scholarly journals Distinct muscle fascicle length changes in feline medial gastrocnemius and soleus muscles during slope walking

2009 ◽  
Vol 106 (4) ◽  
pp. 1169-1180 ◽  
Author(s):  
Huub Maas ◽  
Robert J. Gregor ◽  
Emma F. Hodson-Tole ◽  
Brad J. Farrell ◽  
Boris I. Prilutsky
Keyword(s):  
Inverse Dynamics ◽  
Geometric Model ◽  
Muscle Spindles ◽  
Sensory Function ◽  
Medial Gastrocnemius ◽  
Overground Walking ◽  
Force Output ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Length Changes

On the basis of differences in physiology, e.g., histochemical properties and spindle density, and the structural design of the cat soleus (SO) and medial gastrocnemius (MG) muscles, we hypothesized that 1) fascicle length changes during overground walking would be both muscle and slope dependent, which would have implications for the muscles' force output as well as sensory function, and that 2) muscle-tendon unit (MTU) and fascicle length changes would be different, in which case MTU length could not be used as an indicator of muscle spindle strain. To test these hypotheses, we quantified muscle fascicle length changes and compared them with length changes of the whole MTU in the SO and MG during overground walking at various slopes (0, ± 25, ± 50, +75, and +100%). The SO and MG were surgically instrumented with sonomicrometry crystals and fine-wire electromyogram electrodes to measure changes in muscle fascicle length and muscle activity, respectively. MTU lengths were calculated using recorded ankle and knee joint angles and a geometric model of the hindlimb. The resultant joint moments were calculated using inverse dynamics analysis to infer muscle loading. It was found that although MTU length and velocity profiles of the SO and MG appeared similar, length changes and velocities of muscle fascicles were substantially different between the two muscles. Fascicle length changes of both SO and MG were significantly affected by slope intensity acting eccentrically in downslope walking (−25 to −50%) and concentrically in upslope walking (+25 to +100%). The differences in MTU and fascicle behaviors in both the SO and MG muscles during slope walking were explained by the three distinct features of these muscles: 1) the number of joints spanned, 2) the pennation angle, and 3) the in-series elastic component. It was further suggested that the potential role of length feedback from muscle spindles is both task and muscle dependent.

scholarly journals Automatic tracking of medial gastrocnemius fascicle length during human locomotion

2011 ◽  
Vol 111 (5) ◽  
pp. 1491-1496 ◽  
Author(s):  
Neil J. Cronin ◽  
Christopher P. Carty ◽  
Rod S. Barrett ◽  
Glen Lichtwark
Keyword(s):  
Human Error ◽  
Human Locomotion ◽  
Medial Gastrocnemius ◽  
Fascicle Length ◽  
Tracking Method ◽  
Automated Method ◽  
Lower Extremity Muscle ◽  
Muscle Fascicle ◽  
Length Changes ◽  
Level Of Agreement

During human locomotion lower extremity muscle-tendon units undergo cyclic length changes that were previously assumed to be representative of muscle fascicle length changes. Measurements in cats and humans have since revealed that muscle fascicle length changes can be uncoupled from those of the muscle-tendon unit. Ultrasonography is frequently used to estimate fascicle length changes during human locomotion. Fascicle length analysis requires time consuming manual methods that are prone to human error and experimenter bias. To bypass these limitations, we have developed an automatic fascicle tracking method based on the Lucas-Kanade optical flow algorithm with an affine optic flow extension. The aims of this study were to compare gastrocnemius fascicle length changes during locomotion using the automated and manual approaches and to determine the repeatability of the automated approach. Ultrasound was used to examine gastrocnemius fascicle lengths in eight participants walking at 4, 5, 6, and 7 km/h and jogging at 7 km/h on a treadmill. Ground reaction forces and three dimensional kinematics were recorded simultaneously. The level of agreement between methods and the repeatability of the automated method were quantified using the coefficient of multiple correlation (CMC). Regardless of speed, the level of agreement between methods was high, with overall CMC values of 0.90 ± 0.09 (95% CI: 0.86–0.95). Repeatability of the algorithm was also high, with an overall CMC of 0.88 ± 0.08 (95% CI: 0.79–0.96). The automated fascicle tracking method presented here is a robust, reliable, and time-efficient alternative to the manual analysis of muscle fascicle length during gait.

scholarly journals Muscle spindles in human tibialis anterior encode muscle fascicle length changes

