Dynamometry at Curtin
Like most Schools of Physiotherapy, dynamometry for the assessment of strength and muscle training has been included in the entry-level curriculum. My recollection is that the first significant purchase in this area at Curtin was a Penny and Giles myometer. This enabled isometric muscle actions to be evaluated in a variation on standard manual muscle testing. In the late 70's an Orthotron was purchased and subsequently instrumented with a potentiometer and strain gauges. Knee flexor and extensor, ankle plantarflexor and dorsiflexor, and ankle invertor and evertor muscle groups were assessed.
In 1983 the School purchased the first Kinetic Communicator (Kin-Com) dynamometer in Australia. The original Kin-Com was manufactured in Canada by the designers of the system and the basic operation of the Kin-Com established in that first model. The earliest computer ran the Turbo-dos operating system and soon needed to be upgraded as IBM and IBM-compatible computers became available. A computer was required in the system as this Kin-Com was the first commercially-available computer to offer eccentric capabilities.
In 1987 the School was able to upgrade to the Kin-Com II. The software changed dramatically and additional features were added over the years. In 1992 the more powerful (5Hp) Kin-Com 500H was purchased. The computer with its 80386 chip was soon upgraded to a computer with the even more powerful 80486 chip, and it is this dynamometer and computer combination that continues to operate to this day.
The Kin-Com has been a remarkable dynamometer that has offered a degree of flexibility that I believe has been unmatched by other dynamometers for human muscle performance testing. The ability to alter some of the control parameters enabled a number of novel applications - a protocol for joint position sense following concentric or eccentric loading, and a protocol with short range, high velocity perturbation for muscle stiffness testing. An isotonic protocol and a force-sensitive range of motion (ROM) protocol are two examples of innovative applications provided for the software. Eccentric capabilities for isokinetic testing at 240 deg/s could not be matched by other manufacturers for many years!
An under-rated aspect of the Kin-Com system has been the ability to preload muscle prior to allowing movement through the range of motion. It is still interesting that inaccurate strength curve shapes appear in published literature - shapes that are inaccurate through the first part of the active ROM.
In February 2008 the School took delivery of a Humac NORM system. Following discussion with the manufacturers (CSMI) at the 2007 ACSM annual conference, where Craig Purdham (AIS Physio) and I outlined the necessity of a preload capability in their dynamometer, it was extremely pleasing to be informed some months later that this had been implemented. The School will now embark on a new period of dynamometry experiences.
- Geoffrey R. Strauss
- Senior Lecturer in Exercise Physiology
Muscle Groups Tested
Isolated Joint Testing
| Hip Extensors | Trunk Flexors | Shoulder Internal Rotators |
| Hip Internal Rotators | Trunk Extensors | Shoulder External Rotators |
| Hip External Rotators | Forearm Pronators | |
| Knee Extensors | Forearm Supinators | |
| Knee Flexors | Wrist Extensors | |
| Ankle Plantarflexors | ||
| Ankle Dorsiflexors |
Multi-joint Testing
| Bench Press |
Current Systems
| Kin-Com 500H Dynamometer | Humac Norm Dynamometer | |
|---|---|---|
| Force | 2000N on the load cell | NA, Force = Torque / perpendicular distance |
| Torque | NA, Torque = Force × perpendicular distance | 678 Nm ( 500 ft-lbs) |
| Forward Speed range | 1 to 240 deg/s | 1 to 550 deg/s concentrically 1 to 300 deg/s eccentrically 5 to 150 deg/s CPM |
| Backward Speed range | 1 to 240 deg/s | 1 to 550 deg/s concentrically 1 to 300 deg/s eccentrically 5 to 150 deg/s CPM |
| Modes | Isokinetic (active isokinetic) CPM (passive isokinetic) Isotonic Isometric Range of Motion
|
Isokinetic (active isokinetic) Passive (passive isokinetic) Isotonic Isometric |
| Accessories | Trunk Testing Lever Arm Extension for Bench Press Assessments Knee Clamp for Hip IR/ER Assessments Hand Grip for Wrist Extension Assessments |
Leg Press Attachment |
