scholarly journals Contractile behavior of the gastrocnemius medialis muscle during running in simulated hypogravity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Charlotte Richter ◽  
Bjoern Braunstein ◽  
Benjamin Staeudle ◽  
Julia Attias ◽  
Alexander Suess ◽  
...  
Keyword(s):  
Elastic Element ◽  
Muscle Wasting ◽  
Space Station ◽  
Vigorous Exercise ◽  
Gastrocnemius Medialis ◽  
Gravitational Forces ◽  
Series Elastic Element ◽  
Applied Loading ◽  
Exercise Countermeasures ◽  
Series Elastic

AbstractVigorous 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.

scholarly journals Gastrocnemius Medialis Contractile Behavior Is Preserved During 30% Body Weight Supported Gait Training

2021 ◽  
Vol 2 ◽  
Author(s):  
Charlotte Richter ◽  
Bjoern Braunstein ◽  
Benjamin Staeudle ◽  
Julia Attias ◽  
Alexander Suess ◽  
...  
Keyword(s):  
Body Weight ◽  
Elastic Element ◽  
Gait Training ◽  
Joint Kinematics ◽  
Body Weight Support ◽  
Gait Patterns ◽  
Gastrocnemius Medialis ◽  
Series Elastic Element ◽  
Weight Support ◽  
Series Elastic

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.

Effect of series elasticity on delay in development of tension relative to stiffness during muscle activation

1994 ◽  
Vol 267 (6) ◽  
pp. C1598-C1606 ◽  
Author(s):  
Y. Luo ◽  
R. Cooke ◽  
E. Pate
Keyword(s):  
Elastic Element ◽  
Muscle Activation ◽  
Muscle Length ◽  
Mechanical Stiffness ◽  
Tension Development ◽  
Series Elasticity ◽  
Series Elastic Element ◽  
Bridge Model ◽  
Elastic Strains ◽  
Series Elastic

Experimental data have indicated that during activation, the attachment of myosin to actin, measured by mechanical stiffness, precedes tension generation by 10-30 ms. Using computer simulation, we have investigated the effect of a series elastic element on the lag between stiffness and tension development during muscle activation. Two versions of the two-state cross-bridge model originally proposed by Huxley and a three-state model were considered. After simulated activation, stiffness and tension increased with rates that were strongly dependent on the series elastic strain. In the absence of a series elastic element, the rise in stiffness preceded, lagged, or was coincident with the increase in tension, depending on the model. For large elastic strains, tension lagged stiffness for all models. Lags of 10-30 ms could be obtained with elastic strains of 0.3-1% of the muscle length. This is a realistic value in experiments without sarcomere length servocontrol, suggesting that series elasticity may be an important contributor to the experimentally observed lag between tension and stiffness.

A simple Hill element-nonlinear spring model of muscle contraction biomechanics

1991 ◽  
Vol 70 (2) ◽  
pp. 803-812 ◽  
Author(s):  
A. B. Schultz ◽  
J. A. Faulkner ◽  
V. A. Kadhiresan
Keyword(s):  
Elastic Element ◽  
Mechanical Response ◽  
Contractile Element ◽  
Series Elastic Element ◽  
Hindlimb Muscles ◽  
Velocity Relationship ◽  
Force Velocity ◽  
Experimental Values ◽  
Shortening Contractions ◽  
Series Elastic

The purpose of this study was to develop a model to predict the mechanical response of muscles during isometric tetanic, afterloaded isotonic and isovelocity shortening contractions. Two versions of the model were developed. Both incorporated a contractile element that obeyed a Hill force-velocity relationship and a series elastic element. In a quadratic spring version, the series elastic element force was represented as proportional to the square of the stretch; in a cubic spring version, it was represented as proportional to the cube of the stretch. Both versions provided closed-form equations for response predictions that involved four independent parameters. Once the four parameters were chosen, each of these responses could be predicted. Model validity was established by comparing predicted and observed responses in slow and fast hindlimb muscles of rodents. Significant model-predicted responses seldom differed by more than 15% from experimental values. The model can provide insights into how changes in individual properties affect the overall mechanical behavior of muscles in a variety of circumstances and reduce the need for collection of experimental data.

A compact series elastic element using a rubber compression mechanism

2021 ◽  
Vol 92 (6) ◽  
pp. 065004
Author(s):  
Hyung-Tae Seo ◽  
Ji-il Park ◽  
Jihyuk Park
Keyword(s):  
Elastic Element ◽  
Series Elastic Element ◽  
Compression Mechanism ◽  
Series Elastic

Contribution of Muscle Series Elasticity to Maximum Performance in Drop Jumping

2006 ◽  
Vol 22 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Harald Böhm ◽  
Gerald K. Cole ◽  
Gert-Peter Brüggemann ◽  
Hanns Ruder
Keyword(s):  
Elastic Energy ◽  
Elastic Element ◽  
Muscle Activation ◽  
Rectus Femoris ◽  
Muscle Performance ◽  
Maximum Height ◽  
Shortening Velocity ◽  
Maximum Performance ◽  
Series Elastic Element ◽  
Series Elastic

The contribution of muscle in-series compliance on maximum performance of the muscle tendon complex was investigated using a forward dynamic computer simulation. The model of the human body contains 8 Hill-type muscles of the lower extremities. Muscle activation is optimized as a function of time, so that maximum drop jump height is achieved by the model. It is shown that the muscle series elastic energy stored in the downward phase provides a considerable contribution (32%) to the total muscle energy in the push-off phase. Furthermore, by the return of stored elastic energy all muscle contractile elements can reduce their shortening velocity up to 63% during push-off to develop a higher force due to their force velocity properties. The additional stretch taken up by the muscle series elastic element allows only m. rectus femoris to work closer to its optimal length, due to its force length properties. Therefore the contribution of the series elastic element to muscle performance in maximum height drop jumping is to store and return energy, and at the same time to increase the force producing ability of the contractile elements during push-off.

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