2017 ◽  
Vol 117 (4) ◽  
pp. 1489-1498 ◽  
Author(s):  
James Day ◽  
Leah R. Bent ◽  
Ingvars Birznieks ◽  
Vaughan G. Macefield ◽  
Andrew G. Cresswell
Keyword(s):  
Muscle Spindle ◽  
Tibialis Anterior ◽  
Tibialis Anterior Muscle ◽  
Muscle Length ◽  
Muscle Spindles ◽  
Muscle Spindle Afferents ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Length Changes

Muscle spindles provide exquisitely sensitive proprioceptive information regarding joint position and movement. Through passively driven length changes in the muscle-tendon unit (MTU), muscle spindles detect joint rotations because of their in-parallel mechanical linkage to muscle fascicles. In human microneurography studies, muscle fascicles are assumed to follow the MTU and, as such, fascicle length is not measured in such studies. However, under certain mechanical conditions, compliant structures can act to decouple the fascicles, and, therefore, the spindles, from the MTU. Such decoupling may reduce the fidelity by which muscle spindles encode joint position and movement. The aim of the present study was to measure, for the first time, both the changes in firing of single muscle spindle afferents and changes in muscle fascicle length in vivo from the tibialis anterior muscle (TA) during passive rotations about the ankle. Unitary recordings were made from 15 muscle spindle afferents supplying TA via a microelectrode inserted into the common peroneal nerve. Ultrasonography was used to measure the length of an individual fascicle of TA. We saw a strong correlation between fascicle length and firing rate during passive ankle rotations of varying rates (0.1–0.5 Hz) and amplitudes (1–9°). In particular, we saw responses observed at relatively small changes in muscle length that highlight the sensitivity of the TA muscle to small length changes. This study is the first to measure spindle firing and fascicle dynamics in vivo and provides an experimental basis for further understanding the link between fascicle length, MTU length, and spindle firing patterns. NEW & NOTEWORTHY Muscle spindles are exquisitely sensitive to changes in muscle length, but recordings from human muscle spindle afferents are usually correlated with joint angle rather than muscle fascicle length. In this study, we monitored both muscle fascicle length and spindle firing from the human tibialis anterior muscle in vivo. Our findings are the first to measure these signals in vivo and provide an experimental basis for exploring this link further.

Gastrocnemius Fascicle Length Changes with Two-Joint Passive Movements

2008 ◽  
Vol 24 (3) ◽  
pp. 252-261 ◽  
Author(s):  
Timothy J. Brindle ◽  
Jeri L. Miller ◽  
Maria K. Lebiedowska ◽  
Steven J. Stanhope
Keyword(s):  
Kinematic Model ◽  
Medial Gastrocnemius ◽  
Ultrasound Images ◽  
Fascicle Length ◽  
Knee Motion ◽  
Lateral Gastrocnemius ◽  
Ankle Motion ◽  
Muscle Fascicle ◽  
Length Changes ◽  
Passive Movements

Predicting muscle fascicle length changes during passive movements may lead to a better understanding of muscle function. The purpose of this study was to experimentally compare fascicle length changes in the gastrocnemius during two-joint passive movements with a previously derived kinematic model based on anatomical measures from a cadaver. The ratio of passive ankle to knee motion was manipulated to generate medial gastrocnemius fascicle elongation and lateral gastrocnemius fascicle shortening. Ultrasound images from both heads of the gastrocnemius fascicles were acquired at 10° knee flexion increments and compared with this kinematic model. Our results suggest that the two-joint kinematic model from which we originally based our knee and ankle movements did not adequately reflect fascicle length changes during any of the movement conditions in this study. From our data, we propose that for every degree of ankle motion the medial and lateral gastrocnemius changes 0.42 mm and 0.96 mm, respectively, whereas changes of 0.14 mm and 0.22 mm are observed for the medial and lateral gastrocnemius, respectively, during knee movements.

scholarly journals Gastrocnemius muscle fascicle behavior during stair negotiation in humans

2007 ◽  
Vol 102 (4) ◽  
pp. 1618-1623 ◽  
Author(s):  
M. Spanjaard ◽  
N. D. Reeves ◽  
J. H. van Dieën ◽  
V. Baltzopoulos ◽  
C. N. Maganaris
Keyword(s):  
Joint Kinematics ◽  
Lower Limbs ◽  
Medial Gastrocnemius ◽  
Fascicle Length ◽  
Stair Ascent ◽  
Muscle Fascicle ◽  
Stair Negotiation ◽  
Knee Joint Kinematics ◽  
Length Changes ◽  
Muscle Fascicles

