{ "types" : { "Bookmark" : { "pluralLabel" : "Bookmarks" }, "Publication" : { "pluralLabel" : "Publications" }, "GoldStandardPublication" : { "pluralLabel" : "GoldStandardPublications" }, "GoldStandardBookmark" : { "pluralLabel" : "GoldStandardBookmarks" }, "Tag" : { "pluralLabel" : "Tags" }, "User" : { "pluralLabel" : "Users" }, "Group" : { "pluralLabel" : "Groups" }, "Sphere" : { "pluralLabel" : "Spheres" } }, "properties" : { "count" : { "valueType" : "number" }, "date" : { "valueType" : "date" }, "changeDate" : { "valueType" : "date" }, "url" : { "valueType" : "url" }, "id" : { "valueType" : "url" }, "tags" : { "valueType" : "item" }, "user" : { "valueType" : "item" } }, "items" : [ { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/25f223bfc85d55493de07f7c8c5d9718a/inspo5", "tags" : [ "disorders","apogee","activity","electromyography","lower","muscle","back","exoskeleton","active","musculoskeletal","velocity","movement" ], "intraHash" : "5f223bfc85d55493de07f7c8c5d9718a", "interHash" : "d43970df13496122338acd5777620812", "label" : "Biomechanical analysis of different lifting speeds when using an active exoskeleton", "user" : "inspo5", "description" : "", "date" : "2025-11-14 11:42:57", "changeDate" : "2025-11-14 11:42:57", "count" : 2, "pub-type": "article", "journal": "Frontiers Bioeng. Biotechnol. Sec.Biomechanics", "year": "2025", "url": "https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2025.1685634/full", "author": [ "Dominik Mayer","Tobias Siebert","Jens Hasenmaier","Norman Stutzig" ], "authors": [ {"first" : "Dominik", "last" : "Mayer"}, {"first" : "Tobias", "last" : "Siebert"}, {"first" : "Jens", "last" : "Hasenmaier"}, {"first" : "Norman", "last" : "Stutzig"} ], "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "13","abstract": "Introduction: Musculoskeletal disorders (MSDs), especially lower back pain, are common consequences of repetitive and long-term mechanical stress. Exoskeletons offer a promising approach to reduce this stress by supporting the wearer during physical labour. This study investigated the effect of an active exoskeleton (Apogee) on muscle activation and joint kinematics during load lifting at different lifting speeds and exoskeleton support levels.\r\n\r\nMethods: Sixteen healthy young adults (8 male, 8 female) lifted a 15 kg box at two lifting speeds (9 and 12 lifting cycles/min) and four support levels: 1) without exoskeleton, 2) exoskeleton in passive mode, 3) 50% support and 20% counterforce, 4) 100% support and 60% counterforce. Muscle activity was measured in the M. erector spinae (MES), M. biceps femoris (MBF) and M. vastus medialis (MVM) using EMG. Furthermore, joint range of motion (ROM) in the ankle, knee and hip were analysed using 3D motion capture.\r\n\r\nResults: Faster lifting significantly (p < 0.05) increased MBF (by 4.0% ± 1.5% maximum voluntary contraction, MVC) and MVM (1.6% ± 0.7% MVC) activity, while MES remained unaffected. The highest support level led to a significant decrease in MES and MBF activity by about 22.3% MVC and 10.6% MVC, respectively, as well as a small increase in hip joint ROM by 6° compared to lifting without exoskeleton support. There was no interaction between the level of support and lifting speed.\r\n\r\nDiscussion: The decrease in MES activity of 22.3% MVC with full support suggests a potent reduction in spinal load. MBF activity increased less with higher speeds when support was applied. The MVM showed low and stable activity across all conditions. These findings suggest that the active exoskeleton Apogee provides support regardless of lifting speed and may help prevent MSDs in occupational settings. Users can adjust support levels based on task requirements and personal comfort.", "language" : "English", "doi" : "10.3389/fbioe.2025.1685634", "bibtexKey": "mayer2025biomechanical" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/216b5ea1f1bb5147f2f92564d1767c724/inspo5", "tags" : [ "myown","simulator","Volunteer","posture","Driving","head","Rotated","musculature","testing","Electromyography","Neck" ], "intraHash" : "16b5ea1f1bb5147f2f92564d1767c724", "interHash" : "958da81d5faeafe01668d01f4a237c19", "label" : "Role of Rotated Head Postures on Volunteer Kinematics and Muscle Activity in Braking Scenarios Performed on a Driving Simulator", "user" : "inspo5", "description" : "linked to Adires", "date" : "2024-09-24 