@article{NamAroraBehbahanietal.2010,
  author    = {Nam, J. and Arora, D. and Behbahani, Mehdi and Probst, M. and Benkowski, R. and Behr, M. and Pasquali, M.},
  title     = {New computational method in hemolysis analysis for artificial heart pump},
  year      = {2010},
  language  = {en}
}
@article{BehbahaniProbstMaietal.2010,
  author    = {Behbahani, Mehdi and Probst, M. and Mai, A. and Behr, M. and Tran, L. and Vonderstein, K. and Mottaghy, K.},
  title     = {Numerical Prediction of Blood Damage in Biomedical Devices},
  year      = {2010},
  language  = {en}
}
@article{ProbstBehbahaniBorrmannetal.2010,
  author    = {Probst, M. and Behbahani, Mehdi and Borrmann, E. and Elgeti, S. and Nicolai, M. and Behr, M.},
  title     = {Hemodynamic Modeling for Numerical Analysis and Design of Medical Devices},
  year      = {2010},
  language  = {en}
}
@article{BehbahaniWalugaStocketal.2009,
  author    = {Behbahani, Mehdi and Waluga, C. and Stock, S. and Mai, A. and Bergmann, B. and Behr, M. and Tran, L. and Vonderstein, K. and Scheidt, H. and Oedekoven, B. and Mottaghy, K.},
  title     = {Modelling and Numerical Analysis of Platelet Reactions and Surface Thrombus Growth},
  year      = {2009},
  language  = {en}
}
@article{BehbahaniMaiBergmannetal.2010,
  author    = {Behbahani, Mehdi and Mai, A. and Bergmann, B. and Waluga, C. and Behr, M. and Tran, L. and Vonderstein, K. and Mottaghy, K.},
  title     = {Modeling and Numerical Simulation of Blood Damage},
  year      = {2010},
  language  = {en}
}
@article{BehbahaniWalugaArltetal.2008,
  author    = {Behbahani, Mehdi and Waluga, C. and Arlt, S. and Behr, M. and Mottaghy, K.},
  title     = {Computational Analysis of Platelet Aggregation in a Taylor-Couette System},
  series = {The International Journal of Artificial Organs. 31 (2008), H. 7},
  journal   = {The International Journal of Artificial Organs. 31 (2008), H. 7},
  isbn      = {0391-3988},
  pages     = {643},
  year      = {2008},
  language  = {en}
}
@article{BehbahaniMaiWalugaetal.2010,
  author    = {Behbahani, Mehdi and Mai, A. and Waluga, C. and Bergmann, B. and Tran, L. and Vonderstein, K. and Behr, M. and Mottaghy, K.},
  title     = {Numerical Modeling of Flow-Related Thrombus Formation under Physiological and Non-Physiological Flow Conditions},
  series = {Acta Physiologica},
  volume    = {198},
  journal   = {Acta Physiologica},
  number    = {Supplement 677},
  isbn      = {1748-1716},
  pages     = {185},
  year      = {2010},
  language  = {en}
}
@article{JiminezGermanBehbahaniMiettinenetal.2013,
  author    = {Jiminez German, Salvador and Behbahani, Mehdi and Miettinen, Susanna and Grijpma, Dirk W. and Haimi, Suvi P.},
  title     = {Proliferation and differentiation of adipose stem cells towards smooth muscle cells on poly(trimethylene carbonate) membranes},
  series = {Macromolecular symposia},
  volume    = {Vol. 334},
  journal   = {Macromolecular symposia},
  number    = {Iss. 1},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {0258-0322},
  pages     = {133 -- 142},
  year      = {2013},
  language  = {en}
}
@article{PookhalilAmoabedinyTabeshetal.2016,
  author    = {Pookhalil, Ali and Amoabediny, Ghassem and Tabesh, Hadi and Behbahani, Mehdi and Mottaghy, Khosrow},
  title     = {A new approach for semiempirical modeling of mechanical blood trauma},
  series = {The international journal of artificial organs},
  volume    = {39},
  journal   = {The international journal of artificial organs},
  number    = {4},
  publisher = {Sage},
  address   = {London},
  issn      = {1724-6040},
  doi       = {10.5301/ijao.5000474},
  pages     = {171 -- 177},
  year      = {2016},
  abstract  = {Purpose Two semi-empirical models were recently published, both making use of existing literature data, but each taking into account different physical phenomena that trigger hemolysis. In the first model, hemoglobin (Hb) release is described as a permeation procedure across the membrane, assuming a shear stress-dependent process (sublethal model). The second model only accounts for hemoglobin release that is caused by cell membrane breakdown, which occurs when red blood cells (RBC) undergo mechanically induced shearing for a period longer than the threshold time (nonuniform threshold model). In this paper, we introduce a model that considers the hemolysis generated by both these possible phenomena. Methods Since hemolysis can possibly be caused by permeation of hemoglobin through the RBC functional membrane as well as by release of hemoglobin from RBC membrane breakdown, our proposed model combines both these models. An experimental setup consisting of a Couette device was utilized for validation of our proposed model. Results A comparison is presented between the damage index (DI) predicted by the proposed model vs. the sublethal model vs. the nonthreshold model and experimental datasets. This comparison covers a wide range of shear stress for both human and porcine blood. An appropriate agreement between the measured DI and the DI predicted by the present model was obtained. Conclusions The semiempirical hemolysis model introduced in this paper aims for significantly enhanced conformity with experimental data. Two phenomenological outcomes become possible with the proposed approach: an estimation of the average time after which cell membrane breakdown occurs under the applied conditions, and a prediction of the ratio between the phenomena involved in hemolysis.},
  language  = {en}
}
@article{KoppSchunckGosauetal.2020,
  author    = {Kopp, Alexander and Schunck, Laura and Gosau, Martin and Smeets, Ralf and Burg, Simon and Fuest, Sandra and Kr{\"o}ger, Nadja and Zinser, Max and Krohn, Sebastian and Behbahani, Mehdi and K{\"o}pf, Marius and Lauts, Lisa and Rutkowski, Rico},
  title     = {Influence of the casting concentration on the mechanical and optical properties of Fa/CaCl2-derived silk fibroin membranes},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {18 art. no. 6704},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21186704},
  year      = {2020},
  abstract  = {In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live-dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes.},
  language  = {en}
}
@article{BrockhausBehbahaniMurisetal.2021,
  author    = {Brockhaus, Moritz K. and Behbahani, Mehdi and Muris, Farina and Jansen, Sebastian V. and Schmitz- Rode, Thomas and Steinseifer, Ulrich and Clauser, Johanna C.},
  title     = {In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept},
  series = {Artificial Organs},
  volume    = {45},
  journal   = {Artificial Organs},
  number    = {12},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1525-1594},
  doi       = {10.1111/aor.14046},
  pages     = {1513 -- 1521},
  year      = {2021},
  abstract  = {Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6\% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential.},
  language  = {en}
}
@article{MandekarHollandThielenetal.2022,
  author    = {Mandekar, Swati and Holland, Abigail and Thielen, Moritz and Behbahani, Mehdi and Melnykowycz, Mark},
  title     = {Advancing towards Ubiquitous EEG, Correlation of In-Ear EEG with Forehead EEG},
  series = {Sensors},
  volume    = {22},
  journal   = {Sensors},
  number    = {4},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s22041568},
  pages     = {1 -- 19},
