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Minsoo Kang, Youngdeok Kim and David A. Rowe

Background:

This study examined the optimal measurement conditions to obtain reliable peak cadence measures using the accelerometer-determined step data from the National Health and Nutrition Examination Survey 2005–2006.

Methods:

A total of 1282 adults (> 17 years) who provided valid accelerometer data for 7 consecutive days were included. The peak 1- and 30-minute cadences were extracted. The sources of variance in peak stepping cadences were estimated using Generalizability theory analysis. A simulation analysis was conducted to examine the effect of the inclusion of weekend days. The optimal number of monitoring days to achieve 80% reliability for peak stepping cadences were estimated.

Results:

Intraindividual variability was the largest variance component of peak cadences for young and middle-aged adults aged < 60 years (50.55%–59.24%) compared with older adults aged ≥ 60 years (31.62%–41.72%). In general, the minimum of 7 and 5 days of monitoring were required for peak 1- and 30-minute cadences among young and middle-aged adults, respectively, whereas 3 days of monitoring was sufficient for older adults to achieve the desired reliability (0.80). The inclusion of weekend days in the monitoring frame may not be practically important.

Conclusions:

The findings could be applied in future research as the reference measurement conditions for peak cadences.

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James L. Farnsworth, Youngdeok Kim and Minsoo Kang

Background:

Disruptive sleeping patterns have been linked to serious medical conditions. Regular physical activity (PA) has a positive impact on health; however, few research have investigated the relationships between PA, body mass index (BMI), sedentary behaviors (SB), and sleep disorders (SD).

Methods:

Data from the 2005–2006 NHANES were analyzed for this study. Participants (N = 2989; mean age = 50.44 years) were grouped based upon responses to SD questions. Accelerometers were used to measure the average time spent in moderate or vigorous physical activity (MVPA) and SB. Multinomial logistic regression analyses were used to examine the associations between PA, SB, and SD after controlling for covariates and to explore potential moderation effects among common risk factors and the main study variables.

Results:

Among middle-aged adults, PA was significantly associated with SD [Wald χ2 (8) = 22.21; P < .001]. Furthermore, among adults in the highest tertile of SB, PA was significantly associated with SD [Wald χ2 (8) = 32.29; P < .001].

Conclusions:

These results indicate that middle-aged adults who are less active may have increased likelihoods of SD. It is important for health care professionals to continue developing methods for increasing PA to decrease the risk of SD.

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Youngdeok Kim, Ilhyeok Park and Minsoo Kang

The purpose of this study was to investigate rater effects on the TGMD-2 when it applied to children with intellectual disability. A total of 22 children with intellectual disabilities participated in this study. Children’s performances in each of 12 subtests of the TGMD-2 were recorded via video and scored by three adapted physical activity specialists who have expertise in the TGMD-2. Two advanced measurement theories, Generalizability-theory (G-theory) and many-facet Rasch model (MFRM), were applied in data analyses. There were relatively large variances attributed to rater effects on the scores of the TGMD-2 awarded to children with intellectual disabilities. The severity of each rater significantly differed across all subtests of the TGMD-2. There was a set of biased ratings interacted with measurement conditions of the TGMD-2.

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Youngdeok Kim, Joaquin U. Gonzales and P. Hemachandra Reddy

The purpose of this study was to examine short-term longitudinal relationships between handgrip strength (HGS) and cardiovascular disease (CVD) biomarkers in middle-aged to older adults living in rural areas (N = 138). The association between HGS and CVD biomarkers was examined at baseline, with HGS as a predictor of the annual change in biomarkers, and in a parallel fashion between the annual change in HGS and CVD biomarkers over an average of 2.8 follow-up years. The results showed HGS to cross-sectionally associate with waist circumference and diastolic blood pressure at baseline, but HGS at baseline was not found to predict the annual change in any biomarker. The annual increase in HGS was significantly associated with favorable changes in high-density lipoprotein cholesterol, triglycerides, and systolic/diastolic blood pressures; yet, these associations varied by the baseline levels of biomarkers. The present findings suggest that improved muscle strength with aging is related to favorable changes in CVD biomarkers.

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Youngdeok Kim, Jaehoon Cho, Dana K Fuller and Minsoo Kang

Background:

The purpose of this study was to examine the correlates of physical activity (PA) with personal and environmental factors among people with disabilities in South Korea.

Methods:

Data from the 2011 National Survey for Physical Activity and Exercise for the Disabled, conducted by Korea Sports Association for the Disabled, was used (n = 1478). The personal characteristics (age, gender, occupation, types of disabilities, family income) and the numbers of public PA-related facilities (welfare center, public indoor gym, and public outdoor facilities) and social sports/exercise clubs for people with disabilities across 16 local areas were also obtained. Hierarchical generalized linear model was used to examine subjectively measured PA in relation to personal and environmental factors.

Results:

The likelihood of engaging in PA was significantly lower for women with disabilities. People with hearing and intellectual disabilities were less likely to engage in PA compared with those with physical disabilities. The availability of sports/exercise clubs for people with disabilities was the only environmental factor that was significantly associated with PA.

Conclusions:

These findings suggest the need of systematic intervention strategies based upon personal characteristics of people with disabilities. Further public efforts to promote sports/exercise club activities should be encouraged in this population.

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Saori I. Braun, Youngdeok Kim, Amy E. Jetton, Minsoo Kang and Don W. Morgan

The purpose of this study was to determine if bone health at the femoral neck (FN) and lumbar spine (LS) can be predicted from objectively-measured sedentary behavior and physical activity data in postmenopausal women. Waist-mounted ActiGraph GT1M and GT3X devices were used to quantify levels of sedentary and moderate-to-vigorous intensity behavior during a 7-day period in 44 older females. Bone health (normal and osteopenia/osteoporosis) of FN and LS was derived from T scores generated using dual energy x-ray absorptiometry. Binomial logistic regression analysis indicated that sedentary time and number of breaks in sedentary behavior were significant predictors of osteopenia/osteoporosis at the FN, but not at the LS. Adherence to physical activity guidelines was not a significant predictor of bone health at the FN or LS. Our findings suggest that more frequent interruptions in sedentary behavior are associated with improved bone health in postmenopausal women.