Moderate And Vigorous Physical Activity Research Articles

Accelerometer-Based Physical Activity Levels Differ between Week and Weekend Days in British Preschool Children.

Participation in physical activity (PA) is fundamental to children’s future health. Studies examining the temporal pattern of PA between weekdays and weekends in British preschool children are lacking. Therefore, the aim of this study was to compare PA levels between week and weekend days for UK preschool children, using objective measurements. One hundred and eighty-five preschool children (99 boys, 86 girls, aged 4–5 years), from central England wore a triaxial accelerometer (GENEActiv) for 4 days to determine PA. The time (min) and percentage (%) of time spent in light, moderate and vigorous PA (MVPA) was determined using specific cut-points for counts per minute related to 3–5 year olds. Of the sample, none of the children met the UK recommended 180 min or more of PA per day. A significant difference (P < 0.05) was observed between the amount of time that preschool children spent in sedentary behaviours on weekdays (91.9%) compared to weekend days (96.9%). During weekdays and weekend days, 6.3% and 2.0% of time was spent in MVPA, respectively. Therefore, a substantial proportion of British preschool children’s day is spent in sedentary behaviours, with less MVPA accrued during the weekend. Regular engagement during the weekdays provides opportunities to accrue PA, which may not be present on weekend days.

Drivers of adolescent adiposity: Evidence from the Australian LOOK study

ObjectivesTo contribute to our understanding of the drivers of body composition during adolescence we sought to employ valid and reliable measures to investigate cross-sectional and longitudinal relationships between percentage body fat (%BF) and physical activity (PA), moderate and vigorous PA (MVPA), sedentary time (ST), total energy, sugar and fat intake. DesignLongitudinal cohort study. MethodsWe measured 556 (289 male) participants at age 12.4 (SD 0.4) years, and 269 (123 males) at 16.3 (SD 0.4) years, for %BF (dual energy X-ray absorptiometry); habitual PA, MVPA, ST (accelerometry); and dietary intake (‘multi-pass’ weekday and weekend 24-h recall). Accounting for likely under-reporting of energy intake (Goldberg cut-off), general linear mixed modelling was used to generate relationships with %BF. ResultsCross-sectional analyses indicated that 10min more MVPA per day was associated with 0.6 lower %BF (95%CI 0.4–0.9, p<0.001), and 10min less ST/day with 0.07 lower %BF (95%CI 0.00–0.15, p<0.001), independently of PA. In contrast, %BF was unrelated to total energy (p=0.4), sugar intake (p=0.2) or fat intake (p=0.9). Longitudinal analysis showed that if PA was increased by 3% (10,000 counts/day) over the 4 years, then %BF was reduced by 0.08 (95%CI 0.05–0.12, p=0.06). ConclusionsThe independent relationships of %BF with PA and ST, but absence of relationships with energy, sugar or fat intake, suggest that general community campaigns in a developed country directed at reducing adolescent obesity through modifications to energy intake and output would benefit from a more concerted focus on the latter.

Physical Activity in Young Schoolchildren in After School Programs

ABSTRACTBACKGROUNDAfter‐school programs (ASP) provide opportunities to influence children's physical activity (PA). However, little is known about the PA levels of the youngest schoolchildren. The aim of the study was to describe the level of PA intensity and sedentary time among first graders attending ASP in Norway, and to investigate factors that are associated with PA in the ASP.METHODSFirst graders from 14 ASPs were invited to participate in the study and 426 children were included. The children wore an accelerometer for five consecutive days during their stay in the ASP. Light, moderate, and vigorous PA and sedentary time were registered and analyzed.RESULTSOn average, the children accumulated 25.8 minutes of moderate and vigorous physical activity (MVPA) during their ASP‐stay. However, there was considerable variation within the sample. Sex, as well as body mass, were associated with MVPA. The activity level increased substantially when the children had to be outside.CONCLUSIONSThe findings show that on average, the children were quite physically active in the ASP. However, it seems critical to devote increased attention to the least active children and to include extensive outdoor play‐time in the ASP schedule.

The Association Between Moderate and Vigorous Physical Activity and Time to Medical Clearance to Return to Play Following Sport-Related Concussion in Youth Ice Hockey Players.

