Muscle Physiology - Science topic

There are many conditions, a muscle-tendon-complex can operate on. The force-length relation is only one description, let's say first order. There is the force-velocity relation, too, let's say second order. On top of that, passive tissue like tendon (in serial to fibres) and in parallel to the fibres (titin) can be charged, for example in wallaby hopping (Biewener) or some pre charged motions like catapulting a tongue (de Groot, J. H. & van Leeuwen, J. L. Evidence for an elastic projection mechanism in the chameleon tongue Proceedings. Biological sciences / The Royal Society, 2004, 271, 761-70). In summary, external conditions are of interest and the possible charge (stretch) of passive tissue.

We have been measuring human muscle forces during orthopaedic surgery, directly at their tendon and as a function of joint angle after stimulating them. Hence, we obtain muscle force-joint able characteristics, from which muscle stiffness can be determined in active state. We also measure relevant anthropometrics before surgery, including circumference of the limb and tendon cross-sectional area if relevant. One finding which is very striking is that human muscle forces vary a lot from participant to participant despite their similar conditions. One aim we have is to see if such pre-surgery anthropometrics are good metrics to characterise the target muscle. However, there is almost never a correlation between e.g., the peak force and those metrics. In one particular study (which is attached), we looked to see if tendon stress instead of tendon force can remove the variability. In order to achieve that, we calculated tendon cross-sectional areas of the participants and determined the stress as force/cross-sectional area. This did limit some of the variability but did not eliminate it. We have been measuring forces of spastic hamstring muscles of cerebral palsy patients to characterise the pathological knee condition. However, such anthropometrics and the actual muscle force do not seem to correlate. I will attach one recent example of such intraoperative CP work as well.

I mean when someone consumes food with antioxidants, how does it affect muscle hypertrophy?

There are several muscle onset detection algorithms (Teager–Kaiser energy operator, fuzzy entropy etc.). You can use one of them to determine the first sample of your fixed window.

In my opinion, if you select your windows manually, your experiment will be less reproducible.

Not, it was not the only paper about that cuestion. You need to search for the papers from Steve Nissen. He starts to study HMB suplementation from models in animals and in 1996 he published a interesting paper with his use in sports. On other study he shows that 3 g is better than 1.5 g by day, then most of the studies start to use 3 g. 

The general rule of thought is that muscles hypertrophy/atrophy by increasing/decreasing fiber diameter and not by changing fiber number. However, there is some evidence for fiber number changing, mainly under extreme loading/unloading conditions. Fiber diameter increases/decreases by adding/degrading myofibrils in parallel to the existing ones. Regarding your last question, I would think that the amount of contractile protein per sarcomere would stay constant and not change with training/detraining. I am somewhat guessing on this because I have never heard of sarcomeres or myofibrils changing in size.

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Hi Lu,

we normaly freshly embedd muscle into OCT and snap freeze in liquid nitrogen for 10-13 seconds in relation to the muscle size. You must play attention to well dry muscle tissue before embedding.

Good luck

This is a very rare variant of m.biceps brachii. It should not be called "triceps" because it will cause some confusion. M. triceps brachii is an extensor of the elbow. 

Muscular fatigue is a multifaceted phenomenon that comprises failure at one or more of the sites along the chain of actions that leads to muscular contraction. It can be classified as central or peripheral on the basis of the location of the site of fatigue.

Dear Gregory S Cantrell

perhaps the (partly older) literature can help - at least to avoid to reinvent the wheel:

1: Squintani G, Donato F, Turri M, Deotto L, Teatini F, Moretto G, Erro R.

Cortical and spinal excitability in patients with multiple sclerosis and

spasticity after oromucosal cannabinoid spray. J Neurol Sci. 2016 Nov

15;370:263-268. doi: 10.1016/j.jns.2016.09.054. PubMed PMID: 27772772.

2: Ayromlou H, Mohammad-Khanli H, Yazdchi-Marandi M, Rikhtegar R, Zarrintan S, Golzari SE, Ghabili K. Electrodiagnostic evaluation of peripheral nervous system changes in patients with multiple sclerosis. Malays J Med Sci. 2013

Jul;20(4):32-8. PubMed PMID: 24043994; PubMed Central PMCID: PMC3773350.

3: Stein RB, Everaert DG, Roy FD, Chong S, Soleimani M. Facilitation of

corticospinal connections in able-bodied people and people with central nervous

system disorders using eight interventions. J Clin Neurophysiol. 2013

Feb;30(1):66-78. doi: 10.1097/WNP.0b013e31827ed6bd. PubMed PMID: 23377445.

4: Sosnoff JJ, Motl RW. Effect of acute unloaded arm versus leg cycling exercise

on the soleus H-reflex in adults with multiple sclerosis. Neurosci Lett. 2010 Aug

2;479(3):307-11. doi: 10.1016/j.neulet.2010.05.086. PubMed PMID: 20570604.

5: Motl RW, Snook EM, Hinkle ML, McAuley E. Effect of acute leg cycling on the

soleus H-reflex and modified Ashworth scale scores in individuals with multiple

sclerosis. Neurosci Lett. 2006 Oct 9;406(3):289-92. PubMed PMID: 16916583.

