scholarly journals Muscle Actuators, Not Springs, Drive Maximal Effort Human Locomotor Performance

2021 ◽  
pp. 766-777
Author(s):  
Jeffrey M. McBride
Keyword(s):  
Motion Analysis ◽  
Force Plate ◽  
Triceps Surae ◽  
Active Muscle ◽  
Muscle Work ◽  
Triceps Surae Muscle ◽  
Muscle Fascicle ◽  
Muscle Complex ◽  
Muscle Actuators ◽  
Maximal Effort

The current investigation examined muscle-tendon unit kinematics and kinetics in human participants asked to perform a hopping task for maximal performance with variational preceding milieu. Twenty-four participants were allocated post-data collection into those participants with an average hop height of higher (HH) or lower (LH) than 0.1 m. Participants were placed on a customized sled at a 20º angle while standing on a force plate. Participants used their dominant ankle for all testing and their knee was immobilized and thus all movement involved only the ankle joint and corresponding propulsive unit (triceps surae muscle complex). Participants were asked to perform a maximal effort during a single dynamic countermovement hop (CMH) and drop hops from 10 cm (DH10) and 50 cm (DH50). Three-dimensional motion analysis was performed by utilizing an infrared camera VICON motion analysis system and a corresponding force plate. An ultrasound probe was placed on the triceps surae muscle complex for muscle fascicle imaging. HH hopped significantly higher in all hopping tasks in comparison to LH. In addition, the HH group concentric ankle work was significantly higher in comparison to LH during all of the hopping tasks. Active muscle work was significantly higher in HH in comparison to LH as well. Tendon work was not significantly different between HH and LH. Active muscle work was significantly correlated with hopping height (r = 0.97) across both groups and hopping tasks and contributed more than 50% of the total work. The data indicates that humans primarily use a motor-driven system and thus it is concluded that muscle actuators and not springs maximize performance in hopping locomotor tasks in humans.

Dynamic Versus Fixed Equinus Deformity in Children With Cerebral Palsy: How Does the Triceps Surae Muscle Work?

2010 ◽  
Vol 91 (12) ◽  
pp. 1897-1903 ◽  
Author(s):  
Martin Švehlík ◽  
Ernst B. Zwick ◽  
Gerhard Steinwender ◽  
Tanja Kraus ◽  
Wolfgang E. Linhart
Keyword(s):  
Cerebral Palsy ◽  
Triceps Surae ◽  
Muscle Work ◽  
Triceps Surae Muscle ◽  
Children With Cerebral Palsy ◽  
Equinus Deformity

scholarly journals Energetic costs of producing muscle work and force in a cyclical human bouncing task

2011 ◽  
Vol 110 (4) ◽  
pp. 873-880 ◽  
Author(s):  
Jesse C. Dean ◽  
Arthur D. Kuo
Keyword(s):  
Energy Expenditure ◽  
Human Subjects ◽  
Force Production ◽  
The Body ◽  
Triceps Surae ◽  
Metabolic Energy ◽  
Active Muscle ◽  
Series Elasticity ◽  
Muscle Work ◽  
Near Resonance

Muscles expend energy to perform active work during locomotion, but they may also expend significant energy to produce force, for example when tendons perform much of the work passively. The relative contributions of work and force to overall energy expenditure are unknown. We therefore measured the mechanics and energetics of a cyclical bouncing task, designed to control for work and force. We hypothesized that near bouncing resonance, little work would be performed actively by muscle, but the cyclical production of force would cost substantial metabolic energy. Human subjects ( n = 9) bounced vertically about the ankles at inversely proportional frequencies (1–4 Hz) and amplitudes (15–4 mm), such that the overall rate of work performed on the body remained approximately constant (0.30 ± 0.06 W/kg), but the forces varied considerably. We used parameter identification to estimate series elasticity of the triceps surae tendon, as well as the work performed actively by muscle and passively by tendon. Net metabolic energy expenditure for bouncing at 1 Hz was 1.15 ± 0.31 W/kg, attributable mainly to active muscle work with an efficiency of 24 ± 3%. But at 3 Hz (near resonance), most of the work was performed passively, so that active muscle work could account for only 40% of the net metabolic rate of 0.76 ± 0.28 W/kg. Near resonance, a cost for cyclical force that increased with both amplitude and frequency of force accounted for at least as much of the total energy expenditure as a cost for work. Series elasticity reduces the need for active work, but energy must still be expended for force production.

