"Secular trends (2001-2020) in physical fitness as a health component in physiotherapy students from Bydgoszcz (Poland)".

The aim of this study was to assess changes in the components of physical fitness that are conducive to the health of young people surveyed between 2001 and 2020. Hypotheses were formulated about an increase in the thickness of skinfolds, especially among women, the deterioration of the results of fitness tests and the lack of conditioning of the examined changes with socioeconomic factors. Every year, physiotherapy students at the Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń (Poland) were examined for body height and mass, skinfold thickness, flexibility, static strength, abdominal muscle strength, functional strength and endurance. The results were obtained from 1161 female students and 464 male students. Similar trends were observed for most of the studied characteristics in people of both sexes. In male students, secular trends towards a decrease in the thickness of biceps skinfolds (R 2  = 0.455, p = 0.002) and lower leg skinfolds (R 2  = 0.314, p = 0.015) were found. In female students, secular trends towards an increase in the body mass (R 2  = 0.41, p = 0.003), a decrease in the thickness of skinfolds over the biceps (R 2  = 0.477, p = 0.001) and decreased flexibility (R 2  = 0.283, p = 0.023) were found. Male sex and the thickness of suprailiac skinfolds were frequent predictors of the, assessed motor abilities and socioeconomic factors did not significantly affect their maintenance. The obtained results, except for a few secular trend examples of the somatic features (male student's age and calf skinfold, female student's body mass, male and female student's biceps skinfold) and flexibility in women, showed their stability and the lack of conditioning by social factors and by the fitness test. Attention to the appropriate level of the observed components is justified, especially in light of the identified trend that showed their deterioration.