The effect of tart cherry juice compared to a sports drink on cycling exercise performance, substrate metabolism, and recovery

Ruirui Gao; Nicole Rapin; Justin W. Andrushko; Jonathan P. Farthing; Julianne Gordon; Philip D. Chilibeck

doi:10.1371/journal.pone.0307263

Peer Review History

Original SubmissionDecember 15, 2023
24 Jan 2024 Decision Letter - Franck Carbonero, Editor PONE-D-23-35326The effect of tart cherry juice compared to a sports drink on cycling exercise performance, substrate metabolism, and recoveryPLOS ONE Dear Dr. Chilibeck, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please consider all review comments to improve the readability of the text and provide enough experimental details. Please submit your revised manuscript by Mar 09 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Franck Carbonero, PhD Academic Editor PLOS ONE Journal Requirements: 1. When submitting your revision, we need you to address these additional requirements. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following financial disclosure: This study was funded by the Canadian Cherry Producers and Saskatchewan Academy of Sports Medicine Inc. Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. 3. Thank you for stating the following in the Acknowledgments Section of your manuscript: This study was funded by the Canadian Cherry Producers and Saskatchewan Academy of Sports Medicine Inc. We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: This study was funded by the Canadian Cherry Producers and Saskatchewan Academy of Sports Medicine Inc. Please include your amended statements within your cover letter; we will change the online submission form on your behalf. 4. In the online submission form, you indicated that The data underlying the results presented in the study are available from the corresponding author, Dr. Chilibeck (E-mail: phil.chilibeck@usask.ca). All PLOS journals now require all data underlying the findings described in their manuscript to be freely available to other researchers, either a. In a public repository, b. Within the manuscript itself, or c. Uploaded as supplementary information. This policy applies to all data except where public deposition would breach compliance with the protocol approved by your research ethics board. If your data cannot be made publicly available for ethical or legal reasons (e.g., public availability would compromise patient privacy), please explain your reasons on resubmission and your exemption request will be escalated for approval. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: I appreciate the opportunity to read and review this manuscript. The authors provide a compelling study showing that tart cherry juice consumption as a low glycemic index (GI) drink compared with a sports drink (high GI) has no effect on performance, substrate oxidation, blood pressure and various recovery variables. Major comments • Given that non-trained athletes are not oxygen limited in terms of vigorous intensity aerobic exercise and performance on time-to exhaustion tests why would it be hypothesized that increased blood flow (more oxygen delivery) from increased vasodilation from tart cherry juice would enhance performance? • Why would you expect muscle soreness or DOMS from this protocol? The intervention of 90min cycling at 65% VO2peak and a 10km time trial, that would primarily consist of concentric muscle contractions was used. It would not be expected for these participants to have DOMS or muscle damage since the protocol is not designed to cause muscle damage. All the muscle soreness articles referenced include eccentric damaging protocols. • How is muscle soreness measured? The reference provided described a DOMS visual analog scale assessment, EMG with twitch, ultrasound of muscle thickness. It is not clear what methods you used. The units you provide in figure 2 for muscle soreness is in mm. What is that in reference to? • The results sections should be longer and include all the outcome variables described and recorded. • The discussion paragraph (lines 310-319) needs to include references because there are some specific statements made about glycemic index effecting lactate levels and how fructose is converted into lactate and this needs to have very specific references. I would also provide a reference and some detail from George A Brooks regarding lactate metabolism. • Need to clarify the VO2 decreasing over exercise when the protocol was set at 65% of VO2 max with a fixed workload of 50% max. I would expect with this group of participants, that it would be more likely to see a VO2 slow component (a slow rise in VO2 during constant work rate exercise) as they might be working close to or above their lactate threshold. Was their lactate threshold determined on the preliminary VO2 max testing day? Minor comments • References should be included following the introduction statement. Also reference 1 is more focused on dietary nitrates, l-arginine and l-citrulline supplements and how they can improve