  year      = {2022},
  abstract  = {Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG.},
  language  = {en}
}
@article{TranMottaghyArltKoerferetal.2017,
  author    = {Tran, Linda and Mottaghy, K. and Arlt-K{\"o}rfer, Sabine and Waluga, Christian and Behbahani, Mehdi},
  title     = {An experimental study of shear-dependent human platelet adhesion and underlying protein-binding mechanisms in a cylindrical Couette system},
  series = {Biomedizinische Technik},
  volume    = {62},
  journal   = {Biomedizinische Technik},
  number    = {4},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {0013-5585},
  doi       = {10.1515/bmt-2015-0034},
  pages     = {383 -- 392},
  year      = {2017},
  language  = {en}
}
@article{KoppSchmeetsGosauetal.2019,
  author    = {Kopp, Alexander and Schmeets, Ralf and Gosau, Martin and Friedrich, Reinhard E. and Fuest, Sandra and Behbahani, Mehdi and Barbeck, Mike and Rutkowski, Rico and Burg, Simon and Kluwe, Lan and Henningsen, Anders},
  title     = {Production and Characterization of Porous Fibroin Scaffolds for Regenerative Medical Application},
  series = {In Vivo},
  volume    = {33},
  journal   = {In Vivo},
  number    = {3},
  issn      = {1791-7549},
  doi       = {10.21873/invivo.11536},
  pages     = {757 -- 762},
  year      = {2019},
  language  = {en}
}
@article{MalinowskiFournierHorbachetal.2022,
  author    = {Malinowski, Daniel and Fournier, Yvan and Horbach, Andreas and Frick, Michael and Magliani, Mirko and Kalverkamp, Sebastian and Hildinger, Martin and Spillner, Jan and Behbahani, Mehdi and Hima, Flutura},
  title     = {Computational fluid dynamics analysis of endoluminal aortic perfusion},
  series = {Perfusion},
  volume    = {0},
  journal   = {Perfusion},
  number    = {0},
  publisher = {Sage},
  address   = {London},
  issn      = {1477-111X},
  doi       = {10.1177/02676591221099809},
  pages     = {1 -- 8},
  year      = {2022},
  abstract  = {Introduction: In peripheral percutaneous (VA) extracorporeal membrane oxygenation (ECMO) procedures the femoral arteries perfusion route has inherent disadvantages regarding poor upper body perfusion due to watershed. With the advent of new long flexible cannulas an advancement of the tip up to the ascending aorta has become feasible. To investigate the impact of such long endoluminal cannulas on upper body perfusion, a Computational Fluid Dynamics (CFD) study was performed considering different support levels and three cannula positions. Methods: An idealized literature-based- and a real patient proximal aortic geometry including an endoluminal cannula were constructed. The blood flow was considered continuous. Oxygen saturation was set to 80\% for the blood coming from the heart and to 100\% for the blood leaving the cannula. 50\% and 90\% venoarterial support levels from the total blood flow rate of 6 l/min were investigated for three different positions of the cannula in the aortic arch. Results: For both geometries, the placement of the cannula in the ascending aorta led to a superior oxygenation of all aortic blood vessels except for the left coronary artery. Cannula placements at the aortic arch and descending aorta could support supra-aortic arteries, but not the coronary arteries. All positions were able to support all branches with saturated blood at 90\% flow volume. Conclusions: In accordance with clinical observations CFD analysis reveals, that retrograde advancement of a long endoluminal cannula can considerably improve the oxygenation of the upper body and lead to oxygen saturation distributions similar to those of a central cannulation.},
  language  = {en}
}
@article{LenzKahmannBehbahanietal.2022,
  author    = {Lenz, Maximilian and Kahmann, Stephanie Lucina and Behbahani, Mehdi and Pennig, Lenhard and Hackl, Michael and Leschinger, Tim and M{\"u}ller, Lars Peter and Wegmann, Kilian},
  title     = {Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation},
  series = {Archives of Orthopaedic and Trauma Surgery},
  journal   = {Archives of Orthopaedic and Trauma Surgery},
  publisher = {Springer},
  address   = {Berlin, Heidelberg},
  issn      = {1434-3916},
  doi       = {10.1007/s00402-022-04471-9},
  year      = {2022},
  abstract  = {Introduction In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration. Materials and methods Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer's classification was used to analyse the fractures. Results In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities. Conclusion A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education.},
  language  = {en}
}
@article{ChloeMalyaranCraveiroetal.2022,
  author    = {Chlo{\´e}, Radermacher and Malyaran, Hanna and Craveiro, Rogerio Bastos and Peglow, Sarah and Behbahani, Mehdi and Pufe, Thomas and Wolf, Michael and Neuss, Sabine},
  title     = {Mechanical loading on cementoblasts: a mini review},
  series = {Osteologie},
  volume    = {31},
  journal   = {Osteologie},
  number    = {2},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {1019-1291},
  doi       = {10.1055/a-1826-0777},
  pages     = {111 -- 118},
  year      = {2022},
  abstract  = {Orthodontic treatments are concomitant with mechanical forces and thereby cause teeth movements. The applied forces are transmitted to the tooth root and the periodontal ligaments which is compressed on one side and tensed up on the other side. Indeed, strong forces can lead to tooth root resorption and the crown-to-tooth ratio is reduced with the potential for significant clinical impact. The cementum, which covers the tooth root, is a thin mineralized tissue of the periodontium that connects the periodontal ligament with the tooth and is build up by cementoblasts. The impact of tension and compression on these cells is investigated in several in vivo and in vitro studies demonstrating differences in protein expression and signaling pathways. In summary, osteogenic marker changes indicate that cyclic tensile forces support whereas static tension inhibits cementogenesis. Furthermore, cementogenesis experiences the same protein expression changes in static conditions as static tension, but cyclic compression leads to the exact opposite of cyclic tension. Consistent with marker expression changes, the singaling pathways of Wnt/ß-catenin and RANKL/OPG show that tissue compression leads to cementum degradation and tension forces to cementogenesis. However, the cementum, and in particular its cementoblasts, remain a research area which should be explored in more detail to understand the underlying mechanism of bone resorption and remodeling after orthodontic treatments.},
  language  = {en}
}
@article{ThiebesKleinZingsheimetal.2022,
  author    = {Thiebes, Anja Lena and Klein, Sarah and Zingsheim, Jonas and M{\"o}ller, Georg H. and G{\"u}rzing, Stefanie and Reddemann, Manuel A. and Behbahani, Mehdi and Cornelissen, Christian G.},
  title     = {Effervescent atomizer as novel cell spray technology to decrease the gas-to-liquid ratio},
  series = {pharmaceutics},
  volume    = {14},
  journal   = {pharmaceutics},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/pharmaceutics14112421},
  pages     = {Artikel 2421},
  year      = {2022},
