@article{HessMousikouSchroeder2021, author = {Heß, Stefan and Mousikou, Petroula and Schroeder, Sascha}, title = {Morphological processing in developmental handwriting production}, series = {Reading and writing: An interdisciplinary journal}, volume = {35}, journal = {Reading and writing: An interdisciplinary journal}, number = {4}, publisher = {Springer}, address = {Dordrecht}, issn = {1573-0905}, doi = {10.1007/s11145-021-10204-y}, pages = {899 -- 917}, year = {2021}, abstract = {In this study, we investigated effects of morphological processing on handwriting production in beginning writers of German. Children from Grades 3 and 4 were asked to copy words from a computer screen onto a pen tablet, while we recorded their handwriting with high spatiotemporal resolution. Words involved a syllable-congruent visual disruption (e.g., "Golfer"), a morpheme-congruent visual disruption (e.g., "Golfer"), or had no disruption (e.g., "Golfer"). We analyzed productions in terms of Writing Onset Duration and Letter Duration at the onset of the second syllable ("f" in "Gol.fer") and the onset of the suffix ("e" in "Golf_er"). Results showed that durations were longer at word-writing onset only for words with a morpheme-congruent visual disruption. Also, letter durations were longer at the onset of the second syllable (i.e., "-fer") and shorter at the onset of the suffix (i.e., "-er") only for words with a syllable-congruent visual disruption. We interpret these findings within extant theories of handwriting production and offer an explanation for the observed effects before and during trajectory formation.}, language = {en} } @article{SandauChaabeneGranacher2021, author = {Sandau, Ingo and Chaabene, Helmi and Granacher, Urs}, title = {Concurrent validity of barbell force measured from video-based barbell kinematics during the snatch in male elite weightlifters}, series = {PLOS ONE / Public Library of Science}, volume = {16}, journal = {PLOS ONE / Public Library of Science}, number = {7}, publisher = {PLOS}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0254705}, pages = {11}, year = {2021}, abstract = {This study examined the concurrent validity of an inverse dynamic (force computed from barbell acceleration [reference method]) and a work-energy (force computed from work at the barbell [alternative method]) approach to measure the mean vertical barbell force during the snatch using kinematic data from video analysis. For this purpose, the acceleration phase of the snatch was analyzed in thirty male medal winners of the 2018 weightlifting World Championships (age: 25.2±3.1 years; body mass: 88.9±28.6 kg). Vertical barbell kinematics were measured using a custom-made 2D real-time video analysis software. Agreement between the two computational approaches was assessed using Bland-Altman analysis, Deming regression, and Pearson product-moment correlation. Further, principal component analysis in conjunction with multiple linear regression was used to assess whether individual differences related to the two approaches are due to the waveforms of the acceleration time-series data. Results indicated no mean difference (p > 0.05; d = -0.04) and an extremely large correlation (r = 0.99) between the two approaches. Despite the high agreement, the total error of individual differences was 8.2\% (163.0 N). The individual differences can be explained by a multiple linear regression model (R2adj = 0.86) on principal component scores from the principal component analysis of vertical barbell acceleration time-series waveforms. Findings from this study indicate that the individual errors of force measures can be associated with the inverse dynamic approach. This approach uses vertical barbell acceleration data from video analysis that is prone to error. Therefore, it is recommended to use the work-energy approach to compute mean vertical barbell force as this approach did not rely on vertical barbell acceleration.}, language = {en} }