[Show abstract][Hide abstract] ABSTRACT: Commonly reported relationships of the broad personality traits of Extraversion and Neuroticism with self-reports of physical activity (PA) have not been elaborated within motivational theory that posits how functioning of the behavioral inhibition (BIS) and activation (BAS) systems can explain or modify the influence of personality on physical activity. Whether personality predicts physical activity when it is measured objectively has not been established. Purpose: To test direct, indirect, and interactive relations between Extraversion, Neuroticism, BIS and BAS, and physical activity measured by validated self-report and accelerometry. Methods: Two samples of female undergraduates completed personality questionnaires. Sample two also completed three PA self-reports and wore an accelerometer for 7 days. Factor structure and measurement equivalence of personality measures, structural equivalence of relationships between personality factors, and multivariate prediction of self-reported and objectively measured PA by personality were tested using structural equation modeling. Results: Equivalence between samples for personality models was confirmed. BAS predicted self-reported PA. Neuroticism and BIS predicted objectively measured PA. Conclusions: The relationship between personality and PA may differ according to method used to measure PA. BIS appears to protect against inactivity among young women high in Neuroticism.
Medicine & Science in Sports & Exercise 08/2015; 47(8):1691-1697. DOI:10.1249/MSS.0000000000000570 · 3.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A positive association between physical activity and mental health is well established, particularly for lower symptoms of depression and anxiety among active adults. However, it is unclear whether the association is influenced by personality, which might moderate or otherwise explain the association. Also, past studies have not confirmed the association using an objective measure of physical activity.
To examine whether Extraversion (E) and Neuroticism (N) influence the association between mental health and physical activity measured by convergent self-reports and an accelerometer.
Structural equation modeling (SEM) was used to test competing models of the relationships between personality, physical activity, and mental health in a sample of female undergraduates.
In bivariate analysis, mental health was negatively related to N, and positively related to E, self-reported physical activity (which was related only to E, positively), and objective physical activity (which was related only to N, negatively). In SEM, a three-way interaction indicated that objective physical activity and mental health were unrelated in extraverts, but related positively in neurotic-introverts and negatively in stable-introverts.
Higher levels of physical activity were associated with better mental health only in neurotic-introverts, who are at higher risk for mental health problems.
Journal of Physical Activity and Health 04/2015; DOI:10.1123/jpah.2014-0455 · 1.95 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Greater muscle strength and power are associated with better physical function in middle-aged and older women. The aim of the present study was to determine whether accelerometer-measured physical activity was associated with muscle strength and power in middle-aged postmenopausal women.
Postmenopausal women (N = 60; mean [SD] age, 58.9 [3.9] y) were assessed for physical activity (step count and moderate to vigorous physical activity [MVPA]) via accelerometer, for body composition via dual-energy x-ray absorptiometry, for concentric isokinetic knee torque at 60°/s and 180°/s using isokinetic dynamometry, and for leg extensor power with the Nottingham power rig.
In linear regression analysis, daily step count was independently associated with isokinetic knee torque at 60°/s (standardized β = 0.32, P = 0.01), isokinetic knee torque at 180°/s (standardized β = 0.32, P = 0.01), and total leg extensor power (β = 0.36, P = 0.01) after adjustment for covariates. Daily MVPA had similar associations with isokinetic knee torque at 60°/s (β = 0.38, P < 0.01), isokinetic knee torque at 180°/s (β = 0.41, P < 0.01), and leg power (β = 0.31, P = 0.02). Analysis of covariance indicated that women who engaged in MVPA for 30 minutes or more per day produced significantly greater isokinetic knee torque (60°/s and 180°/s) and leg extensor power compared with women not meeting this guideline (all P < 0.05).
These findings suggest that daily step count and MVPA are independently associated with muscle strength and power in middle-aged postmenopausal women. Future studies should determine whether interventions that increase habitual physical activity in middle-aged women are associated with concomitant improvements in muscle capacity.