  abstract  = {Cell spraying has become a feasible application method for cell therapy and tissue engineering approaches. Different devices have been used with varying success. Often, twin-fluid atomizers are used, which require a high gas velocity for optimal aerosolization characteristics. To decrease the amount and velocity of required air, a custom-made atomizer was designed based on the effervescent principle. Different designs were evaluated regarding spray characteristics and their influence on human adipose-derived mesenchymal stromal cells. The arithmetic mean diameters of the droplets were 15.4-33.5 µm with decreasing diameters for increasing gas-to-liquid ratios. The survival rate was >90\% of the control for the lowest gas-to-liquid ratio. For higher ratios, cell survival decreased to approximately 50\%. Further experiments were performed with the design, which had shown the highest survival rates. After seven days, no significant differences in metabolic activity were observed. The apoptosis rates were not influenced by aerosolization, while high gas-to-liquid ratios caused increased necrosis levels. Tri-lineage differentiation potential into adipocytes, chondrocytes, and osteoblasts was not negatively influenced by aerosolization. Thus, the effervescent aerosolization principle was proven suitable for cell applications requiring reduced amounts of supplied air. This is the first time an effervescent atomizer was used for cell processing.},
  language  = {en}
}
@article{SchoenrockMuckeltHastermannetal.2024,
  author    = {Schoenrock, Britt and Muckelt, Paul E. and Hastermann, Maria and Albracht, Kirsten and MacGregor, Robert and Martin, David and Gunga, Hans-Christian and Salanova, Michele and Stokes, Maria J. and Warner, Martin B. and Blottner, Dieter},
  title     = {Muscle stiffness indicating mission crew health in space},
  series = {Scientific Reports},
  volume    = {14},
  journal   = {Scientific Reports},
  number    = {Article number: 4196},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-024-54759-6},
  pages     = {13 Seiten},
  year      = {2024},
  abstract  = {Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes.},
  language  = {en}
}
@article{KolditzAlbinAbeletal.2016,
  author    = {Kolditz, Melanie and Albin, Thivaharan and Abel, Dirk and Fasse, Alessandro and Br{\"u}ggemann, Gert-Peter and Albracht, Kirsten},
  title     = {Evaluation of foot position and orientation as manipulated variables to control external knee adduction moments in leg extension training},
  series = {Computer methods and programs in biomedicine},
  volume    = {171},
  journal   = {Computer methods and programs in biomedicine},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-2607},
  doi       = {10.1016/j.cmpb.2016.09.005},
  pages     = {81 -- 86},
  year      = {2016},
  abstract  = {Background and Objective Effective leg extension training at a leg press requires high forces, which need to be controlled to avoid training-induced damage. In order to avoid high external knee adduction moments, which are one reason for unphysiological loadings on knee joint structures, both training movements and the whole reaction force vector need to be observed. In this study, the applicability of lateral and medial changes in foot orientation and position as possible manipulated variables to control external knee adduction moments is investigated. As secondary parameters both the medio-lateral position of the center of pressure and the frontal-plane orientation of the reaction force vector are analyzed. Methods Knee adduction moments are estimated using a dynamic model of the musculoskeletal system together with the measured reaction force vector and the motion of the subject by solving the inverse kinematic and dynamic problem. Six different foot conditions with varying positions and orientations of the foot in a static leg press are evaluated and compared to a neutral foot position. Results Both lateral and medial wedges under the foot and medial and lateral shifts of the foot can influence external knee adduction moments in the presented study with six healthy subjects. Different effects are observed with the varying conditions: the pose of the leg is changed and the direction and center of pressure of the reaction force vector is influenced. Each effect results in a different direction or center of pressure of the reaction force vector. Conclusions The results allow the conclusion that foot position and orientation can be used as manipulated variables in a control loop to actively control knee adduction moments in leg extension training.},
  language  = {en}
}
@article{BelavyAlbrachtBruggemannetal.2016,
  author    = {Belavy, Daniel L. and Albracht, Kirsten and Bruggemann, Gert-Peter and Vergroesen, Pieter-Paul A. and Dieen, Jaap H. van},
  title     = {Can exercise positively influence the intervertebral disc?},
  series = {Sports Medicine},
  volume    = {46},
  journal   = {Sports Medicine},
  number    = {4},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1179-2035},
  doi       = {10.1007/s40279-015-0444-2},
  pages     = {473 -- 485},
  year      = {2016},
  abstract  = {To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a 'critical period' for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research.},
  language  = {en}
}
@article{YangKriechbaumerAlbrachtetal.2015,
  author    = {Yang, Peng-Fei and Kriechbaumer, Andreas and Albracht, Kirsten and Sanno, Maximilian and Ganse, Bergita and Koy, Timmo and Shang, Peng and Br{\"u}ggemann, Gert-Peter and M{\"u}ller, Lars Peter and Rittweger, J{\"o}rn},
  title     = {On the relationship between tibia torsional deformation and regional muscle contractions in habitual human exercises in vivo},
  series = {Journal of Biomechanics},
  volume    = {48},
  journal   = {Journal of Biomechanics},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2014.12.031},
  pages     = {456 -- 464},
  year      = {2015},
  language  = {en}
}
@article{SeynnesBojsenMollerAlbrachtetal.2015,
  author    = {Seynnes, O. R. and Bojsen-Moller, J. and Albracht, Kirsten and Arndt, A. and Cronin, N. J. and Finni, T. and Magnusson, S. P.},
  title     = {Ultrasound-based testing of tendon mechanical properties: a critical evaluation},
  series = {Journal of Applied Physiology},
  volume    = {118},
  journal   = {Journal of Applied Physiology},
  number    = {2},
  issn      = {8750-7587},
  doi       = {10.1152/japplphysiol.00849.2014},
  pages     = {133 -- 141},
  year      = {2015},
  language  = {en}
}
@article{AlbrachtArampatzis2013,
  author    = {Albracht, Kirsten and Arampatzis, Adamantios},
  title     = {Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans},
  series = {European Journal of Applied Physiology},
  volume    = {113},
  journal   = {European Journal of Applied Physiology},
  number    = {6},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1439-6327},
  doi       = {10.1007/s00421-012-2585-4},
  pages     = {1605 -- 1615},
  year      = {2013},
  language  = {en}
}
@article{KaramanidisAlbrachtBraunsteinetal.2011,
  author    = {Karamanidis, Kiros and Albracht, Kirsten and Braunstein, Bjoern and Catala, Maria Moreno and Goldmann, Jan-Peter and Br{\"u}ggemann, Gert-Peter},
  title     = {Lower leg musculoskeletal geometry and sprint performance},
  series = {Gait and Posture},
  volume    = {34},
  journal   = {Gait and Posture},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0966-6362},
