Lower Limb Strength Is Significantly Impaired in All Muscle Groups in Ambulatory People With Chronic Stroke: A Cross-Sectional Study

Abstract

ObjectiveTo measure the strength of the major muscle groups of the affected and intact lower limbs in people with stroke compared with age-matched controls. DesignCross-sectional study. SettingUniversity laboratory. ParticipantsAmbulatory stroke survivors (n=60; mean age, 69±11y), who had had a stroke between 1 and 6 years previously, and age-matched controls (n=35; mean age, 65±9y) (N=95). InterventionsNot applicable. Main Outcome MeasuresThe maximum isometric strength of 12 muscle groups (hip flexors and extensors, hip adductors and abductors, hip internal rotators and external rotators, knee flexors and extensors, ankle dorsiflexors and plantarflexors, ankle invertors and evertors) of both lower limbs was measured using handheld dynamometry. All strength measurements were taken in standardized positions by 1 rater. ResultsThe affected lower limb of the participants with stroke was significantly weaker than that of the control participants for all muscle groups (P<.01). Strength (adjusted for age, sex, and body weight) was 48% (range, 34%–62%) of that of the control participants. The most severely affected muscle groups were hip extensors (34% of controls), ankle dorsiflexors (35%), and hip adductors (38%), and the least severely affected muscle groups were ankle invertors (62%), ankle plantarflexors (57%), and hip flexors (55%). The intact lower limb of the participants with stroke was significantly weaker than that of the control participants for all muscle groups (P<.05) except for ankle invertors (P=.25). Strength (adjusted for age, sex, and body weight) was 66% (range, 44%–91%) of that of the control participants. The most severely affected muscle groups were hip extensors (44% of controls), ankle dorsiflexors (52%), and knee flexors (54%). ConclusionsAmbulatory people with chronic stroke have a marked loss of strength in most of the major muscle groups of both lower limbs compared with age-matched controls.