## 3 Results  
Nine runners presented a non-identifiable footstrike pattern (mix of RFS and FFS patterns) and were thus were removed from the analysis. Of the remaining 74 runners, 49 presented the RFS pattern and 25 the FFS pattern. No differences were found for body mass, height, age, self-selected running speed, or Foot Posture Index between the two groups (Table 1).  
In the FFS group, a negative foot angle was associated with a forefoot landing strategy, while in the RFS group, positive values were associated with a heel-first landing strategy (\(p<0.001\)) (Figure 4). The FFS and RFS groups had a similar dorsiflexion of Sha-Foo at footstrike. At around 15% of stance, the Sha-Foo of FFS runners was slightly more dorsiflexed compared to that of RFS. At around 45% of stance, FFS runners reduced the dorsiflexion and returned to a position of greater plantarflexion compared to RFS runners for the remainder of the stance phase (\(p<0.001\)). RFS runners increased Sha-Foo dorsiflexion until 60% of stance, reached a larger dorsiflexion angle, and began plantarflexing later than RFS runners (\(p<0.001\)). FFS runners presented a significantly more adducted Sha-Cal (\(p=0.02\)) (Figure 4) and a less adducted Cal-Met (\(p=0.01\)) with respect to RFS runners during the whole stance phase (Figure 5). The Cal-Mid was significantly less inverted in the FFS group during the whole stance phase (\(p=0.01\)) (Figure 5).  
F2G and S2G angles presented similar patterns at 20-60% of the stance phase, with RFS runners presenting smaller angles at initial contact. FFS runners presented a significantly larger downward rotation of F2G and S2G after 60% of stance time (\(p<0.001\)) (Figure 6). V2G angle was significantly different at initial contact between the two groups (\(p<0.001\)). During the first 25% of stance, FFS runners were in a neutral V2G position, while the RFS showed an upward orientation of the V2G. At about 50% of stance, FFS runners returned to a more downward rotation of F2G, S2G, and V2G (\(p<0.01\)) (Figure 6). No differences were found in S2F, S2V, MLA, Mid-Met, or Met-Hal angles for all planes between F  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **RFS (n = 49)** & **FFS (n = 25)** & **Main Effect (\(p\))** \\ \hline Male/female & 23/26 & 12/13 & \(p=0.563\) \(\dagger\) \\ Age (year) & 41.3 (6.8) & 40.4 (6.0) & \(p=0.558\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\)\(\,\,\Figure 4: Foot angle with respect to the shank (Sha-Foo) and calcaneus with respect to the shank (Sha-Cal) joint angles time normalized across stance phase (0–100%) for forefoot strike (FFS) and rearfoot strike (RFS) patterns. Mean \(\pm\) standard error (SE) bands are reported (shaded regions). Below of each angle plot, there is a between footstrike pattern difference plot (FFS–RFS) containing the mean \(\pm\) 95% confidence interval (CI) bands (in red). Regions where those bands diverge from 0 can be considered regions of significant differences. (Legend: FFS in blue, RFS in green).  
Figure 5: Midfoot with respect to the calcaneus (Cal-Mid), metatarsus with respect to the midfoot (Mid-Met), and metatarsus with respect to the calcaneus (Cal-Met) joint angles time normalized across stance phase (0–100%) for forefoot strike (FFS) and rearfoot strike (RFS) patterns. Mean \(\pm\) standard error (SE) bands are reported (shaded regions). Below of each angle plot, there is a between footstrike pattern difference plot (FFS–RFS) containing the mean \(\pm\) 95% confidence interval (CI) bands (in red). Regions where those bands diverge from 0 can be considered regions of significant differences. (Legend: FFS in blue, RFS in green).