Quantitative assessment of sitting time in ambulant adults with Muscular Dystrophy

Background Current investigations into physical behaviour in Muscular Dystrophy (MD) have focussed largely on physical activity (PA). Negative health behaviours such as sedentary behaviour (Physical Behaviour) and sitting time (Posture Classification) are widely recognised to negatively influence health, but by contrast are poorly reported, yet could be easier behaviours to modify. Methods 14 ambulant men with MD and 12 healthy controls (CTRL) subjects completed 7-days of free-living with wrist-worn accelerometry, assessing physical behaviour (SB or PA) and Posture Classification (Sitting or Standing), presented at absolute (minutes) or relative (% Waking Hours). Participant body composition (Fat Mass and Fat Free Mass) were assessed by Bioelectrical Impedance, while functional status was assessed by 10 m walk test and a functional scale (Swinyard Scale). Results Absolute Sedentary Behaviour (2.2 Hours, p = 0.025) and Sitting Time (1.9 Hours, p = 0.030 was greater in adults with MD compared to CTRL and Absolute Physical Activity (3.4 Hours, p < 0.001) and Standing Time (3.2 Hours, p < 0.001) was lower in adults with MD compared to CTRL. Absolute hours of SB was associated with Fat Mass (Kg) (R = 0.643, p < 0.05) in ambulatory adults with MD, Discussion This study has demonstrated increased Sedentary Behaviour (2.2 hours) and Sitting time (1.9 Hours) in adults with MD compared to healthy controls. Extended waking hours in sitting and SB raises concerns with regards to progression of potential cardio-metabolic diseases and co-morbidities in MD.

A Machine Learning Classification Model for Monitoring the Daily Physical Behaviour of Lower-Limb Amputees

There are currently limited data on how prosthetic devices are used to support lower-limb prosthesis users in their free-living environment. Possessing the ability to monitor a patient’s physical behaviour while using these devices would enhance our understanding of the impact of different prosthetic products. The current approaches for monitoring human physical behaviour use a single thigh or wrist-worn accelerometer, but in a lower-limb amputee population, we have the unique opportunity to embed a device within the prosthesis, eliminating compliance issues. This study aimed to develop a model capable of accurately classifying postures (sitting, standing, stepping, and lying) by using data from a single shank-worn accelerometer. Free-living posture data were collected from 14 anatomically intact participants and one amputee over three days. A thigh worn activity monitor collected labelled posture data, while a shank worn accelerometer collected 3-axis acceleration data. Postures and the corresponding shank accelerations were extracted in window lengths of 5–180 s and used to train several machine learning classifiers which were assessed by using stratified cross-validation. A random forest classifier with a 15 s window length provided the highest classification accuracy of 93% weighted average F-score and between 88 and 98% classification accuracy across all four posture classes, which is the best performance achieved to date with a shank-worn device. The results of this study show that data from a single shank-worn accelerometer with a machine learning classification model can be used to accurately identify postures that make up an individual’s daily physical behaviour. This opens up the possibility of embedding an accelerometer-based activity monitor into the shank component of a prosthesis to capture physical behaviour information in both above and below-knee amputees. The models and software used in this study have been made open source in order to overcome the current restrictions of applying activity monitoring methods to lower-limb prosthesis users.

HYDRAULICS AND HYDROLOGY IN A PASSAGE OF THE KITĀB AL-ĀṮĀR AL-BĀQIYA BY AL-BĪRŪNĪ

The authors translate and comment a digression from the Kitāb al-āṯār al-bāqiya on several hydraulic and hydrological subjects. The passage reveals al-Bīrūnī’s understanding of fluvial regimes, water physical behaviour, and of a handful of peculiar natural phenomena. Al-Bīrūnī departs from a discussion of weather forecast and seasonal fluvial regimes of the Tigris, Euphrates, Oxus, and Nile. The main concern of al-Bīrūnī is to defend the principle that water moves only downwards in absence of external forces. In doing so, the Khwarazmian scientist touches on the origin of salinity of the seas, the functioning of syphons related hydraulic machines, and relates a report of an artificial phenomenon, that he dismisses as result of faulty observations, that could be recognised as a hydraulic jump. In addition, the passage contains much relevant information on al-Bīrūnī’s understanding of the inhabitability of subequatorial regions, the possibility of the void, and the water cycle.