Design: Prospective cohort study.Background: The recommendations regarding the optimal amount and type of rest for promoting recovery following concussion are based on expert opinion rather than evidence-based guidelines due to current a lack of high-level studies. There is an evident need for more research into the parameters of rest and activity and its effects on recovery from concussion.Objective: To evaluate the association between the amount of moderate and vigorous physical activity (MVPA) during the first 3 days following concussion diagnosis and time to medical clearance (days) to return to play in youth ice hockey players.Methods: Thirty youth ice hockey players (12–17 years) that were diagnosed with a concussion sustained during ice hockey were recruited to participate. The exposure was the cumulative amount of MVPA (minutes), measured using a waist-worn Actigraph accelerometer. Participants were dichotomized into high (≥148.5) and low (<148.5) activity groups based on the median of cumulative time spent in MVPA over the first 3 days following injury diagnosis.Results: Participants in both the low and high activity group reported to the clinic at a median time of 4 days post-injury (low activity IQR: 3–5 days; high activity IQR: 3–7 days). The low activity group completed a median time of 110.7 min (IQR: 76.2–131.0 min) in MVPA, whereas the high activity had a median of 217.2 min (IQR 184.2–265.2 min) in MVPA. Kaplan Meier survival curves with Log-rank tests of hypothesis revealed the high activity group took significantly more time to be medically cleared to return to play (p = 0.041) compared to the low activity group.Conclusion: The results from this study suggest that more time in MVPA early in the recovery period may result in a greater time to medical clearance to return to full participation in ice hockey. Future research, using valid measures of activity, are required to better understand the relationship between early activity and recovery following concussion in youth.

Effects of a multicomponent physical activity promoting program on sedentary behavior, physical activity and body measures: a longitudinal study in different office types.

Objectives The aim of this study was to investigate effects of a multicomponent program promoting physical activity on sedentary behavior, physical activity, and body measures, when relocating from cell offices to either a flex or cell office. Methods The Active Office Design (AOD) study is a longitudinal non-randomized controlled study performed in a municipality in northern Sweden. A subsample of 86 participants were randomly recruited from the AOD study to objectively measure sedentary behavior and physical activity, using ActivPAL and ActiGraph, before and after relocation to the two different office types. The multicomponent program promoting physical activity was performed in both offices. Data were analyzed using linear mixed models. Results Eighteen months after relocation, the total number of steps per work day increased by 21% in the flex office and 3% in the cell office group, compared to baseline. Moderate and vigorous physical activity (MVPA) during work hours increased by 42% in the flex office group and 19% in the cell office group. No changes were seen regarding sitting time at work. Small additive effects for walking and MVPA were seen for both groups during non-work time. Weight increased in the flex office group. Conclusions This long-term study shows that a multicomponent workplace intervention can lead to increased walking time, steps, and MVPA in a flex compared to a cell office. Small additive increases of physical activity were seen during non-work time in both groups. More long-term controlled studies are needed to confirm these results.

Sex-specific associations between insulin resistance and bone parameters in overweight and obese older adults.

To determine sex-specific associations between insulin resistance and bone parameters measured by peripheral quantitative computed tomography in overweight and obese community-dwelling older adults. Cross-sectional study of 79 community-dwelling overweight and obese adults (mean±SD age 62.8±7.9years; body mass index 32.3±6.1kg/m2 ; 58% women). Peripheral quantitative computed tomography assessed distal radius and tibia trabecular volumetric bone mineral density (vBMD) and proximal radius and tibia cortical vBMD, periosteal circumference, endosteal circumference and stress-strain index. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) score was calculated from fasting glucose and insulin values. Lean mass was assessed using dual-energy X-ray absorptiometry. Total minutes of moderate and vigorous physical activity (MVPA) were calculated using the Active Australia Survey. Men and women in this cohort had no significant differences in fasting glucose and insulin concentrations, HOMA-IR valuesand diabetes prevalence (all P>0.05). In women, HOMA-IR was positively correlated with proximal radius periosteal and endosteal circumference (r=0.331; P=0.034 and r=0.325; P=0.038, respectively). These associations became nonsignificant in multivariable regression analyses; however, HOMA-IR was negatively associated with proximal radius cortical vBMD (B=-4.79; 95% CI -8.66, -0.92) after adjusting for age, lean mass and MVPA. All associations between HOMA-IR and bone parameters became nonsignificant in a sensitivity analysis excluding individuals with diabetes, or self-reported use of glucose-lowering medications. There were no associations between HOMA-IR and bone parameters in men. Homeostatic Model Assessment of Insulin Resistance was negatively associated with radial cortical vBMD in overweight and obese older women, but not in men. Further studies are needed to clarify sex-specific associations between insulin resistance and bone health in overweight and obese older adults.