6: Magistris MR, Rösler KM, Truffert A, Landis T, Hess CW. A clinical study of

motor evoked potentials using a triple stimulation technique. Brain. 1999 Feb;122

( Pt 2):265-79. PubMed PMID: 10071055.

7: Nielsen J, Petersen N, Crone C. Changes in transmission across synapses of Ia afferents in spastic patients. Brain. 1995 Aug;118 ( Pt 4):995-1004. PubMed PMID: 7655894.

8: Sinkjaer T, Toft E, Hansen HJ. H-reflex modulation during gait in multiple

sclerosis patients with spasticity. Acta Neurol Scand. 1995 Apr;91(4):239-46.

PubMed PMID: 7625147.

9: Toft E, Sinkjaer T. H-reflex changes during contractions of the ankle

extensors in spastic patients. Acta Neurol Scand. 1993 Nov;88(5):327-33. PubMed PMID: 8296530.

10: Feeney DM, Gold GN. Chronic dorsal column stimulation: effects on H reflex

and symptoms in a patient with multiple sclerosis. Neurosurgery. 1980

May;6(5):564-6. PubMed PMID: 6968046.

11: Illis LS, Oygar AE, Sedgwick EM, Awadalla MA. Dorsal-column stimulation in

the rehabilitation of patients with multiple sclerosis. Lancet. 1976 Jun

26;1(7974):1383-6. PubMed PMID: 59019.

Robert Stehle gave an excellent explanation for your findings.

It is possible to prevent myofibrils from over-contracting by slight cross-linking of the actin to myosin (Biochemistry. 1993 Jul 20;32(28):7255-63. A structural and kinetic study on myofibrils prevented from shortening by chemical cross-linking. Herrmann C1, Sleep J, Chaussepied P, Travers F, Barman T.) which will allow you to measure something like the 'true' MgATPase rate under quasi isometric conditions.

The phosphate assay is OK, but it may be easier to use a linked assay in a spectrophotometer cuvette using pyruvate kinase and Phosphoenol pyruvate to replenish the ATP using the ADP produced by the myofibrils. Lactate dehydrogenase in the solution turns pyruvate, the product of the previous reaction, into lactate. The lactate dehydrogenase causes oxidation of NADH to NAD+ which can be detected continuously at 340 nm in a spectrophotometer or by fluorescence. The rate of absorption change is proportional to the ATPase. The assay works well at room temperature. This assay is insensitive to Pi contamination, so this is a real advantage. Look up 'linked-assay, ATP and NAD'. There are plenty of publications giving the required conditions etc.

As Richard Lieber says, contractility is not the same as the ATPase rate.

If the subject is a fully trained stamina athlete such as a long distance runner, he/she may have cardiac hypertrophy that I regard as a pathological condition, but my colleagues above may consider physiological!

Peter,

I have many years of experience.  Can I help you?  RE Garfield

If the Bouin's fixation is not necessary for your staining procedure, the problems you got might  be solved nicely. However, there are several reasons why parts of skeletal muscles shrunk frequently. To keep adhesion on slide glasses, what kind of liquid did you use for coating slide glasses before staining ? The adhesion of frozen sections is important to get good results. T.K.

Dear Shafagat,

Thank you so much for your information. Actually, I already know these links, but I don't know where could I buy the T-clips.It is said only a small company has that product, while I am not sure which company it is.

Sincerely,

Gaoyan

Not to be self serving, but we ran MHC distribution on human limbs along with collagen and titin isoforms.  Bottom line is that humans are more like elephants than mice.  Check this out:

J Exp Biol. 2012 Aug 1;215(Pt 15):2551-9. doi: 10.1242/jeb.069385.

Human skeletal muscle biochemical diversity.

Tirrell TF1, Cook MS, Carr JA, Lin E, Ward SR, Lieber RL.

I know that this might sound a little weird, but try to check pelvic floor on the opposite side. in many cases I treat pelvic floor issues, mandible and relevant muscles react in compensation. look especially for opposite piriformis m. (but - the "internal" part - meaning: palpated vaginally or analy - depends on patient's sex)

Dear Peggy we are practicing pudendal  block for operative delivery only   

Dear Kaniaw,

The following publication entitled " The Loss of Skeletal Muscle Strength, Mass, and Quality in Older Adults: The Health, Aging and Body Composition Study" by Bret H. Goodpaster et al. published in J Gerontol A Biol Sci Med Sci (2006) 61 (10): 1059-1064 describes a study conducted on 1880 older adults for three years and the methods used to determine muscle loss or/and decline:

Background. The loss of muscle mass is considered to be a major determinant of strength loss in aging. However, large-scale longitudinal studies examining the association between the loss of mass and strength in older adults are lacking.

Results. Both men and women lost strength, with men losing almost twice as much strength as women. Blacks lost about 28% more strength than did whites. Annualized rates of leg strength decline (3.4% in white men, 4.1% in black men, 2.6% in white women, and 3.0% in black women) were about three times greater than the rates of loss of leg lean mass (∼1% per year). The loss of lean mass, as well as higher baseline strength, lower baseline leg lean mass, and older age, was independently associated with strength decline in both men and women. However, gain of lean mass was not accompanied by strength maintenance or gain (ß coefficients; men, −0.48 ± 4.61, p =.92, women, −1.68 ± 3.57, p =.64).