Menopause (New York, N.Y.) 03/2015; Publish Ahead of Print. DOI:10.1097/GME.0000000000000447 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Postmenopausal women (PMW) are at high risk for disabling pain and physical inactivity. This study sought to enhance the understanding of relationships between physical activity (PA) and pain among PMW using heat pain sensitivity test and conditioned pain modulation test. We hypothesized that, compared with active women, (i) inactive women would report higher pain intensity and pain unpleasantness ratings; (ii) inactive women in disabling pain would report higher pain intensity and pain unpleasantness at high, but not low, stimulus intensities; and (iii) inactive women would have less modulation.
Sixty-eight PMW rated the pain intensity and pain unpleasantness of hot stimuli presented to the thenar eminence of the hand. A subset of 31 women rated the pain intensity of a test stimulus (noxious heat) and a conditioning stimulus (cold water) as part of the conditioned pain modulation task. PA was assessed objectively with accelerometry.
Mixed-model analysis of variance (2 × 4 × 2; PA × Temperature × Pain Status) showed that inactive women in disabling pain rated pain unpleasantness higher than active women in disabling pain (F3,192 = 3.526, ∂η = 0.052, P = 0.016). Significantly lower pain unpleasantness ratings were found at the highest stimulus intensity (49°C) only for active women in disabling pain compared with inactive women in disabling pain (t11 = 2.523, P = 0.028). The other hypotheses were not supported.
PA is associated with a reduced sensitivity to the unpleasantness of painful high-intensity heat stimuli among women in disabling pain.
Menopause (New York, N.Y.) 12/2014; Publish Ahead of Print(8). DOI:10.1097/GME.0000000000000398 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this investigation was to determine whether 6 weeks of sprint interval training (SIT) is associated with changes in mood and perceived health in women at risk for developing metabolic syndrome (MetS). Physically inactive women (30-65 years) were randomized to 6 weeks of nutrition meetings and SIT (n = 23; 3 bouts/week of 4-8 30-s cycle sprints with 4-min recovery) or a nonexercise control condition (CON; n = 24). Before and after the 6-week intervention, perceived health status and mood were assessed. Clinically relevant increases in role-physical scores (ES = 0.64) and vitality (ES = 0.52) were found after 6 weeks of SIT compared with a nonexercise control group. For middle-aged women at risk for MetS, it is concluded that high-intensity, low-volume SIT (1) increases feelings of vitality and perceptions of having fewer physical limitations and (2) does not induce mood disturbances as occurs with high-volume, high-intensity training.
Journal of sport & exercise psychology 12/2014; 36(6):610-8. DOI:10.1123/jsep.2014-0083 · 2.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: With the increasing prevalence of sedentary behaviors during childhood, a greater understanding of the extent to which excess adiposity and aerobic fitness relate to cognitive health is of increasing importance. To date, however, the vast majority of research in this area has focused on adiposity or fitness, rather than the possible inter-relationship, as it relates to cognition. Accordingly, this study examined the differential associations between body composition, aerobic fitness, and cognitive control in a sample of 204 (96 female) preadolescent children. Participants completed a modified flanker task (i.e., inhibition) and a switch task (i.e., cognitive flexibility) to assess two aspects of cognitive control. Findings from this study indicate that fitness and adiposity appear to be separable factors as they relate to cognitive control, given that the interaction of fitness and adiposity was observed to be nonsignificant for both the flanker and switch tasks. Fitness exhibited an independent association with both inhibition and cognitive flexibility whereas adiposity exhibited an independent association only with cognitive flexibility. These results suggest that while childhood obesity and fitness appear to both be related to cognitive control, they may be differentially associated with its component processes.
Monographs of the Society for Research in Child Development 12/2014; 79(4). DOI:10.1111/mono.12131 · 5.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives
The aim of this study was to examine the relative contributions of physical activity, adiposity, lean mass and muscle quality to lower-extremity physical function (LEPF) in older women.