Accelerometry-assessed physical behaviour and the association with clinical outcomes in implantable cardioverter-defibrillator recipients: a systematic review

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Eurostars Introduction Patients at a high risk of sudden cardiac death (SCD) benefit from an implantable cardioverter defibrillator (ICD). However, they remain at a high risk of (inappropriate) shocks, heart failure, mortality and psychological distress. Consumer-level wearable accelerometry as method for recording physical behaviour (PB) has gained popularity over the past years, but so far the clinical potential is largely underinvestigated. The identification of patterns in PB and the association with clinical outcomes may provide a means to improve ICD therapy. Purpose This review addresses the evidence concerning PB in ICD patients and aims to characterise PB patterns associated with clinical outcomes. Methods A systematic review of studies focussing on accelerometer-assessed PB in patients older than 18 years equipped with an ICD, or patients at a high risk of SCD (e.g. advanced heart failure) was performed. PB could be assessed using a wearable accelerometer or an embedded accelerometer in the ICD (i.e. device-measured physical activity (D-PA)). Papers presenting quantitative data in English language peer reviewed journals published between January 2000 and September 2020 were identified via the OVID MEDLINE and OVID EMBASE databases. A study protocol describing study selection, data charting and summarisation of results was developed apriori. Study selection was conducted by two independent reviewers and a third reviewer in case of disagreement. Results A total of 4219 studies were identified, of which 51 were deemed appropriate for this review. Of these studies, 29 examined D-PA (n = 169.742 patients), 19 examined wearable accelerometery (n = 1.601) and 3 validated wearable accelerometry against D-PA (n = 106). The main findings were that (i) a low level of physical activity (PA) after implantation of the ICD and (ii) a decline in physical activity were both associated with an increased risk of ICD shocks, hospitalization and mortality. Second, PB was affected by cardiac factors (e.g. onset of atrial arrhythmias, ICD shocks) and non-cardiac factors (e.g. seasonal differences, pandemic lockdown). Third, PB was related to left ventricular ejection fraction, physical and cognitive function and quality of life. The evidence regarding wearable accelerometry compared to D-PA was scarce and heterogeneous. Conclusion This review demonstrated the potential of PB as an identifier of clinical deterioration in an ICD population. Accelerometer-assessed PB data could improve early warning systems and facilitate preventive and pro-active strategies, especially considering the nature of PB as modifiable risk factor. We suggest two directions for future research: (i) prospective collection of wearable accelerometry data in an ICD population to identify the most clinically relevant behavioural metrics (ii) investigation of preventive measures that can be undertaken once changes in PB are observed. Abstract Figure. Accelerometry-derived physical behaviour

Trajectories of physical activity and sedentary behaviour during and after cardiac rehabilitation in patients with acute coronary syndrome

