Hand-held Dynamometry
Purpose[edit | edit source]
Handheld Dynamometry (HHD) is a method utilized to assess muscle strength. Although other dynamometers were utilized to assess grip strength, this version of a dynamometer is set up or held by the therapist to derive an objective measurement of force.
Procedure[edit | edit source]
Unlike traditional manual muscle testing as a "break test," the preferred method for HHD is to utilize a "make test" format. This assessment requires the subject to exert a maximum isometric force while the dynamometer is held stationary. [1]
An example procedure is as follows (however, there is some variety in procedures performed; it is important to clearly document the procedure and positioning utilized to ensure consistency and reproducibility):
- The examiner keeps the dynamometer stable
- The patient/client/subject produces maximal force against the instrument while the examiner matches this force
- Verbal commands provided include "push as hard as possible," and "push, push, push, push"
- Each trial is performed over a 3-4 second hold, with 2-3 trials being performed
- The average and individual trial numbers should both be reported
- Common units: pounds (lbs), Newtons (N), or kilogram-force (kgf)
- Can be expressed as a percentage of the unaffected/less impaired extremity (e.g., R knee extension 90% of L knee extension)
The following video demonstrates the use of a hand-held dynamometer in various positions: [2]
Benefits[edit | edit source]
- Decreased subjective interpretation (compared to manual muscle testing grades beyond a 3/5)
- Reliable, objective testing of muscle strength
- Not gravity-dependent in its interpretation
- Minimizes the tester's contribution to error (make test principle)
Drawbacks[edit | edit source]
- No present universal, standardized positions
- Questionable inter-tester reliability (related to lack of standardized positions)
- Error if subject strength greater than tester (concentric contraction)
- Important for tester to ensure good body mechanics for maximum efficiency
- Other devices are more appropriate for assessing Grip Strength
Evidence[edit | edit source]
- In healthy adults aged 20-53 years of age, HHD demonstrated weak-to-moderate concurrent validity (r value 0.37-0.51, p≤0.05) with the "gold standard" measure of muscle strength assessment, isokinetic dynamometry (IKD) for peak torque values in hip extension [3]
- The American Academy of Physical Medicine and Rehabilitation published a systematic review which supports the use of HHD as a reliable and valid measure of muscle strength that is easy to use, portable, and more cost-affordable than IKD, but does question its efficacy for larger joint use such as the knee [4]
- The ActivForce Digital Dynamometer and microFET2 HHDs were found to have similar levels of intra- and inter-tester reliability and criterion validity for assessing shoulder muscle force production of internal rotation, external rotation, and forward elevation. Reported intraclass correlation (ICC) values for intra- and inter-rater reliability were high (0.85-0.99) [5]
- A proposed HHD measurement of 31.1% knee extension force (normalized to bodyweight) was established as necessary for independence in performing a sit to stand in hospitalized adult populations [6]
- In healthy populations, external stabilization of the HHD using a belt (to avoid examiner strength as a confounding variable) has been shown to be reliable and valid for the assessment of hip and knee strength assessment
- Intrarater reliability was excellent (ICC = 0.8-0.96) for hip adductors, abductors, flexors, extensors, right internal rotators, external rotators and the knee extensors, and moderate for bilateral knee flexion (ICC = 0.62–0.66) and left hip internal rotation (ICC = 0.70). Correlation with IKD was moderate to high (r=0.6-0.90)[7]
The following videos demonstrate the use of external fixators (belts, straps, or an alternative dynamometer design) to assess muscle force production: [8] [9]
Resources[edit | edit source]
- Journal of Orthopedic and Sports Physical Therapy Appendices
References[edit | edit source]
- ↑ Bohannon RW. Make tests and break tests of elbow flexor muscle strength. Phys Ther. 1988 Feb;68(2):193-4.
- ↑ HOGGANScientific. Handheld Dynamometry with HOGGAN Scientific’s microFET2. Available from: https://www.youtube.com/watch?v=8G2x1VYsFGU [last accessed 2/29/2024].
- ↑ Keep H, Luu L, Berson A, Garland SJ. Validity of the Handheld Dynamometer Compared with an Isokinetic Dynamometer in Measuring Peak Hip Extension Strength. Physiother Can. 2016;68(1):15-22.
- ↑ Stark T, Walker B, Phillips JK, Fejer R, Beck R. Hand-held dynamometry correlation with the gold standard isokinetic dynamometry: a systematic review. PM R. 2011;3(5):472-9.
- ↑ Karagiannopoulos C, Griech S, Leggin B. Reliability and Validity of the ActivForce Digital Dynamometer in Assessing Shoulder Muscle Force across Different User Experience Levels. Int J Sports Phys Ther. 2022;17(4):669-676.
- ↑ Eriksrud O, Bohannon RW. Relationship of knee extension force to independence in sit-to-stand performance in patients receiving acute rehabilitation. Phys Ther. 2003;83(6):544-51.
- ↑ Martins J, da Silva JR, da Silva MRB, Bevilaqua-Grossi D. Reliability and Validity of the Belt-Stabilized Handheld Dynamometer in Hip- and Knee-Strength Tests. J Athl Train. 2017;52(9):809-819.
- ↑ Physique Management. Using the Activforce 2 Digital Dynamometer Belt for an Accurate Strength Measurement. Available from: https://www.youtube.com/watch?v=lnm5YhuNx7M [last accessed 2/29/2024].
- ↑ Meloq. Measuring the Isometric Muscle Forces of Knee Extension - EasyForce Digital Dynamometer. Available from: https://www.youtube.com/watch?v=F5vDj3gY4Y8 [last accessed 2/29/2024].
