## 3 Results
### Running Economy  
#### 3.1.1 Energy Cost of Transport  
As for the mixed cohort of both sexes, ECT results are summarized in Figure 4b and Table 2. ECT was not affected by the shoes' order (\(F\) = 1.666, \(p\) = 0.167), while the footwear condition significantly affected ECT averaged across intensities (\(F\) = 7.136, \(p\) < 0.001). ECT was significantly reduced by 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) for HOK (2.80%, \(p_{\text{Holm}}\) < 0.001, and \(d_{\text{[PERSON]}}\) = 0.90), 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) for MIZ (2.57%, \(p_{\text{Holm}}\) < 0.001, and \(d_{\text{[PERSON]}}\) = 0.60), 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) for PUM (2.31%, \(p_{\text{[PERSON]}}\) < 0.001, and \(d_{\text{[PERSON]}}\) = 0.80), and 0.02 kcal kg\({}^{-1}\) km\({}^{-1}\) for SAU (1.52%, \(p_{\text{[PERSON]}}\) = 0.016, and \(d_{\text{[PERSON]}}\) = 0.42). Reductions by HOK and SAU were large in magnitude, whereas the effects of ECT reductions by MIZ and PUM were moderate and small, respectively.  
Figure 4: Energy cost of transport (ECT) in the four CPRS models studied, averaged across running speeds and ranked from the least (left) to most (right) economical. The bars show group averages while the connected symbols depict individual responses. (**a**) Sex-specific averages: Darker bar fill colours (left bar of a pair) represent mean values for the male runners whereas the lighter fill colours show female means. Blue connected down triangles (**v**) depict individual male (\(\circ\)) responses and red connected circles (\(\bullet\)) individual female (\(\circ\)) responses. (**b**) Averages for both sexes combined in one group. OWN: subjects’ own preferred pair of running shoes, HOK = Hoka Rocket X2, MIZ = Mizuno Wave Rebellion Pro, PUM = Puma Fast-R Nitro Elite, and SAU = Saucony Endorphin Pro 3.  
Although peak oxygen uptake per body mass was higher for the men than for the women, gender had no impact on the order of ECT reductions (\(p>0.59\), two-way ANOVA with the factors sex and footwear condition), yielding equivalent results for men and women with footwear condition being the only significant influence (\(p<0.001\), \(\eta_{\text{g}}{}^{2}=0.04\)). No interaction effect between sex and footwear condition was found (\(p>0.59\)). In view of these results, the following analyses will focus on the mixed cohort of both sexes.  
When considering footwear effects on ECT at individual running speeds, there were no significant differences in the energy cost of transport between footwear conditions at \(v_{1}\) (\(F=2.375\), \(p=0.060\)). At \(v_{2}\), in contrast, ECT was significantly affected by the footwear condition (\(F=3.514\), \(p=0.011\)), with significant reductions in ECT by 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) for HOK (2.71%, \(p_{\text{Holom}}=0.028\), and \(d_{\text{[PERSON]}}=0.78\)) and 0.02 kcal kg\({}^{-1}\) km\({}^{-1}\) for SAU (2.40%, \(p_{\text{Holom}}=0.023\), and \(d_{\text{[PERSON]}}=0.81\)) as compared to OWN. Reductions by HOK were moderate in magnitude, whereas SAU showed a large effect. MIZ (\(p_{\text{Holom}}=0.230\), \(d_{\text{[PERSON]}}=0.53\)) and PUM (\(p_{\text{[PERSON]}}=0.230\), \(d_{\text{[PERSON]}}=0.55\)) did not significantly affect ECT at this speed. At \(v_{3}\), footwear condition significantly affected ECT (\(F=8.497\), \(p<0.001\)) with significant reductions of 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) by HOK (3.32%, \(p_{\text{[PERSON]}}<0.001\), and \(d_{\text{[PERSON]}}=1.56\)), 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) by MIZ (3.23%, \(p_{\text{[PERSON]}}<0.001\), and \(d_{\text{[PERSON]}}=0.97\)), 0.02 kcal kg\({}^{-1}\) km\({}^{-1}\) by PUM (1.86%, \(p_{\text{[PERSON]}}=0.015\), and \(d_{\text{[PERSON]}}=0.61\)), and 0.03 kcal kg\({}^{-1}\) km\({}^{-1}\) by SAU (2.83%, \(p_{\text{[PERSON]}}<0.001\), and \(d_{\text{[PERSON]}}=1.17\)). The effects of HOK, MIZ, and SAU were large in magnitude, while the effect magnitude for PUM was moderate.