The role of postural control in the association between aerobic capacity and walking capacity in chronic stroke: a cross-sectional analysis.

BACKGROUND: Reports on the association between aerobic capacity and walking capacity in people after stroke show disparate results. AIM: The aim of this study was to determine: 1) if the predictive validity of peak oxygen uptake (VO2peak) for walking capacity post stroke is different from that of maximal oxygen uptake (VO2max), and 2) if postural control, hemiplegic lower extremity muscle strength, age and gender distort the association between aerobic capacity and walking capacity. DESIGN: Cross-sectional study. SETTING: General community in Utrecht, The Netherlands. POPULATION: Community-dwelling people more than three months after stroke. METHODS: Measurement of aerobic capacity were performed with cardiopulmonary exercise testing (CPET) and differentiated between the achievement of VO2peak or VO2max. Measurement of walking capacity with the 6-Minute Walk Test (6MWT), postural control with the Performance-Oriented Mobility Assessment (POMA) and hemiplegic lower extremity muscle strength with the Motricity Index (MI-LE). RESULTS: Fifty-one out of 62 eligible participants, aged 64.7±12.5 years were included. Analysis of covariance (ANCOVA) showed a nonsignificant difference between the predictive validities of VO2max (N.=22, ß=0.56; 95% CI: 0.12-0.97) and VO2peak (N.=29, ß=0.72; 95% CI: 0.38-0.92). Multiple regression analysis of the pooled sample showed a significant decrease in the ß value of VO2peak (21.6%) for the 6MWT when adding the POMA as a covariate in the association model. VO2peak remained significantly related to 6MWT after correcting for the POMA (ß=0.56, 95% CI: 0.39-0.75). CONCLUSIONS: The results suggest similar predictive validity of aerobic capacity for walking capacity in participants achieving VO2max compared to those only achieving VO2peak. Postural control confounds the association between aerobic capacity and walking capacity. Aerobic capacity remains a valid predictor of walking capacity. CLINICAL REHABILITATION IMPACT: Aerobic capacity is an important factor associated with walking capacity after stroke. However, to understand this relationship, postural control needs to be measured. Both aerobic capacity and postural control may need to be addressed during interventions aiming to improve walking capacity after stroke.

Effects of a high-intensity task-oriented training on gait performance early after stroke: a pilot study.

OBJECTIVE: To investigate the feasibility and the effects on gait of a high intensity task-oriented training, incorporating a high cardiovascular workload and large number of repetitions, in patients with subacute stroke, when compared to a low intensity physiotherapy-programme. DESIGN AND SUBJECTS: Randomized controlled clinical trial: Forty-four patients with stroke were recruited at 2 to 8 weeks after stroke onset. MEASURES: Maximal gait speed assessed with the 10-metre timed walking test (10MTWT), walking capacity assessed with the six-minute walk test (6MWT). Control of standing balance assessed with the Berg Balance Scale and the Functional Reach test. Group differences were analysed using a Mann-Whitney U-test. RESULTS: Between-group analysis showed a statistically significant difference in favour of the high intensity task-oriented training in performance on the 10MTWT (Z = -2.13, P = 0.03) and the 6MWT (Z = -2.26, P = 0.02). No between-group difference were found for the Berg Balance Scale (Z = -0.07, P = 0.45) and the Functional Reach test (Z = -0.21, P = 0.84). CONCLUSION: A high-intensity task-oriented training programme designed to improve hemiplegic gait and physical fitness was feasible in the present study and the effectiveness exceeds a low intensity physiotherapy-programme in terms of gait speed and walking capacity in patients with subacute stroke. In a future study, it seems appropriate to additionally use measures to evaluate physical fitness and energy expenditure while walking.