Cross-sectional analysis at a university research laboratory
Main Outcome Measures: Community-dwelling older women (n = 96, 73.9 ± 5.6 y, BMI = 26.5 ± 4.7 kg/m2) were assessed for body composition via dual-energy X-ray absorptiometry, leg extension power using the Nottingham power rig, muscle quality (watts/kg) as the ratio of leg extension power (watts) to lower-body mineral free lean mass (kg) and moderate-intensity physical activity via questionnaire. A composite measure of LEPF was calculated by summing Z-scores of the 6-minute walk, 8-foot up-and-go and 30-s chair stand tests.
Muscle quality and physical activity were associated with all measures of LEPF (all p < 0.01). Relative adiposity was related to the 6-minute walk and 30-s chair stand (both p < 0.01); lower-body mineral-free lean mass was not related to any measure of LEPF (p > 0.05). Hierarchical linear regression analyses revealed that muscle quality (standardized β = 0.47, p < 0.01) and relative adiposity (β = -0.33, p < 0.01) were the strongest independent predictors of composite LEPF Z-score explaining 24% and 17% of the variance, respectively.
Muscle quality and relative adiposity are the strongest independent predictors of LEPF in older women. These findings suggest that maintaining muscle quality, especially relative to adiposity, may be a critical target for interventions to prevent declines in physical function in older women.
[Show abstract][Hide abstract] ABSTRACT: Context:
The purpose of this systematic review and meta-analysis was to assess changes in body weight and relative adiposity (%FAT) during college and identify potential moderating variables.
A review of peer-reviewed articles published before June 28, 2013 identified 49 studies evaluating the effect of the first year of college on the dependent variables of body weight (137 effects from 48 studies) and %FAT (48 effects from 19 studies). Statistical analysis was conducted between July 1, 2013, and May 1, 2014. Effect sizes were calculated by subtracting the mean pre-test measurements from the mean post-test measurements.
Participants' weight increased 1.55 kg (95% CI=1.3, 1.8 kg) during college, with a 1.17% increase in %FAT (95% CI=0.7, 1.6%). Meta-regression analysis concluded that changes in body weight and %FAT were positively associated with study duration, suggesting that effects measuring change over a longer duration yielded larger effects when compared to effects with shorter observations. Sex and baseline BMI were not associated with change in weight or %FAT after accounting for study duration.
The increase in weight and %FAT during the college years is equal to 1.55 kg and 1.17%, respectively. Change in body weight during the first year of college is significantly less than that during the cumulative remaining years of college. By understanding the magnitude of change, appropriate prevention efforts can be designed for the college population, which may be beneficial in reducing adult overweight and obesity rates.
American Journal of Preventive Medicine 09/2014; 47(5). DOI:10.1016/j.amepre.2014.07.035 · 4.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
This study aims were to investigate whether age differentially impacts the relationships between adiposity, muscle quality (MQ), and lower-extremity physical function in young and older women.
Women aged 20 to 30 years (YOUNG group; n = 37) and women aged 64 to 80 years (OLD group; n = 39) were assessed for body composition via dual-energy X-ray absorptiometry. Isokinetic strength at 60 deg/second was assessed on a dynamometer. MQ was calculated as Nm / mineral-free lean mass (kg). Lower-extremity physical function was determined by an up-and-go (UPGO) challenge.
YOUNG women had lower relative adiposity (%Fat), greater leg lean mass, greater MQ, and faster UPGO time compared with OLD women (all P < 0.01). On linear regression analyses, mineral-free upper leg lean mass was the strongest predictor of UPGO performance in YOUNG women and independently explained 36% of the variance; in OLD women, age and adiposity were the strongest predictors and explained 57% and 40% of the variance, respectively.
Predictors of lower-extremity physical function differ between young and old women. These findings suggest that body composition and muscle capacity factors associated with function might change across the age span.