Conclusions. Although the loss of muscle mass is associated with the decline in strength in older adults, this strength decline is much more rapid than the concomitant loss of muscle mass, suggesting a decline in muscle quality. Moreover, maintaining or gaining muscle mass does not prevent aging-associated declines in muscle strength.

In addition the following link contains a number of studies on mechanisms and countermeasures of muscle mass decline  in aging and neuromuscular disorders:

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4821223/

Finally, the following is a review article entitled "Human neuromuscular structure and function in old age: A brief review " by Power et al. published in Journal of Sport and Health Science Volume 2, Issue 4, December 2013, Pages 215–226 which focuses on motor unit loss associated with natural adult aging, age-related fatigability, and the age-related differences in strength across contractile muscle actions:

Natural adult aging is associated with many functional impairments of the human neuromuscular system. One of the more observable alterations is the loss of contractile muscle mass, termed sarcopenia. The loss of muscle mass occurs primarily due to a progressive loss of viable motor units, and accompanying atrophy of remaining muscle fibers. Not only does the loss of muscle mass contribute to impaired function in old age, but alterations in fiber type and myosin heavy chain isoform expression also contribute to weaker, slower, and less powerful contracting muscles. This review will focus on motor unit loss associated with natural adult aging, age-related fatigability, and the age-related differences in strength across contractile muscle actions.

Hoping this will be helpful,

Rafik

Dear Shakil,

that's an interesting topic. What kind of research are you thinking about?

As my previous colleagues already said, you should define the condition of shortened lats. How do you test for this? You con probably find some help in the work by Shirley Sahrmann and by Kendall& Kendall (Muscle testing and function). LBP due to tight and shortened fascia thoracolumbalis and this again due to a short lats, that's quite tricky to show. You may think of intervening with a lats stretch (which has to be addressed specifically) compared to stretching of other muscles which also attache into the fascia thoracolumbalis.

Good luck for that study, I'm already interested in your methods and results

Markus

Here is a paper that our group recently put out on estimating thigh and leg muscle mass with simple circumference and skin fold measures.  Despite being such a simple measurement, it shows very good agreement with values assessed with MRI. Unfortunately, it is only for the lower limb. 

Hi Marcelo,

There is many reports out there. Here are some recent papers:

Age-Related Changes in Dynamic Postural Control and Attentional Demands are Minimally Affected by Local Muscle Fatigue http://www.ncbi.nlm.nih.gov/pubmed/26834626

Acute effects of muscle fatigue on anticipatory and reactive postural control in older individuals: a systematic review of the evidence http://www.ncbi.nlm.nih.gov/pubmed/24978932

Biomechanical reorganisation of stepping initiation during acute dorsiflexor fatigue http://www.ncbi.nlm.nih.gov/pubmed/21605984

Impact of ankle muscle fatigue and recovery on the anticipatory postural adjustments to externally initiated perturbations in dynamic postural control http://www.ncbi.nlm.nih.gov/pubmed/23111432

Those a few recent studies, and you can go from there to access many more.

Hope this helps. Norbert

dear Parinyathip Thongduang

ihope the following site help you

best regards hamdy

Hello Diego. You can check this papers for a actual point of view about the topic (Also the example of Gilles de la Tourette Syndrome):

-Larsman, P., Kadefors, R., & Sandsjö, L. (2013). Psychosocial work conditions, perceived stress, perceived muscular tension, and neck/shoulder symptoms among medical secretaries. International archives of occupational and environmental health, 86(1), 57-63.

-Nielson, K. A., Wulff, L. L., & Arentsen, T. J. (2014). Muscle tension induced after learning enhances long-term narrative and visual memory in healthy older adults. Neurobiology of learning and memory, 109, 144-150.

-Spencer, M. L. (2015). Muscle Tension Dysphonia: A Rationale for Symptomatic Subtypes, Expedited Treatment, and Increased Therapy Compliance. SIG 3 Perspectives on Voice and Voice Disorders, 25(1), 5-15.

-Burns, J. W., Gerhart, J. I., Bruehl, S., Peterson, K. M., Smith, D. A., Porter, L. S., ... & Keefe, F. J. (2015). Anger arousal and behavioral anger regulation in everyday life among patients with chronic low back pain: Relationships to patient pain and function. Health Psychology, 34(5), 547.

I hope this info be useful in some way to your work.

Bests, David 

Dear Saeed,

The following publications describe a method to record EMG under water:

1-

Electromyogr Clin Neurophysiol. 2009 Mar-Apr;49(2-3):103-8.

A novel signal processing method using system identification for underwater surface electromyography.

Uehara S1, Muraoka Y, Tanabe S, Ota T, Kimura A.

Author information

 

Abstract

PURPOSE:

Currently, to record underwater surface electromyography (EMG), electrodes are covered with waterproof tape. For short-term measurement, waterproof tape prevents electrical leakage. However, during long-term measurement, water or sweat can contact the electrodes, changing the measurement conditions and gradually affecting the EMG data. The purpose of present study was to devise a novel method for prolonged underwater EMG recording, which estimate dry-land EMG from underwater EMG recorded by non-waterproofed electrodes using system identification techniques.

