Trunk biomechanical changes between the sit-to-stand and stand-to-sit performed at self-selected and fast speeds in stroke survivors

Purpose: To compare the trunk biomechanical characteristics between the sit-to-stand and stand-to-sit performed at self-selected and fast speeds in stroke survivors and healthy-matched controls. Methods: Thirty individuals (15 stroke survivors and 15 healthy-matched controls) were included. The following biomechanical characteristics were determined: peak of trunk forward flexion and time until the peak of trunk forward flexion, total duration, phase I (sit-to-stand: time spent from the beginning to seat-off; stand-to-sit: time spent from the beginning to seat-on) and II durations (sit-to-stand: time spent from seat-off to the end of the task; stand-to-sit: time spent from the seat-on to the end of the task). Two-way repeated measures ANOVA was used (alpha = 5%). Results: The maximum angle of trunk forward flexion and time spent until the maximum angle of trunk forward flexion in both tasks were significantly higher in stroke survivors. For both groups and speeds, phase I duration and peak of trunk forward flexion of the stand-to-sit were significantly higher than that of the sit-to-stand (11.41 <= F <= 33.60; 0.001 <= p <= 0.002) and, phase II duration was significantly higher during the sit-to-stand than that of the stand-to-sit (21.27 <= F <= 65.10; p <= 0.001). Conclusions: These results confirm specific trunk biomechanical characteristics between sit-to-stand and stand-to-sit in stroke survivors and healthy-matched controls.