ErgonomicsErgonomics

Maximum Voluntary EffortMaximum Voluntary Effort

By: Group 10 - Marcus, Allan, Matt, Andre, By: Group 10 - Marcus, Allan, Matt, Andre, and Lanceand Lance

JAMAR Hand DynamometerJAMAR Hand Dynamometer The JAMAR Hand Dynamometer The JAMAR Hand Dynamometer

is an indispensable is an indispensable tool, to generate accurate and tool, to generate accurate and

objective data required objective data required for reimbursable hand and forearm for reimbursable hand and forearm rehabilitation rehabilitation services. services.

Ideal for routine screening of hand Ideal for routine screening of hand muscle muscle function. The Dynamometer function. The Dynamometer represents an represents an excellent way to track the hand’s excellent way to track the hand’s response and response and progress associated with therapy progress associated with therapy and has been used for and has been used for over 35 years.over 35 years.

Accommodates various hand sizes Accommodates various hand sizes and has 5 and has 5 positions which range form 1 3/8” positions which range form 1 3/8” to 3 3/8”to 3 3/8”

Weighs:Weighs: 3 lbs. 3 lbs.Dimensions:Dimensions: 8" x 11" 8" x 11"PricePrice: Approx. $280: Approx. $280

Reliability and ValidityReliability and Validity How reliable is the JAMAR Hand Dynamometer?How reliable is the JAMAR Hand Dynamometer? VERY!!!!!VERY!!!!! The JAMAR is isometric in use, with almost no The JAMAR is isometric in use, with almost no

perceptible motion of the handles.perceptible motion of the handles. The hand grasp is both comfortable and The hand grasp is both comfortable and

effectiveeffective These features combine to ensure accurate and These features combine to ensure accurate and

reproducible resultsreproducible results Full effort needed for less than 10% variationFull effort needed for less than 10% variation If non-maximal effort given, than as much as If non-maximal effort given, than as much as

100% variation can occur.100% variation can occur. Hamilton, et al.(1994) found that handle position Hamilton, et al.(1994) found that handle position

1 was the least reliable1 was the least reliable

Coefficient of VariationCoefficient of Variation

- Used to determine whether the trials are in the Used to determine whether the trials are in the permissible range permissible range

- SD/mean = coefficient of variationSD/mean = coefficient of variation

- Compare this # to permitted max (found in table)Compare this # to permitted max (found in table)

- If CV is > the permissible CV then trial is If CV is > the permissible CV then trial is inconsistentinconsistent

- If CV is < the permissible CV then trial consistentIf CV is < the permissible CV then trial consistent

- Allowed to have 2/10 coefficients exceeding the Allowed to have 2/10 coefficients exceeding the cut pointscut points

Normative DataNormative Data

Grip StrengthGrip StrengthMales – Right – 104.3 (SD – 28.3)Males – Right – 104.3 (SD – 28.3)

Left – 93.1 (SD – 27.6)Left – 93.1 (SD – 27.6)

Females – Right – 62.8 (SD – 17.0)Females – Right – 62.8 (SD – 17.0)

Left – 53.9 (SD – 15.7)Left – 53.9 (SD – 15.7)

**all values in lbsall values in lbs

A standard position for testing A standard position for testing recommended by the American Society of recommended by the American Society of Hand Therapists requires that the patient:Hand Therapists requires that the patient: Sit in a straight-backed chair Sit in a straight-backed chair Feet flat on the floor Feet flat on the floor Shoulders adducted in neutrally rotatedShoulders adducted in neutrally rotated Elbows flexed at 90 degrees Elbows flexed at 90 degrees Forearm rotation neutral Forearm rotation neutral Wrist 0-30 degrees dorsiflexion and 0-15 Wrist 0-30 degrees dorsiflexion and 0-15

degrees ulnar deviateddegrees ulnar deviated Repeated 3X and take the averageRepeated 3X and take the average

Alternate TestsAlternate Tests

Tekdyne hand dynamometerTekdyne hand dynamometer

DynEx™ Electronic Hand DynEx™ Electronic Hand

Dynamometer Dynamometer

JAMAR Hand Dynamometer Rapid JAMAR Hand Dynamometer Rapid Exchange Grip Test Exchange Grip Test

Although grip strength is not a true Although grip strength is not a true measure of hand function it often aids in measure of hand function it often aids in gauging impairmentgauging impairment

It aids to better identify actual maximum It aids to better identify actual maximum grip strength in individuals with whom the grip strength in individuals with whom the evaluator is querying full effort. evaluator is querying full effort.

