by physiotherapist Megan Fryer BSc (Physio) UFS
Dynamometry is the measurement of power or force expended, especially muscular effort or strength. This is why it is helpful in a physiotherapy setting as it adds additional value in patient assessment.
Isokinetic dynamometry has been the gold standard to quantify muscle strength, however it lacks clinical applicability due to both its cost and size.
This is where handheld dynamometry comes in. A handheld device (HHD) is far more accessible and cost-friendly than its isokinetic counterpart. This allows trained practitioners, like physiotherapists, to bring this technology into daily practice for everyone, not only elite athletes, to benefit from.
With constant progressions in technology, HHD is becoming more accurate. Bagordo et al, 2020, compared HHD and isokinetic dynamometry tests in shoulder rotators. They found that the values for muscle power between both methods were reliable, however isokinetic dynamometry was proven to be better at assessing muscle endurance. Lesnak et al, 2019, compared isokinetic dynamometry and HHD in the measurement of quadriceps muscle power and rotational torque and found that the HHD values were reliable when compared to the isokinetic dynamometer results. A study by McBride et al conducted earlier this year found that dynamometry is effective in isometric muscle power testing of the neck flexor and extensors.
The VALD DynaMo Plus is one of the most advanced handheld dynamometers in the world. It has the capability to perform over 300 strength and ROM tests. It links to a DynaMo app that enables you to both perform tests and record results. You are able to measure the force the muscle expands, the ROM of the joint, and compare asymmetry between the left and right sides.
There are still limitations to dynamometry. The first is that if the client is stronger than the practitioner then the dynamometer is in fact only measuring the muscle power of the practitioner. This is another area in which the VALD DynaMo shines. The DynaMo device is able to test muscle power with both compression and tension settings. The use of the tension bands eliminates the need for force to be applied by the practitioner thus ensuring a more accurate result. The second limitation often noted in research is reliability between different practitioners performing the same test. This can be solved by one practitioner always doing the tests for the same patient.
This new technology is an exciting addition to our “physio toolbox” and helps us to give our best to every person who walks into the practice.
For more information visit www.debbiecameronphysio.co.za or phone 031 765 8898.
Bagordo et al Isokinetic Dynamometry as a Tool to Predict Shoulder Injury in an Overhead Athlete Population: A Systematic Review Sports (2020), 8, 124
Chamorro et al Absolute Reliability and Concurrent Validity of Hand-Held Dynamometry in Shoulder Rotator Strength Assessment: Systematic Review and Meta-Analysis Int. J. Environ. Res. Public Health (2021), 18, 9293 https://www.mdpi.com/1660-4601/18/17/9293
Lesnak et al Validity of hand-held dynamometry in measuring quadriceps strength and rate of torque development Int. J. Sports Physical Therapy (2019) vol 14, No 2, 180
McBride et al Intra and Inter-Rater Reliability of a Novel Isometric Test of Neck Strength Sports (2023), 11, 2