performance. I don’t see how this relates to your intro on low glycemic tart cherry juice given they are rich in anthocyanins and flavonoids. • How were anthocyanins measured in the tart cherry juice provided? • Lines 116-117. You state participants were blinded to elapsed time then the following sentence it says participants were allowed to see elapsed time. Was the second sentence for the 90 min exercise condition? • I don’t see any discussion of tart cherry (anthocyanins, flavonoids) or glycemic index on performance in reference 1. • It would be good to introduce post exercise hypotension since your measure blood pressure as a secondary outcome. I would also include the data in the results on the 24-hr blood pressure monitor. • You specifically mention in your conclusion that blood pressure measurements should be expanded from 1 hour to 48hr post. In the methods you describe that the participants wore a 24hr ambulatory blood pressure monitor after exercise and recorded every 30 minutes during waking hours and every 2 hours during sleep. • It may be interesting to look at muscle recovery with tart cherry juice utilizing an eccentric muscle damaging protocol in both recreationally active individuals and elite athletes. You just mention in your conclusion that elite athletes would warrant further studies. • Did any of the participants report muscle soreness? • Was there a rest period between the 90 minute exercise and time trial? • The figures are very low resolution. Reviewer #2: Abstract Page 2, lines 24-25: I understand that there is a word limit but consider rewriting the first sentence. It sounds awkward. Perhaps add “and” after the word properties. “Tart cherries have low glycemic index, antioxidant and anti-inflammatory properties, and therefore, may benefit performance and enhance recovery from exercise.” Page 2, line 28: Why is it stated that there were 12 recreational cyclists in the study but in parenthesis it provides the background data for 8 males? Is the background data just for the males or also including the females? Introduction Page 3, lines 46-47: Could you provide citations for studies that have shown tart cherry juice can inhibit inflammation and enhance recovery? Page 3, lines 54-58: Can you add citations for the statement about tart cherries protective effect. Likewise, can you add citations for studies that have assessed muscle damage using indirect markers of muscle damage? Also could you address the literature that large doses of antioxidants, found in tart cherries, may also blunt exercise performance/improvements. Page 3, lines 63-65: Why not include a placebo group as a third arm to the study? Methods Page 7, lines 140-142: Were participants instructed not to change their physical activity levels throughout the duration of the entire study, since they may be able to improve performance measures by increasing their physical activity and the amount of time they spend cycling? Page 10-11, lines, 226-229: Could you write out/add the levels of the two-factor repeated measure ANOVA, such as 2(condition: tart cherry vs. high glycemic index drink) x 3( time: pre vs. immediately post vs. 24 h post vs. 48 h post)? Looking at the figures, it appears that the time levels were different for certain variables. This would make it more clear which variables were analyzed during what time. Page 10-11, line 226-229: Was there a specific reason why the study was not designed to examine potential sex differences were not examined? Page 11, lines 233-234: Could the Bonferroni corrected p-values be included in the results as well as the methods were applicable. Results Page 11-12, lines 245-254: I would suggest rewriting the results section to make it more clear for the readers. It is confusing the way it is currently. I would suggest breaking into more sentences. For example, all the dependent t-test results as one or a couple of sentences and then the repeated measure results as separate sentences. It is also unclear what is meant by “increasing over exercise” or “decreasing over exercise”. Does it mean a particular increased/decreased from each time point that was measured or only from one time to another (not all that were measured)? Lastly, please include the Bonferroni correct p-values where applicable. Discussion Page 14, lines 310-311: Please add citations for studies that investigated the effects of foods differing in glycemic index on lactate levels. Page 15, lines 331-332: Please add citations for studies that have found blood pressure-lowering effects of tart cherry juice. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: Yes: Catherine L. Jarrett Reviewer #2: No ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0307263.r001
Revision 1