Low Physical Activity and Cardiorespiratory Fitness in People With Schizophrenia: A Comparison With Matched Healthy Controls and Associations With Mental and Physical Health

Introduction: The aim of this study was to objectively assess time spent in physical activity (PA) and sedentary behavior (SB) in patients with schizophrenia compared to healthy controls matched for age, gender and socioeconomic status. Associations between both PA and cardiorespiratory fitness (CRF) and mental and physical health parameters in patients with schizophrenia were examined.Materials and Methods: Moderate and vigorous PA (MVPA), moderate PA, vigorous PA, total and active energy expenditure (TEE and AEE), number of steps, lying down and sleeping time was assessed with SenseWear Pro-2 body monitoring system for three 24-h bouts in patients with schizophrenia (n = 63) and matched healthy controls (n = 55). Severity of symptoms (Positive and Negative Syndrome Scale and Montgomery and Åsberg Depression Rating Scale), CRF (peak oxygen uptake, VO2peak), body mass index (BMI), and metabolic syndrome were assessed.Results: Patients with schizophrenia performed less MVPA and moderate activity had lower TEE and AEE, spent more time per day lying down and sleeping, and had poorer CRF compared to healthy controls. The amount of MVPA, but especially CRF was associated with severity of negative symptoms in patients with schizophrenia. Only CRF was associated with BMI.Discussion: The current data offer further evidence for interventions aiming to increase physical activity and decrease sedentary behavior. Given strong associations of CRF with both negative symptoms and BMI, treatment aimed at CRF-improvement may prove to be effective.

Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis

ObjectivesVarying hypertension prevalence across different socioeconomic strata within a population has been well reported. However, the causal factors and pathways across different settings are less clear, especially in sub-Saharan Africa....

Dose response association of objective physical activity with mental health in a representative national sample of adults: A cross-sectional study.

Although higher physical activity (PA) levels are associated with better mental health, previous findings about the shape of the dose–response relationship between PA and mental health are inconsistent. Furthermore, this association may differ according to sedentary levels. We investigated the cross-sectional dose-response associations between objectively measured PA and mental health in a representative national sample of adults. We also examined whether sedentary time modified the PA—mental health associations. Based on 2007–2013 Canadian Health Measures Survey data, PA and sedentary time were measured using accelerometry among 8150 participants, aged 20 to 79 years. Generalized additive models with a smooth function were fitted to examine associations between minutes per day of moderate and vigorous PA (MVPA), light PA (LPA), daily steps (combined or not with sedentary time) and self-rated mental health. A significant curvilinear relationship between average daily minutes of MVPA and mental health was observed, with increasing benefits up to 50 minutes/day. For LPA, a more complex shape (monotonic and curvilinear) was found. For daily steps, inverted U-shaped curve suggested increasing benefits until a plateau between 5 000 and 16 000 steps. The MVPA-LPA combination was significantly associated with mental health but with a complex pattern (p < 0.0005E-06). The tested PA-sedentary time combinations showed that increasing sedentary time decreased the positive PA-mental health associations. Non-linear dose-response patterns between the PA modalities and self-reported mental health were observed. Optimal doses of daily minutes of MVPA, LPA, MVPA combined with LPA and daily steps are independently associated with better mental health in adults. The results also suggest that PA-mental health associations could be hampered by daily sedentary time.

Activity Behaviors and Physiological Characteristics of Women With Advanced-Stage Ovarian Cancer: A Preliminary Cross-sectional Investigation.