  doi       = {10.1016/j.gaitpost.2011.03.009},
  pages     = {138 -- 141},
  year      = {2011},
  abstract  = {The purpose of this study was to investigate whether sprint performance is related to lower leg musculoskeletal geometry within a homogeneous group of highly trained 100-m sprinters. Using a cluster analysis, eighteen male sprinters were divided into two groups based on their personal best (fast: N = 11, 10.30 ± 0.07 s; slow: N = 7, 10.70 ± 0.08 s). Calf muscular fascicle arrangement and Achilles tendon moment arms (calculated by the gradient of tendon excursion versus ankle joint angle) were analyzed for each athlete using ultrasonography. Achilles tendon moment arm, foot and ankle skeletal geometry, fascicle arrangement as well as the ratio of fascicle length to Achilles tendon moment arm showed no significant (p > 0.05) correlation with sprint performance, nor were there any differences in the analyzed musculoskeletal parameters between the fast and slow sprinter group. Our findings provide evidence that differences in sprint ability in world-class athletes are not a result of differences in the geometrical design of the lower leg even when considering both skeletal and muscular components.},
  language  = {en}
}
@article{ArampatzisPeperBierbaumetal.2010,
  author    = {Arampatzis, Adamantios and Peper, Andreas and Bierbaum, Stefanie and Albracht, Kirsten},
  title     = {Plasticity of human Achilles tendon mechanical and morphological properties in response to cyclic strain},
  series = {Journal of Biomechanics},
  volume    = {43},
  journal   = {Journal of Biomechanics},
  number    = {16},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2010.08.014},
  pages     = {3073 -- 3079},
  year      = {2010},
  abstract  = {The purpose of the current study in combination with our previous published data (Arampatzis et al., 2007) was to examine the effects of a controlled modulation of strain magnitude and strain frequency applied to the Achilles tendon on the plasticity of tendon mechanical and morphological properties. Eleven male adults (23.9±2.2 yr) participated in the study. The participants exercised one leg at low magnitude tendon strain (2.97±0.47\%), and the other leg at high tendon strain magnitude (4.72±1.08\%) of similar frequency (0.5 Hz, 1 s loading, 1 s relaxation) and exercise volume (integral of the plantar flexion moment over time) for 14 weeks, 4 days per week, 5 sets per session. The exercise volume was similar to the intervention of our earlier study (0.17 Hz frequency; 3 s loading, 3 s relaxation) allowing a direct comparison of the results. Before and after the intervention ankle joint moment has been measured by a dynamometer, tendon-aponeurosis elongation by ultrasound and cross-sectional area of the Achilles tendon by magnet resonance images (MRI). We found a decrease in strain at a given tendon force, an increase in tendon-aponeurosis stiffness and tendon elastic modulus of the Achilles tendon only in the leg exercised at high strain magnitude. The cross-sectional area (CSA) of the Achilles tendon did not show any statistically significant (P>0.05) differences to the pre-exercise values in both legs. The results indicate a superior improvement in tendon properties (stiffness, elastic modulus and CSA) at the low frequency (0.17 Hz) compared to the high strain frequency (0.5 Hz) protocol. These findings provide evidence that the strain magnitude applied to the Achilles tendon should exceed the value, which occurs during habitual activities to trigger adaptational effects and that higher tendon strain duration per contraction leads to superior tendon adaptational responses.},
  language  = {en}
}
@article{AggeloussisGiannakouAlbrachtetal.2010,
  author    = {Aggeloussis, Nickos and Giannakou, Erasmia and Albracht, Kirsten and Arampatzis, Adamantios},
  title     = {Reproducibility of fascicle length and pennation angle of gastrocnemius medialis in human gait in vivo},
  series = {Gait and Posture},
  volume    = {31},
  journal   = {Gait and Posture},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0966-6362},
  doi       = {10.1016/j.gaitpost.2009.08.249},
  pages     = {73 -- 77},
  year      = {2010},
  abstract  = {The purpose of the current study was to examine the reproducibility of fascicle length and pennation angle of gastrocnemius medialis while human walking. To the best of our knowledge, this is the first study of the reproducibility of fascicle length and pennation angle of gastrocnemius medialis in vivo during human gait. Twelve males performed 10 gait trials on a treadmill, in 2 separate days. B-mode ultrasonography, with the ultrasound probe firmly adjusted in the transverse and frontal planes using a special cast, was used to measure the fascicle length and the pennation angle of the gastrocnemius medialis (GM). A Vicon 624 system with three cameras operating at 120 Hz was also used to record the ankle and knee joint angles. The results showed that measurements of fascicle length and pennation angle showed high reproducibility during the gait cycle, both within the same day and between different days. Moreover, the root mean square differences between the repeated waveforms of both variables were very small, compared with their ranges (fascicle length: RMS = ∼3 mm, range: 38-63 mm; pennation angle: RMS = ∼1.5°, range: 22-32°). However, their reproducibility was lower compared to the joint angles. It was found that representative data have to be derived by a wide number of gait trials (fascicle length ∼six trials, pennation angle more than 10 trials), to assure the reliability of the fascicle length and pennation angle in human gait.},
  language  = {en}
}
@article{ArampatzisKaramanidisMademlietal.2009,
  author    = {Arampatzis, Adamantios and Karamanidis, Kiros and Mademli, Lida and Albracht, Kirsten},
  title     = {Plasticity of the human tendon to short and long-term mechanical loading},
  series = {Exercise and Sport Sciences Reviews},
  volume    = {37},
  journal   = {Exercise and Sport Sciences Reviews},
  number    = {2},
  issn      = {1538-3008},
  doi       = {10.1097/JES.0b013e31819c2e1d},
  pages     = {66 -- 72},
  year      = {2009},
  language  = {en}
}
@article{AlbrachtArampatzisBaltzopoulos2008,
  author    = {Albracht, Kirsten and Arampatzis, A. and Baltzopoulos, V.},
  title     = {Assessment of muscle volume and physiological cross-sectional area of the human triceps surae muscle in vivo},
  series = {Journal of Biomechanics},
  volume    = {41},
  journal   = {Journal of Biomechanics},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2008.04.020},
  pages     = {2211 -- 2218},
  year      = {2008},
  language  = {en}
}
@article{QuittmannMeskemperAlbrachtetal.2020,
  author    = {Quittmann, Oliver J. and Meskemper, Joshua and Albracht, Kirsten and Abel, Thomas and Foitschik, Tina and Str{\"u}der, Heiko K.},
  title     = {Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs},
  series = {Journal of Electromyography and Kinesiology},
  volume    = {51},
  journal   = {Journal of Electromyography and Kinesiology},
  number    = {Article 102402},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1050-6411},
  doi       = {10.1016/j.jelekin.2020.102402},
  year      = {2020},
  abstract  = {Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.},
  language  = {en}