METHOD:

One healthy male participated in this study. System identification was used to convert underwater EMG signals to the estimated dry-land signals. Transfer functions were derived using two pairs of surface recording electrodes on the same muscle in parallel. System input was the EMG recorded using non-waterproofed electrodes; the output was the signal recorded underwater using waterproofed electrodes (supposed to be the same as dry-land signals). To examine the validity of the present method, three experiments were conducted.

RESULT:

There was a high positive correlation between the estimated dry-land EMG based on the non-waterproofed electrodes and the EMG obtained using waterproofed electrodes. To test the validity of long-term recording using the novel method, the estimated dry-land EMG signals were measured during 30 minutes of underwater stepping and were stable.

CONCLUSION:

The novel method using non-waterproofed electrodes with system identification techniques eliminated the effect of changes in measurement conditions and appears effective for long-term, underwater surface EMG recording.

2-Journal of Neuroscience Methods 134 (2004) 37–43

A method for positioning electrodes during surface EMG

recordings in lower limb muscles

A. Rainoldi a,b,∗, G. Melchiorri b,c, I. Caruso b,c

a Electronic Department, Bioengineering Center, Polytechnic of Turin, C.so Duca degli Abruzzi, 24. 10129 Torino, Italy b Physical Medicine and Rehabilitation, University of Tor Vergata, Rome, Italy c Don Gnocchi Foundation—Onlus, Rome, Italy

Received 4 July 2003; received in revised form 24 October 2003; accepted 27 October 2003

Abstract

Purpose: The aim of this work is to provide information about the degree of inter-subject uniformity of location of innervation zone

(IZ) in 13 superficial muscles of the lower limb. The availability of such information will allow researchers to standardize and optimize

their electrode positioning procedure and to obtain accurate and repeatable estimates of surface electromyography (sEMG) signal amplitude,

spectral variables and muscle fiber conduction velocity. Methods: Surface EMG signals from gluteus maximus, gluteus medius, tensor faciae

latae, biceps femoris, semitendinosus, vastus medialis obliquus, vastus lateralis, rectus femoris, tibialis anterior, peroneus longus, soleus,

gastrocnemius medialis and lateralis muscles of ten healthy male subjects aged between 25 and 34 years (average = 29.2 years, S.D.= 2.5

years) were recorded to assess individual IZ location and signal quality. Results: Tensor faciae latae, biceps femoris, semitendinosus, vastus

lateralis, gastrocnemius medialis and lateralis showed a high level of both signal quality and IZ location uniformity. In contrast, rectus femoris,

gluteus medius and peroneus longus were found to show poor results for both indexes. Gluteus maximus, vastus medialis obliquus and tibialis

anterior were found to show high signal quality but low IZ location uniformity. Finally, soleus muscle was found to show low signal quality

but high IZ location uniformity. Conclusions: This study identifies optimal electrode sites for muscles in the lower extremity by providing

a standard landmarking technique for the localization of the IZ of each muscle so that surface EMG electrodes can be properly positioned

between the IZ and a tendon.

© 2003 Elsevier B.V. All rights reserved.

Keywords: Electromyography; Electrode positioning; Lower limb muscles; Innervation zone; EMG variables; Standardization

3- Monopolar electromyographic signals recorded by a current amplifier in air and under water without insulation

ARTICLE in JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY 24(6) · SEPTEMBER 2014 

ABSTRACT

It was recently proposed that one could use signal current instead of voltage to collect surface electromyography (EMG). With EMG-current, the electrodes remain at the ground potential, thereby eliminating lateral currents. The purpose of this study was to determine whether EMGcurrents can be recorded in Tap and Salt water, as well as in air, without electrically shielding the electrodes. It was hypothesized that signals would display consistent information between experimental conditions regarding muscle responses to changes in contraction effort. EMG-currents were recorded from the flexor digitorum muscles as participant’s squeezed a pre-inflated blood pressure cuff bladder in each experimental condition at standardized efforts. EMG-current measurements performed underwater showed no loss of signal amplitude when compared to measurements made in air, although some differences in amplitude and spectral components were observed between conditions. However, signal amplitudes and frequencies displayed consistent behavior across contraction effort levels, irrespective of the experimental condition. This new method demonstrates that information regarding muscle activity is comparable between wet and dry conditions when using EMG-current. Considering the difficulties imposed by the need to waterproof traditional bipolar EMG electrodes when underwater, this new methodology is tremendously promising for assessments of muscular function in aquatic environments.

Hoping this will be helpful,

Rafik

1. Striated muscle.

2 Simple columnar epithelium of the small intestine, probably the villus.

3. Mucous acini and striated duct, could be sublingual salivary gland.

4. Spongy, or trabecular bone.

5. Striated muscle.

You have to respect the Nyquist rate to avoid aliasing. As Flavio Castro said the sampling frequency must be, at least, twice the higher expected frequency of the signal. If you have an electromyography instrument with a sampling frequency lower than 2000 Hz, I strongly suggest that you collect data to make a pilot study in an EMG device capable of 2000Hz of sample rate and then apply a Fast Fourier Transform. You can analyse the power spectral density of the signal and determine the minimum frequency that you will need to avoid aliasing. After that maybe will be possible to use a lower sample rate than the usual 2000Hz.