The aim of the present study was to establish the behavior of human medial gastrocnemius (GM) muscle fascicles during stair negotiation. Ten healthy male subjects performed normal stair ascent and descent at their own comfortable speed on a standard-dimension four-step staircase with embedded force platforms in each step. Kinematic, kinetic, and electromyographic data of the lower limbs were collected. Real-time ultrasound scanning was used to determine GM muscle fascicle length changes. Musculotendon complex (MTC) length changes were estimated from ankle and knee joint kinematics. The GM muscle was mainly active during the push-off phase in stair ascent, and the muscle fascicles contracted nearly isometrically. The GM muscle was mainly active during the touch-down phase of stair descent where the MTC was lengthened; however, the GM muscle fascicles shortened by ∼7 mm. These findings show that the behavior and function of GM muscle fascicles in stair negotiation is different from that expected on the basis of length changes of the MTC as derived from joint kinematics.

Plantar Flexor Muscle Architecture Changes as a Result of Eccentric Exercise in Patients With Achilles Tendinosis

2014 ◽  
Vol 7 (6) ◽  
pp. 460-465 ◽  
Author(s):  
Matthew T. Crill ◽  
Gregory Berlet ◽  
Christopher Hyer
Keyword(s):  
Case Series ◽  
Muscle Architecture ◽  
Medial Gastrocnemius ◽  
Eccentric Training ◽  
Plantar Flexors ◽  
Flexor Muscle ◽  
Fascicle Length ◽  
Achilles Tendinosis ◽  
Muscle Fascicle ◽  
Maximal Load

Eccentric training for Achilles tendinosis (AT) has been reported to significantly improve patient symptoms. There has been no biomechanical explanation on the mechanism for specific rehabilitation technique. The purpose of this study was to determine changes in muscle architecture that occurred as a result of Achilles tendinosis injury and a subsequent eccentric rehabilitation program. Twenty-five patients (age, 53.3 ± 17.5 years) diagnosed with AT participated in 6 weeks of rehabilitation. Specific exercises for the ankle plantar flexors consisted of maximal load eccentric muscle action using 3 sets of 15 repetitions. Patients also completed a protocol for AT, which consisting of traditional rehabilitation. Medial gastrocnemius (GM) and lateral gastrocnemius (GL) muscle fascicle length and thickness were measured with ultrasound at 2-week intervals from initial treatment day to the end of 6 weeks of rehabilitation. Medial gastrocnemius fascicle length increased (45.1 ± 10.5 mm to 51.4 ± 10.5 mm; P = .22) between the initial day of rehabilitation and after 6 weeks of rehabilitation. But, GM thickness (16.3 ± 3.5 mm to 16.8 ± 2.0 mm), GL fascicle length (47.2 ± 10.0 mm to 47.1 ± 7.4 mm), and GL thickness (14.9 ± 5.2 mm to 14.4 ± 2.7 mm) did not change as a result of rehabilitation. A 6-week eccentric-biased exercise increased the GM muscle fascicle length by 12%, but GM thickness, GL fascicle length, and GL thickness did not change as a result of rehabilitation. Eccentric training for the treatment of AT is well recognized, but the mechanism of action has not been previously reported. A 6-week eccentric training protocol increased the GM muscle fascicle length by 12%, and this correlated with improvement in a validated patient outcome scoring system. Further study is warranted to determine a predictive relationship between improvement of GM fascicle length and outcome scores. Levels of Evidence: Therapeutic, Level IV: Case series

scholarly journals Ultrasound Structural Changes in Triceps Surae After a 1-Year Daily Self-stretch Program: A Prospective Randomized Controlled Trial in Chronic Hemiparesis

2019 ◽  
Vol 33 (4) ◽  
pp. 245-259 ◽  
Author(s):  
Maud Pradines ◽  
Mouna Ghedira ◽  
Raphaël Portero ◽  
Ingrid Masson ◽  
Christina Marciniak ◽  
...  
Keyword(s):  
Structural Changes ◽  
Controlled Trial ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Plantar Flexors ◽  
Fascicle Length ◽  
Rehabilitation Programs ◽  
Lower Limb Muscles ◽  
Muscle Fascicle ◽  
Prospective Randomized Controlled Trial

