## 4 Discussion
Technique improvement, aimed at minimizing limb asymmetry and reducing unnecessary vertical movements, directly contributes to lowering energy costs, which is crucial for achieving better athletic performance [22]. The one year of training implemented in a group of 12 elite race walkers resulted in lowering the level of total external work, particularly visible during walking at racing speed. However, it is important to note that each athlete followed a slightly different training regimen, tailored to their individual needs and technical errors identified in the initial analysis. The most relevant technical changes observed were a reduction in center ofmass oscillations and improved limb symmetry. While all athletes received corrections, the extent of errors varied, influencing the magnitude of the improvements [7]. The inner group variance analysis performed to determine the significance of statistical differences of energy cost (EE) in the second test during walking at different speeds indicated in the post hoc analysis that there were pairs of variables with statistically significant differences. The differences were registered between mean values of energy cost for vt and vp (\(p<0.005\)), indicating a 36% growth in energy cost when accelerating the body from technical to threshold speeds and a 54% growth when accelerating from vt to vs (\(p<0.001\)). However, mean values of EE did not differ significantly between vp and vs (\(p<0.05\)). ANOVA for reproducible measurements indicated that the mean energy cost (EE) of walking at vt speed calculated per minute of work in the second test was lower by 2.9 kJ-min\({}^{-1}\) on average, which in comparison to the first test amounted to a 5.9% difference. However, mean cost values for technical speed did not differ significantly between tests (\(p<0.05\)). Analogous values of EE standardized by meter of covered distance and body mass were lower in the second test (from 4.9 to 5.9%). Differences between mean values were clear but statistically insignificant. The results for walking at threshold speed present similar features. Lowering of EE calculated per minute of work by 3.5 kJ-min\({}^{-1}\) on average was observed in the second test, which meant a difference at the level of 5.3%. Although the registered differences were remarkable, they turned out to be statistically insignificant (\(p<0.05\)). Energy cost standardized by meter of distance and body mass was lower by 5.4% and 4.9%, respectively, but did not differ significantly between the first and second tests. The lowest values of energy cost in the second test, calculated per minute of work at 3.9 kJ-min\({}^{-1}\) in relation to the first test, were registered for walking at racing speed. Energy cost per meter of covered distance was lower by 5.2% but statistically insignificant (\(p<0.05\)), whereas EE calculated per meter of distance and kilogram of body mass decreased by 8.5% and was on the borderline of statistical significance (\(p=0.058\)). To sum up, it should be stated that the energy cost of EE recorded in the second study was several percent lower for individual walking speeds compared to the results of the first study [7], but the observed contrasts turned out to be statistically insignificant. Recapitulating, it should be stated that the highest, over 8%, energy savings, measured in units taking into account body build and gait kinetics, were recorded during walking at racing speed, but the obtained differences were not clearly confirmed in the statistical analysis performed. The inner group variance analysis within the range comparing mean values of total work realized at accelerating and lifting CoM during walking at technical, threshold, and racing speeds indicated in post hoc testing the occurrence of significant contrasts.