scholarly journals Afferent Contribution to Locomotor Muscle Activity During Unconstrained Overground Human Walking: An Analysis of Triceps Surae Muscle Fascicles

2010 ◽  
Vol 103 (3) ◽  
pp. 1262-1274 ◽  
Author(s):  
R. af Klint ◽  
N. J. Cronin ◽  
M. Ishikawa ◽  
T. Sinkjaer ◽  
M. J. Grey
Keyword(s):  
Soleus Muscle ◽  
Muscle Activity ◽  
Force Feedback ◽  
Triceps Surae ◽  
Human Walking ◽  
Plantar Flexor ◽  
Triceps Surae Muscle ◽  
Muscle Fascicle ◽  
Flexor Muscles ◽  
Plantar Flexor Muscles

Plantar flexor series elasticity can be used to dissociate muscle–fascicle and muscle–tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to ±3° in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.

scholarly journals Electromyographic Analysis of the Triceps Surae Muscle Complex During Achilles Tendon Rehabilitation Program Exercises

2011 ◽  
Vol 3 (6) ◽  
pp. 543-546 ◽  
Author(s):  
Michael Mullaney ◽  
Timothy F. Tyler ◽  
Malachy McHugh ◽  
Karl Orishimo ◽  
Ian Kremenic ◽  
...  
Keyword(s):  
Achilles Tendon ◽  
Repeated Measures ◽  
Tendon Repair ◽  
Rehabilitation Program ◽  
Triceps Surae ◽  
Emg Activity ◽  
Triceps Surae Muscle ◽  
Elastic Resistance ◽  
Therapeutic Exercises ◽  
Muscle Complex

Background: Specific guidelines for therapeutic exercises following an Achilles tendon repair are lacking. Hypothesis: A hierarchical progression of triceps surae exercises can be determined on the basis of electromyographic (EMG) activity. Study Design: Randomized laboratory trial. Methods: Bipolar surface electrodes were applied over the medial and lateral heads of the gastrocnemius as well as the soleus on 20 healthy lower extremities (10 participants, 27 ± 5 years old). Muscle activity was recorded during 8 therapeutic exercises commonly used following an Achilles repair. Maximal voluntary isometric contractions (MVICs) were also performed on an isokinetic device. The effect of exercise on EMG activity (% MVIC) was assessed using repeated measures analysis of variance with Bonferroni corrections for planned pairwise comparisons. Results: Seated toe raises (11% MVIC) had the least amount of activity compared with all other exercises ( P < 0.01), followed by single-leg balance on wobble board (25% MVIC), prone ankle pumps (38% MVIC), supine plantarflexion with red elastic resistance (45% MVIC), normal gait (47% MVIC), lateral step-ups (60% MVIC), single-leg heel raises (112% MVIC), and single-leg jumping (129% MVIC). Conclusion: There is an increasing progression of EMG activity for exercises that target the triceps surae muscle complex during common exercises prescribed in an Achilles tendon rehabilitation program. Seated toe raises offer relatively low EMG activity and can be utilized as an early rehabilitative exercise. In contrast, the single-leg heel raise and single-leg jumping should be utilized only during later-stage rehabilitation. Clinical Relevance: EMG activity in the triceps surae is variable with common rehab exercises.

scholarly journals Bilateral triceps surae muscle focal myositis after a cauda equina syndrome

2021 ◽  
Author(s):  
G.R. González Toledo ◽  
H. Pérez Pérez ◽  
L. Brage Martín ◽  
V. Castro López-Tarruella
Keyword(s):  
Cauda Equina Syndrome ◽  
Cauda Equina ◽  
Triceps Surae ◽  
Triceps Surae Muscle
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