TY  - JOUR
A1  - Stäudle, Benjamin
A1  - Seynnes, Olivier
A1  - Laps, Guido
A1  - Brüggemann, Gert-Peter
A1  - Albracht, Kirsten
T1  - Altered gastrocnemius contractile behavior in former achilles tendon rupture patients during walking
JF  - Frontiers in Physiology
N2  - Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during—low-force—walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s–1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
KW  - tendon rupture
KW  - muscle fascicle behavior
KW  - walking gait
KW  - force generation
KW  - ultrasound imaging
Y1  - 2022
U6  - https://doi.org/10.3389/fphys.2022.792576
SN  - 1664-042X
VL  - 13
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Swat, Maciej
T1  - Quantum States as Probability Measures
JF  - Foundations of Physics Letters. 14 (2001), H. 3
Y1  - 2001
SN  - 1572-9524
SP  - 285
EP  - 293
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Singer, Matthias
T1  - Informational Incompleteness of the Observables Sx,Sy,Sz for Spin-1 Systems. Singer, Matthias; Stulpe, W.
JF  - Foundations of Physics. 20 (1990), H. 4
Y1  - 1990
SN  - 1572-9516
SP  - 471
EP  - 472
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Singer, Matthias
T1  - Phase-Space Representations of General Statistical Physical Theories. Singer, Matthias; Stulpe, Werner
JF  - Journal of Mathematical Physics. 33 (1992), H. 1
Y1  - 1992
SN  - 1089-7658
SP  - 131
EP  - 142
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Singer, Matthias
T1  - Some Remarks on the Determination of Quantum States by Measurements
JF  - Foundations of Physics Letters. 3 (1990), H. 2
Y1  - 1990
SN  - 1572-9524
SP  - 153
EP  - 166
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Scholz, Erhard
T1  - Hilbert Space / Scholz, Erhard ; Stulpe, Werner
JF  - Compendium of Quantum Physics : concepts, experiments, history and philosophy / Daniel Greenberger ... ed.
Y1  - 2009
SN  - 978-3-540-70622-9
SP  - 291
EP  - 295
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Ruch, Ernst
T1  - Proof of the Mixing Theorem for Statistical Systems in Classical Physics. Ruch, Ernst; Stulpe, Werner
JF  - Acta Applicandae Mathematicae. 53 (1998), H. 3
Y1  - 1998
SN  - 1572-9036
SP  - 329
EP  - 352
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Hellwig, K.-E.
T1  - A Classical Reformulation of Finite-Dimensional Quantum Mechanics. Hellwig, K.-E.; Stulpe, W.
JF  - Quantum measurement, irreversibility and the physics of information / Symposium on the Foundations of Modern Physics 1993, Cologne, Germany 1 - 5 June 1993. Ed. Paul Busch
Y1  - 1993
SN  - 981021507X
N1  - Symposium on the Foundations of Modern Physics ; <1993, Köln>
SP  - 209
EP  - 214
PB  - World Scientific
CY  - Singapore [u.a.]
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Hellwig, K.-E.
T1  - A Formulation of Quantum Stochastic Processes and Some of its Properties. Hellwig, K.-E.; Stulpe, W.
JF  - Foundations of Physics. 13 (1983), H. 7
Y1  - 1983
SN  - 1572-9516
SP  - 673
EP  - 699
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Gudder, S.
A1  - Hagler, J.
T1  - An Uncertainty Relation for Joint Position-Momentum Measurements
JF  - Foundations of Physics Letters. 1 (1988), H. 3
Y1  - 1988
SN  - 1572-9524
SP  - 287
EP  - 292
ER  -