Trunk strength is associated with sit-to-stand performance in both stroke and healthy subjects

Since impairments of the trunk muscles are observed in stroke subjects, who also demonstrate limitations in performing the sit-to-stand (STS) task, it is possible that these limitations are related to decreased strength of the trunk muscles.

To compare the STS performances and isokinetic measures of trunk strength between stroke and matched healthy subjects and to investigate if there were associations between STS performances and strength of the trunk muscles.

Exploratory study.

University Laboratory.

Eighteen stroke and 18 match-ed healthy subjects.

Subjects performed the five-repetition sit-to-stand test and were also asked to stand up and sit down at both self-selected and fast speeds (motion analysis system). The scores of the five-repetition sit-to-stand test and the total duration of the STS, as well as the duration of phases I and II were used as measures of STS performances. Isokinetic strength of the trunk muscles was assessed at a speed of 60º/s: concentric peak torque and total normalized work.

Stroke subjects showed poorer STS performances (P≤0.02), except for the duration of phase I at self-selected speed, as well as decreased strength of the trunk muscles (P≤0.001). Significant and negative correlations were found between STS performance and trunk strength variables, which were classified as low (-0.38≤r≤-0.49) or moderate (-0.50≤r≤-0.63).

In general, poorer STS performances observed in stroke subjects was related to weakness of the trunk muscles.

Evaluation and interventions involving trunk strength should be included in rehabilitation of stroke subjects, who show limitations in STS performances.