Muscle Strength Testing Equipment Instruments for Rehab and Physical Therapy


Muscle strength testing is a common test used in physical therapy and other associated health professionals such as sports care and elderly homecare. The test was popularized back in the 1940s in a period where polio outbreaks were rampant. Manual muscle testing (MMT) became an important part of combating the effects of the disease as it was a quick, simple and effective way to assess specific muscle groups. However, MMT isn’t that reliable after all because of a major flaw — inaccuracies on patients with a higher level of strength.

Studies were conducted on manual muscle testing devices to try and address the flaw, and it’s was established that the test is only able to detect weakness in knee extensor. Drawing conclusions that MMT is ideal for testing muscle weakness rather than strength.

Advance Muscle Strength Testing Equipment

It has been established than MMT is limited in its assessment in terms of muscle strength. That’s why the next technology of functional assessment equipment has come to fill the gap in muscle therapy. Here are some of the advanced physical therapy tools for muscle strength testing available today.


The next piece of equipment to hit the market after MMT was dynamometry and initial designs were large compared to the version of dynamometry we have today. It’s was also cost-intensive. With time more innovations came in and handheld isometric dynamometry (HHD) was introduced and serve as the standard.

Dynamometer muscle testing is reliable, accurate, and known to have high levels of inter-and-intra-rater reliability of above 0.9, meaning that the chances of two separate tests from the same patient are likely to have a 90% match. This is even above the standard reliability of 0.75. The efficiency and portability, however, is packed in a high-cost unit limiting its application to only physical therapy.

For average clinicians, there are several options when it comes to muscle strength testing equipment which is as accurate and reliable as a standard dynamometer. And they cost less. They include:

  • Luggage Scale
  • Grip dynamometer
  • Crane Scale

The three options can be used to set up a custom MMT dynamometer for your practice. All you need to do is to attach the equipment to a strong bar or frame of a treatment table, attach a strap, and have your patient pull the strap with a maximum force contraction. For accurate testing, it’s important to develop a standard position of a patient and a specific joint angle under test. Each testing equipment has its merits and demerits, and once you’re able to determine your device functionality, you’re in a better position to administer proper muscle strength testing with a lot of creative room to play in.

Introducing these devices in your practice can help improve the reliability and objectivity of your strength testing services. The three devices, however, represent the manual muscle testing and cannot be considered for functional strength assessment –that recreates the range of motion testing for a patient.

The range of equipment-based testing offers options based on budget, treatment goals, available space, type of patients and how thorough you want your evaluation to be. For example, if you’re running a small outpatient clinic with many minor low back and neck pains cases, the choice of muscle strength testing equipment will greatly vary from what is commonly used in acute care settings. The type of testing-device to be used on children or the elderly will also substantially differ from those applied in sports therapy. The above mentioned equipment-based test signifies the most common approaches and is considered ideal for older adults with their demonstrated effectiveness.

The development of viable and reliable muscle strength testing equipment has improved testing techniques for the identification of muscle weakness. Equipment-based testing is however coupled with some disadvantages including a limited capacity to test all types of muscle groups, movements, and require much space for setup.

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