Table of Contents
Advertisement
Model 01165A/01165APP
Appendix A: Torque measurements with the HHD
In some research and rehabilitation applications, it is necessary to obtain torque measurements for
the limb being tested. Torque is often a more accurate indicator of total strength because it takes into
account the length of the muscle being tested. The Lafayette Hand-held Dynamometer (HHD) can be
used to obtain torque values through a series of basic calculations.
Torque is measured in units of Newton meters (Nwm) in the Metric system and in foot pounds (ftwlbs)
in the English system. Torque is the product of the force applied times the distance between the force
and the pivot point (usually a joint).
Equations for obtaining torque readings with the HHD using metric values:
Torque = Force * Distance
Where force equals the HHD reading converted to Newtons and distance is the length between where
the force is applied and the joint being tested in meters.
Newtons conversions: 1 pound = 4.45 Newtons; 1 kilogram = 9.81 Newtons
Newtons are calculated at sea level.
obtained by dividing the torque by the person's bodyweight in kg.
Strength =
((HHD reading in Newtons) * distance)
bodyweight in kilograms
Appendix B: Calculating Kilopascals with the HHD
Kilopascals can only be measured accurately using the included algometer attachment. Because
the attachment's tip is not precisely 1cm
adjustment to the value when converting to kilopascals. Below is a description of how the conversion
takes place:
2
1 lbf/cm
= 44.4822 kPa
Algometer tip: diameter = 7/16"
HHD reading of 1 lbf / 0.96985 cm
HHD Conversion to kPa: 1.03109 lbf/cm
Conversion from lbf to kPa using algometer tip: 1 lbf
Fax: (765) 423-4111 . www.lafayetteinstrument.com . info@lafayetteinstrument.com
User Instructions
surface area = 0.96985 cm
2
= 1.03109 lbf/cm
2
2
* 44.4822 kPa/(lbf/cm
45.865 kPa
2
2
) = 45.865 kPa
11
Advertisement
Table of Contents