It really depends on what question you are trying to address.  You must be clear that, given the method, you could be measuring muscle-tendon unit length, muscle belly length, muscle fascicle length, muscle sarcomere length or some combination of them.  If you're just trying to establish a valid method, it may not matter.  Sorry I can't provide more information without knowing what you want to do.  

Dear Antonio,

I dont know any specific references, but I would recommend you to check work from Simon Gandevia from UNSW, Sydney Australia. He and his collegues have 100s of electrophysiological studies in humans. If you go through their papers you may find alot of usuful information.

Best wishes,

Refik

Hi Selva

If you want to make sense of these, you will need to carefully explain the experiment, including: which muscle, electrode positioning, load level (fraction of maximal), duration of the exercise, level of pain felt by the volunteer, recording of the torque generated, details of the subjects, and more. My suggestion is that look at the SENIAM guildlines for this. If you are unsure, you may also see one of my pubs on this topic - in IEEE TNSRE in 2012.

Remember- the association of spectrum and fatigue is known, but weak. 

All the best

Thanks a lot!!! Thats very helpful. Happy New Year!

This is a very interesting question. Melatonin has anti-inflammatory effects in different situations (see our review Mauriz et al, 2013). In aging, melatonin has anti-oxidative and anti-apoptotic effects in liver (see our papers Mauriz et al 2007, and Molpeceres et al 2007). Moreover, in exercised aging animals changes in AMK and GLUT have been described by Mendes et al (2013).

Thanks for the reference! 

Try this paper: Lovell GA, Blanch PD, Barnes CJ. EMG of the hip adductor muscles in six clinical examination tests. Physical Therapy in Sport. 2012;13(2):134-40.

We also have a follow up paper to the diagnostic paper (Drew MK, Palsson TS, Izumi M, et al. Resisted adduction in hip neutral is a superior provocation test to assess adductor longus pain: An experimental pain study. Scand J Med Sci Sports. 2015:n/a-n/a.) It assesses EMG and a variety of other metrics which is the full paper to this abstract:

Drew MK, Palsson TS, Hirata RP, et al. The influence of experimental thigh and groin pain on the mechanical sensitivity, pain distribution and clinical tests of the adductor longus. 9th Congress of the European Pain Federation EFIC Vienna, Austria; 2015.

Should be out early next year. I try to keep Research-gate up to date so will be up when available. 

Good luck

You are welcome!

See also the studies of Rohan Edmonds for other approaches with special Olympics:

Cheers,

Daniel

For the task you described, a functional task evaluation would require the weight of the box since the weight of the box would determine if the task is qualified as a task performed as an occasional task (1 - 4 times/hour, 1 - 32 times per day), frequent task (5 - 8 times/hour, 33 - 66 times/day), or constant task (12 - 60 times/hour, 67+ times/day). For occasional tasks loads of 10 - 50 lbs (4.5 -22.7 kg) are considered very light - medium; loads from 50 - 100+ lbs (22.7 - 45.4 kg) are considered medium to very heavy. For frequent tasks loads of < 0.5 kg - 11.4 kg are considered very light - medium, while loads from 11.4 - 22.7+ kg are considered medium to very heavy. Tasks classified as constant involve loads of < 0.5 kg - 4.5 kg for very light to medium; and from 4.5 kg - 9.1 kg are considered medium to very heavy.

The muscles of the trunk (primarily trunk extensors) and the muscles of the lower extremity will be used for stability and moving the box across the 2 meters. The muscles of the upper extremity (shoulder girdle, shoulder, elbow/radioulnar joint, and the wrist and hand) would be used to varying degrees to lift, hold, and lift the box to sternum level and place it in its place. No single muscle would be most active. Which muscles contribute to the specific portion of the task you intend to study will depend on the magnitude of the load, the frequency the task is completed, the velocity at which the task is completed, the height differential between where the box is lifted from to the height at which the box is placed when the task is completed (since the carrying of the box in the hands across the 2 meters does not accomplish any significant work, which could be measured and quantified accurately).

The only significant difference in muscular activity in the task described is not a difference in which muscles are active but the type of muscular activity that is taking place. The same muscles will be used whether lifting, carrying, or lowering the box. When lifting the box the muscles must overcome the effects of gravity on the box, which tends to cause it to remain at knuckle level on the table or supporting surface, this is accomplished using a concentric muscle action. When carrying the box across the floor for 2 meters, the box is basically held in a stable, static condition. The legs provide a propulsive force but the resistance to movement is at the foot/floor interface and no useful work is done to the box, therefore the muscles responsible for controlling the box and its contents are active in an isometric contraction, where the muscle produces a force exactly equal to the force of gravity to maintain control of the box while carrying it across the 2 meter space. When placing the box in its final position, the upper extremity muscles and possibly the trunk and lower extremity muscles will again produce a force greater than the resistive force provided by gravity using a concentric muscle action, just as they did when originally picking up the box. Finally when lowering the box to its final resting position, the same muscles that used a concentric muscle action to lift the box would utilize an eccentric muscle action to allow the box to be safely lowered to its final position.

So your problem is really one of adequately defining the movement or movements you are going to be studying, because the global nature of your current question is too large to provide a specific answer like you appear to be seeking.

