Assessment of The Effect of Oral Potassium Nitrate Supplementation on Post-Exercise Delayed Onset Muscle Soreness (DOMS) Indices Among Sedentary Individuals Between 18 to 40 Years old: A Double-Blind Randomized Cross-Over Clinical Trial

Assessing the effect of potassium nitrate supplement (as a source of nitrate) on Post-exercise delayed onset muscle soreness (DOMS)

This study is a Double-Blind Randomized Cross-Over Clinical Trial. For randomization, block randomization will be used.

This study is performed in three stages, the first stage is for the initial evaluation of demographic, anthropometric characteristics and one repetition maximum of the volunteer. Second and third stages (two weeks apart) include the measurement of variables. All stages of this study were performed in the sports medicine department of Imam Khomeini Hospital and in this study both volunteers and researchers will be blind.

Inclusion criteria includes age between 18 and 40 years old; consent to enter the study; no physical or mental illness which increase the risk of disruption in the study process; sedentary lifestyle, no addiction to drugs, narcotics and tobacco, no pregnancy or breastfeeding, and no injury or pain in the biceps brachii muscle which will be evaluated. Exclusion criteria includes the use of different drugs during the week before the study, use of tonics and sports supplements during the month before the study, history of musculoskeletal injury during three months prior to participation in the study, the consumption of high nitrate containing foods before implementation of the research protocol

The intervention in this study includes the use of 1000 mg of potassium nitrate (containing about 600 mg of nitrate and 400 mg of potassium) in form capsules, 20 minutes before exercise and the control section (placebo) includes the use of capsules containing stevia similar to the intervention section.

Elbow passive and active range of motion; strength of biceps brachii muscle; tenderness of biceps brachii muscle

The allocation of volunteers will be determined by block randomization method with double, quadruple or sextet variable blocks (one group with symbol A and the other group with symbol B) and using the random number table of Random Allocation Software. Blocking and allocation sequencing for concealment will be done by someone other than the researcher (Allocation Concealment). The allocation ratio of samples will be 1:1 and the volunteers will be divided into two groups receiving potassium nitrate or placebo (Assignment).Then, based on the obtained blocks and order of allocation, one of the two types of capsules with unknown content for the researcher and the volunteer (potassium nitrate or placebo) will be given to group A for and the other capsule will be given to group B for consumption. After the wash-out period, each participant will take a capsule that they did not receive in the first round.

The appearance of the intervention and control group capsules is completely the same and only the contents of the capsules are different from each other. All capsules will be given to a third party before the start of the study, and the capsules will be given to the volunteers by a third party before each stage of the study, based on randomization blocks. Only the third party is aware of the contents of the capsules delivered (neither the researcher nor the volunteers will be aware) and the researcher will not be aware of the contents of the capsules given to each candidate until the final analysis of the data. The final analysis of the information will be done by the researcher.

The present study has been registered as a proposal for the thesis of sports medicine residency. The dissertation resulting from this proposal including participants' data (all data), study protocol, statistical analysis and study report (including all variables) will be provided to Tehran University of Medical Sciences and Sports Medicine Department. It should be noted that after the dissertation is approved, an article containing all the items mentioned will be published in one of the journals relevant to the research topic. It should be noted that access to detailed data that were not published in the final report or article, requires communication with the researcher in charge of the study.

The present study started on 23/9/2021 and for all stages until the submission of the dissertation, a period of two years is predicted. The data obtained from this research will be presented in the form of an article after the dissertation is approved (end of 2 years) for publication. Access to the detailed data that were not published in the final report or article will be possible after the publication of the article through direct contact with the researcher in charge of the study.

The data obtained from this research will be available to all applicants and there will be no restrictions.

There is no restriction on the use, dissemination or processing of the data in this study, provided that correspondence is sent via email or other means to the researcher in charge of the study and the necessary permission is issued by the researcher in charge.

To access the information in this study, the applicant can contact the researcher in charge of this study by e-mail or telephone.

The license to use the information is issued to the applicant as soon as possible after receiving and viewing the e-mail or making a phone call, and then the requested information will immediately sent to the applicant via e-mail.