Introduction. The effects of long-term stretching (>6 months) in hemiparesis are unknown. This prospective, randomized, single-blind controlled trial compared changes in architectural and clinical parameters in plantar flexors of individuals with chronic hemiparesis following a 1-year guided self-stretch program, compared with conventional rehabilitation alone. Methods. Adults with chronic stroke-induced hemiparesis (time since lesion >1 year) were randomized into 1 of 2, 1-year rehabilitation programs: conventional therapy (CONV) supplemented with the Guided Self-rehabilitation Contract (GSC) program, or CONV alone. In the GSC group, specific lower limb muscles, including plantar flexors, were identified for a diary-based treatment utilizing daily, high-load, home self-stretching. Blinded assessments included (1) ultrasonographic measurements of soleus and medial gastrocnemius (MG) fascicle length and thickness, with change in soleus fascicle length as primary outcome; (2) maximum passive muscle extensibility (XV1, Tardieu Scale); (3) 10-m maximal barefoot ambulation speed. Results. In all, 23 individuals (10 women; mean age [SD], 56 [±12] years; time since lesion, 9 [±8] years) were randomized into either the CONV (n = 11) or GSC (n = 12) group. After 1 year, all significant between-group differences favored the GSC group: soleus fascicle length, +18.1mm [9.3; 29.9]; MG fascicle length, +6.3mm [3.5; 9.1]; soleus thickness, +4.8mm [3.0; 7.7]; XV1 soleus, +4.1° [3.1; 7.2]; XV1 gastrocnemius, +7.0° [2.1; 11.9]; and ambulation speed, +0.07m/s [+0.02; +0.16]. Conclusions. In chronic hemiparesis, daily self-stretch of the soleus and gastrocnemius over 1 year using GSC combined with conventional rehabilitation increased muscle fascicle length, extensibility, and ambulation speed more than conventional rehabilitation alone.

scholarly journals Functional properties of human muscle spindles

2018 ◽  
Vol 120 (2) ◽  
pp. 452-467 ◽  
Author(s):  
Vaughan G. Macefield ◽  
Thomas P. Knellwolf
Keyword(s):  
Functional Properties ◽  
Somatosensory System ◽  
Muscle Length ◽  
Muscle Spindles ◽  
Human Muscle ◽  
Independent Control ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
The Central Nervous System ◽  
Human Muscles

Muscle spindles are ubiquitous encapsulated mechanoreceptors found in most mammalian muscles. There are two types of endings, primary and secondary, and both are sensitive to changes in muscle length and velocity, with the primary endings having a greater dynamic sensitivity. Unlike other mechanoreceptors in the somatosensory system, muscle spindles are unique in possessing motor innervation, via γ-motoneurons (fusimotor neurons), that control their sensitivity to stretch. Much of what we know about human muscles spindles comes from studying the behavior of their afferents via intraneural microelectrodes (microneurography) inserted into accessible peripheral nerves. We review the functional properties of human muscle spindles, comparing and contrasting with what we know about the functions of muscle spindles studied in experimental animals. As in the cat, many human muscle spindles possess a background discharge that is related to the degree of muscle stretch, but mean firing rates are much lower (~10 Hz). They can faithfully encode changes in muscle fascicle length in passive conditions, but higher level extraction of information is required by the central nervous system to measure changes in muscle length during muscle contraction. Moreover, although there is some evidence supporting independent control of human muscle spindles via fusimotor neurons, any effects are modest compared with the clearly independent control of fusimotor neurons observed in the cat.

scholarly journals Information from dynamic length changes improves reliability of static ultrasound fascicle length measurements

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4164 ◽  
Author(s):  
Jeroen Aeles ◽  
Glen A. Lichtwark ◽  
Sietske Lenchant ◽  
Liesbeth Vanlommel ◽  
Tijs Delabastita ◽  
...  
Keyword(s):  
Length Change ◽  
Medial Gastrocnemius ◽  
Ultrasound Images ◽  
Initial Image ◽  
Fascicle Length ◽  
Mean Squared Errors ◽  
Length Measurements ◽  
Length Changes ◽  
Dynamic Length ◽  
Effectiveness Studies

