Monitoring the training of amateur long-distance cross-country skiers (XCS) can help athletes' achieve a higher exercise capacity and protect their health. The aim of this study was to assess body composition changes and lipid profiles in middle-aged amateur long-distance XCS after four months of training, including specialized roller ski training. The results of the time-to-exhaustion (TTE) test and blood tests and changes in body composition were analyzed with basic descriptive statistics: the paired Wilcoxon test was used to compare the results (initial and final). Spearman's rank correlation coefficient (R) was used to assess the influence of various variables on maximum oxygen uptake (VO2max). The findings show that training of amateur long-distance XCS improved maximal oxygen uptake (p = 0.008) and had a positive effect on fat reduction, measured in percentages (p = 0.038) and in kilograms (p = 0.023), but did not change blood lipids or other parameters. Further research could focus on other aspects of the annual training cycle: the competition period, and women in a larger group of athletes. Training with roller skis and a cross-country skiing training machine (a specialized machine for strengthening the arms and upper body) can support health and prevent obesity, overweight, and cardiovascular disease.
Keywords: amateur; body fat mass; cardiovascular capacity; cross-country skiing; lipid profile; long distance; preparatory period; roller ski.