The effect of chronotype in preferred and non-preferred time on some bio-motor factors in young boys aged 18 to 25 years

The aim of the present study is to compare some bio-motor factors during preferred and non-preferred times based on chronotype in young men aged 18 to 25 years old.

The population included male athletes between the ages of 18 and 25 in Tehran. Using Gpower sample size software, the total sample size of 40 people was calculated. Morningness-Eveningness Questionnaire (MEQ) was used. To measure the internal and external rotation of the shoulder, the Mobee Med device was used, the flexibility of the leg muscles was measured by the Wells test, and the Biodex balance meter was used to evaluate the static and dynamic balance. A mixed ANOVA test was used for data analysis.

The results showed that the main effect of the test and also the effect of the interaction between the group and the test was not significant in any of the variables, but the main effect of the group in the external rotation variable had a significant difference. In the pre-test stage, there was no significant difference between the groups, but in the post-test, evening types had significantly higher scores in the performance variable than morning types. In other words, there was a significant difference in the external rotation range of motion of the shoulder in the evening type group in the morning and in the evening. the results of the present study showed that there was no significant difference between the subjects' performance in the preferred and non-preferred time.