TY  - JOUR
A1  - Stäudle, Benjamin
A1  - Seynnes, Olivier
A1  - Laps, Guido
A1  - Göll, Fabian
A1  - Brüggemann, Gert-Peter
A1  - Albracht, Kirsten
T1  - Recovery from achilles tendon repair: a combination of Postsurgery Outcomes and Insufficient remodeling of muscle and tendon
JF  - Medicine & Science in Sports & Exercise
N2  - Achilles tendon rupture (ATR) patients have persistent functional deficits in the triceps surae muscle–tendon unit (MTU). The complex remodeling of the MTU accompanying these deficits remains poorly understood. The purpose of the present study was to associate in vivo and in silico data to investigate the relations between changes inMTU properties and strength deficits inATR patients. Methods: Elevenmale subjects who had undergone surgical repair of complete unilateral ATR were examined 4.6 ± 2.0 (mean ± SD) yr after rupture. Gastrocnemius medialis (GM) tendon stiffness, morphology, and muscle architecture were determined using ultrasonography. The force–length relation of the plantar flexor muscles was assessed at five ankle joint angles. In addition, simulations (OpenSim) of the GM MTU force–length properties were performed with various iterations of MTU properties found between the unaffected and the affected side. Results: The affected side of the patients displayed a longer, larger, and stiffer GM tendon (13% ± 10%, 105% ± 28%, and 54% ± 24%, respectively) compared with the unaffected side. The GM muscle fascicles of the affected side were shorter (32% ± 12%) and with greater pennation angles (31% ± 26%). A mean deficit in plantarflexion moment of 31% ± 10% was measured. Simulations indicate that pairing an intact muscle with a longer tendon shifts the optimal angular range of peak force outside physiological angular ranges, whereas the shorter muscle fascicles and tendon stiffening seen in the affected side decrease this shift, albeit incompletely. Conclusions: These results suggest that the substantial changes in MTU properties found in ATR patients may partly result from compensatory remodeling, although this process appears insufficient to fully restore muscle function.
KW  - Tendon Rupture
KW  - Stiffness
KW  - Simulation
KW  - Muscle Force
KW  - Muscle Fascicle
Y1  - 2021
U6  - https://doi.org/10.1249/MSS.0000000000002592
SN  - 1530-0315
VL  - 53
IS  - 7
SP  - 1356
EP  - 1366
PB  - American College of Sports Medicine
CY  - Philadelphia, Pa.
ER  - 
TY  - JOUR
A1  - Werkhausen, Amelie
A1  - Albracht, Kirsten
A1  - Cronin, Neil J
A1  - Paulsen, Gøran
A1  - Bojsen-Møller, Jens
A1  - Seynnes, Olivier R
T1  - Effect of training-induced changes in achilles tendon stiffness on muscle-tendon behavior during landing
JF  - Frontiers in physiology
N2  - During rapid deceleration of the body, tendons buffer part of the elongation of the muscle-tendon unit (MTU), enabling safe energy dissipation via eccentric muscle contraction. Yet, the influence of changes in tendon stiffness within the physiological range upon these lengthening contractions is unknown. This study aimed to examine the effect of training-induced stiffening of the Achilles tendon on triceps surae muscle-tendon behavior during a landing task. Twenty-one male subjects were assigned to either a 10-week resistance-training program consisting of single-leg isometric plantarflexion (n = 11) or to a non-training control group (n = 10). Before and after the training period, plantarflexion force, peak Achilles tendon strain and stiffness were measured during isometric contractions, using a combination of dynamometry, ultrasound and kinematics data. Additionally, testing included a step-landing task, during which joint mechanics and lengths of gastrocnemius and soleus fascicles, Achilles tendon, and MTU were determined using synchronized ultrasound, kinematics and kinetics data collection. After training, plantarflexion strength and Achilles tendon stiffness increased (15 and 18%, respectively), and tendon strain during landing remained similar. Likewise, lengthening and negative work produced by the gastrocnemius MTU did not change detectably. However, in the training group, gastrocnemius fascicle length was offset (8%) to a longer length at touch down and, surprisingly, fascicle lengthening and velocity were reduced by 27 and 21%, respectively. These changes were not observed for soleus fascicles when accounting for variation in task execution between tests. These results indicate that a training-induced increase in tendon stiffness does not noticeably affect the buffering action of the tendon when the MTU is rapidly stretched. Reductions in gastrocnemius fascicle lengthening and lengthening velocity during landing occurred independently from tendon strain. Future studies are required to provide insight into the mechanisms underpinning these observations and their influence on energy dissipation.
