A biomechanical model for analysis of muscle force, power output and lower jaw motion in fishes

2003 ◽  
Vol 223 (3) ◽  
pp. 269-281 ◽  
Author(s):  
Mark W. Westneat
Keyword(s):  
Power Output ◽  
Muscle Force ◽  
Biomechanical Model ◽  
Lower Jaw

PECTORALIS MUSCLE FORCE AND POWER OUTPUT DURING DIFFERENT MODES OF FLIGHT IN PIGEONS (COLUMBA LIVIA)

1993 ◽  
Vol 176 (1) ◽  
pp. 31-54 ◽  
Author(s):  
K. P. Dial ◽  
A. A. Biewener
Keyword(s):  
Strain Gauge ◽  
Power Output ◽  
Muscle Force ◽  
Columba Livia ◽  
Principal Strain ◽  
Specific Power ◽  
Single Element ◽  
Pectoralis Muscle ◽  
Level Flight

In vivo measurements of pectoralis muscle force during different modes of free flight (takeoff, level flapping, landing, vertical ascending and near vertical descending flight) were obtained using a strain gauge attached to the dorsal surface of the delto-pectoral crest (DPC) of the humerus in four trained pigeons (Columba livia). In one bird, a rosette strain gauge was attached to the DPC to determine the principal axis of strain produced by tension of the pectoralis. Strain signals recorded during flight were calibrated to force based on in situ measurements of tetanic force and on direct tension applied to the muscle's insertion at the DPC. Rosette strain recordings showed that at maximal force the orientation of tensile principal strain was −15° (proximo-anterior) to the perpendicular axis of the DPC (or +75° to the longitudinal axis of the humerus), ranging from +15 to −25° to the DPC axis during the downstroke. The consistency of tensile principal strain orientation in the DPC confirms the more general use of single-element strain gauges as being a reliable method for determining in vivo pectoralis force generation. Our strain recordings show that the pectoralis begins to develop force as it is being lengthened, during the final one-third of the upstroke, and attains maximum force output while shortening during the first one-third of the downstroke. Force is sustained throughout the entire downstroke, even after the onset of the upstroke for certain flight conditions. Mean peak forces developed by the pectoralis based on measurements from 40 wingbeats for each bird (160 total) were: 24.9+/−3.1 N during takeoff, 19.7+/−2.0 N during level flight (at speeds of about 6–9 m s-1 and a wingbeat frequency of 8.6+/−0.3 Hz), 18.7+/−2.5 N during landing, 23.7+/−2.7 N during near-vertical descent, and 26.0+/−1.8 N during vertical ascending flight. These forces are considerably lower than the maximum isometric force (67 N, P0) of the muscle, ranging from 28 % (landing) to 39 % (vertical ascending) of P0. Based on estimates of muscle fiber length change determined from high- speed (200 frames s-1) light cine films taken of the animals, we calculate the mass-specific power output of the pigeon pectoralis to be 51 W kg-1 during level flight (approximately 8 m s-1), and 119 W kg-1 during takeoff from the ground. When the birds were harnessed with weighted backpacks (50 % and 100 % of body weight), the forces generated by the pectoralis did not significantly exceed those observed in unloaded birds executing vertical ascending flight. These data suggest that the range of force production by the pectoralis under these differing conditions is constrained by the force- velocity properties of the muscle operating at fairly rapid rates of shortening (4.4 fiber lengths s-1 during level flight and 6.7 fiber lengths s-1 during takeoff).

