Stretch-Load Demands of Multiple Hops: Implications for Athletic Performance and Rehabilitation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Line 19 " ...completed the hopping tasks across track-embedded force platforms, where braking and propulsion kinetics were measured across 54x track-embedded force platforms"
This is worded a bit awkward, rewrite it as "... completed the hopping tasks across 54x track-embedded force platforms, where braking and propulsion kinetics were measured"

line 22: Th and QH are not defined in the abstract, making it hard for the reader to understand the overview of this work without reading the details in the main body. Triple hop and Quantuple hops are mentioned in the conclusions of the abstract. Thew simple solution is to reverse the order (use the full names in the results and the abbreviation in the conclusions

The discussion/conclusions do not offer an explanation or a hypothesis as to why the forces change between each hop (e.g. momentum, kinematics etc. ) therefore it is unclear what kind of nuances a practitioner should consider when implementing a multiple hop test, apart from not stressing the limb excessively. For example, when a TH should be used instead of a QH test? Does technique matters? This kind of practical insights can be useful.

Author Response

Comment 1: Line 19 " ...completed the hopping tasks across track-embedded force platforms, where braking and propulsion kinetics were measured across 54x track-embedded force platforms"
This is worded a bit awkward, rewrite it as "... completed the hopping tasks across 54x track-embedded force platforms, where braking and propulsion kinetics were measured"

Response 1: Thank you for this, it has been changed.

Comment 2: Line 22: Th and QH are not defined in the abstract, making it hard for the reader to understand the overview of this work without reading the details in the main body. Triple hop and quintuple hops are mentioned in the conclusions of the abstract. Thew simple solution is to reverse the order (use the full names in the results and the abbreviation in the conclusions

Response 2: Thank you for this, it has been changed.

Comment 3: The discussion/conclusions do not offer an explanation or a hypothesis as to why the forces change between each hop (e.g. momentum, kinematics etc. ) therefore it is unclear what kind of nuances a practitioner should consider when implementing a multiple hop test, apart from not stressing the limb excessively. For example, when a TH should be used instead of a QH test? Does technique matters? This kind of practical insights can be useful.

Response 3: Thank you, this would certainly improve the text. However, the primary aims of the study were to examine the increasing stretch–load demands across successive hops, and to compare these demands between triple- and quintuple-hop tasks, in order to better inform practitioners’ decisions regarding their application and utilisation. The discussion does infer that these findings may have practical applications within progressive return-to-play and athletic development contexts. Furthermore, the results suggest that a combination of strength-focused and coaching-based interventions may improve hopping capability, with the potential for transfer to broader athletic performance outcomes.

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Author

First of all, thank you for submission your work to this journal. This study quantifies and compares the kinetic demands of triple hop (TH) and quintuple hop (QH) tasks in 44 male university athletes, with a focus on progressive stretch-load (eccentric braking) demands. The authors report that braking impulses increase substantially across successive hops, while propulsive impulses decrease, with the final two hops of the QH imposing significantly greater demands than the initial hops or the entire TH. The topic is relevant to strength and conditioning and rehabilitation practitioners.

The manuscript is scientifically sound, novel, and well-written. However, several methodological clarifications, corrections to presentation, and tempering of overreaching conclusions are required before publication. I hope my comments improve your work as well.

 

 Mandatory Revisions (to be addressed before acceptance)

 

1. Correct presentation errors

- Incorrect section numbering: The second "2.2 Participants" (line 92) should be renumbered as "2.3 Testing Procedures." Adjust subsequent numbering accordingly.

- Table 2 labeling error: The post-hoc rows are labeled "TH" (e.g., "TH Maximal Vertical Force") but appear to refer to QH data. Please correct to "QH" or clarify.

 

2. Clarify methods

- Trial numbers: Why were three trials performed for TH but only two for QH? Provide justification (e.g., pilot testing, fatigue prevention, or a priori power analysis).

- Limb dominance definition: Specify how limb dominance was determined (e.g., preferred kicking leg, preferred jumping leg).

- Stretch-load validation (Section 2.3): Report quantitative agreement metrics (e.g., ICC, mean differences, limits of agreement) between force plate-derived braking phase and kinematic events (e.g., maximal knee flexion). Without these, the validation claim is incomplete.

 

3. Temper overreaching conclusions

- Line ~378: The statement that competency with TH is "a sensible progression prior to using" QH implies a causal training sequence not tested in this cross-sectional study. Revise to: "These findings suggest that TH may expose athletes to lower stretch-load demands than later hops of the QH, supporting a progressive loading strategy pending longitudinal validation."

 

 Suggested Revisions (optional but recommended)

1. Acknowledge sample limitations

- The sample includes only male athletes. Please state this explicitly in the abstract and title (if journal allows) or add a sentence in the Discussion: "Findings may not generalize to female athletes or clinical populations."

 

2. Add missing statements

- Conflict of interest: Add a declaration (even if "none").

- Data availability: Add a statement (e.g., "Data are available from the corresponding author upon reasonable request.").

