MET-values of standardised activities in relation to body fat: studies in pregnant and non-pregnant women

Background: Physical activity is associated with health in women. Published MET-values (MET: metabolic equivalent of task) may assess physical activity and energy expenditure but tend to be too low for subjects with a high total body fat (TBF) content and therefore inappropriate for many contemporary women. The MET-value for an activity is the energy expenditure of a subject performing this activity divided by his/her resting energy expenditure, often assumed to be 4.2 kJ/kg/h. Relationships between TBF and MET have been little studied although overweight and obesity is common in women. Available data indicate that MET-values decrease during pregnancy but more studies in pregnant contemporary women are needed. Subjects and methods: Using indirect calorimetry we measured energy expenditure and assessed MET-values in women, 22 non-pregnant (BMI: 18-34) and 22 in gestational week 32 (non-pregnant BMI: 18-32) when resting, sitting, cycling (30 and 60 watts), walking (3.2 and 5.6 km/h) and running (8 km/h). Relationships between TBF and MET-values were investigated and used to predict modified MET-values. The potential of such values to improve calculations of total energy expenditure of women was investigated. Results: The resting energy expenditure was below 4.2 kJ/kg/h in both groups of women. Women in gestational week 32 had a higher resting energy metabolism (p amp;lt; 0.001) and 7-15% lower MET-values (p amp;lt; 0.05) than non-pregnant women. MET-values of all activities were correlated with TBF (p amp;lt; 0.05) in non-pregnant women and modified MET-values improved estimates of total energy expenditure in such women. In pregnant women, correlations (p amp;lt;= 0.03) between TBF and MET were found for running (8 km/h) and for walking at 5.6 km/h. Conclusions: Our results are relevant when attempts are made to modify the MET-system in contemporary pregnant and non-pregnant women. MET-values were decreased in gestational week 32, mainly due to an increased resting energy metabolism and studies describing how body composition affects the one MET-value (i.e. the resting energy metabolism in kJ/kg/h) during pregnancy are warranted. Studies of how pregnancy and TBF affect MET-values of high intensity activities are also needed. Corrections based on TBF may have a potential to improve the MET-system in non-pregnant women.Funding Agencies|Formas; Ostergotland County Council; M Bergvalls foundation; Thurings foundation; Swedish Society of Medicine</p

High variability in strain estimation errors when using a commercial ultrasound speckle tracking algorithm on tendon tissue.

BACKGROUND: Ultrasound speckle tracking offers a non-invasive way of studying strain in the free Achilles tendon where no anatomical landmarks are available for tracking. This provides new possibilities for studying injury mechanisms during sport activity and the effects of shoes, orthotic devices, and rehabilitation protocols on tendon biomechanics. PURPOSE: To investigate the feasibility of using a commercial ultrasound speckle tracking algorithm for assessing strain in tendon tissue. MATERIAL AND METHODS: A polyvinyl alcohol (PVA) phantom, three porcine tendons, and a human Achilles tendon were mounted in a materials testing machine and loaded to 4% peak strain. Ultrasound long-axis cine-loops of the samples were recorded. Speckle tracking analysis of axial strain was performed using a commercial speckle tracking software. Estimated strain was then compared to reference strain known from the materials testing machine. Two frame rates and two region of interest (ROI) sizes were evaluated. RESULTS: Best agreement between estimated strain and reference strain was found in the PVA phantom (absolute error in peak strain: 0.21 ± 0.08%). The absolute error in peak strain varied between 0.72 ± 0.65% and 10.64 ± 3.40% in the different tendon samples. Strain determined with a frame rate of 39.4 Hz had lower errors than 78.6 Hz as was the case with a 22 mm compared to an 11 mm ROI. CONCLUSION: Errors in peak strain estimation showed high variability between tendon samples and were large in relation to strain levels previously described in the Achilles tendon

Impact of a standardized training program on midwive’s ability to assess fetal heart anatomy by ultrasound

Background: Studies of prenatal detection of congenital heart disease (CDH) in the UK, Italy, and Norway indicate that it should be possible to improve the prenatal detection rate of CDH in Sweden. These studies have shown that training programs, visualization of the outflow tracts and color-Doppler all can help to speed up and improve the detection rate and accuracy. We aimed to introduce a more accurate standardized fetal cardiac ultrasound screening protocol in Sweden. Methods: A novel pedagogical model for training midwives in standardized cardiac imaging was developed, a model using a think-aloud analysis during a pre- and post-course test and a subsequent group reflection. The self-estimated difficulties and knowledge gaps of four midwives were identified. A two-day course with mixed lectures, demonstrations and handson sessions was followed by a feedback session one month later consisting of an interview and check-up. The long-term effects were tested two years later. Results: At the post-course test the self-assessed uncertainty was lower than at the pre-course test. The qualitative evaluation showed that the color Doppler images were difficult to interpret, but the training seems to have enhanced the familiarity with the new technique. The ability to perform the method remained at the new level at follow-up both three months and two years later. Conclusions: Our results indicate that by implementing new imaging modalities and providing hands-on training, uncertainty can be reduced and time decreased, but they also show that continuous on-site training with clinical and technical back-up is important

Impact of a standardized training program on midwive’s ability to assess fetal heart anatomy by ultrasound

Background: Studies of prenatal detection of congenital heart disease (CDH) in the UK, Italy, and Norway indicate that it should be possible to improve the prenatal detection rate of CDH in Sweden. These studies have shown that training programs, visualization of the outflow tracts and color-Doppler all can help to speed up and improve the detection rate and accuracy. We aimed to introduce a more accurate standardized fetal cardiac ultrasound screening protocol in Sweden. Methods: A novel pedagogical model for training midwives in standardized cardiac imaging was developed, a model using a think-aloud analysis during a pre- and post-course test and a subsequent group reflection. The self-estimated difficulties and knowledge gaps of four midwives were identified. A two-day course with mixed lectures, demonstrations and handson sessions was followed by a feedback session one month later consisting of an interview and check-up. The long-term effects were tested two years later. Results: At the post-course test the self-assessed uncertainty was lower than at the pre-course test. The qualitative evaluation showed that the color Doppler images were difficult to interpret, but the training seems to have enhanced the familiarity with the new technique. The ability to perform the method remained at the new level at follow-up both three months and two years later. Conclusions: Our results indicate that by implementing new imaging modalities and providing hands-on training, uncertainty can be reduced and time decreased, but they also show that continuous on-site training with clinical and technical back-up is important