@inproceedings{DroszezSannoGoldmannetal.2016, author = {Droszez, Anna and Sanno, Maximilian and Goldmann, Jan-Peter and Albracht, Kirsten and Br{\"u}ggemann, Gerd-Peter and Braunstein, Bjoern}, title = {Differences between take-off behavior during vertical jumps and two artistic elements}, series = {34th International Conference of Biomechanics in Sport, Tsukuba, Japan, July 18-22, 2016}, booktitle = {34th International Conference of Biomechanics in Sport, Tsukuba, Japan, July 18-22, 2016}, issn = {1999-4168}, pages = {577 -- 580}, year = {2016}, 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{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{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{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} } @inproceedings{RichterBraunsteinStaeudleetal.2018, author = {Richter, Charlotte and Braunstein, Bjoern and St{\"a}udle, Benjamin and Attias, Julia and Suess, Alexander and Weber, T. and Rittweger, Joern and Green, David A. and Albracht, Kirsten}, title = {In vivo fascicle length of the gastrocnemius muscle during walking in simulated martian gravity using two different body weight support devices}, series = {23rd Annual Congress of the European College of Sport Science, Dublin, Irland}, booktitle = {23rd Annual Congress of the European College of Sport Science, Dublin, Irland}, year = {2018}, 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{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{KetelhutGoellBraunsteinetal.2018, author = {Ketelhut, Maike and G{\"o}ll, Fabian and Braunstein, Bj{\"o}rn and Albracht, Kirsten and Abel, Dirk}, title = {Comparison of different training algorithms for the leg extension training with an industrial robot}, series = {Current Directions in Biomedical Engineering}, volume = {4}, journal = {Current Directions in Biomedical Engineering}, number = {1}, publisher = {De Gruyter}, address = {Berlin}, issn = {2364-5504}, doi = {10.1515/cdbme-2018-0005}, pages = {17 -- 20}, year = {2018}, abstract = {In the past, different training scenarios have been developed and implemented on robotic research platforms, but no systematic analysis and comparison have been done so far. This paper deals with the comparison of an isokinematic (motion with constant velocity) and an isotonic (motion against constant weight) training algorithm. Both algorithms are designed for a robotic research platform consisting of a 3D force plate and a high payload industrial robot, which allows leg extension training with arbitrary six-dimensional motion trajectories. In the isokinematic as well as the isotonic training algorithm, individual paths are defined i n C artesian s pace by sufficient s upport p oses. I n t he i sotonic t raining s cenario, the trajectory is adapted to the measured force as the robot should only move along the trajectory as long as the force applied by the user exceeds a minimum threshold. In the isotonic training scenario however, the robot's acceleration is a function of the force applied by the user. To validate these findings, a simulative experiment with a simple linear trajectory is performed. For this purpose, the same force path is applied in both training scenarios. The results illustrate that the algorithms differ in the force dependent trajectory adaption.}, language = {en} }