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Big Medilytics - Horizon 2020 Background Physical behaviour is a multidimensional construct comprising physical activity (PA) and sedentary behaviour. PA adherence, during and after cardiac rehabilitation (CR), is problematic with less than 55% of the patients meeting recommended levels. Furthermore, CR only results in limited improvements in sedentary behaviour. To optimize CR programs, more information is needed on which patients could benefit from additional physical behaviour counselling. Purpose To explore trajectories (improvement, stabilization, or worsening) of moderate-to-vigorous PA (MVPA) and sedentary behaviour during and after CR, and to identify predictors for trajectory membership in patients with acute coronary syndrome (ACS). Methods The study was performed among 533 patients (mean age 57.9 ± 8.9years; 18.2% women) who participated in a 12-week multi-dimensional CR program that started (median) 35 days after hospitalization for ACS. Physical behaviour was measured using accelerometry at CR start, CR completion and 12 and 18 months follow-up. Latent class trajectory modelling was applied to explore trajectories for MVPA and sedentary behaviour. Separate trajectories were determined for the CR period and post-CR period. Using multinomial logistic regression, potential demographic, psychological, and cardiovascular predictors for each of the trajectories were explored. Results Using trajectory analyses, three classes of patients were identified for MVPA and sedentary behaviour both during and after CR: an increasing group, a declining group, and a steady group with only minor changes (see figure 1). Baseline physical behaviour level was the main predictor for declining trajectories, where, interestingly, patients with a higher starting level of the specific physical behaviour were more likely to be in the declining group as compared to the steady group (odds ratio (OR) for MVPA and sedentary behaviour during and post-CR ranging from 1.06-1.45, all p &lt; 0.05). During CR, smokers were less likely to be in the declining group for sedentary behaviour (OR 0.29 (0.09-0.96)) as compared to the steady group. Post-CR, participants with a higher age were less likely to be in the increasing group for MVPA and more likely to be in the increasing group for sedentary behaviour (OR respectively 0.96 (0.93-1.00), 1.04 (1.01-1.07)). Furthermore, participants with a higher BMI were also less likely to be in the increasing group for MVPA post-CR (0.91 (0.84-1.00)). Conclusion: Distinct trajectories for MVPA and sedentary behaviour exist for CR patients, which are mainly distinguished by baseline physical behaviour level, where patients with a higher starting level of the specific physical behaviour were more likely to be in the declining class. We did not see this for the increasing group, suggesting that this phenomenon was not only explained by regression to the mean. Abstract Figure.

GRANADA consensus on analytical approaches to assess associations with accelerometer-determined physical behaviours (physical activity, sedentary behaviour and sleep) in epidemiological studies

The inter-relationship between physical activity, sedentary behaviour and sleep (collectively defined as physical behaviours) is of interest to researchers from different fields. Each of these physical behaviours has been investigated in epidemiological studies, yet their codependency and interactions need to be further explored and accounted for in data analysis. Modern accelerometers capture continuous movement through the day, which presents the challenge of how to best use the richness of these data. In recent years, analytical approaches first applied in other scientific fields have been applied to physical behaviour epidemiology (eg, isotemporal substitution models, compositional data analysis, multivariate pattern analysis, functional data analysis and machine learning). A comprehensive description, discussion, and consensus on the strengths and limitations of these analytical approaches will help researchers decide which approach to use in different situations. In this context, a scientific workshop and meeting were held in Granada to discuss: (1) analytical approaches currently used in the scientific literature on physical behaviour, highlighting strengths and limitations, providing practical recommendations on their use and including a decision tree for assisting researchers’ decision-making; and (2) current gaps and future research directions around the analysis and use of accelerometer data. Advances in analytical approaches to accelerometer-determined physical behaviours in epidemiological studies are expected to influence the interpretation of current and future evidence, and ultimately impact on future physical behaviour guidelines.

Hydraulics and Hydrology in a Passage of the Kitāb al-Ātār al-Bāqiya by al-Bīrūnī

The authors translate and comment a digression from the Kitāb al-Āṯār al-Bāqiya on several hydraulic and hydrological subjects. The passage reveals al-Bīrūnī’s understanding of fluvial regimes, water physical behaviour, and of a handful of peculiar natural phenomena. Al-Bīrūnī departs from a discussion of weather forecast and seasonal fluvial regimes of the Tigris, Euphrates, Oxus, and Nile. The main concern of al-Bīrūnī is to defend the principle that water moves only downwards in absence of external forces. In doing so, the Khwarazmian scientist touches on the origin of salinity of the seas, the functioning of syphons related hydraulic machines, and relates a report of an artificial phenomenon, that he dismisses as result of faulty observations, that could be recognized as a hydraulic jump. In addition, the passage contains much relevant information on al-Bīrūnī’s understanding of the inhabitability of subequatorial regions, the possibility of the void, and the water cycle.