Lation aged 10 yr and older using accelerometry. Methods The accelerometers were worn for four consecutive days, and a valid record was defined as at least 3 d with 10 h of wear time, including one weekend day. Considering these conditions, 4696 participants were included. Results According to the recommendations of 60 min·d−1 of physical activity, 36% of participants age 10–11 yr (boys = 51.6%, girls = 22.5%) and 4% age 16–17 yr (boys = 7.9%, girls = 1.2%) were considered sufficiently active. In adulthood, ∼70% of participants age 18–64 yr (men = 76.6%, women = 65.2%) and 35% age older than 64 yr (men = 46%, women = 29%) reached the recommendation of 30 min·d−1 of physical activity, when counting every minute of moderate or greater intensity. Considering bouts of 10 min or more of moderate or greater intensity in participants older than 17 yr, the prevalence was 4%–6% at 18–39 yr, 7%–9% at 40–64 yr, and ∼3% in persons age 65 yr or older. Conclusions The design and implementation of strategies to promote physical activity for health among children and adolescents and older adults, particularly girls/women, should be encouraged....

Physical function is a key determinant that corresponds to the physiological capacity of older adults to perform normal everyday activities, safely and independently, without undue fatigue. We examined the associations of sedentary behavior (SB), breaks in sedentary time (BST), and moderate-to-vigorous physical activity (MVPA) with physical function in older adults. Physical activity and SB were assessed with accelerometers (ActiGraph, GT1M) and physical function with the Senior Fitness Test battery, among 87 males and 128 females aged between 65 and 94 years. A composite Z-score was created based on the individual scores for each Senior Fitness Test battery item. Associations of SB, BST, and MVPA with physical function were examined, adjusting for demographic attributes, physical independence, and medical status. A significant positive association was found between BST and the composite physical function Z-score, after adjusting for total SB, MVPA, and potential confounders. MVPA was also positively associated with physical function, after adjusting for SB, BST, and potential confounders. Those with low BST in conjunction with performing less than 30min/d of MVPA had lower physical function. Breaking-up sedentary time is associated with better physical function in older adults; and, it may have an important place in future guidelines on preserving older adults’ physical function to support activities of daily living.

Objective The objective of this study was to pool, harmonise and re-analyse national accelerometer data from adults in four European countries in order to describe population levels of sedentary time and physical inactivity. Methods Five cross-sectional studies were included from England, Portugal, Norway and Sweden. ActiGraph accelerometer count data were centrally processed using the same algorithms. Multivariable logistic regression analyses were conducted to study the associations of sedentary time and physical inactivity with sex, age, weight status and educational level, in both the pooled sample and the separate study samples. Results Data from 9509 participants were used. On average, participants were sedentary for 530 min/day, and accumulated 36 min/day of moderate to vigorous intensity physical activity. Twenty-three percent accumulated more than 10 h of sedentary time/day, and 72% did not meet the physical activity recommendations. Nine percent of all participants were classified as high sedentary and low active. Participants from Norway showed the highest levels of sedentary time, while participants from England were the least physically active. Age and weight status were positively associated with sedentary time and not meeting the physical activity recommendations. Men and higher-educated people were more likely to be highly sedentary, while women and lower-educated people were more likely to be inactive. Conclusions We found high levels of sedentary time and physical inactivity in four European countries. Older people and obese people were most likely to display these behaviours and thus deserve special attention in interventions and policy planning. In order to monitor these behaviours, accelerometer-based cross-European surveillance is recommended.

OBJECTIVE. The purpose of this work was to analyze the relationship between intensity and duration of physical activity and composite indices of femoral neck strength and bone-mineral content of the femoral neck, lumbar spine, and total body. METHODS. Physical activity was assessed by accelerometry in 143 girls and 150 boys (mean age: 9.7 years). Measurement of bone-mineral content, femoral neck bone-mineral density, femoral neck width, hip axis length, and total body fat-free mass was performed with dual-energy radiograph absorptiometry. Compressive [(bone-mineral density × femoral neck width/weight)] and bending strength [(bone-mineral density × femoral neck width2)/(hip axis length × weight)] express the forces that the femoral neck has to withstand in weight bearing, whereas impact strength [(bone-mineral density × femoral neck width × hip axis length)/(height × weight)] expresses the energy that the femoral neck has to absorb in an impact from standing height. RESULTS. Analysis of covariance (fat-free mass and age adjusted) showed differences between boys and girls of ∼9% for compressive, 10% for bending, and 9% for impact strength. Stepwise regression analysis using time spent at sedentary, light, moderate, and vigorous physical activity as predictors revealed that vigorous physical activity explained 5% to 9% of femoral neck strength variable variance in both genders, except for bending strength in boys, and ∼1% to 3% of total body and femoral neck bone-mineral content variance. Vigorous physical activity was then used to categorize boys and girls into quartiles. Pairwise comparison indicated that boys in the third and fourth quartiles (accumulation of >26 minutes/day) demonstrated higher compressive (11%–12%), bending (10%), and impact (14%) strength than boys in the first quartile. In girls, comparison revealed a difference between the fourth (accumulation of >25 minutes/day) and first quartiles for bending strength (11%). We did not observe any relationship between physical activity and lumbar spine strength. CONCLUSIONS. Femoral neck strength is higher in boys than girls. Vigorous intensity emerged as the main physical activity predictor of femoral neck strength but did not explain gender differences. Daily vigorous physical activity for at least ∼25 minutes seems to improve femoral neck bone health in children.

Previous bone comparison studies between subjects with and without Down syndrome (DS) were performed using bone mineral density (BMD) as the dependent variable, and mainly focused on lumbar spine region. The purpose of this study was to compare bone mineral mass adjusted for bone and body size, in limbs, lumbar spine, and femoral neck between males and females with and without DS. Subjects were 66 females (33 with DS) and 68 males (34 with DS) aged 14–40 years. Analysis of covariance (ANCOVA) was used to analyze the main and interaction effects of gender and condition on bone mineral mass. For this purpose, adjusted bone mineral content (BMC) (for bone area, height, and age), volumetric bone mineral density (vBMD) (for age), and composite indices of femoral neck strength (for age), were used as the dependent variables, corrected additionally for body composition variables selected by regression analysis. ANCOVA revealed lower lumbar spine vBMD in DS than in control subjects with (−5%, P=0.013), or without body weight adjustments (−6%, P=0.003). In femoral neck, the mean of each strength measure was also lower in DS than in control subjects. Mean differences between groups were, with and without additional adjustments for fat mass, respectively, −8% (P=0.009), and −13% (P20 years) and not significant in adolescents. No interaction effect was observed between gender and condition. In conclusion, DS was shown to be a risk factor for low vBMD in lumbar spine, and for diminished bone strength relative to the loads that the femoral neck must bear. Body composition did not reach statistical significance as predictor of bone differences in these sites between subjects with and without DS, suggesting that other factors may be involved in this detrimental bone status, particularly in young adults compared with adolescents.