2 Apr 2024 Author Response Response to editors: We have removed mention of funding sources from the manuscript. We have uploaded a file with all the study data Response to reviewers Thanks to the reviewers for taking the time to review our manuscript. We have responded to all comments below. Please note that references to page numbers are for the tracked changes version of the manuscript, which follows the clean, revised manuscript in the pdf. We refer to page numbers for revisions rather than line numbers because the line numbers shift when the journal converts our Word document to pdf. Reviewer 1 Major comments • Given that non-trained athletes are not oxygen limited in terms of vigorous intensity aerobic exercise and performance on time-to exhaustion tests why would it be hypothesized that increased blood flow (more oxygen delivery) from increased vasodilation from tart cherry juice would enhance performance? Response: We have added the possibility that non-trained athletes might not be oxygen-limited during the testing in our study to the start of the discussion section: “Our study indicates that perhaps the participants in our study were not limited by oxygen delivery because they were not trained athletes and therefore any vasodilatory effect of the cherry juice would not have an effect on performance.” (page 14) • Why would you expect muscle soreness or DOMS from this protocol? The intervention of 90min cycling at 65% VO2peak and a 10km time trial, that would primarily consist of concentric muscle contractions was used. It would not be expected for these participants to have DOMS or muscle damage since the protocol is not designed to cause muscle damage. All the muscle soreness articles referenced include eccentric damaging protocols. Response: We agree with the reviewer that the optimal muscle-damaging protocol involves eccentric contractions; however, we would argue that high-intensity cycling can still result in muscle damage. For example, there is a growing number of cases of exertional rhabdomyolysis in people undertaking “spin” classes, cycling classes that would involve little eccentric contractions. There is also evidence for an elevation in markers of muscle damage with cycling. We have added this to the introduction, citing the references below. Masuda Y, Wam R, Paik B, Ngoh C, Choong AM, Ng JJ. Clinical characteristics and outcomes of exertional rhabdomyolysis after indoor spinning: a systematic review. Phys Sportsmed. 2023 Aug;51(4):294-305. doi: 10.1080/00913847.2022.2049645. Epub 2022 Mar 10. PMID: 35254210. Hebisz R, Borkowski J, Hebisz P. Creatine Kinase and Myoglobin Plasma Levels in Mountain Bike and Road Cyclists 1 h after the Race. Int J Environ Res Public Health. 2022 Aug 2;19(15):9456. doi: 10.3390/ijerph19159456. PMID: 35954814; PMCID: PMC9367889. We have added the following to our introduction: “Although eccentric contractions are typically used in studies to induce muscle damage, high-intensity concentric contractions induced by repetitive cycling still has the potential to induce muscle damage.” (page 3) We also highlight in our discussion the limitation that if we used a protocol involving eccentric contractions, we may have seen a greater amount of muscle damage. • How is muscle soreness measured? The reference provided described a DOMS visual analog scale assessment, EMG with twitch, ultrasound of muscle thickness. It is not clear what methods you used. The units you provide in figure 2 for muscle soreness is in mm. What is that in reference to? Response: Our apologies...somehow these methods were omitted from the manuscript. We have added greater details to the methods: “Using an Algometer (WAGNER Instruments, FDK 60 Force Dial; Greenwich, CT), 5kg of pressure was applied on four different sites of the knee extensors. While the participants were seated upright with a 90-degree bend in the knee, the distance between the anterior superior iliac crest and proximal edge of the patella was measured. Four locations were marked with a permanent marker: 25, 50, 75 and 100% of the distance between the two anatomical landmarks with 0% indicating the proximal landmark (anterior superior iliac crest). Participants reported pain on a 100mm visual analog scale, with 0mm indicating no pain and 100 mm indicating maximal pain. A total pain score was derived by taking an average of the pain from all four sites.” (page 6) • The results sections should be longer and include all the outcome variables described and recorded. Response: We double-checked the results section to ensure that all outcome variables were described. The only outcome variable we did not describe in full detail were the blood pressure results. These have been added to a table in the results section. We have expanded the results section to include all the post-hoc testing on the time main effects across different variables. • The discussion paragraph (lines 310-319) needs to include references because there are some specific statements made about glycemic index effecting lactate levels and how fructose is converted into lactate and this needs to have very specific references. I would also provide a reference and some detail from George A Brooks regarding lactate metabolism. Response: We have added references to support glycemic index affecting lactate levels and how fructose is converted to lactate in the liver, including a reference from George A Brooks: Kaviani M, Chilibeck PD, Jochim J, Gordon J, Zello GA. The Glycemic Index of Sport Nutrition Bars Affects Performance and Metabolism During Cycling and Next-Day Recovery. J Hum Kinet. 