}
@article{QuittmannMeskemperAbeletal.2018,
  author    = {Quittmann, Oliver J. and Meskemper, Joshua and Abel, Thomas and Albracht, Kirsten and Foitschik, Tina and Rojas-Vega, Sandra and Str{\"u}der, Heiko K.},
  title     = {Kinematics and kinetics of handcycling propulsion at increasing workloads in able-bodied subjects},
  series = {Sports Engineereing},
  volume    = {21},
  journal   = {Sports Engineereing},
  number    = {21},
  publisher = {Springer Nature},
  address   = {Cham},
  issn      = {1460-2687},
  doi       = {10.1007/s12283-018-0269-y},
  pages     = {283 -- 294},
  year      = {2018},
  abstract  = {In Paralympic sports, biomechanical optimisation of movements and equipment seems to be promising for improving performance. In handcycling, information about the biomechanics of this sport is mainly provided by case studies. The aim of the current study was (1) to examine changes in handcycling propulsion kinematics and kinetics due to increasing workloads and (2) identify parameters that are associated with peak aerobic performance. Twelve non-disabled male competitive triathletes without handcycling experience voluntarily participated in the study. They performed an initial familiarisation protocol and incremental step test until exhaustion in a recumbent racing handcycle that was attached to an ergometer. During the incremental test, tangential crank kinetics, 3D joint kinematics, blood lactate and ratings of perceived exertion (local and global) were identified. As a performance criterion, the maximal power output during the step test (Pmax) was calculated and correlated with biomechanical parameters. For higher workloads, an increase in crank torque was observed that was even more pronounced in the pull phase than in the push phase. Furthermore, participants showed an increase in shoulder internal rotation and abduction and a decrease in elbow flexion and retroversion. These changes were negatively correlated with performance. At high workloads, it seems that power output is more limited by the transition from pull to push phase than at low workloads. It is suggested that successful athletes demonstrate small alterations of their kinematic profile due to increasing workloads. Future studies should replicate and expand the test spectrum (sprint and continuous loads) as well as use methods like surface electromyography (sEMG) with elite handcyclists.},
  language  = {de}
}
@article{ArampatzisKaramanidisAlbracht2007,
  author    = {Arampatzis, Adamantios and Karamanidis, Kiros and Albracht, Kirsten},
  title     = {Adaptational responses of the human Achilles tendon by modulation of the applied cyclic strain magnitude},
  series = {Journal of Experimental Biology},
  volume    = {210},
  journal   = {Journal of Experimental Biology},
  number    = {15},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.003814},
  pages     = {2743 -- 2753},
  year      = {2007},
  language  = {en}
}
@article{AlbrachtArampatzis2006,
  author    = {Albracht, Kirsten and Arampatzis, Adamantios},
  title     = {Influence of the mechanical properties of the muscle-tendon unit on force generation in runners with different running economy},
  series = {Biological Cybernetics},
  volume    = {95},
  journal   = {Biological Cybernetics},
  number    = {1},
  issn      = {1432-0770},
  doi       = {10.1007/s00422-006-0070-z},
  pages     = {87 -- 96},
  year      = {2006},
  language  = {en}
}
@article{HeinkeKnickerAlbracht2018,
  author    = {Heinke, Lars N. and Knicker, Axel J. and Albracht, Kirsten},
  title     = {Evaluation of passively induced shoulder stretch reflex using an isokinetic dynamometer in male overhead athletes},
  series = {Isokinetics and Exercise Science},
  volume    = {26},
  journal   = {Isokinetics and Exercise Science},
  number    = {4},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {1878-5913},
  doi       = {10.3233/IES-184111},
  pages     = {265 -- 274},
  year      = {2018},
  abstract  = {BACKGROUND: Muscle stretch reflexes are widely considered to beneficially influence joint stability and power generation in the lower limbs. While in the upper limbs and especially in the muscles surrounding the shoulder joint such evidence is lacking. OBJECTIVE: To quantify the electromyographical response in the muscles crossing the shoulder of specifically trained overhead athletes to an anterior perturbation force. METHODS: Twenty healthy male participants performed six sets of different external shoulder rotation stretches on an isokinetic dynamometer over a range of amplitudes and muscle pre-activation moment levels. All stretches were applied with a dynamometer acceleration of 10,000∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexes were not observed in all experimental conditions. The reflex latencies revealed a significant muscle main effect (F (2,228) = 99.31, p< 0.001; η2= 0.466; f= 0.934) and a pre-activation main effect (F (1,228) = 142.21, p< 0.001; η2= 0.384; f= 1.418). The stretch reflex amplitude yielded a significant pre-activation main effect (F (1,222) = 470.373, p< 0.001; η2= 0.679; f= 1.454). CONCLUSION: Short latency muscle reflexes showed a tendency to an anterior to posterior muscle recruitment whereby the main internal rotator muscles of the shoulder revealed the most consistent results.},
  language  = {en}
}
@article{QuittmannAbelAlbrachtetal.2020,
  author    = {Quittmann, Oliver J. and Abel, Thomas and Albracht, Kirsten and Meskemper, Joshua and Foitschik, Tina and Str{\"u}der, Heiko K.},
  title     = {Biomechanics of handcycling propulsion in a 30-min continuous load test at lactate threshold: Kinetics, kinematics, and muscular activity in able-bodied participants},
  series = {European Journal of Applied Physiology},
  journal   = {European Journal of Applied Physiology},
  number    = {120},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1439-6327},
  doi       = {10.1007/s00421-020-04373-x},
  pages     = {1403 -- 1415},
  year      = {2020},
  abstract  = {Purpose This study aims to investigate the biomechanics of handcycling during a continuous load trial (CLT) to assess the mechanisms underlying fatigue in upper body exercise. Methods Twelve able-bodied triathletes performed a 30-min CLT at a power output corresponding to lactate threshold in a racing recumbent handcycle mounted on a stationary ergometer. During the CLT, ratings of perceived exertion (RPE), tangential crank kinetics, 3D joint kinematics, and muscular activity of ten muscles of the upper extremity and trunk were examined using motion capturing and surface electromyography. Results During the CLT, spontaneously chosen cadence and RPE increased, whereas crank torque decreased. Rotational work was higher during the pull phase. Peripheral RPE was higher compared to central RPE. Joint range of motion decreased for elbow-flexion and radial-duction. Integrated EMG (iEMG) increased in the forearm flexors, forearm extensors, and M. deltoideus (Pars spinalis). An earlier onset of activation was found for M. deltoideus (Pars clavicularis), M. pectoralis major, M. rectus abdominis, M. biceps brachii, and the forearm flexors. Conclusion Fatigue-related alterations seem to apply analogously in handcycling and cycling. The most distal muscles are responsible for force transmission on the cranks and might thus suffer most from neuromuscular fatigue. The findings indicate that peripheral fatigue (at similar lactate values) is higher in handcycling compared to leg cycling, at least for inexperienced participants. An increase in cadence might delay peripheral fatigue by a reduced vascular occlusion. We assume that the gap between peripheral and central fatigue can be reduced by sport-specific endurance training.},
