How to Score the Peak Oxygen Consumption Obtained Through Cardiopulmonary Exercise Test in Individuals after Stroke?

OBJECTIVES: To compare five distinct methods to score the peak of oxygen consumption (VO2peak) obtained through the cardiopulmonary exercise testing (CPET) in individuals after stroke. MATERIALS AND METHODS: The VO2peak was obtained through the CPET with five methods: method-1: the highest value of the test; method-2: the highest value of the last 30 seconds at peak exercise; method-3: the mean of the last 30 seconds at peak exercise; method-4: the mean of the last 20 seconds at peak exercise; method-5: the highest value averaged of the 3 last blocks of 10 seconds at peak exercise. The coefficient of variance (CV) and the mean differences with 95% confidence interval (CI) between the scoring methods were calculated. A post-hoc test (Tukey HSD) was performed to calculate the adjusted 95%CI. RESULTS: Fifty-nine individuals were included (54±12 years, 56±60 months after stroke). The CV of the methods 1-to-5 were, respectively: 27.91%, 25.77%, 23.38%, 23.83%, and 23.33%. There was no difference between method-1 and method-2 (95%CI: -1.10 to 4.69) and between methods 3 to 5: method-3 and method-4 (95%CI: -2.97 to 2.82); method-3 and method-5 (95%CI: -3.57 to 2.22); method-4 and method-5 (95%CI: -3.49 to 2.30). However, method-1 and -2 provided VO2peak values different from that of methods 3-to-5. CONCLUSIONS: The scoring method of obtaining the VO2peak has an influence on its magnitude. Since methods 3-to-5 showed lower CV and provided similar values, they should be used to calculate the VO2peak obtained through the CPET in individuals after stroke.

Effects of detraining on cardiorespiratory fitness of individuals with chronic stroke.

BACKGROUND: Aerobic training can improve cardiorespiratory fitness in individuals after stroke. However, the effects of short-term and long-term detraining are not well known. OBJECTIVE: To determine the effects of short-term (1-month) and long-term (6-month) detraining on cardiorespiratory fitness (VO2peak) of individuals after stroke, who participated in aerobic training. METHODS: A cohort study was developed. Twenty adults (57 ± 11 years old) with stroke were included. After completing an outpatient aerobic training, participants were divided into gain group (VO2peak increase >1.3 ml.kg-1.min-1 from before to immediately after the training) or non-gain group (VO2peak change ≤1.3 ml.kg-1.min-1). Cardiorespiratory fitness (VO2peak), obtained by the cardiopulmonary exercise test was assessed one and 6 months after the end of the training (short- and long-term detraining, respectively), or collected retrospectively from patient chart (before and after the training). RESULTS: There was found a significant interaction effect (time*group) for VO2peak (F= 6.108;p < 0,001). Higher values in the VO2peak observed in the gain group with the aerobic training (F = 25.86; p< .001) were significantly reduced with short-term detraining, reaching values similar to that observed before the training and to that of the non-gain group (F = 14.81;p= .001). Both groups had similar VO2peak values within long-term detraining (F = 2.70;p= .12), with no significant differences from the values observed before the training and after short-term detraining (0.11 ≤ p≤ 1.00). CONCLUSIONS: Detraining on cardiorespiratory fitness of individuals after chronic stroke occurred within only 1 month. Therefore, it is important to maintain aerobic training throughout life.

Reliability and validity of the incremental shuttle walking test in individuals after stroke.

BACKGROUND: There are limitations to perform the cardiopulmonary exercise test (CPET) and the six-minute walking test (6MWT) in clinical settings. The incremental shuttle walking test (ISWT) might be an alternative assessment of exercise capacity and an estimation of cardiopulmonary fitness after stroke. OBJECTIVES: To investigate the test-retest and inter-rater reliabilities, the standard error of measurement (SEM) and the minimal detectable change (MDC) of the ISWT, its construct validity to assess exercise capacity and its concurrent validity to estimate cardiopulmonary fitness after stroke. METHODS: Prospective diagnostic accuracy study. Fifty-one individuals (54 ± 11 years) at the chronic phase (65 ± 73 months after stroke) were included. The distance walked, in meters, during the 12-stage-ISWT and the 6MWT and the peak oxygen uptake (VO2peak, ml.kg-1.min-1) in the CPET (gold standard) were assessed. RESULTS: Significant and high to very high magnitude test-retest and inter-rater reliabilities (0.88≤ICC≤0.93) of the ISWT was found. The SEM for both reliabilities was small (-23.35 m≤ SEM≤41.47 m). The MDC for test-retest and inter-rater reliabilities were 114.63 m and 64.53 m, respectively. For construct validity, a significant and high magnitude correlation between the ISWT and the 6MWT was found (ICC = 0.82). For the concurrent validity, a significant, but low magnitude correlation was found between the ISWT and the VO2peak (rho = 0.42). CONCLUSIONS: The ISWT demonstrated adequate reliabilities and construct validity for exercise capacity assessment. However, the concurrent validity of the ISWT as an estimation of cardiopulmonary fitness still requires further research.

A Single Trial May Be Used for Measuring Muscle Strength With Dynamometers in Individuals With Stroke: A Cross-Sectional Study.

BACKGROUND: The mean of 3 trials is commonly employed to report measures of muscle strength after a stroke. However, consistent and reliable results have been found for single trial dynamometric measures of grip, pinch, and trunk strength in individuals with stroke. Nevertheless, no studies were found that investigated whether only a single trial could be used for the assessment of the strength of both the upper and lower limb muscles. OBJECTIVE: To determine the best scoring method (one vs the means of 2 or 3 trials) to measure the strength of the upper and lower limb muscles in individuals with sub-acute and chronic stroke. DESIGN: Cross-sectional observational study. SETTING: Research laboratory, participants' homes, and community-based settings. PARTICIPANTS: Fifty-five individuals at the sub-acute (mean age: 61 ± 13 years; 3.7 ± 0.7 months poststroke) and 59 at the chronic poststroke phases (mean age: 57 ± 130 years; 90 ± 71 months poststroke). MAIN OUTCOME MEASUREMENTS: Bilateral maximum isometric strength measures of the shoulder, elbow, and wrist flexors/extensors; shoulder abductors; hip, knee, and ankle flexors/extensors; and hip abductors were obtained with a hand-held dynamometer. METHODS: After familiarization, 3 trials of maximal isometric strength were obtained for all evaluated muscle groups. One-way analysis of variance was used to compare the results obtained with the first vs the means of 2 and 3 trials for all the assessed muscle groups. RESULTS: The values provided by the different scoring methods were similar for all evaluated muscle groups in individuals with sub-acute (.68 ≤ P ≤ .99) and chronic (.69 ≤ P ≤ .99) stroke. CONCLUSIONS: A single trial, after familiarization, may be used for measuring the strength of the upper and lower limb muscles with hand-held dynamometers in individuals with sub-acute and chronic stroke. This increases the clinical applicability of hand-held dynamometers for strength measurement, as it reduces the assessment burden placed on the participants and therapists. LEVEL OF EVIDENCE: III.