1. Introduction
revalence of Exercise-associated muscle cramp (EAMC) has been reported in different studies and groups of athletes [1, 2, 3, 4, 5]. One of these groups is runners [6, 7]. Due to the fact that a lot of muscles are used during running and the amount of energy consumed in these runners is high, and considering that no review study was not found that addressed the causes of EAMC in runners, this review study aims to investigate EAMC in runners to determine the cause and general nature of EAMC in this sport to provide more complete and better information for interventions and future studies on EAMC in runners. As a result, it can help prevent, treat and reduce its occurrence.
2. Methods
A search was conducted for studies on EAMC in runners published in Persian or English from 1997 to 2021 in MEDLINE/PubMed, EMBASE/SCOPUS, LILACS, CINAHL, CENTRAL (Cochrane Central Register of Controlled Trials), Web of Science, PEDro, Google Scholar, MAGIRAN, IRANDOC, IranMedex, MedLib, and SID using the MeSH keywords: Muscle cramp or muscle fatigue or chronic disease, running, ultra-marathon or half-marathon or marathon or ultrarunning or athletes or athletic performance, exercise or endurance exercise, water-electrolyte imbalance, electrolytes or dehydration or sports nutrition or hydration. After finding articles, first their title and abstracts and then their contents were read. If they met the inclusion criteria, they would be used in the review. Inclusion criteria were: Being published in Persian or English, studies on EAMC in runners, and availability of fulltexts. 
3. Results
The search in online databases yielded 326 articles. By reviewing their reference sections, 5 more articles were yielded. After removing duplicates, 241 were identified for review. After reviewing their titles and abstracts, 202 were deleted and 39 remained for reading their fulltexts. Finally, 15 eligible articles were selected and their results were reported (Table 1).




4. Discussion and Conclusion
The purpose of this study was to investigate EAMC in runners. Studies have reported a variety of information on EAMC in runners. Studies showed that the causes of EAMC are: dehydration and electrolyte deficiency, cold, prolonged training or competition, increased body temperature during training or competition, history of muscle injuries and cramps in the past, increased intensity of training in a short time, and dietary restrictions. Therefore, in order to reduce the occurrence EAMC in runners, it is necessary to consider these factors and study them in detail.

Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or profit-non sectors.

Authors' contributions
All authors equally contributed to preparing this article.

Conflicts of interest
The authors declared no conflict of interest.


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