MUSCLE BULGING REDUCES MUSCLE FORCE AND LIMITS THE MAXIMAL EFFECTIVE MUSCLE SIZE

2006 ◽  
Vol 06 (03) ◽  
pp. 229-239 ◽  
Author(s):  
KARL DAGGFELDT
Keyword(s):  
Muscle Force ◽  
Muscle Length ◽  
Biomechanical Model ◽  
Muscle Performance ◽  
Muscle Size ◽  
Intramuscular Pressure ◽  
Shortening Velocity ◽  
Muscle Shortening ◽  
Force Reduction ◽  
Total Muscle

A biomechanical model was generated in order to investigate the possible mechanisms behind reductions in muscle performance due to muscle bulging. It was shown that the proportion of fiber force contributing to the total muscle force is reduced with fiber bulging and that the cause of this reduction is due to the intramuscular pressure (IMP) created by the bulging fibers. Moreover, it was established that the amount of IMP generated muscle force reduction is determined by the extent to which muscle thickening restricts muscle fibers from shortening, thereby limiting their power contribution. It was shown that bulging can set a limit to the maximal size a muscle can take without losing force and power producing capability. Possible effects, due to bulging, on maximal muscle force in relation to both muscle length and muscle shortening velocity were also demonstrated by the model.

Bite performance surfaces of three ecologically divergent Iguanidae lizards: relationships with lower jaw bones

2019 ◽  
Vol 127 (4) ◽  
pp. 810-825
Author(s):  
Monique Nouailhetas Simon ◽  
Renata Brandt ◽  
Tiana Kohlsdorf ◽  
Stevan J Arnold
Keyword(s):  
Biomechanical Model ◽  
Disruptive Selection ◽  
Head Shape ◽  
Linear Combinations ◽  
Mechanical Advantage ◽  
Jaw Bones ◽  
Correlational Selection ◽  
Lower Jaw ◽  
Linear Selection ◽  
Non Linear

Abstract Traits that interact to perform an ecologically relevant function are expected to be under multivariate non-linear selection. Using the lower jaw morphology as a biomechanical model, we test the hypothesis that lower jaw bones of lizards are subjected to stabilizing and correlational selection, associated with mechanical advantage and maximum bite force. We used three closely related tropidurine species that differ in size, head shape and microhabitat: Eurolophosaurus nanuzae, Tropidurus hispidus and Tropidurus semitaeniatus. We predicted a common pattern of correlational selection on bones that are part of in-levers or part of the out-lever of the lower jaw. The predicted pattern was found in E. nanuzae and T. hispidus, but this could not be shown to be statistically significant. For T. semitaeniatus, we found significant disruptive selection on a contrast involving the surangular, and also significant directional selection on linear combinations of traits in all species. The results indicate that the non-linear selection on lower jaw bones does not reflect an optimum to enhance mechanical advantage in all species. Divergent functional demands and specific ecological contexts of species seem relevant in shaping patterns of selection on morphology.

PECTORALIS MUSCLE FORCE AND POWER OUTPUT DURING FLIGHT IN THE STARLING

1992 ◽  
Vol 164 (1) ◽  
pp. 1-18 ◽  
Author(s):  
ANDREW A. BIEWENER ◽  
KENNETH P. DIAL ◽  
G. E. GOSLOW
Keyword(s):  
Power Output ◽  
Muscle Force ◽  
Muscle Power ◽  
Isometric Force ◽  
Attachment Site ◽  
Bone Strain ◽  
Pectoralis Muscle ◽  
Live Animal ◽  
Level Flight ◽  
Length Changes

Force recordings of the pectoralis muscle of European starlings have been made in vivo during level flight in a wind tunnel, based on bone strain recordings at the muscle's attachment site on the humerus (deltopectoral crest). This represents the first direct measurement of muscle force during activity in a live animal based on calibrated bone strain recordings. Our force measurements confirm earlier electromyographic data and show that the pectoralis begins to develop force during the final one-third of the upstroke, reaches a maximal level halfway through the downstroke, and sustains force throughout the downstroke. Peak forces generated by the pectoralis during level flight at a speed estimated to be 13.7ms−1 averaged 6.4N (28% of maximal isometric force), generating a mean mass-specific muscle power output of 104 W kg−1. Combining our data for the power output of the pectoralis muscle with data for the metabolic power of starlings flying at a similar speed yields an overall flight efficiency of 13 %. The force recordings and length changes of the muscle, based on angular displacements of the humerus, indicate that the pectoralis muscle undergoes a lengthening--shortening contraction sequence during its activation and that, in addition to lift and thrust generation, overcoming wing inertia is probably an important function of this muscle in flapping flight.

