Isometric muscle function of knee extensors and the relation with functional performance in patients with stroke.
OBJECTIVE
(1) To examine the isometric strength, speed, and fatigue resistance of the knee extensors of the paretic limb and nonparetic limb in patients with stroke and compare these with able-bodied subjects. (2) To relate the contractile properties with different indices of functional performance.


METHODS
Case-control study.


METHODS
Rehabilitation center research laboratory.


METHODS
Eighteen stroke patients and 10 able-bodied controls.


METHODS
Not applicable.


METHODS
Maximal voluntary torque (MVT), maximal rate of torque development, time to maximal rate of torque development, half relaxation time ((1/2)RT), and fatigue index. Scores on the Functional Ambulation Category scale, Berg Balance Scale, and Rivermead Mobility Index as well as distance walked during the six-minute walk test were obtained.


RESULTS
MVT of the paretic leg was lower than of the nonparetic leg (P<.05), and both limbs had lower MVT than controls (P<.05). Both the paretic and the nonparetic leg showed longer (1/2)RT compared with controls (P<.05). The fatigue index was reduced in the paretic leg (P<.05) but not in the nonparetic leg compared with controls. MVT and fatigue index of the paretic leg were related to indices of functional performance (r=0.49-0.64; P<.05).


CONCLUSIONS
Apart from bilateral weakness, knee extensors in patients with stroke showed a lower rate of torque development and relaxation (both paretic and nonparetic leg) and lower fatigue resistance (paretic leg only) than controls, which in part may be a consequence of changes within the muscles. Strength and fatigue resistance relate to functional performance, indicating that these muscle properties should be addressed during rehabilitation. However, future research is needed to elucidate the efficacy of exercise programs.
Gerrits
Karin H
KH
Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands. k_gerrits@fbw.vu.nl
Beltman
Marijke J
MJ
Koppe
Peter A
PA
Konijnenbelt
Hermanna
H
Elich
Peter D
PD
de Haan
Arnold
A
Janssen
Thomas W
TW
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007717:Knee / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D055815:Young Adult