limb muscular fitness and aimed to give a similar level of moderate-to-vigorous exercise (Supplement table 1). However, these activities were not fully standardized or measured. It therefore remains difficult to determine whether the observed benefits are specifically attributable to Wushu motor patterns or to differences between structured and unstructured physical activity exposure. Future studies could compare Wushu with other structured, lower-limb-focused activities such as roller skating or small-sided soccer.

 

Comment 5：There are additionally several smaller issues that should be corrected. The statistical analysis section contains an incomplete sentence (“Correlation analyses were performed to examine…”). The abstract repeats the sentence describing the standing long jump as the primary outcome. Table numbering and group labels should be carefully revised because there are inconsistencies between Experiment 1 and Experiment 2 tables (e.g., CON-1/INT-1 appearing in Experiment 2 tables). The notation in Figure 2 (“*** p < 0.005”) should also be verified, as the conventional threshold is usually p < 0.001.

Response: We sincerely thank the reviewer for the meticulous reading. We have corrected all the noted issues, including the incomplete statistical sentence, the repeated abstract statement, and the inconsistent table labels. Regarding Figure 2, the “*** p < 0.005” was a typo in the caption and has been corrected to “p < 0.001”; this does not affect the actual data or figure content.

 

Comment 6：Finally, the Discussion section related to flexibility outcomes could be shortened, as this finding is secondary and currently overemphasized relative to the main outcomes.

Response: We thank the reviewer for this suggestion. The flexibility outcomes were found to be secondary and were not statistically significant. Therefore, these aspects were overemphasized in the original Discussion. In response, this section of the Discussion has been significantly shortened. Specifically, we condensed the flexibility discussion to a single sentence stating the non-significant result, supported only by Refs. [3] and [15] to briefly acknowledge the broader literature without speculative elaboration. All other explanatory references and redundant statements have been removed. 

 

Overall, this manuscript has merit and contributes relevant information regarding martial arts interventions in preschool children. Addressing the points above would substantially improve the methodological rigor and interpretation of the findings.

We sincerely thank the reviewer for the encouraging comment. We will carefully revise the manuscript to address all the points raised.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Congratulations on the improved work, I have nothing more to add.