2019 Mar 27;66:69-79. doi: 10.2478/hukin-2018-0050. PMID: 30988841; PMCID: PMC6458587. Burns SP, Murphy HC, Iles RA, Bailey RA, Cohen RD. Hepatic intralobular mapping of fructose metabolism in the rat liver. Biochem J. 2000 Jul 15;349(Pt 2):539-45. doi: 10.1042/0264-6021:3490539. PMID: 10880353; PMCID: PMC1221177. Brooks GA. What the Lactate Shuttle Means for Sports Nutrition. Nutrients. 2023 May 3;15(9):2178. doi: 10.3390/nu15092178. PMID: 37432330; PMCID: PMC10180760. • Need to clarify the VO2 decreasing over exercise when the protocol was set at 65% of VO2 max with a fixed workload of 50% max. I would expect with this group of participants, that it would be more likely to see a VO2 slow component (a slow rise in VO2 during constant work rate exercise) as they might be working close to or above their lactate threshold. Was their lactate threshold determined on the preliminary VO2 max testing day? Response: The lactate threshold was not determined; however, based on the lactate response to the exercise test (which decreased over the 90 minutes of cycling) we assume they were below their lactate threshold. The VO2 slow component correlates to blood lactate concentrations, so perhaps the increased removal of lactate during the test (i.e., through the Cori Cycle or lactate shuttle) may be associated with the slight reduction in VO2 during the test. We have added the following text to the discussion section: “There was a slight, but statistically significant decrease in VO2 across our exercise test (across both drink conditions) (Figure 1). This is contrary to the VO2 drift (i.e., slow component) that might be expected. The VO2 slow component is correlated with lactate concentration [32]. Lactate concentration decreased throughout our exercise test indicating our participants were most likely working below their lactate threshold. We speculate that the reduced VO2 observed during our exercise test may be related to the reduced lactate concentration, which is most likely due to the lactate shuttle or Cori Cycle during exercise [33].” (page 16) Costa MM, Russo AK, Pićarro IC, Barros Neto TL, Silva AC, Tarasantchi J. Oxygen consumption and ventilation during constant-load exercise in runners and cyclists. J Sports Med Phys Fitness. 1989 Mar;29(1):36-44. PMID: 2770266. Brooks GA. What the Lactate Shuttle Means for Sports Nutrition. Nutrients. 2023 May 3;15(9):2178. doi: 10.3390/nu15092178. PMID: 37432330; PMCID: PMC10180760. Minor comments • References should be included following the introduction statement. Also reference 1 is more focused on dietary nitrates, l-arginine and l-citrulline supplements and how they can improve performance. I don’t see how this relates to your intro on low glycemic tart cherry juice given they are rich in anthocyanins and flavonoids. Response: We have added the following references to support the opening sentence on the potential for tart cherry juice to improve recovery from exercise and exercise performance. We also replaced reference 1 with a reference that is focused on tart cherry juice (the first reference listed below). Connolly DA, McHugh MP, Padilla-Zakour OI, Carlson L, Sayers SP. Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. Br J Sports Med. 2006 Aug;40(8):679-83; discussion 683. doi: 10.1136/bjsm.2005.025429. Epub 2006 Jun 21. PMID: 16790484; PMCID: PMC2579450. Bowtell JL, Sumners DP, Dyer A, Fox P, Mileva KN. Montmorency cherry juice reduces muscle damage caused by intensive strength exercise. Med Sci Sports Exerc. 2011 Aug;43(8):1544-51. doi: 10.1249/MSS.0b013e31820e5adc. PMID: 21233776. Gao R, Chilibeck PD. Effect of Tart Cherry Concentrate on Endurance Exercise Performance: A Meta-analysis. J Am Coll Nutr. 2020 Sep-Oct;39(7):657-664. doi: 10.1080/07315724.2020.1713246. Epub 2020 Jan 27. PMID: 31986108. • How were anthocyanins measured in the tart cherry juice provided? Response: Anthocyanins were estimated based on the Cherry Juice product label and not measured directly. This has been added as a limitation in the discussion section. (page 16) • Lines 116-117. You state participants were blinded to elapsed time then the following sentence it says participants were allowed to see elapsed time. Was the second sentence for the 90 min exercise condition? Response: Participants were blinded to elapsed time during the 10km time trial. The following sentence indicates that they were allowed to see the elapsed distance. (page 6) • I don’t see any discussion of tart cherry (anthocyanins, flavonoids) or glycemic index on performance in reference 1. Response: This reference has been replaced with a few references that mention the effect of tart cherries on recovery from exercise and performance. • It would be good to introduce post exercise hypotension since your