Ovarian cancer (OC) survivors experience many disease and treatment adverse effects. However, the impact of OC and its treatment on objective activity behaviors and physiological status have not been examined. The purpose of this study was to compare objectively measured activity behaviors and physiological characteristics of advanced-stage OC survivors to age-matched controls. Twenty stage III-IV OC survivors and 20 controls completed assessments of activity behaviors (7-day accelerometry), physical function (400-meter walk as indicator of cardiorespiratory fitness, repeated chair rise, 6-meter walking tests), muscle strength (1-repetition maximum and handgrip), body composition (dual-energy x-ray absorptiometry), and musculoskeletal morphology (peripheral quantitative computed tomography). Compared with controls, OC survivors spent more time/day in prolonged sedentary bouts (P = 0.039, r = 0.32), had lower cardiorespiratory fitness (P = 0.041, r = 0.33) and upper body strength (P = 0.023, r = 0.37), had higher areal bone mineral content (P = 0.047, r = 0.33) and volumetric trabecular density (P = 0.048, r = 0.31), but were not different in other measures of body composition nor in muscle morphology (P > 0.050). Only 20% (n = 4) of OC survivors accrued 150 minutes/week or greater moderate and vigorous physical activity (MVPA) time in 10-minute bouts or greater. Moderate and vigorous physical activity time/day in 10-minute bouts or greater was strongly associated with cardiorespiratory fitness (P = 0.001, ρ = -0.702) and lower extremity function (P = 0.019, ρ = -0.519) and moderately associated with muscle cross-sectional area (P = 0.035, ρ = 0.473). Posttreatment OC survivors spent more time in prolonged sedentary bouts and had lower cardiorespiratory fitness and upper body strength compared with controls. Moderate and vigorous physical activity was associated with physical function and muscle cross-sectional area. Future studies should test the efficacy of exercise interventions to increase MVPA, reduce sedentary behavior, and increase cardiorespiratory fitness and muscle strength in OC survivors.

Workplace health and safety intervention for child care staff: Rationale, design, and baseline results from the CARE cluster randomized control trial

BackgroundLow-wage workers suffer disproportionately high rates of chronic disease and are important targets for workplace health and safety interventions. Child care centers offer an ideal opportunity to reach some of the lowest paid workers, but these settings have been ignored in workplace intervention studies. MethodsCaring and Reaching for Health (CARE) is a cluster-randomized controlled trial evaluating efficacy of a multi-level, workplace-based intervention set in child care centers that promotes physical activity and other health behaviors among staff. Centers are randomized (1:1) into the Healthy Lifestyles (intervention) or the Healthy Finances (attention control) program. Healthy Lifestyles is delivered over six months including a kick-off event and three 8-week health campaigns (magazines, goal setting, behavior monitoring, tailored feedback, prompts, center displays, director coaching). The primary outcome is minutes of moderate and vigorous physical activity (MVPA); secondary outcomes are health behaviors (diet, smoking, sleep, stress), physical assessments (body mass index (BMI), waist circumference, blood pressure, fitness), and workplace supports for health and safety. ResultsIn total, 56 centers and 553 participants have been recruited and randomized. Participants are predominately female (96.7%) and either Non-Hispanic African American (51.6%) or Non-Hispanic White (36.7%). Most participants (63.4%) are obese. They accumulate 17.4 (±14.2) minutes/day of MVPA and consume 1.3 (±1.4) and 1.3 (±0.8) servings/day of fruits and vegetables, respectively. Also, 14.2% are smokers; they report 6.4 (±1.4) hours/night of sleep; and 34.9% are high risk for depression. ConclusionsBaseline data demonstrate several serious health risks, confirming the importance of workplace interventions in child care.

Cross-lagged structural equation models for the relationship between health-related state and behaviours and body bullying in adolescence: findings from longitudinal study ELANA.