16:48:48", "changeDate" : "2024-09-24 16:48:48", "count" : 5, "pub-type": "article", "journal": "Springer Link", "year": "2024", "url": "https://link.springer.com/article/10.1007/s10439-022-03087-9", "author": [ "Fabian Kempter","Lorena Lantella","Norman Stutzig","Jörg Fehr","Tobias Siebert" ], "authors": [ {"first" : "Fabian", "last" : "Kempter"}, {"first" : "Lorena", "last" : "Lantella"}, {"first" : "Norman", "last" : "Stutzig"}, {"first" : "Jörg", "last" : "Fehr"}, {"first" : "Tobias", "last" : "Siebert"} ], "volume": "51","pages": "771\u2013782","abstract": "Occupants exposed to low or moderate crash events can already suffer from whiplash-associated disorders leading to severe and long-lasting symptoms. However, the underlying injury mechanisms and the role of muscle activity are not fully clear. Potential increases in injury risk of non-nominal postures, i.e., rotated head, cannot be evaluated in detail due to the lack of experimental data. Examining changes in neck muscle activity to hold and stabilize the head in a rotated position during pre-crash scenarios might provide a deeper understanding of muscle reflex contributions and injury mechanisms. In this study, the influence of two different head postures (nominal vs. rotation of the head by about 63\u2009±\u20099° to the right) on neck muscle activity and head kinematics was investigated in simulated braking experiments inside a driving simulator. The braking scenario was implemented by visualization of the virtual scene using head-mounted displays and a combined translational-rotational platform motion. Kinematics of seventeen healthy subjects was tracked using 3D motion capturing. Surface electromyography were used to quantify muscle activity of left and right sternocleidomastoideus (SCM) and trapezius (TRP) muscles. The results show clear evidence that rotated head postures affect the static as well as the dynamic behavior of muscle activity during the virtual braking event. With head turned to the right, the contralateral left muscles yielded higher base activation and delayed muscle onset times. In contrast, right muscles had much lower activations and showed no relevant changes in muscle activation between nominal and rotated head position. The observed delayed muscle onset times and increased asymmetrical muscle activation patterns in the rotated head position are assumed to affect injury mechanisms. This could explain the prevalence of rotated head postures during a crash reported by patients suffering from WAD. The results can be used for validating the active behavior of human body models in braking simulations with nominal and rotated head postures, and to gain a deeper understanding of neck injury mechanisms.", "doi" : "10.1007/s10439-022-03087-9", "bibtexKey": "noauthororeditor2024rotated" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/293dbfd71d89a98b4b0b93df76d9f3ec4/inspo5", "tags" : [ "activity","occupational","Cray","lower","back","exertion","disorders","perceived","PN2-8","electromyography","safety","muscle","X","exoskeleton","musculoskeletal" ], "intraHash" : "93dbfd71d89a98b4b0b93df76d9f3ec4", "interHash" : "f4b756ccc11536a1ccd58f2bb493eb66", "label" : "Active exoskeleton reduces erector spinae muscle activity during lifting", "user" : "inspo5", "description" : "", "date" : "2023-05-16 10:14:06", "changeDate" : "2024-09-13 10:28:08", "count" : 6, "pub-type": "article", "journal": "Frontiers in Bioengineering and Biotechnology", "year": "2023", "url": "https://www.frontiersin.org/articles/10.3389/fbioe.2023.1150170/full", "author": [ "Tobias Walter","Norman Stutzig","Tobias Siebert" ], "authors": [ {"first" : "Tobias", "last" : "Walter"}, {"first" : "Norman", "last" : "Stutzig"}, {"first" : "Tobias", "last" : "Siebert"} ], "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "11","abstract": "Neuromuscular control loops feature substantial communication delays, but mammals run robustly even in the most adverse conditions. In vivo experiments and computer simulation results suggest that muscles\u2019 preflex\u2014an immediate mechanical response to a perturbation\u2014could be the critical contributor. Muscle preflexes act within a few milliseconds, an order of magnitude faster than neural reflexes. Their short-lasting action makes mechanical preflexes hard to quantify in vivo. Muscle models, on the other hand, require further improvement of their