JTech Power Track II
The Commander PowerTrack II manual muscle tester is a brilliant dynamometer for clinical and research purposes, used extensively in Australia and internationally. Consisting of a wrist console and a hand held dynamometer (transducer), it allows fast and accurate testing of isometric muscle strength. The digital wrist console stores and analyses up to 40 bilateral tests. The PowerTrack II (written PowerTrack rather than Power Track) is designed to measure forces using either the make or brake isometric strength measuring techniques.
Importance & Reliability of the PowerTrack Hand Held Dynamometer
When testing a patient who you suspect is impaired on one side, with manual muscle testing (MMT) one might be able to say that the impaired side is weaker than the unimpaired side, but the unimpaired side may not be normal either! Thus it is important to test using the PowerTrack as it provides a numerical objective measure of force.
Researchers have used hand held dynamometers like the PowerTrack to compile databases on populations of normals. These databases record how many Newtons force particular muscle groups generate in specified age groups. Databases exist for stating if the strength of the limbs are within the normal range or not. Using these databases and their regression equations one is able to say if a 67 year old male patient who has a body weight of 765 Newtons and an elbow flexion force on his non-dominant side of 130.8 N is impaired or not. In this case the patient's force is actually 46.5% below the predicted value and more than two standard deviations below the mean values for his age group.
This is obviously a lot more informative than merely saying his non-dominant side is weaker than his dominant side! It is also much more informative than merely saying he has a ranking of Grade 2 as measured using a five point subjective MMT scale. Also it should be noted that if the MMT score differs by only one grade this represents an error of 20% in a five-grade system.
Some researchers have found that therapists using MMT could not distinguish knee extensor forces that varied as much as 25%, and that they graded as normal patients who had lost as much as 50% of the muscle's tension production. The PowerTrack hand held dynamometer has been used to measure hip abduction and adduction isometric strength in elite soccer players, in order to help prevent groin injuries.
The PowerTrack II Commander Manual Muscle Tester unit consists of:*
- PowerTrack II dynamometer and wrist console
- Battery supplied
- Spiral bound Flip Chart
- Spiral bound Users Manual
- Formatted pad for manual recording of results
- Two transducer heads (one scooped and one flat & round)
- Two leads (one short and one long) for connecting the transducer to the wrist console.
- A hard, foam cushioned carry case
*Contents may vary without notification
Please refer to the following document for details of published studies that have involved the PowerTrack dynamometer.
Commander Echo Wireless Muscle Tester
This brilliant unit has many of the same benefits and features as the PowerTrack II, plus a lot more!
- Test protocols can be customised according to number of tests, starting force, Newtons, Kilgrams or Pounds and number of repetitions
- Reduces "roll-over" and tilting with a 53mm (2.11") high ergonomic design that fits comfortably in the palm
- Measures up to 150 pounds for very strong performers
PowerTrack II and Commander Echo Compared
|Function||Commander Echo||PowerTrack II|
|No. of Tests Stored on Console||Maximum of 20||Maximum of 40|
|No. of Repetitions per Test||1 to 4||1 to 4|
|Load Cell Capacity / Display||150 lbs / 150 lbs||150 lbs / 125 lbs*|
|Automatic CV Calculation||Yes||Yes|
|Units of Measure||lb kg N||lb N|
*Note: The Load cells are identical in both units. The can both safely operate to 150lbs, but the Power Track II only displays to 125lbs. As both units share the same load cells and transducer pads, measurement results from both units are expected to be interchangeable.
Commander Echo Console
Just as the Power Track II dynamomenter incorporates a console used to display measurement results, so too does the Commander Echo Wireless Muscle Tester. However, being wireless there is no cable linking the transducer to the console. One major benefit is that the console can be used with many different devices, so if you later purchase any of the following Echo products, you can connect them to the same console: goniometer, dual inclinometers, grip strength dynamometer, pinch dynamometer, and static force gauge dynamometer.
Large LCD window with easy-to-read characters
- Automatic test sequencing
- Automatically calculates appropriate statistics
- Measures in pounds, kilograms, Newtons, and degrees
- Wireless console is independent of the testing device, allowing the tester to review the data during active testing, without influencing patient effort.
- A Rechargeable Lithium-polymer battery. If fully charged provides about 15 hours of continual use.