Increases the validity of the maximal Increases the validity of the maximal voluntary effort voluntary effort

Used as alternate test, to confirm if the person is lackingUsed as alternate test, to confirm if the person is lackingfull effort in Max Voluntary Grip Testfull effort in Max Voluntary Grip Test

ProcedureProcedure - use setting at which person did his/her best- use setting at which person did his/her best- Switch hands rapidly from right to left, while giving Switch hands rapidly from right to left, while giving

max grip effortmax grip effort- Dynamometer held by evaluator, resetting gauge after Dynamometer held by evaluator, resetting gauge after

each trialeach trial- Test completed after result of test determined as Test completed after result of test determined as

positive or negativepositive or negative

- Positive – score greater than or equal to the static Positive – score greater than or equal to the static scorescore

- Negative – score less than (approx 15%) the static Negative – score less than (approx 15%) the static scorescore

JAMAR Hydraulic Pinch GaugeJAMAR Hydraulic Pinch Gauge designed for use in hand strength testing designed for use in hand strength testing

applications – ie. measurement of tip, key applications – ie. measurement of tip, key and palmar pinch. and palmar pinch.

used effectively as a diagnostic tool, or as used effectively as a diagnostic tool, or as a means of monitoring progress of rehab a means of monitoring progress of rehab of the handof the hand

Reliability and ValidityReliability and Validity

- The unique design of this gauge frees the The unique design of this gauge frees the client to perform a true pinch pattern client to perform a true pinch pattern because the therapist, supports the weight because the therapist, supports the weight of the gauge. A highly accurate pinch-of the gauge. A highly accurate pinch-force measurement is the result.force measurement is the result.

- Full effort needed for less than 10% - Full effort needed for less than 10% variationvariation

- If non-maximal effort given, than as much - If non-maximal effort given, than as much as 100% variation can occur.as 100% variation can occur.

Normative DataNormative Data

Palmar PinchPalmar PinchMales – Right - 23.4 (SD – 5.0)Males – Right - 23.4 (SD – 5.0)

Left – 23.0 (SD – 5.3)Left – 23.0 (SD – 5.3)Females – Right – 16.3 (SD – 3.8)Females – Right – 16.3 (SD – 3.8)

Left – 15.7 (SD – 3.6)Left – 15.7 (SD – 3.6)

Key PinchKey PinchMales – Right - 24.5 (SD – 4.6)Males – Right - 24.5 (SD – 4.6)

Left – 23.6 (SD – 4.6)Left – 23.6 (SD – 4.6)Females – Right – 16.2 (SD – 3.0)Females – Right – 16.2 (SD – 3.0)

Left – 15.3 (SD – 3.1)Left – 15.3 (SD – 3.1)

Normative DataNormative Data

Tip PinchTip PinchMales – Right - 17.0 (SD – 4.1)Males – Right - 17.0 (SD – 4.1)

Left – 16.4 (SD – 4.0)Left – 16.4 (SD – 4.0)

Females – Right – 11.3 (SD – 2.6)Females – Right – 11.3 (SD – 2.6)

Left – 10.8 (SD – 2.4)Left – 10.8 (SD – 2.4)

* All values are in lbs* All values are in lbs

ProcedureProcedure

1. Patient should be seated1. Patient should be seated 2. Shoulders adducted and neutrally rotated2. Shoulders adducted and neutrally rotated 3. Elbow flexed at 90 degrees3. Elbow flexed at 90 degrees 4. Forearm and wrist in neutral position4. Forearm and wrist in neutral position

Pinch StylesPinch Styles 1. Tip Pinch – thumb tip to index fingertip1. Tip Pinch – thumb tip to index fingertip 2. Key Pinch - thumb pad to later aspect of middle 2. Key Pinch - thumb pad to later aspect of middle

phalanx of index fingerphalanx of index finger 3. Palmar Pinch - thumb pad to pads of index and middle 3. Palmar Pinch - thumb pad to pads of index and middle

fingerfinger

Key Pinch

Alternate TestsAlternate Tests

Baseline Hydraulic Pinch GuageBaseline Hydraulic Pinch Guage

ReferencesReferences Hamilton, A., Balnave, R., & Adams,R. (1994). Grip Hamilton, A., Balnave, R., & Adams,R. (1994). Grip

strength testing reliability. Journal of Hand strength testing reliability. Journal of Hand Therapy,7,163-170 Therapy,7,163-170

Niebuhr, B. R., & Marion, R., & Fike, M. L. (1994). Niebuhr, B. R., & Marion, R., & Fike, M. L. (1994). Reliability of grip strength assessment with the Reliability of grip strength assessment with the computerised Jamar dynanometer. Occupational computerised Jamar dynanometer. Occupational Therapy Journal of Research,14,3-18Therapy Journal of Research,14,3-18Ev Innes : Handgrip strength testing: A review of the Ev Innes : Handgrip strength testing: A review of the literature Australian Occupational Therapy Journal literature Australian Occupational Therapy Journal (1999) 46, 120-140. (1999) 46, 120-140.

Internet Scientific Publications Internet Scientific Publications http://www.ispub.com/ostia/index.php?http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijs/vol5n2/strength.xml#e5xmlFilePath=journals/ijs/vol5n2/strength.xml#e5