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Kristen M. Metcalf, Elena M. Letuchy, Steven M. Levy and Kathleen F. Janz

Purpose: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. Methods: Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age − age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA–biological age interaction. Results: Individual-centered VPA and the VPA–biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. Conclusion: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.

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Mariana R. Silva, Cristine L. Alberton, Caroline O. Braga and Stephanie S. Pinto

Background: To compare the acute effects of water-based aerobic–resistance and resistance–aerobic concurrent training (CT) sessions on energy expenditure (EE) during and postexercise in young women. Methods: Nine active women (24 [3] y; 60 [5] kg) completed 4 sessions: (1) familiarization, (2) aquatic maximal test to determine the heart rate corresponding to the anaerobic threshold, (3) CT protocol with aerobic–resistance sequence, and (4) CT protocol with resistance–aerobic sequence. Both protocols started and ended with the participants in the supine position for 30 minutes to perform resting and postexercise oxygen consumption measurements. The water-based resistance protocol comprised 4 sets of 15 seconds at maximal velocity, and the water-based aerobic protocol was performed at a continuous intensity (heart rate corresponding to the anaerobic threshold). EE measurements were calculated based on oxygen consumption and the corresponding caloric equivalent. Paired t test was used to compare the EE values between the water-based CT intrasession exercise sequences (α = .05). Results: There was no difference between the water-based aerobic–resistance and resistance–aerobic in total EE (330.78 vs 329.56 kcal; P = .96), EE per minute (7.35 vs 7.32 kcal·min−1; P = .96), and postexercise EE (63.65 vs 59.92 kcal; P = .50). Conclusions: The intrasession exercise sequence during water-based CT had no influence on the EE in young women.

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Kent Upham, Brandon J. Auer, Christopher N. Sciamanna, Andrew J. Mowen, Joshua M. Smyth, David E. Conroy, Matthew Silvis, Jennifer L. Kraschnewski, Liza S. Rovniak, Erik Lehman, Kalen Kearcher, Maggie Vizzini and Louis Cesarone

Background: Few adults in the United States obtain sufficient physical activity (PA) despite knowledge of the associated health benefits. The current feasibility study examined the feasibility of a novel modified sports intervention designed to promote enjoyment and sustained PA in sedentary adults. Methods: The US adults (N = 22, mean age 39.2 y, male/female percentage 54.5/45.5) in Central Pennsylvania participated in the PlayFit sports program for 60-minute sessions, 2 to 3 times per week, over the course of 10 weeks and 24 game sessions; completing 198 person sessions collectively. Primary outcomes were PA (accelerometry) and intervention satisfaction. Results: Percentage of time in moderate to vigorous activity ranged from 35.0% (volleyball) to 91.2% (ultimate frisbee). Percentage of time spent in vigorous activity ranged from 0.0% (volleyball) to 29.5% (team handball). Satisfaction, based on a 10-point scale with 10 being the most satisfied, ranged from 7.7 (kickball) to 8.7 (floor hockey and soccer). On average, all sports were rated highly, with the majority rated >8.5 and one rated <8.0. Percentage of time spent in the moderate to vigorous range was lower in men than in women (73.2% vs 80.0%, P = .01), but did not differ by age or body mass index. Conclusions: PlayFit is a promising first step in exploring the potential of modified sports programs to enhance population PA levels.

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Mark Ward, Sarah Gibney, David O’Callaghan and Sinead Shannon

Despite the benefits, one in three older adults in Ireland has low activity levels. This study examined associations between the local social and built environment and physical activity of older adults to identify age-friendly factors that support physical activity among the aging population. Data were from the population-representative Healthy and Positive Ageing Initiative Age-Friendly City and Counties Survey (N = 10,540). Physical activity was measured using a short-form of the International Physical Activity Questionnaire. Mixed-effects negative binomial regression models were adjusted for known health and sociodemographic correlates of physical activity. Results are reported as unstandardized beta coefficients (β) with standard errors. Loneliness, community participation, and difficulty in accessing green spaces partially explained the differences in the number of minutes that respondents were physically active. Combined with individual-level behavior change interventions, improvements to the local environment and promoting social connectedness may also be useful in promoting physical activity among older adults.

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Xiaoxia Zhang, Xiangli Gu, Tao Zhang, Priscila Caçola and Jing Wang

Purpose: Using 2012 National Health and Nutrition Examination Survey (NHANES) National Youth Fitness Survey data, the authors conducted a cross-sectional secondary analysis to examine the associations of movement behaviors (ie, physical activity [PA] and screen-based sedentary behaviors) and fundamental motor skills (FMS) with fitness (ie, muscular fitness) and fatness (ie, body mass index and waist circumference) in 3- to 5-year-old children. The effect of ethnicity (Hispanic vs non-Hispanic) on these associations was also examined. Methods: A total of 352 children (173 girls; mean age = 4.02 y) from the 2012 NHANES data set were included. Parents reported their child’s PA and screen-based sedentary behaviors. FMS (ie, locomotor and object control) were assessed with the Test of Gross Motor Development, 2nd edition. Other variables used were body mass index, waist circumference, and plank. Results: Hispanic children demonstrated lower levels of PA than non-Hispanic children (P < .05). Children’s FMS emerged as significant predictors of muscular fitness and waist circumference, but not for body mass index in the Hispanic group. In the non-Hispanic group, FMS (ie, object control skills) and PA accounted for significant variances of muscular fitness and waist circumference, respectively. Conclusion: The associations of movement behaviors and FMS with fitness and fatness are different between Hispanic and non-Hispanic young children. Changes in policy or early childhood curriculum may be tailed to promote FMS for an impact on fitness and fatness in both Hispanic and non-Hispanic children.