KW  - achilles tendon
KW  - energy absorption
KW  - energy dissipation
KW  - mechanical buffer
KW  - stiffness
Y1  - 2018
U6  - https://doi.org/10.3389/fphys.2018.00794
SN  - 1664-042X
IS  - 9
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Yang, Peng-Fei
A1  - Kriechbaumer, Andreas
A1  - Albracht, Kirsten
A1  - Sanno, Maximilian
A1  - Ganse, Bergita
A1  - Koy, Timmo
A1  - Shang, Peng
A1  - brüggemann, Gert-Peter
A1  - Müller, Lars Peter
A1  - Rittweger, Jörn
T1  - A novel optical approach for assessing in vivo bone segment deformation and its application in muscle-bone relationship studies in humans
JF  - Journal of Orthopaedic Translation
Y1  - 2014
U6  - https://doi.org/10.1016/j.jot.2014.07.078
SN  - 2214-0328
SN  - 2214-031X
VL  - 2
IS  - 4
SP  - 238
EP  - 238
PB  - Elsevier
CY  - Singapore
ER  - 
TY  - JOUR
A1  - Liphardt, Anna-Maria
A1  - Fernandez-Gonzalo, Rodrigo
A1  - Albracht, Kirsten
A1  - Rittweger, Jörn
A1  - Vico, Laurence
T1  - Musculoskeletal research in human space flight – unmet needs for the success of crewed deep space exploration
JF  - npj Microgravity
N2  - Based on the European Space Agency (ESA) Science in Space Environment (SciSpacE) community White Paper “Human Physiology – Musculoskeletal system”, this perspective highlights unmet needs and suggests new avenues for future studies in musculoskeletal research to enable crewed exploration missions. The musculoskeletal system is essential for sustaining physical function and energy metabolism, and the maintenance of health during exploration missions, and consequently mission success, will be tightly linked to musculoskeletal function. Data collection from current space missions from pre-, during-, and post-flight periods would provide important information to understand and ultimately offset musculoskeletal alterations during long-term spaceflight. In addition, understanding the kinetics of the different components of the musculoskeletal system in parallel with a detailed description of the molecular mechanisms driving these alterations appears to be the best approach to address potential musculoskeletal problems that future exploratory-mission crew will face. These research efforts should be accompanied by technical advances in molecular and phenotypic monitoring tools to provide in-flight real-time feedback.
Y1  - 2023
U6  - https://doi.org/10.1038/s41526-023-00258-3
SN  - 2373-8065
VL  - 9
IS  - Article number: 9
SP  - 1
EP  - 9
PB  - Springer Nature
ER  - 
TY  - JOUR
A1  - Richter, Charlotte
A1  - Braunstein, Bjoern
A1  - Stäudle, Benjamin
A1  - Attias, Julia
A1  - Suess, Alexander
A1  - Weber, Tobias
A1  - Mileva, Katja N.
A1  - Rittweger, Joern
A1  - Green, David A.
A1  - Albracht, Kirsten
T1  - Gastrocnemius medialis contractile behavior is preserved during 30% body weight supported gait training
JF  - Frontiers in Sports and Active Living
N2  - Rehabilitative body weight supported gait training aims at restoring walking function as a key element in activities of daily living. Studies demonstrated reductions in muscle and joint forces, while kinematic gait patterns appear to be preserved with up to 30% weight support. However, the influence of body weight support on muscle architecture, with respect to fascicle and series elastic element behavior is unknown, despite this having potential clinical implications for gait retraining. Eight males (31.9 ± 4.7 years) walked at 75% of the speed at which they typically transition to running, with 0% and 30% body weight support on a lower-body positive pressure treadmill. Gastrocnemius medialis fascicle lengths and pennation angles were measured via ultrasonography. Additionally, joint kinematics were analyzed to determine gastrocnemius medialis muscle–tendon unit lengths, consisting of the muscle's contractile and series elastic elements. Series elastic element length was assessed using a muscle–tendon unit model. Depending on whether data were normally distributed, a paired t-test or Wilcoxon signed rank test was performed to determine if body weight supported walking had any effects on joint kinematics and fascicle–series elastic element behavior. Walking with 30% body weight support had no statistically significant effect on joint kinematics and peak series elastic element length. Furthermore, at the time when peak series elastic element length was achieved, and on average across the entire stance phase, muscle–tendon unit length, fascicle length, pennation angle, and fascicle velocity were unchanged with respect to body weight support. In accordance with unchanged gait kinematics, preservation of fascicle–series elastic element behavior was observed during walking with 30% body weight support, which suggests transferability of gait patterns to subsequent unsupported walking.