Testing of a Biomechanical Model of the Lumbar Muscle Force Distribution Using Quasi-Static Loading Exercises

1992 ◽  
Vol 114 (4) ◽  
pp. 442-449 ◽  
Author(s):  
Z. Ladin ◽  
K. M. Neff
Keyword(s):  
Muscle Force ◽  
Biomechanical Model ◽  
Design Tool ◽  
Emg Activity ◽  
Force Distribution ◽  
Lumbar Region ◽  
Erect Posture ◽  
Biomechanical Models ◽  
Lumbar Muscle ◽  
The Subject

The study of lumbar muscle force distribution in response to externally applied loads is based on the introduction of biomechanical models of the lumbar region. The evaluation of such models requires the execution of loading exercises while monitoring the EMG activity of certain lumbar muscles. This work uses muscle activity maps as the major design tool of such exercises, provided that the subject is constrained to an upright erect posture. The maps describe the predicted muscle force for a given combination of externally applied bending moments. A series of shoulder adduction exercises were designed and the EMG signals of eight lumbar muscles were measured while subjects performed the exercises. The results show good agreement between the model predictions and the EMG measurements, especially when the load and the muscle were contralateral to one another.

A review of the stem amniote Eldeceeon rolfei from the Viséan of East Kirkton, Scotland

2020 ◽  
pp. 1-20 ◽  
Author(s):  
Marcello RUTA ◽  
Jennifer A. CLACK ◽  
Timothy R. SMITHSON
Keyword(s):  
Stride Length ◽  
Muscle Force ◽  
Sister Group ◽  
Stride Frequency ◽  
Sister Group Relationship ◽  
Postcranial Skeleton ◽  
Lower Jaw ◽  
Cladistic Analyses ◽  
Lateral Margins ◽  
Large Muscle

ABSTRACT The late Viséan anthracosauroid Eldeceeon rolfei from the East Kirkton Limestone of Scotland is re-described. Information from two originally described and two newly identified specimens broadens our knowledge of this tetrapod. A detailed account of individual skull bones and a revision of key axial and appendicular features are provided, alongside the first complete reconstructions of the skull and lower jaw and a revised reconstruction of the postcranial skeleton. In comparison to Silvanerpeton, the only other anthracosauroid from East Kirkton, Eldeceeon is characterised by a proportionally wider semi-elliptical skull, comparatively smaller nostrils set farther apart, smaller and more rounded orbits, a shorter skull table with gently convex lateral margins, and a deeper suspensorium with a straight posterior margin and a small dorsal embayment. The remarkably large hind feet and elongate toes of Eldeceeon presumably represent an adaptation for attaining high locomotory speed through increased stride length and reduced stride frequency. This would necessitate great muscle force but few muscle contractions. At the beginning of a new stride cycle, repositioning the pes anteriorly and lifting the toes off the ground would require a strong and large muscle to pull the femur upward and rotate it inward and forward. It is hypothesised that such muscle might correspond to the puboischiofemoralis internus 2, which would extend along the posterior half of the vertebral column, consistent with the occurrence of long, curved ribs in the anterior half of the trunk. Using maximum parsimony and Bayesian inference, cladistic analyses of all major groups of stem amniotes retrieve a sister group relationship between Eldeceeon and Silvanerpeton, either as the most plesiomorphic stem amniote clade or as a clade immediately crownward of anthracosauroids.

scholarly journals Racing an Opponent: Alteration of Pacing, Performance, and Muscle-Force Decline but Not Rating of Perceived Exertion

