1.    Introduction
Exercises are done by the general public for various purposes. Having never experienced such a situation before, the sports community is facing a different situation with the sudden spread of the Corona virus, as all aspects of human life have undergone fundamental changes. Children in sports have been severely affected by the COVID-19 crisis in a way that has never been seen before (1). All physical activities and group sports were suddenly restricted in many countries with the spread of coronavirus and were often transferred to exercise at home (2). Nanoparticles have new and improved properties compared to larger particles and bulk materials due to their size, particle distribution and morphology. Studies show that silver nanoparticles are superior to other metals in many fields. The main properties of silver nanoparticles are: non-allergenicity, high stability, hydrophilicity, environmental compatibility, heat resistance, non-creation or increase of resistance and compatibility in microorganisms (4), also, high ability to add to fibers, Polymers, ceramics, stones, and dyes have the same properties without changing the properties of the material.
Cook et al. Prepared silver nanoparticles with an average particle size of 37 nm by microwave irradiation and investigated the antibacterial properties of nanoparticles at five different concentrations. The results showed that the antibacterial property of these nanoparticles is higher against gram-positive bacteria than gram-negative (7). Studies have also shown that polymer nanocomposites containing silver nanoparticles have high thermal stability and long-lasting antibacterial activity, and yet are not toxic to human cells and tissues. Besides, these nanocomposites are a good choice for killing many species of bacteria and fungi (8).
Sweating during sports activities creates a suitable environment for the growth of bacteria and bad odor. Staphylococcus aureus is common bacteria in the sports community that causes infectious diseases. Therefore, sports equipment such as antibacterial sports clothes can protect athletes from microorganisms and unpleasant odors and at the same time prevent fiber damage and decay (10).
Based on the research conducted at the Hohenstein Institute, Germany, the most important measure to eliminate bacteria in sports clothes is to create antibacterial properties in them, and this effect should be permanent. On the other hand, elimination of skin reactions (allergy, irritation) or negative effects on skin microflora should also be considered (8).  
There are some reports that evaluate the environmental risks of clothes containing silver, and the concentration of nano silver is kept as a critical factor to prevent the risks in the minimum range (9). It has been emphasized that the use of nano in the design of sports clothes according to the standard concentration should be considered; otherwise, the use of silver sports clothes should be minimized (11).
Therefore, according to the mentioned cases, the development of new sports equipment has created a new revolution in all sports competitions and engineers who are developing sports equipment to increase and improve the performance of athletes. By examining some of the major influences related to the development of sports equipment, many advances have taken place through the engineering of materials used in the construction of sports equipment (13, 12). Also, other chemical nanocomposites such as nano-titanium reinforced with fibers which are materials with light weight, high resistance, and with unique design and features, have been widely used in sports equipment (14).
On the other hand, humanity is living in an exceptional time in the era of Covid-19, not because it is involved in a global disease, as it has witnessed global diseases several times in the past, sometimes with even more devastating results such as the Black Death (1333-1340) or the plague epidemic in the 16th century, but because many industries have been closed and, and sports travels have been restricted. Studies have shown that Covid-19 causes emotional distress and disorders in athletes. (15), in addition, this disease or its secondary damages can also be very important for participating in sports and especially for bearing the sports load and the physical load of sufferers, especially in high-performance sports; therefore, the significant effects of Covid-19 on the performance capacity of athletes cannot be rejected (16). Thus, the aim of the present study is to design and manufacture new antimicrobial shoes using nano-silver in order to prevent germs and viruses in the community of athletes.
2.    Methods
The present study is an applied and laboratory type of research for designing and manufacturing new antimicrobial shoes using nano-silver in order to prevent the spread of germs and viruses in the athlete community. Initially, in order to antimicrobize sports shoes to control and prevent germs and viruses, 1 pair of Shima model sports shoes made in Iran were prepared. To prepare the samples, first different percentages of nano-silver solution including 25, 50, 75 to 100 ppm were prepared and then different parts of the sample sports shoes were cut in the dimensions of 5 x 5 cm2. In this study, due to the specific type of sample, the spray method was used to add antimicrobial compounds. To perform the test, the processed samples were separated and prepared for antibacterial test by cutting them into discs with a diameter of one centimeter. They were then sterilized using UV rays. The samples were then placed in 1 ml of Müller-Hinton broth medium for 24 hours. The supernatant was then isolated and evaluated as a sample extract. Counting the number of bacterial colonies and bacterial colonies of the control sample, the amount of bacterial reduction was calculated using the following formula.
C= A-B × 100 ÷ A
 A stands fo the number of primary bacteria (CFU / ML); B indicates the number of bacteria after proximity and C (CFU / ML) shows the percentage of bacterial reduction. Also, a positive control group (culture medium with bacteria) and a negative control group (culture medium and test material) were considered. After the desired time, 5 μl of the suspension was obtained on Mulherington culture medium. Agar was cultured and incubated for 24 hours at 37 ° C.
3.    Results
The results of the present study, as can be seen in Table 1, had a minimum nanoparticle solution error of 0.025 (25 ppm) with 50% bactericidal properties, although this value was obtained by bacterial colony count (CFU / ML1.8 × 104) of a type of Staphylococcus aureus.
 Based on the results, the concentration of S. aureus was reduced by 70 and 90% from 50 and 75 ppm, respectively. Also, the results showed that from 100 ppm onwards, the reduction of S. aureus was 99.99%.
The results also showed that the resistance of nanosilver solution at concentrations of 75, 50, 25 ppm against E.coli bacteria continues with a decrease of 70, 90 and 97.88%, respectively. Moreover, the results show S. aureus is reduced from 99 ppm to 99.78, which is also a problem. From 100 ppm, the color changes from yellow to brown. as a result of an oxidation reaction; however, this is not the case at very low concentrations. We tried to use a thinner nanosilver suspension in antibacterial tests to save on the color of the supplement while saving on the consumption of additives.
4.    Conclusion
The use of nano-silver in the design and manufacture of sports shoes to prevent and control many microbes and viruses can be an effective intervention.

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 non-profit sectors.
Authors' contributions
All authors equally contributed to preparing article.
Conflicts of interest
The authors declared no conflict of interest.