  language  = {en}
}
@article{WerkhausenAlbrachtCroninetal.2017,
  author    = {Werkhausen, Amelie and Albracht, Kirsten and Cronin, Neil J. and Meier, Rahel and Mojsen-Moeller, Jens and Seynnes, Olivier R.},
  title     = {Modulation of muscle-tendon interaction in the human triceps surae during an energy dissipation task},
  series = {Journal of Experimental Biology},
  volume    = {220},
  journal   = {Journal of Experimental Biology},
  number    = {22},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.164111},
  pages     = {4141 -- 4149},
  year      = {2017},
  language  = {en}
}
@article{RittwegerAlbrachtFluecketal.2018,
  author    = {Rittweger, J{\"o}rn and Albracht, Kirsten and Fl{\"u}ck, Martin and Ruoss, Severin and Brocca, Lorenza and Longa, Emanuela and Moriggi, Manuela and Seynnes, Olivier and Di Giulio, Irene and Tenori, Leonardo and Vignoli, Alessia and Capri, Miriam and Gelfi, Cecilia and Luchinat, Claudio and Franceschi, Claudio and Bottinelli, Roberto and Cerretelli, Paolo and Narici, Marco},
  title     = {Sarcolab pilot study into skeletal muscle's adaptation to longterm spaceflight},
  series = {npj Microgravity},
  volume    = {4},
  journal   = {npj Microgravity},
  number    = {1},
  publisher = {Nature Portfolio},
  issn      = {2373-8065},
  doi       = {10.1038/s41526-018-0052-1},
  pages     = {1 -- 9},
  year      = {2018},
  language  = {en}
}
@article{WerkhausenCroninAlbrachtetal.2019,
  author    = {Werkhausen, Amelie and Cronin, Neil J. and Albracht, Kirsten and Bojsen-M{\o}ller, Jens and Seynnes, Olivier R.},
  title     = {Distinct muscle-tendon interaction during running at different speeds and in different loading conditions},
  series = {Journal of Applied Physiology},
  volume    = {127},
  journal   = {Journal of Applied Physiology},
  number    = {1},
  issn      = {1522-1601},
  doi       = {10.1152/japplphysiol.00710.2018},
  pages     = {246 -- 253},
  year      = {2019},
  language  = {en}
}
@article{CapriMorsianiSantoroetal.2019,
  author    = {Capri, Miriam and Morsiani, Cristina and Santoro, Aurelia and Moriggi, Manuela and Conte, Maria and Martucci, Morena and Bellavista, Elena and Fabbri, Cristina and Giampieri, Enrico and Albracht, Kirsten and Fl{\"u}ck, Martin and Ruoss, Severin and Brocca, Lorenza and Canepari, Monica and Longa, Emanuela and Giulio, Irene Di and Bottinelli, Roberto and Cerretelli, Paolo and Salvioli, Stefano and Gelfi, Cecilia and Franceschi, Claudio and Narici, Marco and Rittweger, J{\"o}rn},
  title     = {Recovery from 6-month spaceflight at the International Space Station: muscle-related stress into a proinflammatory setting},
  series = {The FASEB journal : official publication of the Federation of American Societies for Experimental Biology},
  volume    = {33},
  journal   = {The FASEB journal : official publication of the Federation of American Societies for Experimental Biology},
  number    = {4},
  doi       = {10.1096/fj.201801625R},
  pages     = {5168 -- 5180},
  year      = {2019},
  language  = {en}
}
@article{QuittmannAbelAlbrachtetal.2019,
  author    = {Quittmann, Oliver J. and Abel, Thomas and Albracht, Kirsten and Str{\"u}der, Heiko K.},
  title     = {Reliability of muscular activation patterns and their alterations during incremental handcycling in able-bodied participants},
  series = {Sports Biomechanics},
  journal   = {Sports Biomechanics},
  number    = {Article in press},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {1752-6116},
  doi       = {10.1080/14763141.2019.1593496},
  year      = {2019},
  language  = {en}
}
@article{HeinkeKnickerAlbracht2020,
  author    = {Heinke, Lars N. and Knicker, Axel J. and Albracht, Kirsten},
  title     = {Increased shoulder muscle stretch reflex elicitability in supine subject posture},
  series = {Isokinetics and Exercise Science},
  volume    = {28},
  journal   = {Isokinetics and Exercise Science},
  number    = {2},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {1878-5913},
  doi       = {10.3233/IES-192219},
  pages     = {139 -- 146},
  year      = {2020},
  abstract  = {BACKGROUND: Muscle stretch reflexes are widely used to examine neural muscle function. The knowledge of reflex response in muscles crossing the shoulder is limited. OBJECTIVE: To quantify reflex modulation according to various subject postures and different procedures of muscle pre-activation steering. METHODS: Thirteen healthy male participants performed two sets of external shoulder rotation stretches in various positions and with different procedures of muscle pre-activation steering on an isokinetic dynamometer over a range of two different pre-activation levels. All stretches were applied with a dynamometer acceleration of 104∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexive response was observed in all tested muscles in all experimental conditions. The reflex elicitation rate revealed a significant muscle main effect (F (5,288) = 2.358, ρ= 0.040; η2= 0.039; f= 0.637) and a significant test condition main effect (F (1,288) = 5.884, ρ= 0.016; η2= 0.020; f= 0.143). Reflex latency revealed a significant muscle pre-activation level main effect (F (1,274) = 5.008, ρ= 0.026; η2= 0.018; f= 0.469). CONCLUSION: Muscular reflexive response was more consistent in the primary internal rotators of the shoulder. Supine posture in combination with visual feedback of muscle pre-activation level enhanced the reflex elicitation rate.},
  language  = {en}
}
@article{RichterBraunsteinStaeudleetal.2021,
  author    = {Richter, Charlotte and Braunstein, Bjoern and Staeudle, Benjamin and Attias, Julia and Suess, Alexander and Weber, Tobias and Mileva, Katya N. and Rittweger, Joern and Green, David A. and Albracht, Kirsten},
  title     = {Contractile behavior of the gastrocnemius medialis muscle during running in simulated hypogravity},
  series = {npj Microgravity},
  volume    = {7},
  journal   = {npj Microgravity},
  number    = {Article number: 32},
  publisher = {Springer Nature},
  address   = {New York},
  issn      = {2373-8065},
  doi       = {10.1038/s41526-021-00155-7},
  pages     = {7 Seiten},
  year      = {2021},
  abstract  = {Vigorous exercise countermeasures in microgravity can largely attenuate muscular degeneration, albeit the extent of applied loading is key for the extent of muscle wasting. Running on the International Space Station is usually performed with maximum loads of 70\% body weight (0.7 g). However, it has not been investigated how the reduced musculoskeletal loading affects muscle and series elastic element dynamics, and thereby force and power generation. Therefore, this study examined the effects of running on the vertical treadmill facility, a ground-based analog, at simulated 0.7 g on gastrocnemius medialis contractile behavior. The results reveal that fascicle-series elastic element behavior differs between simulated hypogravity and 1 g running. Whilst shorter peak series elastic element lengths at simulated 0.7 g appear to be the result of lower muscular and gravitational forces acting on it, increased fascicle lengths and decreased velocities could not be anticipated, but may inform the development of optimized running training in hypogravity. However, whether the alterations in contractile behavior precipitate musculoskeletal degeneration warrants further study.},