We investigated the stability and the directionality of being body bullied and a set of four variables– 1) Body Mass Index (BMI), 2) moderate and vigorous physical activity (MVPA), 3) television time (TV) and 4) video game/computer time (VG)-, termed in the present study as ‘health-related state and behaviours (HRSB)’–across adolescence. The Adolescent Nutritional Assessment Longitudinal Study (ELANA) is a cohort study conducted among middle school students from two public and four private schools in Rio de Janeiro-Brazil. We analysed data from 2010 (T1) and 2012 (T2) among 810 adolescents (aged 9–15 at T1). Gender-specific structural equation models (SEM) were estimated, including autoregressive paths for the HRSB and being body bullied over time, correlations at T1 and T2, respectively, and cross-lagged effects. The results presented significant stability coefficients for almost all variables over time in both genders (except for MVPA in boys and girls and TV time among girls). There were positive correlations between BMI and being body bullied, as well as between TV and VG for boys (0.32, p<0.001 and 0.24, p<0.001, respectively) and girls (0.30, p<0.001 and 0.30, p<0.001, respectively) at T1. It remained significant at T2 (boys: 0.18, p<0.05 and 0.16, p<0.01; girls: 0.21, p<0.01 and 0.22, p<0.01, respectively). Examining the cross-lagged paths between being body bullied and HRSB, we observed that the reciprocal model provided the best fit for boys, indicating that BMI at T1 had a significant effect in being body bullied at T2 (0.12, p<0.05) and being body bullied at T1 had an effect on VG at T2 (0.14, p<0.01). Among girls the forward causation model showed the best fit, demonstrating a significant effect of being body bullied at T1 on VG at T2 (0.16, p<0.01). Apart from MVPA, both being body bullying and HRSB were largely stable across adolescence. For boys and girls alike, exposure to being body bullied seemed to increase their time spent on VG, while for boys BMI also predicted being body bullied. This study highlighted the complex interplay between being body bullied and HRSB and the importance of acknowledging gender differences in this context.

Validity and correlates of the International Physical Activity Questionnaire in first-episode psychosis.

The International Physical Activity Questionnaire (IPAQ) is a self-report tool commonly used in mental healthcare settings to assess physical activity. However, its validity has not yet been investigated in first-episode psychosis (FEP). The aim of this study was to examine the concurrent validity of the IPAQ compared with an objective real-life measure, the Sensewear Armband (SWA), in assessing moderate and vigorous physical activity (MVPA) in people with FEP. A secondary aim was to explore whether there are differences in correlates of the IPAQ vs SWA scores. In total, 19 outpatients with FEP (15 men; 24.4 ± 5.1 years) wore an SWA for 5 full consecutive days, subsequently completed the IPAQ, performed a maximal cardiorespiratory fitness test and were assessed with the Positive and Negative Syndrome Scale (PANSS). There was no significant correlation between time spent in MVPA according to the IPAQ and SWA. In contrast with SWA scores, there were no significant associations between IPAQ scores and cardiorespiratory fitness levels. No correlations with PANSS scores were observed in both measures. The current results suggest that the IPAQ should be used with caution when assessing levels of MVPA in FEP. More accurate methods of measuring physical activity are needed in this population.

Clustering of multiple energy balance related behaviors is associated with body fat composition indicators in adolescents: Results from the HELENA and ELANA studies

The objective of this study was to identify clustering patterns of four energy balance-related behaviors (EBRB): television (TV) watching, moderate and vigorous physical activity (MVPA), consumption of fruits and vegetables (F&V), and consumption of sugar-sweetened beverages (SSB), among European and Brazilian adolescents. EBRB associations with different body fat composition indicators were then evaluated. Participants included adolescents from eight European countries in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescents) study (n = 2,057, 53.8% female; age: 12.5–17.5 years) and from the metropolitan region of Rio de Janeiro/Brazil in the ELANA study (the Adolescent Nutritional Assessment Longitudinal Study) (n = 968, 53.2% female; age: 13.5–19 years). EBRB data allowed for sex- and study-specific clusters. Associations were estimated by ANOVA and odds ratios. Five clustering patterns were identified. Four similar clusters were identified for each sex and study. Among boys, different cluster identified was characterized by high F&V consumption in the HELENA study and high TV watching and high MVPA time in the ELANA study. Among girls, the different clusters identified was characterized by high F&V consumption in both studies and, additionally, high SSB consumption in the ELANA study. Regression analysis showed that clusters characterized by high SSB consumption in European boys; high TV watching, and high TV watching plus high MVPA in Brazilian boys; and high MVPA, and high SSB and F&V consumption in Brazilian girls, were positively associated with different body fat composition indicators. Common clusters were observed in adolescents from Europe and Brazil, however, no cluster was identified as being completely healthy or unhealthy. Each cluster seems to impact on body composition indicators, depending on the group. Public health actions should aim to promote adequate practices of EBRB.

