Affiliations: [a] Biomechanics and Ergonomics Laboratory, School of
Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada | [b] School of Rehabilitation Therapy, Queen's University,
Kingston, ON, Canada | [c] Human Mobility Research Centre, Queen's University and
Kingston General Hospital, Kingston, ON, Canada
Note: [] Address for correspondence: S. Almosnino, Human Mobility
Research Centre, Syl and Molly Apps Medical Research Centre, Kingston General
Hospital, Kingston, Ontario, Canada K7L 2V7. E-mail: [email protected]
Abstract: Isokinetic assessment of knee extensors muscle group function in
patients suffering from knee osteoarthritis has exclusively been achieved using
time-domain based variables. While useful, these analyses do not quantify the
conspicuously irregular moment-time pattern exhibited by the involved knee when
compared to the contralateral knee. The purpose of this investigation was to
assess whether the frequency content of the isokinetic curve can quantify this
latter phenomenon. Thirty two patients with knee osteoarthritis participated in
this study. Each participant performed 5 maximal concentric knee extensions
bilaterally at 60°/s using an isokinetic dynamometer.
For each time-domain extension curve, the power spectrum was calculated via
Fast Fourier Transform and the maximum frequency content value contained within
99% of total signal power was extracted. Of the 32 participants, 26
exhibited higher frequency contents in the isokinetic curves obtained from
their involved knee (p= 0.002, effect size =0.35). The results suggest that the frequency content of
isokinetic moment-time curves may provide useful quantitative information
regarding the smoothness of moment production, and as such, may be used in
conjunction with traditional time-domain variables in the assessment of knee
extensors function in patients suffering from knee osteoarthritis.
