Body Composition and Physical Fitness: Does This Relationship Change in 4 Years in Young Adults?

(1) Background: There are few studies investigating the relationship between physical fitness and body composition in young adults and, to our knowledge, there are no such reports focusing specifically on physiotherapy students. This observational study aimed to assess the relationship between physical fitness and selected anthropometric measurements as well as body composition in Polish students in the first year and in the final year of a university course in physiotherapy. (2) Methods: A group of 100 randomly selected individuals were recruited among first- and fifth-year students of physiotherapy (50% women), who were assigned to two groups: A (aged 19 years) and B (aged 23 years). Body composition was assessed using a Tanita TBF-300 Analyzer, and physical fitness was measured using Zuchora’s Physical Fitness Index. (3) Results: A higher level of general fitness was identified in students from Group B ( p = 0.0261), and lower values of the fat mass index was found in Group A ( p = 0.0441). Group A was found with correlations between general level of physical fitness and the following indexes: fat% ( R = −0.4; p = 0.0018), FM ( R = −0.3; p = 0.0310), FFM ( R = 0.3; p = 0.0229) and TBW ( R = 0.4; p = 0.0024), whereas Group B was found with correlations between general physical fitness and BMI ( R = 0.3; p = 0.0308) as well as FM index ( R = 0.3; p = 0.0431). (4) Conclusions: The findings show significant differences between the groups in physical fitness, body composition and selected anthropometric measurements. Older students presented higher level of general fitness, whereas younger students were found with a lower mean value of fat index.