 

3. Statistical reporting

- For the TH, pairwise t-tests were used only between Steps 1 and 2. Why was a repeated measures ANOVA not applied to Steps 1–3 for consistency with QH analysis? Please comment or justify.

 

Conclusion to Authors

This is a valuable and novel study that addresses an important gap in the literature. The kinetic data provided will be useful for practitioners. Please address the mandatory revisions (particularly the presentation errors, validation metrics, and tempered conclusions) and consider the suggested improvements. With these changes, the manuscript will be suitable for publication.

 

Recommendation after revision: Accept with minor revisions.

Author Response

Dear Author

First of all, thank you for submission your work to this journal. This study quantifies and compares the kinetic demands of triple hop (TH) and quintuple hop (QH) tasks in 44 male university athletes, with a focus on progressive stretch-load (eccentric braking) demands. The authors report that braking impulses increase substantially across successive hops, while propulsive impulses decrease, with the final two hops of the QH imposing significantly greater demands than the initial hops or the entire TH. The topic is relevant to strength and conditioning and rehabilitation practitioners.

The manuscript is scientifically sound, novel, and well-written. However, several methodological clarifications, corrections to presentation, and tempering of overreaching conclusions are required before publication. I hope my comments improve your work as well.

 Mandatory Revisions (to be addressed before acceptance)

1. Correct presentation errors

Comment 1: Incorrect section numbering: The second "2.2 Participants" (line 92) should be renumbered as "2.3 Testing Procedures." Adjust subsequent numbering accordingly.

Response 1: Thank you for this, it has been changed.

Comment 2: Table 2 labelling error: The post-hoc rows are labelled "TH" (e.g., "TH Maximal Vertical Force") but appear to refer to QH data. Please correct to "QH" or clarify.

Response 2: Thank you for this, it has been changed.

 

2. Clarify methods

Comment 3: Trial numbers: Why were three trials performed for TH but only two for QH? Provide justification (e.g., pilot testing, fatigue prevention, or a priori power analysis).

Response 3: Trial numbers were limited to 3 × TH and 2 × QH for each limb due to the higher physical demands and ground contact loads associated with the hops, particularly for the QH. With the inclusion of warm-ups and preparatory activities, fatigue was likely becoming a contributing factor, potentially increasing injury risk and affecting movement quality. This is discussed in 2.3 Testing Procedures

Comment 4: Limb dominance definition: Specify how limb dominance was determined (e.g., preferred kicking leg, preferred jumping leg).

Response 4: Limb dominance was determined by asked the subjects which foot they would kick a ball with (dominant). This has been added to the text.

Comment 5: Stretch-load validation (Section 2.3): Report quantitative agreement metrics (e.g., ICC, mean differences, limits of agreement) between force plate-derived braking phase and kinematic events (e.g., maximal knee flexion). Without these, the validation claim is incomplete.

Response 5: ICC’s were used (ICC = 1.00) and absolute agreement observed. This has been added in the text.

 

3. Temper overreaching conclusions

Comment 6: Line ~378: The statement that competency with TH is "a sensible progression prior to using" QH implies a causal training sequence not tested in this cross-sectional study. Revise to: "These findings suggest that TH may expose athletes to lower stretch-load demands than later hops of the QH, supporting a progressive loading strategy pending longitudinal validation."

Response 6: Thank you, this has been changed in the text.

 

Suggested Revisions (optional but recommended)

1. Acknowledge sample limitations

Comment 7: The sample includes only male athletes. Please state this explicitly in the abstract and title (if journal allows) or add a sentence in the Discussion: "Findings may not generalize to female athletes or clinical populations."

Response 7: Thank you this has been added to the discussion

 

2. Add missing statements

Comment 8: Conflict of interest: Add a declaration (even if "none").

Response 8: There is a declaration stating ‘no conflicts of interest’ in the footnotes of the paper.

Comment 9: Data availability: Add a statement (e.g., "Data are available from the corresponding author upon reasonable request.").

Response 9: There is a declaration stating ‘availability of data’ in the footnotes of the paper.

 

3. Statistical reporting

Comment 10: For the TH, pairwise t-tests were used only between Steps 1 and 2. Why was a repeated measures ANOVA not applied to Steps 1–3 for consistency with QH analysis? Please comment or justify.

Response 10: Thank you for this question. For the triple hop analysis, paired-samples t-tests were performed because the comparison involved only two repeated measures (2 x ground contacts). A repeated measures ANOVA with two levels is mathematically equivalent to a paired t-test and does not provide additional inferential benefit. Therefore, the paired t-test was selected as the simpler and more interpretable approach. Repeated measures ANOVA was used for the quintuple hop analysis, where four repeated measures were assessed (4 x ground contacts).

 

Conclusion to Authors

This is a valuable and novel study that addresses an important gap in the literature. The kinetic data provided will be useful for practitioners. Please address the mandatory revisions (particularly the presentation errors, validation metrics, and tempered conclusions) and consider the suggested improvements. With these changes, the manuscript will be suitable for publication.