Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm(2) ) and bone area (mm(2) ) were measured repeatedly by dual-energy X-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow-up. There were 21.7 low and moderate energy-related fractures per 1000 person-years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009?g/cm(2) (0.003, 0.015) larger gain annually in spine BMD, 0.07?g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1?mm(2) (0.5, 7.8) larger gain in femoral neck area, and at follow-up 24.1?g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9?mm(2) (5.27, 42.6) larger tibial cross-sectional area. Boys with daily PE had 0.006?g/cm(2) (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow-up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6- to 9-year-olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.
Comment In: J Bone Miner Res. 2014 Jun;29(6):1322-424764102
To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.
We updated the evidence-based recommendations for the diagnosis, assessment, prevention, and treatment of hypertension in adults for 2013. This year's update includes 2 new recommendations. First, among nonhypertensive or stage 1 hypertensive individuals, the use of resistance or weight training exercise does not adversely influence blood pressure (BP) (Grade D). Thus, such patients need not avoid this type of exercise for fear of increasing BP. Second, and separately, for very elderly patients with isolated systolic hypertension (age 80 years or older), the target for systolic BP should be
When assessing population adherence to physical activity (PA) recommendation using accelerometers, absolute intensity threshold definition is applied despite having limited validity in those with low cardiorespiratory fitness (CRF), who are unable to reach them (e.g older adults). Thus, PA thresholds relative to CRF may be an alternative approach. We compared the proportion of the older adults meeting the PA recommendation when PA is assessed using absolute versus sex-and-CRF-adjusted (relative) accelerometer thresholds and determined the association between relative versus absolute moderate PA (MPA), vigorous PA (VPA) and moderate-to-vigorous PA (MVPA) and metabolic syndrome (MetS).
Cross-sectional study of 509 men and 567 women aged 70-77. Accelerometer assessed MPA, VPA and MVPA were analyzed using absolute and relative thresholds. Meeting the PA-recommendation was defined as amounting =150 min/week in MPA/MVPA or 75 min/week in VPA, respectively. CRF was directly measured as peak oxygen uptake (VO2peak). MetS was defined as 3 or more of the following: elevated waist circumference, fasting glucose, hypertension, triglycerides, decreased HDL-cholesterol or diabetes, dyslipidemia or hypertension medication.
Higher proportion of the population met the recommendation when PA was assessed with relative compared to absolute thresholds: VPA (72.4% vs. 1.7%) and MVPA (75.2% vs. 33.8%). Logistic regression analysis revealed that men and women not meeting the relative-MVPA or VPA recommendation had higher likelihood of MetS (Men: MVPA OR: 1.59, 95% CI: 1.08-2.33.
1.81, 95%CI: 1.23-2.67 and Women: MVPA OR: 2.12, 95% CI: 1.36-3.31; VPA OR: 1.95, 95% CI: 1.29-2.95), compared to men and women meeting the relative MVPA or VPA recommendation. There was no significant association between MetS and absolute MVPA, MPA or VPA recommendations in the fully adjusted model.
The association between meeting/not meeting the PA recommendation and MetS differed with method. Not meeting relative MVPA and VPA recommendation was associated with significantly higher likelihood for presence of MetS. Since relative intensity is part of the current PA recommendation, it should be considered when assessing population PA and associated health risks in the older adults.
Clinical Trial Registration: NCT01931111 (Date of trial registration: July 19, 2013).
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Middle-aged women with active commuting had significantly lower risk for wrist fracture than women commuting by car/bus.
Our purpose was to investigate whether a physically active lifestyle in middle-aged women was associated with a reduced risk of later sustaining a low-trauma wrist fracture.
The Umeå Fracture and Osteoporosis (UFO) study is a population-based nested case-control study investigating associations between lifestyle and fragility fractures. From a cohort of ~35,000 subjects, we identified 376 female wrist fracture cases who had reported data regarding their commuting habits, occupational, and leisure physical activity, before they sustained their fracture. Each fracture case was compared with at least one control drawn from the same cohort and matched for age and week of reporting data, yielding a total of 778 subjects. Mean age at baseline was 54.3?±?5.8 years, and mean age at fracture was 60.3?±?5.8 years.
Conditional logistic regression analysis with adjustments for height, body mass index, smoking, and menopausal status showed that subjects with active commuting (especially walking) were at significantly lower risk of sustaining a wrist fracture (OR 0.48; 95 % CI 0.27-0.88) compared with those who commuted by car or bus. Leisure time activities such as dancing and snow shoveling were also associated with a lower fracture risk, whereas occupational activity, training, and leisure walking or cycling were unrelated to fracture risk.