Menopause (New York, N.Y.) 09/2014; 22(3). DOI:10.1097/GME.0000000000000333 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
Feelings of fatigue and low energy are widespread among middle-aged women and have been shown to negatively affect quality of life. The aim of the present study was to examine the associations among adiposity, physical activity, and feelings of fatigue and energy in postmenopausal women.
Postmenopausal women (N = 74; mean [SD] age, 58.9 [3.8] y) were assessed for adiposity (via dual-energy x-ray absorptiometry), steps per day, minutes of moderate to vigorous physical activity per day (via an accelerometer), prior week intensity of psychological vigor (via the Profile of Mood States-Short Form), and prior month frequency of energy feelings (via the vitality scale of the 36-item Medical Outcomes Survey--Short Form). Sleep quality was measured using the Pittsburgh Sleep Quality Index, depression was measured using the Beck Depression Inventory-II, and perceived stress was measured using the Perceived Stress Scale.
Adiposity was negatively related to steps per day (r = -0.55, P < 0.05) and minutes of moderate to vigorous physical activity per day (r = -0.48, P < 0.05). Adiposity was not significantly related to vigor, vitality, or any other psychological measures. Greater vitality was associated with lower total number of medications (r = -0.31, P < 0.01), more steps per day (r = 0.28, P < 0.05), and higher minutes of moderate to vigorous physical activity per day (r = 0.37, P < 0.01). Prior week feelings of vigor were unrelated to any variable of interest. Regression analyses revealed that minutes of moderate to vigorous physical activity per day independently explained 8% of the variance in vitality, whereas sleep quality was also a significant predictor of vitality (both P < 0.05).
Engaging in recommended amounts of moderate to vigorous physical activity per day is associated with higher monthly frequency of energy feelings, regardless of adiposity status, in middle-aged postmenopausal women.
Menopause (New York, N.Y.) 08/2014; 22(3). DOI:10.1097/GME.0000000000000315 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
This study aims to determine the sex-specific relationships of physical activity, body composition, and muscle quality with lower-extremity physical function in older men and women.
Seventy-nine community-dwelling men (n = 39; mean [SD] age, 76.1 [6.2] y; mean [SD] body mass index, 27.3 [3.8] kg/m(2)) and women (n = 40; mean [SD] age, 75.8 [5.5] y; mean [SD] body mass index, 27.0 [3.8] kg/m(2)) were assessed for physical activity via questionnaire, body composition via dual-energy x-ray absorptiometry scanning, leg extension power using the Nottingham power rig, and muscle quality (W/kg; the ratio of leg extension power [W] to lower-body mineral-free lean mass [kg]). A composite measure of physical function was obtained by summing Z scores from the 6-minute walk, 8-ft up-and-go test, and 30-second chair-stand test.
As expected, men had significantly greater levels of physical activity, lower adiposity, greater lean mass, higher leg extension power, and greater muscle quality compared with women (all P < 0.05). In linear regression analyses, muscle quality and physical activity were the strongest predictors of lower-extremity physical function in men and independently explained 42% and 29% of the variance, respectively. In women, muscle quality (16%) and percent body fat (12%) were independent predictors after adjustment for covariates.
Muscle quality is the strongest predictor of lower-extremity physical function in men and women, but sex impacts the importance of physical activity and adiposity. These findings suggest that older men and women may benefit from different intervention strategies for preventing physical disability and also highlight the importance of weight management for older women to preserve physical function.
Menopause (New York, N.Y.) 08/2014; 22(3). DOI:10.1097/GME.0000000000000313 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction
We assessed the independent effects of socioeconomic status, sex, adiposity, and physical activity on C-reactive protein in young adults.
During the fall semester of their first year, college students (n = 177; mean age, 18.1 y; 66.7% female; 65.5% white) were assessed for adiposity via dual x-ray absorptiometry, physical activity via accelerometer, and serum C-reactive protein. Area-level socioeconomic status was based on self-reported home zip code. Hierarchical linear modeling was used to assess the relationship of sex, adiposity, and physical activity on the dependent variable of C-reactive protein, with participants nested within geographic regions of similar socioeconomic characteristics.
