Fig 1.
Experimental setup of the fencing lunge simulator.
The fencer initially stoods on 2 platforms recording ground reaction forces. An optoelectronic system captured the movements of markers attached to the sword and the fencer. Target, plastron and surrounding color indicating the task to perform are back projected onto a wide screen of 5 x 2.2m. Green color here indicates the target will remain fixed during next attack.
Fig 2.
The ground reaction force threshold triggering the target motions was set so that half of the total impulse of a standard fencing assault had been produced.
The mean ground reaction force norm leading to this condition corresponded to 106% of the subject body weight.
Fig 3.
Plastron representation with target zones.
Grey shaded areas represent the zones in which the targets could appear. The scenario only defined a target’s appearance zone, and the target appeared randomly in this zone. Plastron dimensions were computed with regard to the average height of a fencer. Shoulder to shoulder and shoulder to knee distances (0.26 x 0.82m) were computed from [26, 27]. The plastron height was adapted to be the same as the fencer’s one [23].
Fig 4.
End of a successful lunge trial with a big target (0.10m diameter).
Success information was displayed in real time by the system on the top of the plastron. Muscle activity and motion of the fencer were captured for further investigations.
Fig 5.
Overall mean results under the 3 different conditions (averaged by all the subjects).
Significance of the Wilcoxon signed-rank test is expressed as follow: *** (p < 0.001); ** (p < 0.01); * (p < 0.05). NB: conditions Fixed/Uncertain Moving and Moving/Uncertain Fixed were not tested.
Table 1.
Mean changes in the variable values (Shift), averaged for all the subjects, when comparing the different uncertainty conditions.
For instance, the average Success rate was 15.5% lower in the Moving condition than in the Fixed one. Significance of the Wilcoxon signed-rank test is expressed as follow: *** (p < 0.001); ** (p < 0.01); * (p < 0.05). Matched-Pairs Rank-Biserial correlations (Rank Corr.) provides information on the effect size (a value above 0.8 indicates a large effect).
Fig 6.
Individual results on accuracy (top), reaction time (middle) and movement time (bottom) under the 4 different conditions.
Fencers are sorted according to their accuracy. For each fencer on x-axis, mean pooled values (large bars) are followed by 4 thin bars corresponding to Fixed, Moving, Uncertain Fixed and Uncertain Moving conditions (see legend). Both small and big targets have been taken into account here. Fencer #1 to #5 have participated in national competition, fencer #6 to #9 in regional competition, Fencer #10 was foil, Fencer #11 was recreational.
Table 2.
Mean changes in the variable values (Shift), averaged for all the subjects, when target size changes from Big (0.10m) to Small (0.05m). For example, success was 29.8% lower with small targets than with big ones. Significance of the Wilcoxon signed-rank test is expressed as follow: *** (p < 0.001); ** (p < 0.01); * (p < 0.05).