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Rachel G. Curtis, Dorothea Dumuid, Timothy Olds, Ronald Plotnikoff, Corneel Vandelanotte, Jillian Ryan, Sarah Edney and Carol Maher

Background: Substantial evidence links activity domains with health and well-being; however, research has typically examined time-use behaviors independently, rather than considering daily activity as a 24-hour time-use composition. This study used compositional data analysis to estimate the difference in physical and mental well-being associated with reallocating time between behaviors. Methods: Participants (n = 430; 74% female; 41 [12] y) wore an accelerometer for 7 days and reported their body mass index; health-related quality of life (QoL); and symptoms of depression, anxiety, and stress. Regression models determined whether time-use composition, comprising sleep, sedentary behavior, light physical activity (LPA), and moderate to vigorous physical activity (MVPA), was associated with well-being. Compositional isotemporal substitution models estimated the difference in well-being associated with reallocating time between behaviors. Results: Time-use composition was associated with body mass index and physical health-related QoL. Reallocating time to MVPA from sleep, sedentary behavior, and LPA showed favorable associations with body mass index and physical health-related QoL, whereas reallocations from MVPA to other behaviors showed unfavorable associations. Reallocations from LPA to sedentary behavior were associated with better physical health–related QoL and vice versa. Conclusion: Results reinforce the importance of MVPA for physical health but do not suggest that replacing sedentary behavior with LPA is beneficial for health and well-being.

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Mitali S. Thanawala, Juned Siddique, John A. Schneider, Alka M. Kanaya, Andrew J. Cooper, Swapna S. Dave, Nicola Lancki and Namratha R. Kandula

Background: Eliminating racial/ethnic disparities in physical activity remains a challenge in the United States. South Asian immigrants in the United States have particularly low physical activity levels, and evidence suggests that social context may be important. This study examined associations between personal social networks and moderate to vigorous leisure-time physical activity (MVPA) among South Asians in the United States. Methods: We used cross-sectional data (2014–2017) from 689 South Asians (aged 43–85 y) who participated in the Mediators of Atherosclerosis in South Asians Living in America study. Self-reported physical activity and egocentric network data were collected from participants about their network members. Regression models were used to determine associations between social network characteristics and participants’ MVPA. Results: Participants were on average 59 years old (SD = 9) and reported 1335 metabolic equivalent minutes per week of MVPA (interquartile range = 735, 2212). Having network members who exercised or who were exercise partners associated with increased MVPA in men (β coefficient = 241 MET min/wk [95% confidence interval, 63 to 419] and β = 520 MET min/wk [95% confidence interval, 322 to 718], respectively). For women, the association was only significant if the exercise partner was a spouse. Conclusion: Physical activity interventions utilizing network members as exercise partners may have potential in South Asians but must consider gender differences.

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Ka Man Leung and Pak-Kwong Chung

This study examined the associations between physical environment, social environment, and walking for transportation and recreation among older adults in Hong Kong. Cross-sectional data from 450 older adults (79 years or younger [71.9%], female [79.7%]) from 18 districts in Hong Kong were used. The participants’ perceptions of their physical and social environments were collected, and their walking behaviors were self-reported. The results revealed that positive physical environment facilitators and social environments were associated with increased total walking. Only positive physical environment facilitators were associated with increased walking for transportation, and physical and social environments had no notable effect on walking for recreation. These findings suggest that policy makers and walking intervention designers should develop strategies to enhance physical and social environments to promote total walking and walking for transportation.

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Jeffrey C. Cowley, Steven T. McCaw, Kelly R. Laurson and Michael R. Torry

Purpose: Children who are overweight typically do not perform motor skills as well as normal-weight peers. This study examined whether vertical jump kinetics and kinematics of children who are overweight differ from nonoverweight peers. Methods: Thirty-nine children completed maximum-effort countermovement vertical jumps. Motion capture was used to complete lower extremity kinematic and kinetic analyses. Results: The overweight group (body mass index ≥ 85th percentile; N = 11; age = 6.5 [1.6] y) jumped lower relative to their mass (0.381 cm/kg lower; P < .001) than normal-weight peers (N = 28; age = 6.4 [1.7] y). Compared with children who are normal weight, children who were overweight exhibited a shallower countermovement (knee: 12° less flexion, P = .02; hip: 10° less flexion, P = .045), lower hip torque (0.06 N·m/kg lower, P = .01) and hip work (40% less work, P = .01), and earlier peak joint angular velocities (knee: 9 ms earlier, P = .001; hip: 14 ms earlier, P = .004). Conclusion: Children who are overweight do not achieve optimal jumping mechanics and exhibit jumping characteristics of an earlier developmental stage compared with their peers. Interventions should help children who are overweight learn to execute a proper countermovement.

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Julia C. Orri, Elizabeth M. Hughes, Deepa G. Mistry and Antone Scala

The authors compared the linear and nonlinear heart rate variability dynamics from rest through maximal exercise in postmenopausal women who trained at either moderate or high intensities. The outcome variables included the RR triangular index, TINN, SD1, SD2, SD1/SD2, DFA α1, DFA α2, and α1/α2. Maximal exercise reduced SD1, SD2, DFA α1, DFA α2, α1/α2, RRTri, and TINN in both groups and increased SD1/SD2 (p < .05). Two minutes of active recovery produced significant increases in SD1, SD2, DFA α1, and TINN, compared with exercise in both groups (p < .0001). There was also a significant main effect between groups for RRTri during exercise recovery, with the moderate group achieving higher levels (p < .04). The authors have shown that both moderate and vigorous exercise training can lead to a healthy response to maximal exercise and recovery, with the moderate group having a slightly improved recovery in the triangular index.