C-reactive protein was positively associated with adiposity and inversely associated with socioeconomic status (both P < .05). Area-level socioeconomic status explained 28.2% of the variance in C-reactive protein. Adiposity was significantly associated with C-reactive protein in the full model (P = .006); physical activity was not associated with C-reactive protein (P = .48), and area-level socioeconomic status approached significance (P = .05) within the age range of our analysis after accounting for the variance explained by adiposity.
The significant positive association between adiposity and C-reactive protein suggests that young adults with higher adiposity have higher C-reactive protein levels after accounting for area-level socioeconomic status, sex, and physical activity.
[Show abstract][Hide abstract] ABSTRACT: Lifestyle interventions commonly measure psychosocial beliefs as precursors to positive behavior change, but often overlook questionnaire validation. This can affect measurement accuracy if the survey has been developed for a different population, as differing behavioral influences may affect instrument validity. The present study aimed to explore psychometric properties of self-efficacy and outcome expectation scales-originally developed for younger children-in a population of female college freshmen (N = 268). Exploratory principal component analysis was used to investigate underlying data patterns and assess validity of previously published subscales. Composite scores for reliable subscales (Cronbach's α ≥ .70) were calculated to help characterize self-efficacy and outcome expectation beliefs in this population. The outcome expectation factor structure clearly comprised of positive (α = .81-.90) and negative outcomes (α = .63-.67). The self-efficacy factor structure included themes of motivation and effort (α = .75-.94), but items pertaining to hunger and availability cross-loaded often. Based on cross-loading patterns and low Cronbach's alpha values, respectively, self-efficacy items regarding barriers to healthy eating and negative outcome expectation items should be refined to improve reliability. Composite scores suggested that eating healthfully was associated with positive outcomes, but self-efficacy to do so was lower. Thus, dietary interventions for college students may be more successful by including skill-building activities to enhance self-efficacy and increase the likelihood of behavior change.
[Show abstract][Hide abstract] ABSTRACT: Abstract Objective: To examine weight management barriers, using the Health Belief Model, in first-year college students. Participants: First-year college students (n = 45), with data collected in April, May, and November 2013. Methods: Nominal Group Technique sessions (n = 8) were conducted. Results: First-year students recognize benefits to weight management beyond physical attractiveness to quality of life domains including social (e.g. bonding opportunities and energy to socially engage) and mental health (e.g. stress management). Men believe weight management is important for career/financial reasons; whereas, women voiced it will allow them to live a full independent life with a high level of multi-tasking. Men believed their barriers were external (e.g. campus resources/programs) while females perceived their barriers to be internal (e.g. poor time management). Conclusions: College students are challenged by weight management and want the institution to provide resources, including curriculum, to help them manage their physical activity and nutrition behaviors.
[Show abstract][Hide abstract] ABSTRACT: Objectives: To investigate the impact of body mass index (BMI) (normal weight, overweight, obese) on the relationship between muscle quality (MQ) and physical function in community-dwelling older women. Design: Cross-sectional study. Setting: University research laboratory. Participants: Community-dwelling older women (n = 94, 73.6 ± 5.4 y) stratified by BMI (normal weight: 20.0-24.9 kg/m2; overweight: 25.0-29.9 kg/m2; obese: ≥ 30.0 kg/m2). Measurements: Body mass index using height and weight, leg extension power via the Nottingham power rig, body composition using dual-energy X-ray absorptiometry, and physical function (6-minute walk, 8-foot up-and-go, 30-second chair stand). Muscle quality was defined as leg power (watts) normalized for lower-body mineral-free lean mass (kg). Results: Following adjustments for covariates, muscle quality was significantly higher in women of normal BMI compared to overweight (10.0 ± 0.4 vs 8.7 ± 0.4 watts/kg, p = 0.03). Muscle quality was a significant predictor of performance on the 6-minute walk and 8-foot up-and-go in normal and overweight women (all p < 0.05) and performance on the 30-second chair stand in normal and obese women (both p < 0.05). Body mass index did not significantly impact the association between MQ and physical function (all p > 0.05). Conclusions: Muscle quality varies by BMI, yet the relationship to physical function is not significantly different across BMI groups. The results imply that interventions that increase MQ in older women may improve physical function, regardless of BMI.
