Purpose: To examine the test–retest reliability and validity of ten activity trackers for step counting at three different walking speeds. Methods:Thirty-one healthy participants walked twice on a treadmill for 30 min while wearing 10 activity trackers (Polar Loop, GarminVivosmart, Fitbit Charge HR, Apple Watch Sport, Pebble Smartwatch, Samsung Gear S, Misfit Flash, Jawbone Up Move, Flyfit, andMoves). Participants walked three walking speeds for 10 min each; slow (3.2 kmIhj1), average (4.8 kmIhj1), and vigorous (6.4 kmIhj1).To measure test–retest reliability, intraclass correlations (ICC) were determined between the first and second treadmill test. Validity wasdetermined by comparing the trackers with the gold standard (hand counting), using mean differences, mean absolute percentage errors,and ICC. Statistical differences were calculated by paired-sample t tests, Wilcoxon signed-rank tests, and by constructing Bland–Altmanplots. Results: Test–retest reliability varied with ICC ranging from j0.02 to 0.97. Validity varied between trackers and different walkingspeeds with mean differences between the gold standard and activity trackers ranging from 0.0 to 26.4%. Most trackers showed relativelylow ICC and broad limits of agreement of the Bland–Altman plots at the different speeds. For the slow walking speed, the GarminVivosmart and Fitbit Charge HR showed the most accurate results. The Garmin Vivosmart and Apple Watch Sport demonstrated the bestaccuracy at an average walking speed. For vigorous walking, the Apple Watch Sport, Pebble Smartwatch, and Samsung Gear S exhibitedthe most accurate results. Conclusion: Test–retest reliability and validity of activity trackers depends on walking speed. In general,consumer activity trackers perform better at an average and vigorous walking speed than at a slower walking speed.
This article investigates the phenomenon of rebound effects in relation to a transition to a Circular Economy (CE) through qualitative inquiry. The aim is to gain insights in manifestations of rebound effects by studying the Dutch textile industry as it transitions to a circular system, and to develop appropriate mitigation strategies that can be applied to ensure an effective transition. The rebound effect, known originally from the energy efficiency literature, occurs when improvements in efficiency or other technological innovations fail to deliver on their environmental promise due to (behavioral) economic mechanisms. The presence of rebound in CE contexts can therefore lead to the structural overstatement of environmental benefits of certain innovations, which can influence reaching emission targets and the preference order of recycling. In this research, the CE rebound effect is investigated in the Dutch textile industry, which is identified as being vulnerable to rebound, yet with a positive potential to avoid it. The main findings include the very low awareness of this effect amongst key stakeholders, and the identification of specific and general instances of rebound effects in the investigated industry. In addition, the relation of these effects to Circular Business Models and CE strategies are investigated, and placed in a larger context in order to gain a more comprehensive understanding about the place and role of this effect in the transition. This concerns the necessity for a new approach to how design has been practiced traditionally, and the need to place transitional developments in a systems perspective. Propositions that serve as theory-building blocks are put forward and include suggestions for further research and recommendations about dealing with rebound effects and shaping an eco-effective transition. Thomas Siderius, Kim Poldner, Reconsidering the Circular Economy Rebound effect: Propositions from a case study of the Dutch Circular Textile Valley, Journal of Cleaner Production, Volume 293, 2021, 125996, ISSN 0959-6526, https://doi.org/10.1016/j.jclepro.2021.125996.
In reflecting on Dutch Christmas shoppers, this article will discuss environmental Kuznets curve (EKC), postmaterialist values hypothesis, and ecological modernization theory. According to the EKC hypothesis, while at the initial stages of industrialization material resources are often used unsustainably, continuing industrialization leads to a threshold after which lead to progressively more sustainable technologies. According to the postmaterialist values hypothesis, only wealthier societies can ‘afford’ to care about the environment, assuming that wealth will lead to development of greater concern about and valuation of environment. Finally, ecological modernization theory postulates that environmental conditions improve with advanced technological development and suggests that enlightened self-interest, economy and ecology can be favourably combined and that productive use of natural resources can be a source of future growth. In generalizing economic, political and social trends in relation to consumption in The Netherlands, the aim of this article is to consider the consequences of Western-style consumption for the enterprise of global development. https://doi.org/10.1016/j.scs.2013.05.004 https://www.linkedin.com/in/helenkopnina/
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