• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
2  Measurement of Muscle Performance with instrument
 

2 Measurement of Muscle Performance with instrument

on

  • 3,732 views

 

Statistics

Views

Total Views
3,732
Views on SlideShare
3,732
Embed Views
0

Actions

Likes
0
Downloads
30
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    2  Measurement of Muscle Performance with instrument 2 Measurement of Muscle Performance with instrument Presentation Transcript

    • Measurement of MusclePerformance With Instrument LECTURE II DR. AMAL HM. IBRAHIM
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com INTRODUCTIONIn this lecture we will emphasis onclinical practice and selectivereview of literature.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com INTRODUCTION Muscle testing to be meaningful it must reflect muscle performance and not other variables. We test muscle to determine patient restrictions and collect information that will help us make decisions. The most common decision is whether or not we want to exercise specific muscles.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESS The terms used most often to describe muscle performance are “strength “ and “weakness”, both have no units of measurement. The only definition of strength suggest that it is the maximal force can be exerted during a single isometric contraction. This definition implies that all other forms of measurement (isokinetic, manual muscle test) do not assess strength.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESSIf someone tells you they have measured strength. Do you know what they did? Do you know what units they obtained? Did they measure force, torque, or power? Under what conditions and with what type of device did they measure?
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESS Using the term “strength” give a false impression that the same thing is being measured in the same way. A fundamental question in muscle assessment concerns the best approach to measurement.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESS Are force measurement better than torque? Does use of one type of device or one type of contraction tell us more than use of another? From publications we found many authors said they measuring strength. The authors were not measuring the same thing but they all described what they were measuring by using the same term.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESS We have avoided using term “strength” and prefer using “muscle performance”. We can measure muscle performance isokinetically, isometrically, etc.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRENGTH AND WEAKNESS “Weakness” obviously depends on a definition of strength. There are lack of data that can be used to make judgment. We should use terms which indicate that we are expressing opinion not terms that imply documented levels of performance.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com UNITS OF MEASUREMENT One of the advantages of using instrument to measure muscle performance is that they yield units that have universal meaning. If you are measuring force although you may use English or metric units, it is always: force= mass X acceleration. work = force X distance. power = work X time. Torque = force X perpendicular distance from the axis of rotation
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com UNITS OF MEASUREMENT Redefinitionof terms adds nothing to our understanding muscle performance (assessment of power during isokinetic high speed or low speed testing).
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com UNITS OF MEASUREMENT Which of the units (force, torque, power or work) best describes muscle performance? That will depend on the reason muscle performance is being measured.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com UNITS OF MEASUREMENT Therapist must ask what aspect of muscle performance needs assessment? Therapist need understanding of muscle biology and kinesiology.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.comMUSCLE BIOLOGY AND KINESIOLOGY Muscle has been described as a physiological transducer of chemical energy (ATP) to mechanical (muscle tension). Tension is actually a type of force that can be measured by instrument (usually a strain gauge) which must be attached to the muscle or tendon.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com MUSCLE BIOLOGY AND KINESIOLOGY Wecannot measure muscle tension in humans but measure force created when muscle tension acts through skeletal leverage system.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com MUSCLE BIOLOGY AND KINESIOLOGY Forces and torques will vary because of biomechanical factors ( changes in angle of insertion, rotational and compression components). Forces and tension are both vectors (have magnitude, direction, a line of application and angle of application). Forces and torques are consistently reflect tension during isometric contraction.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com MUSCLE BIOLOGY AND KINESIOLOGY when we assess muscle, we are measuring forces of which only the magnitude element varies. example: biomechanically biceps brachii might measure more force with elbow 90°than at 120°of flexion- even though there could be more tension developed at 120° of flexion.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com SPEED OF MOVEMENT AND SPEED OF CONTRACTION When a limb moves, we can measure its speed or with isokinetic devices we can control the angular speed. The rate of tension development is speed of contraction.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com SPEED OF MOVEMENT AND SPEED OF CONTRACTION Two legs may be moving through an arc with the same speed of movement. but if one has a greater mass, it will develop more tension per unit time to move the heavier limb at the same speed as the lighter limb.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com TORQUE AND FORCE It is better to measure force, which is a linear quantity, or to use the rotational measurement, which is torque? Measurement of force using cable tensiometer or hand-held dynamometer. Torque is difficult to drive unless a device is used has an axis of rotation aligned with the subject’s anatomical axis of rotation. But we can measure torque from (force X distance between resistance and axis of rotation). Muscle torque can only be estimated by calculating from anatomical studies.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com ISSUES Muscle contraction have been described as eccentric, isometric, or concentric. Greatest tension per unit of muscle can be generated eccentrically, less can be generated isometrically and less concentrically. Eccentric contraction use less metabolic energy (ATP) per unit of tension than do other contractions.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com ISSUES when we assess muscles, we must be aware of the type of contraction we are measuring. a major clinical concern is whether the performance in any one mode reflects the others and whether training in one mode increases performance in the others, we do not know the answer.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com ASSESSMENT CRITERIA Comparison between “affected” and “non affected” limbs may be useful, but there are no data that tell us how much inter-limb variation is normal. We advocate good clinical sense- that is we urge clinicians to use all available data and not to be tempted to relay on questionable criterion