The contribution of area-level walkability to geographic variation in physical activity: a spatial analysis of 95,837 participants from the 45 and Up Study living in Sydney, Australia

BackgroundIndividual-level studies support a positive relation between walkable built environments and participation in moderate-intensity walking. However, the utility of this evidence for population-level planning is less clear as it is derived at much finer spatial scales than those used for regional programming. The aims of this study were to: evaluate if individual-level relations between walkability and walking to improve health manifest at population-level spatial scales; assess the specificity of area-level walkability for walking relative to other moderate and vigorous physical activity (MVPA); describe geographic variation in walking and other MVPA; and quantify the contribution of walkability to this variation.MethodsData on sufficient walking, sufficient MVPA, and high MVPA to improve health were analyzed for 95,837 Sydney respondents to the baseline survey of the 45 and Up Study between January 2006 and April 2010. We used conditional autoregressive models to create smoothed MVPA “disease maps” and assess relations between sufficient MVPA to improve health and area-level walkability adjusted for individual-level demographic, socioeconomic, and health factors, and area-level relative socioeconomic disadvantage.ResultsWithin-cohort prevalence of meeting recommendations for sufficient walking, sufficient MVPA, and high MVPA were 31.7 (95% CI 31.4–32.0), 69.4 (95% CI 69.1–69.7), and 56.1 (95% CI 55.8–56.4) percent. Prevalence of sufficient walking was increased by 1.20 (95% CrI 1.12–1.29) and 1.07 (95% CrI 1.01–1.13) for high and medium-high versus low walkability postal areas, and for sufficient MVPA by 1.05 (95% CrI 1.01–1.08) for high versus low walkability postal areas. Walkability was not related to high MVPA. Postal area walkability explained 65.8 and 47.4 percent of residual geographic variation in sufficient walking and sufficient MVPA not attributable to individual-level factors.ConclusionsWalkability is associated with area-level prevalence and geographic variation in sufficient walking and sufficient MVPA to improve health in Sydney, Australia. Our study supports the use of walkability indexes at multiple spatial scales for informing population-level action to increase physical activity and the utility of spatial analysis for walkability research and planning.

Comparison Of Weekend And Weekdays Physical Activity Levels In Korean Professional Golfers.

The dominance of the U.S based LPGA/PGA tour by Korean-born golfers over the past decade has been well recognized. The sheer volume of quality golfers being produced by this relatively small golfing nation has certainly caught the attention of the field of golf. However, the level of physical activity in Korean professional golfers has never been systematically examined. PURPOSE: The present study was to describe the baseline characteristics of the participant and to compare the physical activity level between weekdays and weekends in Korean professional golfers using objective physical assessment tools (i.e., Accelerometer). METHODS: Fourteen (male=7; female=8) young Korean professional golfers (23 ± 2.4 yrs; height = 171±7.5 cm; weight = 73.7±7.5 kg, experience = 6.6 yrs) consented to participate in the study. Participants were asked to wear the accelerometer (i.e., Actigraph) on their right wrist for 24 hours/day, 7 consecutive days to provide data on time in moderate and vigorous physical activity (MVPA). ActiLife software (version 6.11.2) was used to download all data. Raw data were processed with the R package GGIR and associated Hilderband milling (mg) cut points. Descriptive for all variables was calculated and Pearson product moment correlations were used to test for relationships between weekdays and weekends. A paired sample t-test was used to evaluate differences between weekday and weekend physical activity level. RESULTS: The accelerometer wear compliance was excellent 6.8 days, 98% of the time. Time in MVPA was 99.5 ± 35.79 mins/day and 136.4 ± 35.2 mins/day for weekends, weekdays, respectively. There is no significant difference on physical activity levels on weekdays (t(12) = .379, p =.329) and weekends (t(12) = -.004, p=.997) between male and female golfers. No correlation was observed between weekdays MVPA and years of experience. However, weekends MVPA were inversely correlated with years of experience (r = -215, p=.48). Similar correlations were found between weekdays MVPA (r = -.432, p=.141) and weekends MVPA (r = -438, p=.134) with golfers’ age. DISCUSSIONS: Our data demonstrates that Korean professional golfers were highly active during weekdays compared to weekends. Experienced golfers were associated with little time spent in MVPA regardless of the days of the week.

