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 (α = 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.

Implications for RehabilitationSpecific biomechanical characteristics between the sit-to-stand and stand-to-sit were confirmed in stroke survivors and healthy-matched controls at both speeds.Fast speeds showed differences that were not observed at self-selected speeds.Trunk biomechanical characteristics must be carefully evaluated and should be considered in rehabilitation programs that aim to improve sit-to-stand and stand-to-sit performance.

Trunk flexor and extensor muscle performance in chronic stroke patients: a case-control study.

BACKGROUND: Although chronic stroke patients commonly show impairment of trunk muscle performance, this disability has only been analyzed in terms of peak torque. Therefore, other measures are needed for a more adequate description. OBJECTIVE: This study aimed to compare concentric muscle performance of trunk flexor/extensor muscles between chronic stroke patients and matched-healthy subjects. METHODS: 18 chronic stroke patients and 18 healthy subjects were matched according to their age, sex, body mass index and level of physical activity. After familiarization, trunk flexor/extensor concentric muscle strength was measured using an isokinetic dynamometer (Biodex Medical Systems Inc, Shirley, NY, USA) with 3 repetitions at a velocity of 60°/s and 5 repetitions at a velocity of 120°/s. Trunk muscular performance was characterized by peak torque, torque at 90°, total work, and total work normalized by trunk mass. Student's t-test was used for independent samples (α=0.05) for group comparisons. RESULTS: All trunk muscle performance variables values investigated were significantly lower in chronic stroke patients when compared to matched-healthy subjects (p≤0.001). The obtained ratios of chronic stroke patients scores to that of the matched-healthy subjects at velocities of 60°/s and 120°/s were, respectively: flexor peak torque (60% & 53%)/extensor (54% & 53%); flexor torque at 90° (56.20% & 36.58%)/extensor (57.92% & 30.65%); flexor total muscular work (51.27% & 38.03%)/extensor (47.97% & 39.52%); and flexor total muscular work normalized by trunk mass (55.57% & 40%)/extensor (51.40% & 42%). CONCLUSIONS: Chronic stroke patients showed decreased trunk muscle performance when compared to matched-healthy subjects in all variables investigated.

Trunk kinematics related to generation and transfer of the trunk flexor momentum are associated with sit-to-stand performance in chronic stroke survivors.

BACKGROUND: Stroke subjects show poorer sit-to-stand (STS) performance when compared to matched-healthy subjects, but it is still unclear the trunk role in this poorer performance. OBJECTIVES: To compare the trunk kinematics related to the generation/transfer of the flexor momentum during the STS task between stroke and matched-healthy subjects, and to investigate if there were relationships between these variables and STS performance. METHODS: Eighteen chronic stroke survivors and 18 matched-healthy subjects were assessed. The score of the five-repetition STS test and the total/phases duration of the STS (motion analysis system) at both self-selected/fast speeds characterized STS performance. Trunk kinematic variables were maximum forward flexion, peak flexor momentum, and its temporal framework in the STS. Between groups comparisons (Independent Student's t-tests) and correlations (Pearson correlation) were performed (α= 0.05). RESULTS: Stroke subjects showed poorer STS performance, greater values of maximum forward flexion at fast speeds, and a lower peak flexor momentum at both speeds (0.001≤p≤0.022). In general, the correlations were significant, moderate (0.001≤p≤0.028), and positive to maximum forward flexion (0.37≤r≤0.54) and negative to peak flexor momentum (-0.58≤r≤-0.71). CONCLUSIONS: The poorer STS performance in stroke survivors is associated to the kinematic changes of the trunk related to the poorer ability to generate/transfer the trunk flexor momentum.