measure blood pressure as a secondary outcome. I would also include the data in the results on the 24-hr blood pressure monitor. Response: We add the following to the discussion section: “Blood pressure in the current study was measured post-exercise. The well-known post-exercise hypotension, which can last up to 24 hours, may have masked any effects of the tart cherry juice.” (page 18) Alpsoy Ş. Exercise and Hypertension. Adv Exp Med Biol. 2020;1228:153-167. doi: 10.1007/978-981-15-1792-1_10. PMID: 32342456. We have also added a table in the results section describing in more detail the 24-hour blood pressure results. • You specifically mention in your conclusion that blood pressure measurements should be expanded from 1 hour to 48hr post. In the methods you describe that the participants wore a 24hr ambulatory blood pressure monitor after exercise and recorded every 30 minutes during waking hours and every 2 hours during sleep. Response: This is an error in our conclusion. We have deleted mention of the 1 hour measurement to simply state that measurements could be expanded to 48 hours. • It may be interesting to look at muscle recovery with tart cherry juice utilizing an eccentric muscle damaging protocol in both recreationally active individuals and elite athletes. You just mention in your conclusion that elite athletes would warrant further studies. Response: We have modified our conclusion to suggest this as a future direction. • Did any of the participants report muscle soreness? Response: Muscle soreness results are presented in bottom panel of figure 2. Overall, the increase in muscle soreness was not statistically significant (p=0.078), but given this trend, some of the participants would have reported muscle soreness, especially immediately post-exercise. • Was there a rest period between the 90 minute exercise and time trial? Response: There was no rest between the 90 minute exercise and the time trial. This is clarified in the methods where we now state the time trial was performed immediately after the 90-minutes of exercise. • The figures are very low resolution. Response: We have submitted high-resolution figures as individual figure files (tifs). The resolution may have been lost when the manuscript was converted to pdf for review. Reviewer #2: Abstract Page 2, lines 24-25: I understand that there is a word limit but consider rewriting the first sentence. It sounds awkward. Perhaps add “and” after the word properties. “Tart cherries have low glycemic index, antioxidant and anti-inflammatory properties, and therefore, may benefit performance and enhance recovery from exercise.” Response: This has been corrected as suggested Page 2, line 28: Why is it stated that there were 12 recreational cyclists in the study but in parenthesis it provides the background data for 8 males? Is the background data just for the males or also including the females? Response: When we put in “8 males” we assumed the reader would be able to determine the remaining participants were females and that the background data referred to all 12 participants. To make this clearer we have added “4 females” in the parenthesis. Introduction Page 3, lines 46-47: Could you provide citations for studies that have shown tart cherry juice can inhibit inflammation and enhance recovery? Response: We have added several references here, as suggested: Connolly DA, McHugh MP, Padilla-Zakour OI, Carlson L, Sayers SP. Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. Br J Sports Med. 2006 Aug;40(8):679-83; discussion 683. doi: 10.1136/bjsm.2005.025429. Epub 2006 Jun 21. PMID: 16790484; PMCID: PMC2579450. Bowtell JL, Sumners DP, Dyer A, Fox P, Mileva KN. Montmorency cherry juice reduces muscle damage caused by intensive strength exercise. Med Sci Sports Exerc. 2011 Aug;43(8):1544-51. doi: 10.1249/MSS.0b013e31820e5adc. PMID: 21233776. Gao R, Chilibeck PD. Effect of Tart Cherry Concentrate on Endurance Exercise Performance: A Meta-analysis. J Am Coll Nutr. 2020 Sep-Oct;39(7):657-664. doi: 10.1080/07315724.2020.1713246. Epub 2020 Jan 27. PMID: 31986108. Page 3, lines 54-58: Can you add citations for the statement about tart cherries protective effect. Likewise, can you add citations for studies that have assessed muscle damage using indirect markers of muscle damage? Also could you address the literature that large doses of antioxidants, found in tart cherries, may also blunt exercise performance/improvements. Response: We have again cited the following studies to support the statement on cherries protective effect using indirect markers of muscle damage: Connolly DA, McHugh MP, Padilla-Zakour OI, Carlson L, Sayers SP. Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. Br J Sports Med. 2006 Aug;40(8):679-83; discussion 683. doi: 10.1136/bjsm.2005.025429. Epub 2006 Jun 21. PMID: 16790484; PMCID: PMC2579450. Bowtell JL, Sumners DP, Dyer A, Fox P, Mileva KN. Montmorency cherry juice reduces muscle damage caused by intensive strength exercise. Med Sci Sports Exerc. 