Background: The aim of the study was to compare the mobility of the thoracic-lumbar segment of the spine and the mobility of its separate segments - the thoracic and lumbar ones in the saggital and transverse plane among young men divided into three groups that differ in the current commitment to physical activity.Material/Methods: 135 young men - students of Physical Education Faculty and of Tourism and Recreation Faculty at the Academy of Physical Education and Sport in Gdansk as well as students from the University of Gdansk aged 21-22 who did not participate actively in any sports discipline were involved in the study. In the saggital plane in the range of bending the torso forwards the flexibility of the thoracic-lumbar segment of the spine was tested according to Wolański's assumptions, the flexibility of the thoracic segment of the spine with Otto and Wurm's test and the lumbar segment of the spine with Schober's test. In the transverse plane in the range of torso twist to the right and to the left the mobility of the thoracic-lumbar segment of the spine and the lumbar segment were examined with the usage of Pavelek's tests.Results: In the saggital plane of the body among men from individual groups, the mobility of the thoracic-lumbar and lumbar segments of the spine during bend forwards was in the norm and above it, whereas the mobility of the thoracic segment of the spine was above the norm. In the transverse plane the range of the spine movement in the thoracic-lumbar and the lumbar spine to the right and left was similar among all the tested men, whereas the range of the thoracic-lumbar segment movement was above and of the lumbar segment below the norm. The students from Physical Education Faculty were characterised as having the highest flexibility of the thoracic-lumbar segment of the spine in the saggital plane in comparison with other students' flexibility. Against the background of the other groups the students of Tourism and Recreation Faculty demonstrated the highest mobility of the lumbar spine in the saggital plane. The stated differences were statistically significant.Conclusions: Higher frequency of participation in physical exercises and their longer duration among the students of Physical Education (PE) in comparison with the other groups did not influence significantly the range of their spine mobility apart from the range of bend forwards of the whole thoracic-lumbar segment of the spine in the saggital plane.