2018 ◽  
Vol 13 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Marco J. Konings ◽  
Jordan Parkinson ◽  
Inge Zijdewind ◽  
Florentina J. Hettinga
Keyword(s):  
Power Output ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Muscle Force ◽  
Internal State ◽  
Rating Of Perceived Exertion ◽  
Voluntary Activation ◽  
Peak Power Output ◽  
Mean Power ◽  
Experimental Conditions

Purpose: Performing against a virtual opponent has been shown to invite a change in pacing and improve time-trial (TT) performance. This study explored how this performance improvement is established by assessing changes in pacing, neuromuscular function, and perceived exertion. Methods: After a peak-power-output test and a familiarization TT, 12 trained cyclists completed two 4-km TTs in randomized order on a Velotron cycle ergometer. TT conditions were riding alone (NO) and riding against a virtual opponent (OP). Knee-extensor performance was quantified before and directly after the TT using maximal voluntary contraction force (MVC), voluntary activation (VA), and potentiated doublet-twitch force (PT). Differences between the experimental conditions were examined using repeated-measures ANOVAs. Linear-regression analyses were conducted to associate changes in pacing to changes in MVC, VA, and PT. Results: OP was completed faster than NO (mean power output OP 289.6 ± 56.1 vs NO 272.2 ± 61.6 W; P = .020), mainly due to a faster initial pace. This was accompanied by a greater decline in MVC (MVC pre vs post −17.5% ± 12.4% vs −11.4% ± 10.9%, P = .032) and PT (PT pre vs post −23.1% ± 14.0% vs −16.2% ±11.4%, P = .041) after OP than after NO. No difference between conditions was found for VA (VA pre vs post −4.9% ± 6.7% vs −3.4% ± 5.0%, P = .274). Rating of perceived exertion did not differ between OP and NO. Conclusion: The improved performance when racing against a virtual opponent was associated with a greater decline in voluntary and evoked muscle force than riding alone, without a change in perceived exertion, highlighting the importance of human–environment interactions in addition to one’s internal state for pacing regulation and performance.

ESTIMATING MUSCLE FORCES AND KNEE JOINT TORQUE USING SURFACE ELECTROMYOGRAPHY: A MUSCULOSKELETAL BIOMECHANICAL MODEL

2017 ◽  
Vol 17 (04) ◽  
pp. 1750069 ◽  
Author(s):  
JIANGCHENG CHEN ◽  
XIAODONG ZHANG ◽  
LINXIA GU ◽  
CARL NELSON
Keyword(s):  
Knee Joint ◽  
Surface Electromyography ◽  
Neural Control ◽  
Muscle Activation ◽  
Muscle Force ◽  
Dynamic Properties ◽  
Biomechanical Model ◽  
Joint Torque ◽  
Muscle Forces ◽  
Flexion Extension

Surface electromyography (sEMG) is a useful tool for revealing the underlying musculoskeletal dynamic properties in the human body movement. In this paper, a musculoskeletal biomechanical model which relates the sEMG and knee joint torque is proposed. First, the dynamic model relating sEMG to skeletal muscle activation considering frequency and amplitude is built. Second, a muscle contraction model based on sliding-filament theory is developed to reflect the physiological structure and micro mechanical properties of the muscle. The muscle force and displacement vectors are determined and the transformation from muscle force to knee joint moment is realized, and finally a genetic algorithm-based calibration method for the Newton–Euler dynamics and overall musculoskeletal biomechanical model is put forward. Following the model calibration, the flexion/extension (FE) knee joint torque of eight subjects under different walking speeds was predicted. Results show that the forward biomechanical model can capture the general shape and timing of the joint torque, with normalized mean residual error (NMRE) of [Formula: see text]10.01%, normalized root mean square error (NRMSE) of [Formula: see text]12.39% and cross-correlation coefficient of [Formula: see text]0.926. The musculoskeletal biomechanical model proposed and validated in this work could facilitate the study of neural control and how muscle forces generate and contribute to the knee joint torque during human movement.

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