TY - JOUR
T1 - Voluntary stepping behavior under single- and dual-task conditions in chronic stroke survivors
T2 - A comparison between the involved and uninvolved legs
AU - Melzer, Itshak
AU - Goldring, Melissa
AU - Melzer, Yehudit
AU - Green, Elad
AU - Tzedek, Irit
N1 - Funding Information:
This study was supported by internal grant from the Recanati School of Community Health Professions in the Faculty of Health Sciences at Ben-Gurion University of the Negev. We would also like to thank the Ne’eman Association for Stroke Survivors and their members who volunteered for this research study.
PY - 2010/12/1
Y1 - 2010/12/1
N2 - Objective: If balance is lost, quick step execution can prevent falls. Research has shown that speed of voluntary stepping was able to predict future falls in old adults. The aim of the study was to investigate voluntary stepping behavior, as well as to compare timing and leg push-off force-time relation parameters of involved and uninvolved legs in stroke survivors during single- and dual-task conditions. We also aimed to compare timing and leg push-off force-time relation parameters between stroke survivors and healthy individuals in both task conditions. Methods: Ten stroke survivors performed a voluntary step execution test with their involved and uninvolved legs under two conditions: while focusing only on the stepping task and while a separate attention-demanding task was performed simultaneously. Temporal parameters related to the step time were measured including the duration of the step initiation phase, the preparatory phase, the swing phase, and the total step time. In addition, force-time parameters representing the push-off power during stepping were calculated from ground reaction data and compared with 10 healthy controls. Results: The involved legs of stroke survivors had a significantly slower stepping time than uninvolved legs due to increased swing phase duration during both single- and dual-task conditions. For dual compared to single task, the stepping time increased significantly due to a significant increase in the duration of step initiation. In general, the force time parameters were significantly different in both legs of stroke survivors as compared to healthy controls, with no significant effect of dual compared with single-task conditions in both groups. Conclusions: The inability of stroke survivors to swing the involved leg quickly may be the most significant factor contributing to the large number of falls to the paretic side. The results suggest that stroke survivors were unable to rapidly produce muscle force in fast actions. This may be the mechanism of delayed execution of a fast step when balance is lost, thus increasing the likelihood of falls in stroke survivors.
AB - Objective: If balance is lost, quick step execution can prevent falls. Research has shown that speed of voluntary stepping was able to predict future falls in old adults. The aim of the study was to investigate voluntary stepping behavior, as well as to compare timing and leg push-off force-time relation parameters of involved and uninvolved legs in stroke survivors during single- and dual-task conditions. We also aimed to compare timing and leg push-off force-time relation parameters between stroke survivors and healthy individuals in both task conditions. Methods: Ten stroke survivors performed a voluntary step execution test with their involved and uninvolved legs under two conditions: while focusing only on the stepping task and while a separate attention-demanding task was performed simultaneously. Temporal parameters related to the step time were measured including the duration of the step initiation phase, the preparatory phase, the swing phase, and the total step time. In addition, force-time parameters representing the push-off power during stepping were calculated from ground reaction data and compared with 10 healthy controls. Results: The involved legs of stroke survivors had a significantly slower stepping time than uninvolved legs due to increased swing phase duration during both single- and dual-task conditions. For dual compared to single task, the stepping time increased significantly due to a significant increase in the duration of step initiation. In general, the force time parameters were significantly different in both legs of stroke survivors as compared to healthy controls, with no significant effect of dual compared with single-task conditions in both groups. Conclusions: The inability of stroke survivors to swing the involved leg quickly may be the most significant factor contributing to the large number of falls to the paretic side. The results suggest that stroke survivors were unable to rapidly produce muscle force in fast actions. This may be the mechanism of delayed execution of a fast step when balance is lost, thus increasing the likelihood of falls in stroke survivors.
KW - Balance
KW - Falls
KW - Stroke
KW - Voluntary step execution times
UR - http://www.scopus.com/inward/record.url?scp=77957020862&partnerID=8YFLogxK
U2 - 10.1016/j.jelekin.2010.07.001
DO - 10.1016/j.jelekin.2010.07.001
M3 - Article
AN - SCOPUS:77957020862
VL - 20
SP - 1082
EP - 1087
JO - Journal of Electromyography and Kinesiology
JF - Journal of Electromyography and Kinesiology
SN - 1050-6411
IS - 6
ER -