prediction accuracy during the non-standard conditions of perturbed locomotion. Our study aims to quantify the mechanical work done by muscles during the preflex phase (preflex work) and test their mechanical force modulation. We performed in vitro experiments with biological muscle fibers under physiological boundary conditions, which we determined in computer simulations of perturbed hopping. Our findings show that muscles initially resist impacts with a stereotypical stiffness response\u2014identified as short-range stiffness\u2014regardless of the exact perturbation condition. We then observe a velocity adaptation to the force related to the amount of perturbation similar to a damping response. The main contributor to the preflex work modulation is not the change in force due to a change in fiber stretch velocity (fiber damping characteristics) but the change in magnitude of the stretch due to the leg dynamics in the perturbed conditions. Our results confirm previous findings that muscle stiffness is activity-dependent and show that also damping characteristics are activity-dependent. These results indicate that neural control could tune the preflex properties of muscles in expectation of ground conditions leading to previously inexplicable neuromuscular adaptation speeds.", "language" : "English", "doi" : "10.3389/fbioe.2023.1150170", "bibtexKey": "siebert2023active" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/288f633199ed2d6814a99626939d3d01b/inspo5", "tags" : [ "surface","isometric","voluntary","maximal","muscles","s","electromyography","PFM","pelvic","MVC","contraction","floor","EMG" ], "intraHash" : "88f633199ed2d6814a99626939d3d01b", "interHash" : "daa15e055c72f0862fdcf0dab766cd8b", "label" : "Intraday and interday reliability of pelvic floor muscles electromyography in continent woman. Neurourol Urodyn", "user" : "inspo5", "description" : "", "date" : "2022-07-19 11:10:29", "changeDate" : "2022-07-19 09:10:56", "count" : 1, "pub-type": "article", "journal": "Wiley Online Library Neurourology and Urodynamics", "year": "2020", "url": "", "editor": [ "Tobias Siebert" ], "editors": [ {"first" : "Tobias", "last" : "Siebert"} ], "volume": "39","number": "1","pages": "271-278","abstract": "Aims\nVaginal surface electromyography (sEMG) is a tool used for the diagnosis and therapeutic intervention of urinary incontinence. Current sEMG systems differ in regard to electrode arrangement and data reproducibility. The aim of this study was to determine the intrasession, intraday, and interday reliabilities of sEMG parameters using a probe with circumferential electrode-position.\n\nMethods\nThe intrasession, intraday, and interday reliabilities of maximum isometric voluntary contractions (MVC) of the pelvic floor muscles were assessed for 19 healthy continent women. Three sEMG parameters that are used to describe muscle activity were verified: maximal EMG (EMGmax), mean over 500\u2009ms around EMGmax (EMGA0.5), and mean over 2\u2009seconds during MVC plateau (EMGA2-4). Relative and absolute reliability parameters were calculated, and the statistical methods described by Bland and Altman were applied to the data.\n\nResults\nWe observed substantial reliabilities for all obtained parameters (EMGmax, EMGA2-4, and EMGA0.5) in regard to the intrasession measurements (ICC\u2009=\u20090.93-0.97; CI\u2009=\u20090.86-0.99). Overall, the intraday reliability has been moderate (ICC\u2009=\u20090.64-0.75; CI\u2009=\u20090.27-0.90). EMGmax (ICC\u2009=\u20090.75; CI\u2009=\u20090.45-0.90) and EMGA2-4 (ICC\u2009=\u20090.73, CI\u2009=\u20090.42-0.89) were higher than EMGA0.5 (ICC\u2009=\u20090.64; CI\u2009=\u20090.27-0.85). However, the interday reliability was only fair for EMGmax (ICC\u2009=\u20090.48; CI\u2009=\u20090.04-0.77) and EMGA0.5 (ICC\u2009=\u20090.51; CI\u2009=\u20090.07-0.78) but moderate for EMGA2-4 (ICC\u2009=\u20090.65; CI\u2009=\u20090.28-0.85).\n\nConclusions\nThis intrasession, intraday, and interday reliability results are similar to the results reported in the literature using probes with longitudinally oriented bars. The mean sEMG signal over 2\u2009seconds (EMGA2-4) exhibited the highest reliability and is recommended for further studies. The interday reliability might be enhanced by considering the menstruation cycle.", "doi" : "https://doi.org/10.1002/nau.24187", "bibtexKey": "siebert2020intraday" } ] }