PurposeVarious strategies for improving reliability of fascicle identification on ultrasound images are used in practice, yet these strategies are untested for effectiveness. Studies suggest that the largest part of differences between fascicle lengths on one image are attributed to the error on the initial image. In this study, we compared reliability results between different strategies.MethodsStatic single-image recordings and image sequence recordings during passive ankle rotations of the medial gastrocnemius were collected. Images were tracked by three different raters. We compared results from uninformed fascicle identification (UFI) and results with information from dynamic length changes, or data-informed tracking (DIT). A second test compared tracking of image sequences of either fascicle shortening (initial-long condition) or fascicle lengthening (initial-short condition).ResultsIntra-class correlations (ICC) were higher for the DIT compared to the UFI, yet yielded similar standard error of measurement (SEM) values. Between the initial-long and initial-short conditions, similar ICC values, coefficients of multiple determination, mean squared errors, offset-corrected mean squared errors and fascicle length change values were found for the DIT, yet with higher SEM values and greater absolute fascicle length differences between raters on the first image in the initial-long condition and on the final image in the initial-short condition.ConclusionsDIT improves reliability of fascicle length measurements, without lower SEM values. Fascicle length on the initial image has no effect on subsequent tracking results. Fascicles on ultrasound images should be identified by a single rater and care should be taken when comparing absolute fascicle lengths between studies.

scholarly journals Machine Learning to Extract Muscle Fascicle Length Changes from Dynamic Ultrasound Images in Real-Time

2021 ◽  
Author(s):  
Luis G. Rosa ◽  
Jonathan S. Zia ◽  
Omer T. Inan ◽  
Gregory S. Sawicki
Keyword(s):  
Machine Learning ◽  
Real Time ◽  
Muscle Length ◽  
Ground Truth ◽  
Length Change ◽  
Fascicle Length ◽  
Automated Tracking ◽  
Direct Training ◽  
Muscle Fascicle ◽  
Length Changes

AbstractBackground and objectiveDynamic muscle fascicle length measurements through B-mode ultrasound have become popular for the non-invasive physiological insights they provide regarding musculoskeletal structure-function. However, current practices typically require time consuming post-processing to track muscle length changes from B-mode images. A real-time measurement tool would not only save processing time but would also help pave the way toward closed-loop applications based on feedback signals driven by in vivo muscle length change patterns. In this paper, we benchmark an approach that combines traditional machine learning (ML) models with B-mode ultrasound recordings to obtain muscle fascicle length changes in real-time. To gauge the utility of this framework for ‘in-the-loop’ applications, we evaluate accuracy of the extracted muscle length change signals against time-series’ derived from a standard, post-hoc automated tracking algorithm.MethodsWe collected B-mode ultrasound data from the soleus muscle of six participants performing five defined ankle motion tasks: (a) seated, constrained ankle plantarflexion, (b) seated, free ankle dorsi/plantarflexion, (c) weight-bearing, calf raises (d) walking, and then a (e) mix. We trained machine learning (ML) models by pairing muscle fascicle lengths obtained from standardized automated tracking software (UltraTrack) with the respective B-mode ultrasound image input to the tracker, frame-by-frame. Then we conducted hyperparameter optimizations for five different ML models using a grid search to find the best performing parameters for a combination of high correlation and low RMSE between ML and UltraTrack processed muscle fascicle length trajectories. Finally, using the global best model/hyperparameter settings, we comprehensively evaluated training-testing outcomes within subject (i.e., train and test on same subject), cross subject (i.e., train on one subject, test on another) and within/direct cross task (i.e., train and test on same subject, but different task).ResultsSupport vector machine (SVM) was the best performing model with an average r = 0.70 ±0.34 and average RMSE = 2.86 ±2.55 mm across all direct training conditions and average r = 0.65 ±0.35 and average RMSE = 3.28 ±2.64 mm when optimized for all cross-participant conditions. Comparisons between ML vs. UltraTrack (i.e., ground truth) tracked muscle fascicle length versus time data indicated that ML tracked images reliably capture the salient qualitative features in ground truth length change data, even when correlation values are on the lower end. Furthermore, in the direct training, calf raises condition, which is most comparable to previous studies validating automated tracking performance during isolated contractions on a dynamometer, our ML approach yielded 0.90 average correlation, in line with other accepted tracking methods in the field.ConclusionsBy combining B-mode ultrasound and classical ML models, we demonstrate it is possible to achieve real-time tracking of human soleus muscle fascicles across a number of functionally relevant contractile conditions. This novel sensing modality paves the way for muscle physiology in-the-loop applications that could be used to modify gait via biofeedback or unlock novel wearable device control techniques that could enable restored or augmented locomotion performance.

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