Absolute Accelerometer-Based Intensity Prescription Compared to Physiological Variables in Pregnant and Nonpregnant Women.
Philipp Birnbaumer, Pavel Dietz, Estelle Dorothy Watson, Gudani Mukoma, Alexander Müller, Matteo Christian Sattler, Johannes Jaunig, Mireille Nicoline Maria van Poppel, Peter Hofmann
Author Information
Philipp Birnbaumer: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria.
Pavel Dietz: Institute of Occupational, Social and Environmental Medicine, University Medical Center of the University of Mainz, 55131 Mainz, Germany. ORCID
Estelle Dorothy Watson: School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa.
Gudani Mukoma: Department of Pediatrics, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa.
Alexander Müller: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria.
Matteo Christian Sattler: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria. ORCID
Johannes Jaunig: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria.
Mireille Nicoline Maria van Poppel: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria.
Peter Hofmann: Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria. ORCID
Estimation of the intensity of physical activity (PA) based on absolute accelerometer cut points (Cp) likely over- or underestimates intensity for a specific individual. The purpose of this study was to investigate the relationship between absolute moderate intensity Cp and the first ventilatory threshold (VT). A group of 24 pregnant and 15 nonpregnant women who performed a submaximal incremental walking test with measures of ventilatory parameters and accelerations from three different accelerometers on the wrist (ActiGraph wGT3X-BT, GENEActiv, Axivity AX3) and one on the hip (Actigraph wGT3X-BT) were analyzed. Cp were determined corresponding to 3 metabolic equivalents of task (MET), using the conventional MET definition (Cp) (3.5 mL/kg×min) and individual resting metabolic rate (Cp). The ventilatory equivalent (VE/VO) was used to determine VT. Accelerations at VT were significantly higher ( < 0.01) compared to Cp and Cp in both groups. Cp and Cp were significantly different in nonpregnant ( < 0.01) but not in pregnant women. Walking speed at VT (5.7 ± 0.5/6.2 ± 0.8 km/h) was significantly lower ( < 0.01) in pregnant compared to nonpregnant women and correspondent to 3.8 ± 0.7/4.9 ± 1.4 conventional METs. Intensity at absolute Cp was lower compared to the intensity at VT independent of the device or placement in pregnant and nonpregnant women. Therefore, we recommend individually tailored cut points such as the VT to better assess the effect of the intensity of PA.