We need more information. One, is the "signal" an electromyographic signal?  If so, what kind of electrodes are being used, indwelling or surface? Is "MPF" median power frequency or mean power frequency or neither? What is happening to the amplitude of the "signal"? What is the work task? One with a constant power output? What muscle group is involved? Is the "signal" from one or all muscles in the muscle group?

I agree with Ingred in that you first have to decide if you can get biopsies.  That said, saying a muscle is "uninjured" is nearly impossible.  It is tough to even get general agreement on what "injured" means.  This has been debated for decades in the eccentric contraction literature (see, for example, Yu JG, Carlsson L, Thornell LE.Histochem Cell Biol. 2004 Mar;121(3):219-27).  Once you decide the level at which you will study this, we can provide you with more specifics.  At the ultrasound or MR level, you will simply be "deciding" what injured or noninsured means but it will not be generally acceptable.  Good luck

Your best chance here would be to use traction force microscopy. little fluorescent beads in a gel layer will move in response to the forces applied to it by the smooth muscle cells. as you can vary the elasticity of the gel you can change between measuring mostly the force (small displacements) or focus on displacements alone. alternatively you could bind fluorescent beads to your smooth muscle cells and track their movement. Lastly, if you want to keep it experimentally simple but are willing to to go a bit deeper in image analysis is to use difference imaging in which you subtract the original image from the image in which the cells have contracted. this should easily identify the contracting cells, and in most cases makes it quite easy to see how much they contracted too.

Good Luck!

Hi Robert,

How do you currently separate and permeabilize fibers?  Also, what species are you studying?

Regardless, I would recommend watching this JoVE video for how to separate fibers:  http://www.jove.com/video/2431/respirometric-oxidative-phosphorylation-assessment-saponin

The Oroboros website (http://oroboros.at) is also an excellent resource for both protocols and theories relating to respirometry.

Dear Raul a few resources to help you may be as follows:

In an article Core Stability Exercise Principles, they define it as "The so-called core is the group of trunk muscles that surround the spine and abdominal viscera"

In "Muscles of the core", they define it as "The major muscles that move, support and stabilize your spine are called the muscles of the core or trunk"

In "The myth of core stability", they say "In essence the passive human spine is an unstable structure and therefore further stabilisation is provided by the activity of the trunk muscles. These muscles are often referred to in the CS approach as the ‘‘core’’ muscles, assuming that there is a distinct group, with an anatomical and functional characteristics specifically designed to provide for the stability"

In "Core Training: Evidence Translating to Better Performance and Injury Prevention" they say "These muscles act to stiffen the torso and function primarily to prevent motion. This is a fundamentally different function from those muscles of the limbs, which create motion. By stiffening the torso, power generated at the hips is transmitted more effectively by the core"

I think it would suffice. Best of luck!

Aamir

Dear Tyler Thomas, 

Some addition to the comments, following papers may help:

Muscle fiber type

Muscle fibre type distribution, muscle cross-sectional areaand maximal voluntary strength in humans

The influence of variations in muscle fibre composition on muscle strength and cross-sectional area in untrained males.

Effects of exercise training on skeletal muscle fiber type distribution in chronic heart failure patients

Contractile Properties and Fiber Type Distribution of Quadriceps Muscles in Adults with Childhood-Onset Growth Hormone Deficiency

Fiber Type Transformation in Human Skeletal Muscle

THE RELATIONSHIP OF BODY COMPOSITION, MUSCLE FUNCTION, AND MUSCLE FIBER TYPE TO LOWER BODY PHYSICAL PERFORMANCE IN OVERWEIGHT AND OBESE OLDER ADULTS

Relationship Between Muscle Fiber Type and Reactive Balance: A Preliminary Study

Aamir

Human models

The gold standard is resonance imaging. You can do that using US too, but the evidence in literature for this procedure are very poor. Finally, you can use a doubly indirect ways as maximal voluntary strength, ROM, or even seric markers as CK, lactate deydrogenase and Mb. Some researchs have used a visual analog scales for pain.

The above assumption is logical. However, the literature is not enough data to draw conclusions. It is possible to partially solve the problem of muscle growth with a lack of methylation Supplementing the necessary amino acids.

Do as you see fit. Explain your thought colleagues.

dear i hope this research help you

Hello Ponmathi

I used to do this for the majority of woman who I saw, with pelvic floor symptoms; I used the method that Jo Laycock and colleagues designed and validated. I don't know if you've seen this method - I was introduced to it by Jo, and never changed from this.

Laycock, J., & Jerwood, D. (2001). Pelvic floor muscle assessment: the PERFECT scheme. Physiotherapy, 87(12), 631-642.

Part of this is available from ResearchGate:

You might want to read a previous ResearchGate Question/Answer where other members also made suggestions:

The other paper I mentioned in this answer was:

Jeyaseelan, S. M., Haslam, J., Winstanley, J., Roe, B. H., & Oldham, J. A. (2001). Digital vaginal assessment: An inter-tester reliability study. Physiotherapy, 87(5), 243-250.

If you are unable to access the full text, I have a copy  that I could send you on ResearchGate messages, for your attention only.