The Validity of Fitbit Charge in Free Living Conditions

PURPOSE: Research is accumulating regarding the accuracy of wrist-worn consumer activity monitors in controlled lab settings. However, there is a lack of evidence of validity under free living conditions. The study investigated the accuracy of Fitbit Charge (FBC) for estimating minutes of moderate and vigorous physical activity (MVPA) compared to research grade accelerometers. A secondary purpose was to evaluate the accuracy of steps/day. METHODS: Ninety-four healthy men and women (mean age 41 ± 9 years) wore a FBC as part of a 12-week intervention. The participants were also asked to wear research grade accelerometers concurrently as the criterion physical activity measure during the last week of intervention. A minimal of 10 hours/day wear-time was applied to both methods. Estimated daily MVPA and steps taken from the FBC were compared against the criterion using indicators of Pearson correlation, mean absolute percent errors, mean percent errors, and equivalence testing. The activity classification agreement of MVPA at the minute level was evaluated with Kappa, sensitivity and specificity. RESULTS: Complete data were collected on 61 individuals with an average of 5.5 days of wear-time. The average daily MVPA measured by accelerometer was 76.3 minutes compared to a higher value, 118.7 minutes, estimated by the FBC. The correlation between the two methods was 0.8 (p<0.0001). The mean absolute percent errors and mean percent errors were 68.2% and -64.2% indicating a consistent overestimating MVPA by the FBC. The average daily steps were 8,897 and 7,716 measured by FBC and accelerometer, respectively, with a correlation of 0.76 (p<0.0001). The mean absolute percent errors and mean percent errors of steps estimated by FBC were 30.0% and -20.1%. Neither of the MVPA and steps measured by FBC fell into the ±10% equivalence zone set up by the accelerometer. The Kappa statistics of the classification agreement between the two methods was 0.32 with a low the sensitivity of 30.1% but a high specificity of 96.7%. CONCLUSIONS: This FBC estimated substantially higher minutes of MVPA in free living conditions among healthy adults and significantly higher steps compared to research grade accelerometer. The researchers who use FBC to track physical activity need to interpret their results with caution.

Longitudinal Influence Of Prolonged And Short Bouts Of Sedentary Time On Mental Wellbeing

Excessive sedentary time is related to poor mental wellbeing. However, the differential influence of sedentary time accumulated in prolonged versus short bouts on factors related to mental wellbeing is unknown. PURPOSE: To examine the longitudinal influence of sedentary bout length on mood, stress, and sleep over one year. METHODS: Two hundred and seventy healthy adults (48% women; age 27.8 ± 3.7) completed the Profile of Mood States (POMS) and the Perceived Stress Scale (PSS), and wore a Sensewear Armband to objectively measure sedentary time, physical activity, and sleep duration and efficiency at baseline and one year later. Prolonged and short bouts of sedentary time were operationalized to those greater and less than 30 minutes in duration. Fixed effects regression analyses were performed with baseline minutes and changes in prolonged and short bouts of sedentary time and minutes of moderate and vigorous physical activity (MVPA) as predictors of changes in mood disturbance, stress, and sleep duration and efficiency over one year as outcomes. RESULTS: For mood, the overall model was significant (p = 0.04) with changes in prolonged (p = 0.004) and short bouts (p = 0.006) of sedentary time positively predicting changes in mood disturbance. For stress, the overall model trended towards significance (p = 0.06) with only changes in prolonged bouts of sedentary time as a positive predictor (p = 0.003). For sleep duration, the overall model was significant (p < 0.0001) with changes in prolonged and short bouts of sedentary time as inverse predictors and change in MVPA as a positive predictor (all p < 0.0001). For sleep efficiency, the overall model was significant (p < 0.03) with changes in both prolonged (p = 0.017) and short bouts of sedentary time (p = 0.008) as inverse predictors. CONCLUSIONS: Changes in both prolonged and shorter bouts of sedentary time are predictive of future mood, stress, and sleep in healthy young adults adding to the evidence that sedentary time has negative, long-term consequences for wellbeing, regardless of how it is accumulated. Interestingly, in this sample of healthy adults, baseline levels of sedentary time and MVPA were not predictive of changes in mental wellbeing-related outcomes. Interventions targeting sedentary time may not need to target specific bout lengths to realize benefits.