  language  = {en}
}
@article{HeinkeKnickerAlbracht2021,
  author    = {Heinke, Lars N. and Knicker, Axel J. and Albracht, Kirsten},
  title     = {Test-retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men},
  series = {Journal of Electromyography and Kinesiology},
  volume    = {62},
  journal   = {Journal of Electromyography and Kinesiology},
  number    = {Article 102611},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1050-6411},
  doi       = {10.1016/j.jelekin.2021.102611},
  year      = {2021},
  abstract  = {Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall "good" relative reliability. SRD 95\% lay between ±7,0 to ±12,3 ms.. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.},
  language  = {en}
}
@article{ZangeSchopenAlbrachtetal.2017,
  author    = {Zange, Jochen and Schopen, Kathrin and Albracht, Kirsten and Gerlach, Darius A. and Frings-Meuthen, Petra and Maffiuletti, Nicola A. and Bloch, Wilhelm and Rittweger, J{\"o}rn},
  title     = {Using the Hephaistos orthotic device to study countermeasure effectiveness of neuromuscular electrical stimulation and dietary lupin protein supplementation, a randomised controlled trial},
  series = {Plos one},
  volume    = {12},
  journal   = {Plos one},
  number    = {2},
  doi       = {10.1371/journal.pone.0171562},
  year      = {2017},
  language  = {en}
}
@article{KolditzAlbinBrueggemannetal.2016,
  author    = {Kolditz, Melanie and Albin, Thivaharan and Br{\"u}ggemann, Gert-Peter and Abel, Dirk and Albracht, Kirsten},
  title     = {Robotergest{\"u}tztes System f{\"u}r ein verbessertes neuromuskul{\"a}res Aufbautraining der Beinstrecker},
  series = {at - Automatisierungstechnik},
  volume    = {64},
  journal   = {at - Automatisierungstechnik},
  number    = {11},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {2196-677X},
  doi       = {10.1515/auto-2016-0044},
  pages     = {905 -- 914},
  year      = {2016},
  abstract  = {Neuromuskul{\"a}res Aufbautraining der Beinstrecker ist ein wichtiger Bestandteil in der Rehabilitation und Pr{\"a}vention von Muskel-Skelett-Erkrankungen. Effektives Training erfordert hohe Muskelkr{\"a}fte, die gleichzeitig hohe Belastungen von bereits gesch{\"a}digten Strukturen bedeuten. Um trainingsinduzierte Sch{\"a}digungen zu vermeiden, m{\"u}ssen diese Kr{\"a}fte kontrolliert werden. Mit heutigen Trainingsger{\"a}ten k{\"o}nnen diese Ziele allerdings nicht erreicht werden. F{\"u}r ein sicheres und effektives Training sollen durch den Einsatz der Robotik, Sensorik, eines Regelkreises sowie Muskel-Skelett-Modellen Belastungen am Zielgewebe direkt berechnet und kontrolliert werden. Auf Basis zweier Vorstudien zu m{\"o}glichen Stellgr{\"o}ßen wird der Aufbau eines robotischen Systems vorgestellt, das sowohl f{\"u}r Forschungszwecke als auch zur Entwicklung neuartiger Trainingsger{\"a}te verwendet werden kann.},
  language  = {de}
}
@article{WaldvogelRitzmannFreyleretal.2021,
  author    = {Waldvogel, Janice and Ritzmann, Ramona and Freyler, Kathrin and Helm, Michael and Monti, Elena and Albracht, Kirsten and St{\"a}udle, Benjamin and Gollhofer, Albert and Narici, Marco},
  title     = {The Anticipation of Gravity in Human Ballistic Movement},
  series = {Frontiers in Physiology},
  journal   = {Frontiers in Physiology},
  publisher = {Frontiers},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2021.614060},
  year      = {2021},
  abstract  = {Stretch-shortening type actions are characterized by lengthening of the pre-activated muscle-tendon unit (MTU) in the eccentric phase immediately followed by muscle shortening. Under 1 g, pre-activity before and muscle activity after ground contact, scale muscle stiffness, which is crucial for the recoil properties of the MTU in the subsequent push-off. This study aimed to examine the neuro-mechanical coupling of the stretch-shortening cycle in response to gravity levels ranging from 0.1 to 2 g. During parabolic flights, 17 subjects performed drop jumps while electromyography (EMG) of the lower limb muscles was combined with ultrasound images of the gastrocnemius medialis, 2D kinematics and kinetics to depict changes in energy management and performance. Neuro-mechanical coupling in 1 g was characterized by high magnitudes of pre-activity and eccentric muscle activity allowing an isometric muscle behavior during ground contact. EMG during pre-activity and the concentric phase systematically increased from 0.1 to 1 g. Below 1 g the EMG in the eccentric phase was diminished, leading to muscle lengthening and reduced MTU stretches. Kinetic energy at take-off and performance were decreased compared to 1 g. Above 1 g, reduced EMG in the eccentric phase was accompanied by large MTU and muscle stretch, increased joint flexion amplitudes, energy loss and reduced performance. The energy outcome function established by linear mixed model reveals that the central nervous system regulates the extensor muscles phase- and load-specifically. In conclusion, neuro-mechanical coupling appears to be optimized in 1 g. Below 1 g, the energy outcome is compromised by reduced muscle stiffness. Above 1 g, loading progressively induces muscle lengthening, thus facilitating energy dissipation.},
  language  = {en}
}
@article{MoratFaudeHanssenetal.2020,
  author    = {Morat, Mareike and Faude, Oliver and Hanssen, Henner and Ludyga, Sebastian and Zacher, Jonas and Eibl, Angi and Albracht, Kirsten and Donath, Lars},
  title     = {Agility Training to Integratively Promote Neuromuscular, Cognitive, Cardiovascular and Psychosocial Function in Healthy Older Adults: A Study Protocol of a One-Year Randomized-Controlled Trial},
  series = {International Journal of Environmental Research and Public Health},
  volume    = {17},
  journal   = {International Journal of Environmental Research and Public Health},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1660-4601},
  doi       = {10.3390/ijerph17061853},
  pages     = {1 -- 14},
  year      = {2020},
  abstract  = {Exercise training effectively mitigates aging-induced health and fitness impairments. Traditional training recommendations for the elderly focus separately on relevant physiological fitness domains, such as balance, flexibility, strength and endurance. Thus, a more holistic and functional training framework is needed. The proposed agility training concept integratively tackles spatial orientation, stop and go, balance and strength. The presented protocol aims at introducing a two-armed, one-year randomized controlled trial, evaluating the effects of this concept on neuromuscular, cardiovascular, cognitive and psychosocial health outcomes in healthy older adults. Eighty-five participants were enrolled in this ongoing trial. Seventy-nine participants completed baseline testing and were block-randomized to the agility training group or the inactive control group. All participants undergo pre- and post-testing with interim assessment after six months. The intervention group currently receives supervised, group-based agility training twice a week over one year, with progressively demanding perceptual, cognitive and physical exercises. Knee extension strength, reactive balance, dual task gait speed and the Agility Challenge for the Elderly (ACE) serve as primary endpoints and neuromuscular, cognitive, cardiovascular, and psychosocial meassures serve as surrogate secondary outcomes. Our protocol promotes a comprehensive exercise training concept for older adults, that might facilitate stakeholders in health and exercise to stimulate relevant health outcomes without relying on excessively time-consuming physical activity recommendations.},