KW  - AlterG
KW  - rehabilitation
KW  - gait
KW  - walking
KW  - ultrasound imaging
KW  - series elastic element behavior
KW  - muscle fascicle behavior
KW  - unloading
Y1  - 2021
U6  - https://doi.org/10.3389/fspor.2020.614559
SN  - 2624-9367
VL  - 2021
IS  - 2
PB  - Frontiers
CY  - Lausanne
ER  - 
TY  - CHAP
A1  - Richter, Charlotte
A1  - Braunstein, Bjoern
A1  - Stäudle, Benjamin
A1  - Attias, Julia
A1  - Suess, Alexander
A1  - Weber, T.
A1  - Rittweger, Joern
A1  - Green, David A.
A1  - Albracht, Kirsten
T1  - In vivo fascicle length of the gastrocnemius muscle during walking in simulated martian gravity using two different body weight support devices
T2  - 23rd Annual Congress of the European College of Sport Science, Dublin, Irland
Y1  - 2018
ER  - 
TY  - JOUR
A1  - Kotliar, Konstantin
A1  - Koshitz, I. N.
A1  - Svetlowa, O. V.
A1  - Zaseeva, M. V.
T1  - Physiological principles of hypotensive therapy of open-angle glaucoma during presbyopic period. Part II Promising algorithms of practical sparing applications / Koshitz, I. N. ; Svetlova, O. V. ; Zaseeva, M. V. ; Shuhaev, S. V. ; Makarov, F. N. ; Kotliar
JF  - Glaukoma (2006)
Y1  - 2006
N1  - Original in Russisch
SP  - 51
EP  - 70
PB  - -
ER  - 
TY  - JOUR
A1  - Kotliar, Konstantin
A1  - Koshitz, I. N.
A1  - Svetlowa, O. V.
A1  - Makarov, F. N.
T1  - Biomechanical analysis of traditional and contemporary conceptions on pathogenesis of the primary open angle glaucoma / Koshitz, I. N. ; Svetlova, O. V. ; Kotliar, K. E. ; Makarov, F. N. ;  Smolnikov, B. A.
JF  - Glaukoma (2005)
Y1  - 2005
N1  - Original in Russisch
SP  - 41
EP  - 63
PB  - -
ER  - 
TY  - JOUR
A1  - Kotliar, Konstantin
A1  - Svetlova, O. V.
A1  - Stegaev, V. A.
A1  - Parkhomov, S. D.
T1  - Biomechanical substantiation of relatively low efficiency of recurrent laser trabeculoplasty / Svetlova, O. V. ; Stagaev, V. A. ; Parkhomov, S. D. ; Kotliar, K. E. ; Makarov, F. N. ;  Smolnikov, B. A. ; Koshitz, I. N.
JF  - Glaukoma (2004)
Y1  - 2004
N1  - Original in Russisch
SP  - 29
EP  - 39
PB  - -
ER  - 
TY  - JOUR
A1  - Kotliar, Konstantin
A1  - Svetlova, O. V.
A1  - Sourjikov, A. V.
A1  - Zaseeva, M. V.
T1  - Biomechanical peculiarities of aqueous humor production system and outflow regulation system / Svetlova, O. V. ; Sourjikov, A. V. ; Kotliar, K. E. ; Zaseeva, M. V. ; Shukhaev, S. V. ; Koshitz, I. N.
JF  - Glaukoma (2004)
Y1  - 2004
N1  - Original in Russisch
SP  - 66
EP  - 76
PB  - -
ER  -