Fig 1.
The ensemble-averaged trunk angle across the stance phase of the level-step (A) and the drop-step (B) during running with backward (TI¯; green), self-selected (TI0; black, shaded area: ± 1 SD), low forward (TI+; red) and high forward (TI++; blue) trunk inclinations. (C) Main effects of Step and Posture on the mean trunk angle. Between-steps difference: *: significant difference from the level-step (p < 0.05). Between-postures differences: a: significant difference from TI¯; b: significant difference from TI0; c: significant difference from TI+. Error bars denote ± 1 SD.
Fig 2.
Lower-limb joints’ mechanical power.
Ensemble-averaged instantaneous hip, knee and ankle powers in the level-step (left) and drop-step (right) during running with backward (TI¯; green), self-selected (TI0; black, shaded area ± SD), low forward (TI+; red) and high forward (TI++; blue) trunk inclinations.
Fig 3.
Lower-limb joints’ negative and positive powers.
Boxplots depict the average negative and positive powers produced at the (A) hip, (B) knee, (C) ankle and (D) total (sum of the hip, knee and ankle) during running with backward (TI¯; green), self-selected (TI0; black), low forward (TI+; red) and high forward (TI++; blue) trunk inclinations across the level-step (darker) and the drop-step (lighter). a: significant difference from TI¯; *: significant difference from the level-step (p < 0.05). Error bars denote ± 1 SD.
Fig 4.
Main effects of Step and Posture.
Shown are the separate main effects (mean ± SD) of Step (left) and Posture (right) for average negative and positive powers without interactions. Between-postures differences are denoted as follow: a, significant difference from TI¯; b, significance different from TI0; c, significant difference from TI+. Between-steps difference is indicated by * for significant difference from the level-step (p < 0.05). Error bars denote ± 1 SD.
Table 1.
Descriptive overview of lower-limb joint average mechanical power measures.
Fig 5.
The relative contribution of the hip, knee and ankle joints to total limb power.
Pie charts depict the percentage of total average negative (A, level-step; B, drop-step) and positive (C, level-step; D, drop-step) power contributed at the hip (darker grey), knee (black) and ankle (lighter grey) joints during running with backward (TI¯), self-selected (TI0), low forward (TI+) and high forward (TI++) trunk inclinations. Green and black boxes indicate significant differences from TI¯ and TI0, respectively, while white boxes indicate a significant difference from the level-step. The size of each pie represents total average negative or positive power. In the absence of interaction effects, the horizontal and vertical lines denote significant differences between posture (in case of a Posture main effect) and step (in case of a Step main effect) conditions, respectively.
Table 2.
Relative contribution of each joint to total limb power.