  language  = {en}
}
@article{HerssensCowburnAlbrachtetal.2022,
  author    = {Herssens, Nolan and Cowburn, James and Albracht, Kirsten and Braunstein, Bjoern and Cazzola, Dario and Colyer, Steffi and Minetti, Alberto E. and Pavei, Gaspare and Rittweger, J{\"o}rn and Weber, Tobias and Green, David A.},
  title     = {Movement in low gravity environments (MoLo) programme - the MoLo-L.O.O.P. study protocol},
  series = {PLOS ONE / Public Library of Science},
  volume    = {17},
  journal   = {PLOS ONE / Public Library of Science},
  number    = {11},
  editor    = {Cattaneo, Luigi},
  publisher = {Plos},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0278051},
  pages     = {e0278051},
  year      = {2022},
  abstract  = {Exposure to prolonged periods in microgravity is associated with deconditioning of the musculoskeletal system due to chronic changes in mechanical stimulation. Given astronauts will operate on the Lunar surface for extended periods of time, it is critical to quantify both external (e.g., ground reaction forces) and internal (e.g., joint reaction forces) loads of relevant movements performed during Lunar missions. Such knowledge is key to predict musculoskeletal deconditioning and determine appropriate exercise countermeasures associated with extended exposure to hypogravity.},
  language  = {en}
}
@article{WaldvogelFreylerHelmetal.2023,
  author    = {Waldvogel, Janice and Freyler, Kathrin and Helm, Michael and Monti, Elena and St{\"a}udle, Benjamin and Gollhofer, Albert and Narici, Marco V. and Ritzmann, Ramona and Albracht, Kirsten},
  title     = {Changes in gravity affect neuromuscular control, biomechanics, and muscle-tendon mechanics in energy storage and dissipation tasks},
  series = {Journal of Applied Physiology},
  volume    = {134},
  journal   = {Journal of Applied Physiology},
  number    = {1},
  publisher = {American Physiological Society},
  address   = {Bethesda, Md.},
  issn      = {1522-1601 (Onlineausgabe)},
  doi       = {10.1152/japplphysiol.00279.2022},
  pages     = {190 -- 202},
  year      = {2023},
  abstract  = {This study evaluates neuromechanical control and muscle-tendon interaction during energy storage and dissipation tasks in hypergravity. During parabolic flights, while 17 subjects performed drop jumps (DJs) and drop landings (DLs), electromyography (EMG) of the lower limb muscles was combined with in vivo fascicle dynamics of the gastrocnemius medialis, two-dimensional (2D) kinematics, and kinetics to measure and analyze changes in energy management. Comparisons were made between movement modalities executed in hypergravity (1.8 G) and gravity on ground (1 G). In 1.8 G, ankle dorsiflexion, knee joint flexion, and vertical center of mass (COM) displacement are lower in DJs than in DLs; within each movement modality, joint flexion amplitudes and COM displacement demonstrate higher values in 1.8 G than in 1 G. Concomitantly, negative peak ankle joint power, vertical ground reaction forces, and leg stiffness are similar between both movement modalities (1.8 G). In DJs, EMG activity in 1.8 G is lower during the COM deceleration phase than in 1 G, thus impairing quasi-isometric fascicle behavior. In DLs, EMG activity before and during the COM deceleration phase is higher, and fascicles are stretched less in 1.8 G than in 1 G. Compared with the situation in 1 G, highly task-specific neuromuscular activity is diminished in 1.8 G, resulting in fascicle lengthening in both movement modalities. Specifically, in DJs, a high magnitude of neuromuscular activity is impaired, resulting in altered energy storage. In contrast, in DLs, linear stiffening of the system due to higher neuromuscular activity combined with lower fascicle stretch enhances the buffering function of the tendon, and thus the capacity to safely dissipate energy.},
  language  = {en}
}
@article{HeieisBoeckerD'Angeloetal.2023,
  author    = {Heieis, Jule and B{\"o}cker, Jonas and D'Angelo, Olfa and Mittag, Uwe and Albracht, Kirsten and Sch{\"o}nau, Eckhard and Meyer, Andreas and Voigtmann, Thomas and Rittweger, J{\"o}rn},
  title     = {Curvature of gastrocnemius muscle fascicles as function of muscle-tendon complex length and contraction in humans},
  series = {Physiological Reports},
  volume    = {11},
  journal   = {Physiological Reports},
  number    = {11},
  publisher = {Wiley},
  issn      = {2051-817X},
  doi       = {10.14814/phy2.15739},
  pages     = {e15739, Seite 1-11},
  year      = {2023},
  abstract  = {It has been shown that muscle fascicle curvature increases with increasing contraction level and decreasing muscle-tendon complex length. The analyses were done with limited examination windows concerning contraction level, muscle-tendon complex length, and/or intramuscular position of ultrasound imaging. With this study we aimed to investigate the correlation between fascicle arching and contraction, muscle-tendon complex length and their associated architectural parameters in gastrocnemius muscles to develop hypotheses concerning the fundamental mechanism of fascicle curving. Twelve participants were tested in five different positions (90°/105°*, 90°/90°*, 135°/90°*, 170°/90°*, and 170°/75°*; *knee/ankle angle). They performed isometric contractions at four different contraction levels (5\%, 25\%, 50\%, and 75\% of maximum voluntary contraction) in each position. Panoramic ultrasound images of gastrocnemius muscles were collected at rest and during constant contraction. Aponeuroses and fascicles were tracked in all ultrasound images and the parameters fascicle curvature, muscle-tendon complex strain, contraction level, pennation angle, fascicle length, fascicle strain, intramuscular position, sex and age group were analyzed by linear mixed effect models. Mean fascicle curvature of the medial gastrocnemius increased with contraction level (+5 m-1 from 0\% to 100\%; p = 0.006). Muscle-tendon complex length had no significant impact on mean fascicle curvature. Mean pennation angle (2.2 m-1 per 10°; p < 0.001), inverse mean fascicle length (20 m-1 per cm-1; p = 0.003), and mean fascicle strain (-0.07 m-1 per +10\%; p = 0.004) correlated with mean fascicle curvature. Evidence has also been found for intermuscular, intramuscular, and sex-specific intramuscular differences of fascicle curving. Pennation angle and the inverse fascicle length show the highest predictive capacities for fascicle curving. Due to the strong correlations between pennation angle and fascicle curvature and the intramuscular pattern of curving we suggest for future studies to examine correlations between fascicle curvature and intramuscular fluid pressure.},
  language  = {en}
}