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com ASSESSMENT CRITERIA Some forms of fatigue tests measure the number of contractions it takes before a subject reaches a percentage of their maximal force or torque. Although such an index may reflect on a relative basis the biological properties of muscle that relate to “endurance” The problem arises because “fatigue” and “endurance” lack clinically applicable operational definitions.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com CABLE TENSIOMETERS Cable tensiometers are used to test muscle performance, one end of the cable is attached to some fixed (stable) object and the other end is attached to a limb segment.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com CABLE TENSIOMETERS The tensiometer is placed at some point between the two sites of fixation. As a cable is pulled, it presses on the tensiometer’s rises (a bar) which is connected to a gauge that measures in relative units.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com CABLE TENSIOMETERS The cable must be fixed to immovable object (a wall, column, or floor). The other end of the cable must be attached to whatever body segment is being tested. The cable must be in the plane of the movement
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com RELIABILITY Clarke’s systemic investigation tested 64 subjects twice within a single session by two different examiners not specified. The paired measures (the values obtained by each examiner) were correlated. Clarke states that coefficients of 0.90 or greater are (desirable) whereas coefficients as low as 0.80 indicate that the test can be used for individual measurements
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com RELIABILITY Alderman and Banfield tested the reliability of cable tensiometer for three sets of muscles (knee extension, elbow flexion and extension) were tested bilaterally in 32 male using modified Hettinger chair for stabilization. The inter tester reliability are reasonably in agreement with Clarke.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com VALIDITY Clarke compared cable tensiometer, a Wakim- porter strain gauge, a spring scale, and a Newman Myometer on the basis of which instrument were the most reliable and equivalent. Finger flexion, wrist dorsal flexion, shoulder outward rotation, neck extension, knee extension and ankle planter flexion were examined as strong or weak.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com VALIDITY The cable tensiometer and strain gauge were used for al tests, whole spring scale was used to examine shoulder rotation and neck extension only. The myometer was used only for wrist and finger tests. Clarke argued that strain gauge was less useful because it was too sensitive and other two devices had limited application for many muscles.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com VALIDITY The tensiometer was the best overall instrument. This conclusion is clearly based on his subjective observations relative to the ease of application of the various instruments rather than on reported data.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.comSTRAIN-GAUGE DEVICE
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRAIN-GAUGE DEVICES Used for muscle performance measurement with great differences in design, electronics and methods of application. Loads (tension, compression, or shear) applied to material cause a change (deformation) called strain which is measurable.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com STRAIN-GAUGE DEVICES Strain gauge are made of electroconductive material and are usually applied to the surfaces of finely machined metal ring or rods. When load is applied to the ring, the metal deforms with strain gauge leading to a change in the electrical resistance of the gauge. The current or voltage passed through the gauge will vary ( Ohm’s Law) as a function of the applied load.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com Various strain gauge designs in the form of geometrically formed foil made of conductive material. Foil must be positioned on the supporting surface, to achieve sensitivity to the application of force in the desired direction
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.comMUSCLE EVALUATION BY STRAIN GAUGEStrain gauge devices have been most often used formuscle evaluation by having the metal ringattached to an object that a limb segment caneither push or pull against (creating eithercompressive or tensile strain).If the device is calibrated, the voltage or currentchange can be converted into measurements offorce.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com Other uses of strain gaugeThe basic system FDM-T consists of atreadmill ergometer with an integrated,calibrated measuring sensor. The sensorelement itself consists of numerous high-quality capacitive force sensors. On atreading area of 150 x 50 cm the sensorunit comprises more than 5000 pressure/ force sensor
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com DYNATRON PINCH GAUGE Using The Same Accurate Gauge As The Hand Dynamometer, The Dynatron Pinch Gauge Measures Forces Up To 45-lbs/20 Kg. Peak/hold Needle Stays At The Highest Reading Until Reset. Wrist Strap For Practitioner To Hold Gauge While Testing. Comes In A Padded Case.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 THE DIFFERENCES aebrahim123@hotmail.comBETWEEN VARIOUS TYPES OF STRAIN GAUGE The manner in which the voltage or current change is displayed (strip-chart, digital displays, or voltmeter). Application of device to the limb segment ( push or pull)
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011THE DIFFERENCES aebrahim123@hotmail.comBETWEEN VARIOUS TYPESOF STRAIN GAUGE The type of interfaces used to connect limb segments (cuffs, pads, or straps). Methods of applications (easy in use or difficult).
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com RELIABILITY OF STRAIN GAUGE Asmussen and his colleagues used five different strain gauge dynamometers to demonstrate that the force measurement obtained were replicable. Six muscle groups in 50 normal young men were tested twice (forward and backward trunk flexion, downward pull of the arm, hand grip, knee flexion and extension). Reliability coefficient ranged from .91 to .96 with no report about statistical method used.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com RELIABILITY OF STRAIN GAUGE Clarke compared the reliability of cable tensiometer and the Wakim-porter strain gauge of six muscle group in 64 nondisabled male college students. Tests were also performed with a spring scale and a myometer for some muscles. The results of test- retest correlation were very similar to cable tensiometer results (ranged from .81 to.94).
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.comCAUSES OF ERRORS IN STRAIN GAUGE Limb must either push or pull and in the same line. The application during different tests must be identical. Stabilization of the limbs must be maintained to localize force measurement only to that muscle tested.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com VALIDITY Some investigators imply validity because strain gauge instrument accurately reflect applied load. The comparisons with loads and tensiometers have been used to justify the use of strain-gauge devices to measure muscle performance.
    • Dr. Amal Hassan Mohammed Ibrahim - 10/16/2011 aebrahim123@hotmail.com VALIDITY The strain gauge can be applied to objectify the subjective test as manual muscle test. Validating one test by comparing it with another test is legitimate.
    • QUISTIONS????? Dr. Amal Hassan Mohammed Ibrahim -10/16/2011 aebrahim123@hotmail.com