Fatores relacionados à atividade física pós acidente vascular encefálico

Abstract

Individuals after stroke remain with several long-term disabilities. In this sense, therapeutic approaches should be implemented for a broad view of the deficiencies in structure and body function, and limitations in activity and restrictions of social participation of these individuals. Thus, there is growing interest in understanding the global mechanisms related to post-stroke physical activity, since the inactivity cause a vicious cycle, leading to sedentary lifestyles, decreasing cardiorespiratory fitness, and, therefore, decreasing the social participation of these individuals. In this theses, four studies were carried-out, in order to fill the gap in the literature regarding the factors related to post-stroke physical activity. The first study aimed to verify if the mechanically assisted walking training would increase walking speed or distance in ambulatory people with stroke, compared with no intervention/non-walking intervention, or overground walking. In this sense, a systematic review of randomized clinical trials (PROSPERO CRD 42012002622) was performed. To be included in the systematic review, the studies should have mechanically assisted gait without partial body weight support as intervention; outcomes related to gait, such as speed and distance covered. Nine studies, which used the treadmill training as intervention, were included, comprising 977 participants. The meta-analysis showed that treadmill training resulted in greater gains in gait speed, when compared to no intervention or non-walking intervention (MD 0.14 m/s, 95% CI 0.09 to o.19), immediately after the training. These benefits were maintained beyond the intervention period (MD 0.12 m/s, 95% CI 0.08 to 0.17). The treadmill gait training also provided increases in the distance covered immediately after the intervention (MD 40 m, 95% CI 27 to 53), and this increase was maintained beyond the intervention period (MD 40 m, 95% CI 24 to 55 ). No statistically differences were observed immediately after the intervention, when treadmill and overground walking training were compared, in terms of speed (MD 0.05 m/s, 95% CI 0.12- to 0.21) or distance covered (MD -6 m, 95% CI -45 to 33). The second study aimed to determine whether conventional physiotherapy sessions provide appropriate duration (>10 minutes) and intensity (>40% heart rate reserve) to induce adequate cardiorespiratory stress in individuals with chronic stroke. Two sessions were observed, with one week interval between them of 20 stroke individuals (mean age 58 years, 45% male, post-onset time 26 months). The activities were categorized as: upper limb activities, standing, stepping, basic walking, and advanced walking. Descriptive statistics showed that there were no differences between the activity intensity and duration between the sessions. None of the activities were carried out with sufficient intensity or duration to provide cardiorespiratory stress. The activity that provided the greatest intensity was advanced walking, and the individuals achieved, on average, 32% of their heart rate reserve values. The upper limb activities were the ones with longest duration (25 minutes).The third study aimed to evaluate the test-retest reliability of Cortex MetaMax 3B® ergospirometer in chronic stroke individuals during the 6-minute walk test (6MWT). For this methodological study, 21 stroke individuals (13 men, mean age of 59 years, and mean time post-stroke of 30 months) performed two sessions of the 6MWT with the Cortex MetaMax 3B®, with one week interval between the measurements. Statistical analyses were based upon intra-class correlation coefficients, t tests, standard errors of the measurement, and Bland-Altman plots for the cardiorespiratory variables (absolute oxygen consumption, relative oxygen consumption, carbon dioxide production, respiratory exchange ratio, minute ventilation, and heart rate) during the 6MWT. The intra-class correlation coefficients ranged from 0.76 to 0.97. The mean difference between the tests varied between 0 and 3% and the standard error of measurement from 1 to 12%.The results showed appropriate values for the test-retest reliability of the Cortex MetaMax 3B®. The fourth study aimed to evaluate if the energy cost of stroke individuals during the performance of functional activities related to the lower limbs could be predicted by their functional levels. This experimental study included 55 chronic stroke individuals, 33 men, mean age of 59 years, and mean time post stroke of 25 months. The predictor variable was the functional level, determined by the walking speed, assessed by the 10 meter walking test. The outcome of interest was the energy cost during the performance of functional activities (comfortable and fast gait speeds and stair ascent/descent), which was measured by the portable ergospirometer Cortex MetaMax 3B®. The relative oxygen consumption was divided by the distance covered during the functional activities, resulting in the energy cost. The mean walking speed was 0.84 m/s. The energy cost during comfortable walking was 0.24±0.11 ml mlkg-1m-1 and during fast walking, 0.24±0.10 mlkg-1m-1. For the stairs, the energy cost was 1.13±0.43 mlkg-1m-1. The quadratic regression model demonstrated that the functional level explained 81% of the variance in the energy cost. The energy cost can be predicted by the following equation: EC (mlkg-1m-1) = 0.95 1.28* comfortable walking speed, in m/s + 0.47*comfortable walking speed2 + 0.91*activity (walking speed = 0; stairs = 1). The findings of the studies included in this thesis support the following conclusions: In post stroke individuals, the treadmill training without partial body weight support resulted in higher walking speed and distance covered for ambulatory individuals, when compared to no intervention or intervention without walking training, and these benefits were kept beyond the intervention. In addition, no differences were observed immediately after the intervention, when treadmill and overground walking training were compared, in terms of speed or distance covered. Moreover, conventional physical therapy sessions do not provide adequate intensity and duration to induce cardiorespiratory stress. Adequate test-retest reliability was found for the portable ergospirometer Cortex MetaMax 3B® in stroke individuals. Finally, the observed findings showed a quadratic relationship between the functional level and energy cost of stroke individuals during activities related to the lower limbs, such as the comfortable/fast gait speeds and managing stairs. These findings led to the establishment of a prediction equation regarding the energy cost of stroke individuals, based upon their functional levels.