Very best wishes

Mary 

There is a good reason why the original Goldspink paper has not been followed up - it is a difficult system.  The suggestion of tritium label is probably the best way of getting high resolution data because of the short range of radiation emission but this is also a drawback because it lowers the sensitivity - in tissue most of the emission decays within 2µm, so much of the signal never gets into the emulsion from standard wax or frozen sections.  This can be improved by cutting thin sections in acrylate embedded material but this requires a long exposure and, as implied by Dr Morgan, noise is a problem that you need to minimize by keeping the exposing slides in lead boxes and by meticulous darkroom work.

The suggestion of using antibody against developmental myosins may work but I would think that it would be technically possible nowadays to produce a mouse with a conditional expression of a tagged actin, myosin, or other sarcomeric protein that could  be activated prior to eliciting regeneration.  The Pax7Cre-ERT system would be suitable for regeneration experiments. Whether you could get funding for such a system is another matter.

At a low resolution, one of my colleagues has tried to use pulsed Stable Isotope Labelling in the Mouse (SILAM) and analysis of the ends versus the middle of the muscle fibres by Mass Spec. So far, his produced very variable results.

Perhaps I can if you are interested. I am finishing my master on BD with young and active males in extension and flexion of knee using an isokinetic dynamometer modified.

Ok thanks so much!

Hello Vishnu;

First, is it human or animal speciment.

If it is animal: There is no standardize protocol for CK measurement, because protocol might be significantly different and they depends from analysis and condition. Protocols depend from kit to kit. You should use the instructions, from the kit you plan to use.

Human sample: As mentioned above, any pathology lab can do this easily, and you should check with them from protocol, they might vary as well, or if you have a kit, follow the kit instructions.

First I do need to know for which type of experiments are you trying to obtain these myofrils. Are these for functional experiments such as Force vs. pCa?

Dear Rene Attal,

I think that article could be useful to you!

Harsten, A. 2015 Tourniquet versus no tourniquet on knee-extension strength early after fast-track total knee arthroplasty; a randomized controlled trial

Knee

Have a nice day!

Giacomo

Dear Ali,

I think the answer is pretty straightforward if you want a general answer, the classic papers are:

For changes in muscle force with length:  

Gordon AM, Huxley AF, and Julian FJ. The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J. Physiol. (Lond.) 184: 170-192, 1966.

For variations in muscle force with shortening velocity:

Hill AV. The mechanics of active muscle. Proceedings of the Royal Society of London.  Series B: Biological Sciences 141: 104-117, 1953.

For variations in muscle force with lengthening velocity:

Katz B. The relation between force and speed in muscular contraction. J. Physiol. (Lond.) 96: 45-64, 1939.

These have all been implemented in various models, so it really depends on your application.  Good luck!

Rick

The gold standard marker for SMC lineages is Myh11 (aka SM-MHC, smooth muscle myosin heavy chain).  Acta2 or SMA may be induced in a variety of fibroblasts and myeloid cells as well as glial cells and stellate cells of liver.  I also think it can be expressed in mesagial cells of kidney under stress conditions.  There is quite a literature on this subject.  My question relates to Brian's :  what exactly are you trying to do?

You can read this article

Eur J Pharmacol. 1994 Mar 11;254(1-2):97-104.

Age-induced alteration of neuromuscular transmission: effect of halothane.

Bhattacharyya BJ1, Tsen K, Sokoll MD

Hi Koushik,

There is an electrostatic interaction between kinesin head and tubulin. This electrostatic interaction keeps the motors (especially single headed motors) from diffusing away. There is a a structural difference in B amd A tubulin. You can refer to the following paper for further details.

"Structure of the alpha beta tubulin dimer by electron crystallography." by Nogales, E

Wolf, S G Downing, K H

This question is certainly at the forefront of the current state of dynamic in vivo imaging and our 3D models of complex muscle architecture.  All models are wrong, and some models are useful.  That Lieber guy should be commended for acting like a scientist and relying on data to increase our understanding.  Most scientist of his stature would pronounce their previous findings as the gospel.  

Often, these muscles wrap around a joint or bony structure, and their actions cause compressive, tensile or twisting deformations of their constrained space during shortening, further complicating models of force production.  It appears they may be a career's worth of research waiting here for someone.

Sylvania, I'm sending a few links that may be of help. Rachel.

Thanks

We used to call this spontaneous activity and Dr Ward is absolutely right; it is really not a problem as long as you are able to quantify changes in vessel tone.

I remember on the other hand that mesenteric arteries (rat, rabbit, mouse, dog etc) actually show this type of 'behaviour' even at basal tone (i.e. without being pre-contracted with NE, Ang II or KCl).

Are these helicoidal strips and which physiological buffer are you using? In addition, if  you want to reduce these oscillations at least with an alpha agonist, try methoxamine instead and add indomethacin in your assay buffer. The addition of an inexpensive betablocker may also help.

Good luck

The answer will depend on the muscle group you're interested in. Chronically-active muscles (e.g., lower-body muscles) are more susceptible to disuse.

Assuming you're interested in such muscles, the loss of lower-body lean mass appears to be around 100-200 g/wk during bed-rest (See some references below.) With this number, you can estimate the necessary duration of bed-rest if you know the resolution of the instrument you are using to assess atrophy.

