Aim: The aim of the study was to compare the strength and fatigue of ankle plantarflexor/dorsiflexor muscles using isokinetic dynamometer in patients with ankylosing spondylitis (AS) versus healthy control subjects.
Design: A controlled study.
Setting: Outpatients clinic of our Department of Physical Medicine and Rehabilitation.
Population: Twenty-six AS patients and 26 control subjects participated in this study.
Methods: In both groups the isokinetic tests are conducted by isokinetic dynamometer.The evaluations were made in plantarflexion/dorsiflexion patterns;peak torque, agonist/antagonist ratio and work fatigue isokinetic parameters were evaluated for the ankle 30 º/s, 60º/s, 120º/s angular velocities. Pain severity, clinical findings, and functional status were also evaluated in the study group.
Results: In the patient group, ankle plantarflexion muscle strength was significantly lower compared to the control group in all angular velocities (P<0.05). Agonist/antagonist ratio was significantly lower in the patient group compared to the control group in all angular velocities (P<0.01). The work fatigue was decreased for bilateral ankle plantarflexors at 120º/s angular velocities (P<0.05). There was no significant difference between the measurements of ankle dorsiflexors (P>0.05). There was no relation between the decreased muscle strength and pain severity, clinical findings, and functional status of AS patients.
Conclusion: We found ankle muscles fatigue and decreased ankle plantarflexor muscle strength in patients with AS compared to control subjects.