2011 Aug;43(8):1544-51. doi: 10.1249/MSS.0b013e31820e5adc. PMID: 21233776. Regarding the comment that excessive antioxidant supplementation may blunt exercise performance: I think this is more of a chronic effect; however, to address your point, we have added a statement on this in the conclusion of the manuscript: “It should also be noted that although foods such as tart cherries may protect against muscle damage, the high amount of antioxidants may hinder long-term adaptation to exercise training (e.g., mitochondrial biogenesis) because much of the cell-signaling required for chronic adaptation involves signaling initiated by free-radicals produced during h Attachments Attachment Submitted filename: response to reviewer comments.docx https://doi.org/10.1371/journal.pone.0307263.r002
30 Apr 2024 Decision Letter - Franck Carbonero, Editor PONE-D-23-35326R1The effect of tart cherry juice compared to a sports drink on cycling exercise performance, substrate metabolism, and recoveryPLOS ONE Dear Dr. Chilibeck, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please answer Reviewer 1's questions and implement their minor edits suggestions. Please submit your revised manuscript by Jun 14 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Franck Carbonero, PhD Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments: Please answer Reviewer 1's questions and implement their minor edits suggestions. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #1: All comments have been addressed Reviewer #2: All comments have been addressed ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The authors provided detailed responses and edited the manuscript with more references regarding tart cherry juice. They also clarified methods that were lacking and data that was missing from the results. I selected minor revisions, because I would like the authors to confirm that power output was maintained during the 90 minutes. I think the results would benefit from a figure that shows the power output during the 90min cycling test. One minor comment is the first panel of figure one y-axis is labeled "pre-exercise glucose" and the x axis is labeled with times post exercise. Also, it doesn't appear that post exercise blood pressure is discussed in the results section. The authors added results regarding excluded participant data that was not in the original version, the participant numbers should be included in the figure/table legends. Reviewer #2: Thank you to the authors for responding to my comments. The manuscript is well written and well thought out! Great work! ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0307263.r003
Revision 2
28 Jun 2024 Author Response Reviewer #1: The authors provided detailed responses and edited the manuscript with more references regarding tart cherry juice. They also clarified methods that were lacking and data that was missing from the results. I selected minor revisions, because I would like the authors to confirm that power output was maintained during the 90 minutes. I think the results would benefit from a figure that shows the power output during the 90min cycling test. Response: Power output was maintained throughout the test by the researcher watching closely that the participants maintained the required pedaling rate. We have added a statement on this to the manuscript (lines 164-166). We do not have the data for a figure showing the power output during the test. One minor comment is the first panel of figure one y-axis is labeled "pre-exercise glucose" and the x axis is labeled with times post exercise. Response: The “post” indicators on the x-axis of the graph refer to post-drink consumption and not post-exercise. We have clarified this in the legend for the figure (line 270) . Also, it doesn't appear that post exercise blood pressure is discussed in the results section. Response: The blood pressure results are mentioned on line in the results section (line 275). The authors added results regarding excluded participant data that was not in the original version, the participant numbers should be included in the figure/table legends. Response: We have added the participant numbers to the figure legends and blood pressure table, and in the text of the results section as suggested. Attachments Attachment Submitted filename: Responses to reviewer comments2.docx https://doi.org/10.1371/journal.pone.0307263.r004
2 Jul 2024 Decision Letter - Franck Carbonero, Editor The effect of tart cherry juice compared to a sports drink on cycling exercise performance, substrate metabolism, and recovery PONE-D-23-35326R2 Dear Dr. Chilibeck, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Franck Carbonero, PhD Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0307263.r005
Formally Accepted
4 Jul 2024 Acceptance Letter - Franck Carbonero, Editor PONE-D-23-35326R2 PLOS ONE Dear Dr. Chilibeck, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Franck Carbonero Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0307263.r006

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .