Accelerometric estimates of physical activity vary unstably with data handling.
    
    
        
    
    
        
        PLoS ONE 12:e0187706 (2017)
    
    
    
		
		
			
				BACKGROUND: Because of unreliable self-report, accelerometry is increasingly used to objectively monitor physical activity (PA). However, results of accelerometric studies vary depending on the chosen cutpoints between activity intensities. Population-specific activity patterns likely affect the size of these differences. To establish their size and stability we apply three sets of cutpoints, including two calibrated to a single reference, to our accelerometric data and compare PA estimates. METHODS: 1402 German adolescents from the GINIplus and LISAplus cohorts wore triaxial accelerometers (Actigraph GT3x) for one week (mean 6.23 days, 14.7 hours per day) at the hip. After validation of wear, we applied three sets of cutpoints for youth, including the most common standard (Freedson, 2005) and two calibrated to a single reference, (Romanzini uni- and triaxial, from Romanzini, 2014) to these data, estimating daily sedentary, light, moderate, vigorous and moderate-to-vigorous PA (MPA, VPA, MVPA). Stability of differences was assessed by comparing Romanzini's two sets of cutpoints. RESULTS: Relative agreement between cutpoints was closer for activity of lower intensities (largest difference for sedentary behaviour 9%) but increased for higher intensities (largest difference for light activity 40%, MPA 102%, VPA 88%; all p<0.01). Romanzini's uniaxial and triaxial cutpoints agreed no more closely with each other than with Freedson's. CONCLUSIONS: Estimated PA differed significantly between different sets of cutpoints, even when those cutpoints agreed perfectly on another dataset (i.e. Romanzini's.) This suggests that the detected differences in estimated PA depend on population-specific activity patterns, which cannot be easily corrected for: converting activity estimates from one set of cutpoints to another may require access to raw data. This limits the utility of accelerometry for comparing populations in place and time. We suggest that accelerometric research adopt a standard for data processing, and apply and present the results of this standard in addition to those from any other method.
			
			
				
			
		 
		
			
				
					
					Impact Factor
					Scopus SNIP
					Web of Science
Times Cited
					Scopus
Cited By
					
					Altmetric
					
				 
				
			 
		 
		
     
    
        Publikationstyp
        Artikel: Journalartikel
    
 
    
        Dokumenttyp
        Wissenschaftlicher Artikel
    
 
    
        Typ der Hochschulschrift
        
    
 
    
        Herausgeber
        
    
    
        Schlagwörter
        Adolescents; Validation; Tracking; Children
    
 
    
        Keywords plus
        
    
 
    
    
        Sprache
        
    
 
    
        Veröffentlichungsjahr
        2017
    
 
    
        Prepublished im Jahr 
        
    
 
    
        HGF-Berichtsjahr
        2017
    
 
    
    
        ISSN (print) / ISBN
        1932-6203
    
 
    
        e-ISSN
        
    
 
    
        ISBN
        
    
 
    
        Bandtitel
        
    
 
    
        Konferenztitel
        
    
 
	
        Konferzenzdatum
        
    
     
	
        Konferenzort
        
    
 
	
        Konferenzband
        
    
 
     
		
    
        Quellenangaben
        
	    Band: 12,  
	    Heft: 11,  
	    Seiten: ,  
	    Artikelnummer: e0187706 
	    Supplement: ,  
	
    
 
  
        
            Reihe
            
        
 
        
            Verlag
            Public Library of Science (PLoS)
        
 
        
            Verlagsort
            Lawrence, Kan.
        
 
	
        
            Tag d. mündl. Prüfung
            0000-00-00
        
 
        
            Betreuer
            
        
 
        
            Gutachter
            
        
 
        
            Prüfer
            
        
 
        
            Topic
            
        
 
	
        
            Hochschule
            
        
 
        
            Hochschulort
            
        
 
        
            Fakultät
            
        
 
    
        
            Veröffentlichungsdatum
            0000-00-00
        
 
         
        
            Anmeldedatum
            0000-00-00
        
 
        
            Anmelder/Inhaber
            
        
 
        
            weitere Inhaber
            
        
 
        
            Anmeldeland
            
        
 
        
            Priorität
            
        
 
    
        Begutachtungsstatus
        Peer reviewed
    
 
    
        Institut(e)
        Institute of Epidemiology (EPI)
    
 
    
        POF Topic(s)
        30503 - Chronic Diseases of the Lung and Allergies
    
 
    
        Forschungsfeld(er)
        Genetics and Epidemiology
    
 
    
        PSP-Element(e)
        G-503900-001
    
 
    
        Förderungen
        
    
 
    
        Copyright
        
    
 	
    
    
    
    
    
        Erfassungsdatum
        2017-11-14