Author(s): BRAUN, I., BECKMANN, J., SCHMITTER, F., HAAG, I., BUECHEL, D., GROSPRETRE, S., WOLLESEN, B., Institution: GERMAN SPORT UNIVERSITY COLOGNE, Country: GERMANY, Abstract-ID: 2157

INTRODUCTION:
Work-related musculoskeletal disorders (WMSDs) are highly prevalent globally and pose substantial health and economic challenges. Exoskeletons might reduce physical load and biomechanical stress during physically demanding tasks. However, operating such assistive devices requires additional motor and cognitive resources, potentially leading to cognitive-motor interference (CMI). Thus far, the influence of exoskeleton use on accuracy and speed in precision tasks has received limited attention. Building on previous work, this study assessed the reproducibility of speed-accuracy trade-off slopes during an exoskeleton-supported overhead drilling Fitts task, comparing long (12 repetitions) and short versions (8 repetitions) under single-task (ST) and dual-task (DT) conditions in a simulated work environment.
METHODS:
Fifteen participants (mean age M = 25.2 years, SD = 3.99 years; 20% males, 80% females) without neurological or musculoskeletal disorders were recruited from the German Sport University Cologne and performed an overhead drilling Fitts task with indices of difficulty 2.32, 3.91 and 5.39 across eight simulated working conditions. Four conditions were completed with and without an active upper body exoskeleton: (1) ST long version (3 sets of 12 repetitions), (2) ST short version (2 sets of 8 repetitions), (3) visual DT (DTv) long version, and (4) DTv short version. Slopes of the speed-accuracy trade-off were evaluated across all conditions. The reliability of the speed-accuracy trade-off slopes for the long and short conditions was assessed using an intraclass correlation coefficient (ICC), mean differences were calculated in SPSS.
RESULTS:
The slopes of the speed-accuracy trade-off showed low agreement between the long and short conditions. Most of the mean comparisons of the slopes were non-significant (p < = 0.05), with ICC values of 0.119 for ST with exoskeleton use, and 0.288 and 0.018 for ST and DTv without exoskeleton use, respectively. A significant mean difference with an ICC of 0.542 was observed only for DTv with exoskeleton use. Several outliers were detected in the initial analysis.
CONCLUSION:
The speed-accuracy trade-off slopes of the long and short versions of the Fitts task showed low and generally non-significant ICCs, indicating limited reliability and reproducibility between the two versions. These results might be influenced by the relatively small sample size and the uneven gender distribution of the participants. The present analysis will be verified to identify potential reasons for the outlier values as part of a data quality assessment.