Affiliations: [a] Department of Community Medicine and Rehabilitation,
Umeå University, Umeå, Sweden Tel.: +46 90 786 98 68; Fax: +46
90 786 927; E-mail: [email protected] | [b] Department of Health Sciences, Mid-Sweden University,
Östersund, Sweden | [c] Department of Public Health and Clinical Medicine,
Umeå University, Umeå, Sweden
Note: [] Corresponding author: Mattias Hedlund, Department Community
Medicine and Rehabilitation, Physiotherapy, Umeå University, SE-901 87,
Umeå, Sweden. Tel.: +46 90 786 98 68; Fax: +46 90 786 927; E-mail:
[email protected]
Abstract: The aim of this study was to compare the effect of isokinetic
contraction mode and velocity on the torque-angle relationship during maximum
voluntary elbow flexion in patients with stroke, age-matched healthy subjects
and young subjects. To eliminate the effect of torque amplitude differences
between subjects and groups, the torque values throughout the ROM were
individually normalized to the peak value for each contraction velocity. The
results indicate that in stroke patients the normalized torque angle
relationship during the eccentric contractions was better preserved than during
concentric contractions. Specifically, during eccentric contractions, stroke
patients exhibited a torque-angle relationship that was closer to normal as the
test velocity increased. The opposite trend could be seen in concentric
contractions where the torque-angle relationship became more divergent from
normal with a rise in the velocity. The torque-angle relationships were
essentially the same for the control groups, irrespective of contraction mode
or velocity. These findings may have significance for loading patterns of
resistance training exercises used with stroke patients as such exercises
normally are biomechanically designed for normal torque angle relationships. In
clinical practice, these findings may partly explain why the strength increases
due to resistance training are limited for patients with stroke.
Keywords: Elbow, concentric, eccentric, strength, torque-angle relationship, resistance training
