Comparison of motion sensor and heart rate monitor for assessment of physical activity intensity in stroke outpatient rehabilitation sessions: an observational study.

OBJECTIVE: To compare the estimation of time spent on 4 categories of physical activity intensity (sedentary behaviour, light physical activity, moderate physical activity, and vigorous physical activity) between a motion sensor and a heart rate monitor during a stroke outpatient rehabilitation session. DESIGN: A multicentre cross-sectional observational study. SUBJECTS/PATIENTS: Participants with stroke (> 6 months) undergoing outpatient rehabilitation sessions. METHODS: Participants wore the SenseWear Armband motion sensor and the Polar H10 heart rate monitor during 2 rehabilitation sessions. The times estimated by each device were compared using a generalized linear mixed model and post-hoc tests. RESULTS: Ninety-nine participants from 29 clinics were recruited and data from 146 sessions were included in the analysis. The estimated times depended on the devices and the physical activity intensity category (F = 135, p < 0.05). The motion sensor estimated more time spent in sedentary behaviour and less time spent in moderate physical activity and vigorous physical activity than the heart rate monitor. CONCLUSION: The motion sensor and heart rate monitor provide different estimates of physical activity intensity during stroke rehabilitation. Further research is needed to establish the most appropriate device for each physical activity category.

Impact of Active Physiotherapy on Physical Activity Level in Stroke Survivors: A Systematic Review and Meta-Analysis.

BACKGROUND: Stroke survivors are frequently physically inactive. However, evidence of the effectiveness of active physiotherapy on physical activity level in stroke survivors is scarce. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement, covering electronic searches from inception to March 16, 2022. Participants: Stroke survivors living in the community. Intervention: Any active physiotherapy, that is, involving exercises that require voluntary effort. Outcome measure: Objective and subjective physical activity level. RESULTS: Of 5590 identified references, 25 randomized controlled trials were eligible, and 21 had available data. The random-effects meta-analysis resulted in a small, significant effect size in favor of active physiotherapy measured using objective or subjective tools (21 studies, 1834 participants, standardized mean difference, 0.22 [95% CI, 0.04-0.40]; heterogeneity I2=65%), and a medium significant effect when objective tools were used (9 studies, 424 participants, standardized mean differences, 0.48 [95% CI, 0.03-0.92]; I2=73%). Meta-regression showed that 35% of the variance in trial outcome was explained by the measurement tool (objective or subjective) and 23% by age. None of the variances were associated with a specific dosage in terms of frequency, time, exercise duration, or the severity of the disability. CONCLUSIONS: Active physiotherapy seems to increase objective physical activity in community-dwelling stroke survivors. However, the evidence is of very low certainty. REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42022315639.

Effect of polar interactions on the magnetorheology of silica-coated magnetite suspensions in oil media.

This work deals with the role of nonmagnetic interactions on the magnetorheological (MR) response of suspensions of magnetic particles in nonaqueous carriers (MR fluids). Although electrostatic interactions between particles are negligible, van der Waals and, eventually, polar forces might be present. Nevertheless, they are typically neglected when compared to magnetic or hydrodynamic ones. In order to perform a comparative evaluation of the contributions of these interactions, we carried out an MR investigation on two samples of silica-coated magnetite: one (MagSilica 50-H8) is hydrophobic and the other (MagSilica 50-85) is hydrophilic. We describe a careful surface thermodynamic characterization of the two kinds of silicas, confirming their very different hydrophobicities. MR measurements show that only the suspensions of 50-85 particles change from Newtonian to pseudoplastic when a magnetic field is applied, with a yield stress increasing with field strength H, and saturating when H approximately = 100 kA/m. The experimental values of yield stress are compared to theoretical predictions based on the chain model, and it is found that the theory overestimates the experimental values. It is suggested that the nonnegligible interfacial interactions are responsible for both the absence of MR effect in 50-H8 samples and the low yield stress in 50-85 suspensions.