Effects of Vitamin D3 Supplementation on Lean Mass, Muscular Strength, and Cardiorespiratory Fitness

Low levels of serum 25-hydroxyvitamin D [25(OH)D] are associated with low lean mass, decreased muscle strength, and poor cardiorespiratory fitness. However, the evidence in support of the effect of vitamin D supplementation on lean mass and physical fitness is inconsistent. PURPOSE: To clarify whether there is a direct effect of a 1-year vitamin D3 supplementation on lean mass, muscular strength and cardiorespiratory fitness in healthy adults. METHODS: Ninety-five participants (34 men) randomly received either 420 IU vitamin D3 per day or placebo in a double-blind manner for 1-year. Lean body mass and fat mass were determined by dual energy X-ray absorptiometry (DXA). Hand grip strength (HGS) was measured using a hand grip dynamometer and leg extension power (LEP) was measured using a leg extension power measurement system. Cardiorespiratory fitness (CRF) was assessed by measuring peak oxygen uptake (VO2peak) using bicycle ergometer. Physical activity (PA) was assessed using uniaxial accelerometer and quantified as time spent in moderate- and vigorous physical activity (MVPA). Serum 25(OH)D and 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations were assessed using commercial ELISA kits. RESULTS: Serum 25(OH)D and 1,25(OH)2D concentrations were significantly increased by approximately 29.5nmol/L and 7.0 pg/mL, respectively, after 1-year vitamin D3 supplementation. After vitamin D3 supplementation, lean body mass was significantly increased from 43.8 kg to 44.3 kg (P<0.05), while the muscle strength and cardiorespiratory fitness were not changed. CONCLUSION: The present study indicates that vitamin D3 supplementation for one year effectively improves lean mass, but not muscle strength and cardiorespiratory fitness in healthy adults. Supported by a Grant-in-Aid for Scientific Research (C), National Natural Science Foundation of China (No. 31571226), and Program for Professors of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (No. TP2014057) to ZBC.

Impact of Prescribed Exercise on Physical Activity Compensation in Young Adults.

Liguori, G, Schuna, JM Jr, Tucker, J, and Fountaine, CM. Impact of prescribed exercise on physical activity compensation in young adults. J Strength Cond Res 31(2): 503-508, 2017-Army Reserve Officers' Training Corps cadets present a unique subpopulation because they are required to participate in regular physical activity (PA). This study describes PA patterns of cadets and attempts to identify evidence of nonexercise PA compensation (activitystat) as a result of prescribed PA (pPA) by comparing differences between training and nontraining days for (a) autonomous PA among cadets and (b) PA between cadets and noncadets. Participants included 84 university students (33 cadets and 51 noncadets) who each wore an accelerometer for 5 consecutive days to estimate moderate and vigorous physical activity (MVPA). A 2×2 mixed model analysis of variance was used to examine within- and between-group differences in MVPA on training and nontraining days. This analysis was repeated after removing the cadet's pPA. Cadets had lower-body fat than noncadets (p = 0.044), but all other characteristics were similar. Overall, moderate PA (MPA) and vigorous PA (VPA) were significantly greater among cadets (p = 0.048 and p < 0.001), because of greater weekend MPA (p = 0.021) and greater weekday VPA (p < 0.001). Cadets accumulated more MVPA on training days than nontraining days (p < 0.001) and accumulated more MVPA than noncadets on training days (p = 0.004). However, after accounting for pPA, cadet MVPA did not differ between training and nontraining days (within 1.2Â ± 18.4 min·d) and was similar between cadets and noncadets (within 1.5Â ± 5.9 min·d). These results suggest that cadets were significantly more active than noncadets due mainly to pPA. When controlling for pPA, cadets were similarly active across all days, and were as active as noncadets, indicating no evidence of activitystat in this population.