Paddon-Jones D, Sheffield-Moore M, Urban RJ, et al. Essential amino acid and carbohydrate supplementation ameliorates muscle protein loss in humans during 28 days bedrest. J Clin Endocrinol Metab. 2004;89:4351–4358.

LeBlanc AD, Schneider VS, Evans HJ, et al. Regional changes in muscle mass following 17 weeks of bed rest. J Appl Physiol. 1992;73:2172–2178.

Please let me know if these two articles help:-

1. Generalized anxiety disorder: is there any specific symptom?

Faravelli C1, Castellini G, Benni L, Brugnera A, Landi M, Lo Sauro C, Pietrini F, Rotella F, Ricca V.

Compr Psychiatry. 2012 Nov;53(8):1056-62. doi: 10.1016/j.comppsych.2012.04.002. Epub 2012 May 11.

2. The relationships between measures of stature recovery, muscle activity and psychological factors in patients with chronic low back pain.

Lewis S1, Holmes P, Woby S, Hindle J, Fowler N.

Man Ther. 2012 Feb;17(1):27-33. doi: 10.1016/j.math.2011.08.001. Epub 2011 Sep 7.

Any survey, including the BORG scale, will be pretty vague and vary a lot between individuals. Monitoring the MEDIAN FREQUENCY of an EMG signal would be more sensitive to a change in fatigue status.

From Jansson & Sylven (Histochemistry 78:121-4, 1983), the mean concentration of myoglobin in slow- and fast-twitch fibers from human vastus lateralis was 31 and 20 mg/g dry weight, respectively. Since most human muscle is mixed in terms of fiber type, you could estimate that the average muscle content is ~25 mg/g dry weight. If you want to convert to myoglobin content per wet weight of muscle multiply by 0.25 (i.e., the normal dry-to-wet weight ratio for muscle). You can estimate the total amount of muscle in the human body as 40% of body weight

A molecule of myoglobin can bind one molecule of oxygen (O2).

If you're looking for something a little more specific to the topic, here are two I refer to quite a bit:

The skeletal muscle book is great for the PNS, and covers the motor neuron (or motor unit) control of muscle quite well.  However, it doesn't cover the CNS much at all.  The first book, by Latash, is a good mix of both.

This is related to the individual differences (in humans they are significant) and very small sample sizes. Increasing the sample size would decrease the SD and show more valid results.

using comparative accessment of pre- stress and post- stress dynamics is a convenient instrument for variety of diognosis.

Thank you both for the responses! I figured there wasn't a way around this but thought it was worth a shot. I have samples from a previous project in a -80 freezer that can be used at my disposal but they were simply cooled on ice and then brought to the freezer afterwards. I'm pretty sure I can't do any enzyme work on these but could this be useful in some kind of oxidative analysis? I don't have the option to take the fish back with me because I am working with species that are experiencing population declines so killing them is not ideal!  Thanks

Physiotherapy can start when the first muscular contraction is noticed. Time for this to occur ranges widely, from just over 1 month to 6 months. Once this occur, apart from strengthening the excursion, the most important aspect of physiotherapy is to prevent  or suppress synkinesis.

These goals can be achieved by exercises such as swallowing with abduction of oral commissures, mirror therapy, and smiling with tongue pressure.

Hello,

You may also consider incubating the muscle bundle in "skinning solution" (active ingredient potassium propionate/propionic acid) to poke holes in the sarcolemma (see attached paper for recipe). We do this for isolating single fibers from human tissue samples to investigate contractile properties. After 5-7 days in solution (at -20 degrees C) the fibers pull extremely easily and the microstructure is still intact. 

Hope this helps,

James

The most straight forward could be to use anti-alpha-actinin primary antibody.

Hi Paulo,

If I understand your question correctly, the answer is yes. With superthreshold stimulation of the alpha motor neuron and plenty of time between stimuli the muscle AP recorded should be quite standard representing in amplitude and time characteristics number of muscle fibers within given NM unit, their type (slow/fast) and sinchronicity of their activation.

Max 

The short answer to your main question is yes you can and many people do, without any problems.

However some potassium channel  blockers will have profound effects on contractile tone especially if they have off target  (non-selective) effects so you must do appropriate control experiments (e.g. study the effect of the blocker on contractile and relaxation responses and ability of artery to maintain tone in the blockers presence). Thus it is worth to check the literature for these non selective effects before use.As there are many types of potassium channel it is impossible to really give a more specific answer

It is unlikely that that most potassium channel blocking drugs will destroy the structure of the artery if used at sensible concentrations (i.e sufficient to fully block the channel you are interested in) but as I mentioned before both their specific effect on a potassium channel and side effects may have unexpected effects on the function of an artery.

A good starting point to choose the "gold standard" blocker for the potassium channel you are interested in is to use the British Pharmacology Society/IUPHAR "guide to pharmacology" (link Below)

Thanks a lot again, Flora! A very good protocol in detail. So you also use cryosections or paraffin sections to analyze muscle viability? 

I use one of my own hairs!... I do it while the artery is mounted between wires with some tension on and gently rub in a circular motion with very gentle pressue against the artery wall/endothelium in one direction....this decreases Ach responses to less then 10%.