Comparison of frequency of electrical activity values of lower limb muscles before and after fatigue in people with history of covid-19 compared to healthy people during walking

Fatigue is one of the effective factors in changing the electrical activity of muscles, so that this index is directly related to the increase in the potential of muscle injuries and performance loss in various sports stages. Therefore, the aim of the present study was to compare the electrical activity values of the lower limb muscles before and after fatigue in the people with a history of Covid-19 compared to healthy people during walking.

The present research was of semi-experimental and laboratory one. The statistical population of the present study included women with a history of Covid-19 and healthy women in Ardabil province. A statistical sample of 28 people with an age range of 18-30 years was selected by purposive sampling. The statistical samples included two groups of 14 healthy people and 14 people with covid-19. The method of asking people for their history of contracting the Covid-19 disease was in such a way that at least two months had passed from their infection and their PCR test results were already positive. healthy people didn't have any symptoms and had negative PCR results. Electromyography data were analyzed using Datalite Biometric program before and after the fatigue protocol. Two-way analysis of variance (ANOVA) with repeated measures was used for statistical analysis, and bonferroni post hoc test was used at the significance level of P<0.05.

The results showed significant group-by-fatigue interaction effect for frequency of the vastus latlarais (P=0.031), vastus medialis (P=0.029), and gluteus medius (P=0.035) muscles during loading response phase. The reduction of frequency content at post-test compared with pre-test in healthy group was greater than that Covid-19 group.

It seems that the difference in the frequency of electrical activity of the muscles of the lower limbs in different phases of walking after fatigue in people with Covid-19 compared to healthy ones can be a serious reason for the occurrence of injury and decrease in the stability of the joints during walking. However, more confirmatory researches in the future are needed to prove this relationship.