Affiliations: [a] Ergonomics Research Laboratory, Faculty of
Rehabilitation Medicine, University of Alberta, Edmonton, Alberta,
Canada | [b] Professor Emeritus of Physical Therapy and Physical
and Health Education, School of Rehabilitation Therapy, Queen's University,
Kingston, Ontario, Canada
Note: [] Ergonomics Research Laboratory, Faculty of Rehabilitation
Medicine, Room 3-74 Corbett Hall, University of Alberta, Edmonton, AB, Canada
T6G 2G4. Tel.: +1 780 492 7187; Fax: +1 780 492 1626; E-mail:
tamell@ualberta.ca
Note: [1] This research project was approved by the Queen’s University Faculty of Medicine Ethics Committee on the use of Human Subjects.
Abstract: {\it Purpose:} The purpose of this study was to assess the effect of
varying the measurement axis of the subject relative to an isokinetic
dynamometer on the peak flexion and extension moment of the trunk. The effect
of testing position (sitting or standing) on peak moment was also investigated.
{\it Methods:} Thirty healthy young subjects [8 male, 22 female] were selected
at random from a pool of 90 volunteers and asked to perform concentric sagittal
flexion-extension cycles at velocities of 60 deg/s, 120 deg/s and 180 deg/s in
both the seated and standing position with respect to 5 measurement axes. The
subjects were initially aligned with the highest point on the iliac crest
(reference axis) and then aligned with 4 measurement axes displaced from the
reference axis (25~mm anterior/posterior and 50mm superior/inferior). {\it
Results:} Two-way repeated measures ANOVA revealed significant differences
($\alpha < 0.05$) between peak moments recorded between axes and velocity
for flexion and extension, however no difference with respect to testing
position, i.e., sitting versus standing. Post hoc multiple comparison tests by
the Scheff?method revealed that all measurement axes tested were statistically
different [$P < 0.001$] from the reference axis, however there were no
differences between the two inferior axes [$P = 0.999$] and the two superior
axes [$P = 0.982$]. The inferior measurement axes consistently produced greater
peak moments than the reference axis while the superior axes consistently
produced lower peak moments than the reference axis. Males produced
significantly greater peak moments than did females [$P = 0.000$]. {\it
Conclusions:} Measurement axis alignment significantly effects the peak moment
recorded. Furthermore, these results reinforce the need for accurate and
consistent alignment between the subject and the dynamometer. The position of
the subject [seated/standing] did not significantly affect the measured peak
moment when using the Lido Active Back System in this study.