This study suggests that active commuting is associated with a lower wrist fracture risk, in middle-aged women.
The purpose was to describe the patterns of commuting to school in young people and to examine its associations with physical activity (PA) and cardiorespiratory fitness.
The sample comprised 2271 Estonian and Swedish children and adolescents (1218 females) aged 9-10 years and 15-16 years. Data were collected in 1998/99. Mode of commuting to and from school was assessed by questionnaire. Time spent (min/day) in PA and average PA (counts/min) was measured by accelerometry. Cardiorespiratory fitness was assessed by means of a maximal cycle ergometer test.
Sixty-one percent of the participants reported active commuting to school (ACS). Estonian youth showed lower levels of ACS than Swedish (odds ratio, 0.64; 95% confidence interval, 0.53-0.76) and girls reported lower levels than boys (0.74; 0.62-0.88). ACS boys showed higher PA levels than non-ACS boys for moderate, vigorous, MVPA, and average PA levels (all p = 0.01). Participants who cycled to school had higher cardiorespiratory fitness than walkers or passive travellers (p
The objective of this cross-sectional study was to study associations between low back pain (LBP) and modes of transport to school and leisure activities among adolescents. The study population included all adolescents in eighth and ninth grade in two geographic areas in eastern Norway. Eighty-eight adolescents participated (mean age 14.7 years), making the response rate 84%. Data concerning active (walking/bicycling) and passive (bus/car) journeys were obtained from lists and maps from local authorities, and from the pupils, using a questionnaire that also included LBP, activities and wellbeing. Distance walked/bicycled to school was slightly shorter among those reporting LBP in bivariate analyses. Walking/bicycling more than 8 km weekly to regular activities was inversely associated with LBP in multivariate analysis (OR 0.3; 95% confidence interval 0.1-1.0). No associations were found between passive journeys and LBP. The results raise the question for future research of whether lack of active transport may be one cause behind the increase in juvenile LBP.
This study examines how active transportation could help increase the daily physical activity volume of school-aged children.
Using data from the 2003 Origin-Destination Survey carried out among 5% of the 3.5 million residents of the Greater Montreal Area, we determined the proportion of short motorized trips made daily by children 5-14 years old (16 837 children sampled) and estimated the number of steps these trips would account for if they were travelled by foot, taking into account variables such as age, sex and height of children. Modal choice and trip purpose were also examined.
In 2003, 31.2% of the daily trips made by children aged 5-14 years in the Greater Montreal Area were 1 km or less (0.6 mile). Of these, 33.0% were motorized trips. Overall, 13.1% of the children in the area had 'steps in reserve', an average of 2238 steps per child per day. If they were performed, these steps would account for 16.6% of the daily recommended volume of physical activity for children.
Replacing short motorized trips with walking could increase the physical activity level of children and contribute to meet the recommended guidelines, as long as these walking trips add to their daily physical activity volume. It could also reduce their dependence towards adults for moving around.
PURPOSE: Assess the physical activity and body mass index (BMI) levels of children in the United States, Sweden, and Australia. METHODS: A total of 1954 children, 6-12 yr old (711 American, 563 Australian, and 680 Swedish) wore sealed pedometers for four consecutive days. Height and weight measures were obtained. RESULTS: Descriptive data for step counts and BMI by sex, age, and country were calculated to determine activity levels and BMI. Three-way multivariate ANOVA for step counts and BMI between countries at each age and sex found that, in general, the Swedish children were significantly more active than the Australian and American children, and the American children were significantly heavier than the Australian and Swedish children. For boys, the mean step counts ranged from 15673 to 18346 for Sweden, 13864 to 15023 for Australia, and 12554 to 13872 for America. For girls, the mean step counts ranged from 12041 to 14825 for Sweden, 11221 to 12322 for Australia, and 10661 to 11383 for America. The activity curve is somewhat level during the preadolescent years. The rate of increase in BMI with age is much greater in the American children than in the Swedish or Australian children. The percent of American, Swedish, and Australian boys classified as overweight/obese was 33.5, 16.6, and 15.8, respectively. The percent of American, Swedish, and Australian girls classified as overweight/obese was 35.6, 16.8, and 14.4, respectively. Correlation analysis found few significant negative relationships between step counts and BMI. CONCLUSIONS: American children tend to be the least active and heaviest with the greatest rate of increase in BMI. The Swedish children are the most active group followed by Australia. Swedish and Australian children maintain lower BMI throughout their prepubescent years than do the American children who have a greater percentage who are classified as overweight.