The Journal of Nutrition Health and Aging 04/2014; 18(4):378-82. DOI:10.1007/s12603-013-0421-0 · 3.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Adiposity, lean mass, and physical activity (PA) are known to influence physical function in older adults, although the independent influences are not completely characterized. Older adults (N = 156, M age = 68.9 ± 6.7 yr, 85 men) were assessed for body composition via dual-energy X-ray absorptiometry, PA by accelerometer, and physical function via timed up-and-go (UP&GO), 30-s chair stand, 6-min walk (6-min WALK), and Star-Excursion Balance Test. In the absence of percentage-body-fat by PA interactions (p >.05), main effects existed such that a higher percentage body fat was associated with poorer performance in UP&GO, 30-s chair stand, and 6-min WALK (p <.05). No significant main effects were found for PA and functional performance. Adiposity explains 4.6-11.4% in physical functional variance (p <.05). Preventing increases in adiposity with age may help older adults maintain functional independence.
Journal of aging and physical activity 04/2014; 22(2):284-293. DOI:10.1123/JAPA.2012-0098 · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of a 9-month physical activity intervention on cardiorespiratory fitness and adiposity among prepubertal children.
Prepubertal children (8- to 9-year-olds, N = 220, 103 girls) were randomly assigned to a 9-month physical activity intervention or a control group. The intervention provided 70 minutes (5 days/week) of moderate to vigorous physical activity. Maximum oxygen consumption (Vo2max percentile) and dual-energy radiograph absorptiometry measured cardiorespiratory fitness and adiposity, respectively. Intention-to-treat analysis was performed to assess baseline and follow-up cardiorespiratory fitness, percentage fat mass (%FM), percentage central fat mass (%CFM), and estimated visceral adipose tissue (VAT) area.
The intervention group increased in cardiorespiratory fitness (5.4th percentile; 95% confidence interval [CI], 1.8 to 8.9) and decreased in %FM (-0.7%; 95% CI, -1.1 to -0.4) and %CFM (-1.3%; 95% CI, -1.9 to -0.7). Reductions in %FM were evident for both nonoverweight (-0.62%; 95% CI, -1.07 to -0.17) and overweight or obese (-0.86%; 95% CI,-1.46 to -0.25) intervention participants. Conversely, the control group displayed no change in cardiorespiratory fitness while exhibiting increases in %FM (0.4%; 95% CI, 0.1 to 0.7), %CFM (0.6; 95% CI, 0.1 to 1.1), and VAT area (3.0 cm(2); 95% CI, 1.6 to 4.4). Nonoverweight control participants increased in %FM (0.52%; 95% CI, 0.13 to 0.91), and their overweight and obese counterparts increased in VAT (4.76 cm(2); 95% CI, 1.90 to 7.63).
The physical activity intervention improved cardiorespiratory fitness, reduced %FM, and prevented accumulation of %CFM among prepubertal children with varying adiposity levels. These findings provide support for daily physical activity recommendations to prevent excess fat mass accumulation in childhood.
[Show abstract][Hide abstract] ABSTRACT: Poor physical function performance is associated with risks for disability in late life; however, determinants of physical function are not well characterized in middle-aged women. The aim of this cross-sectional study was to examine the contributions of body composition, physical activity, muscle capacity, and muscle quality to physical function performance.
Postmenopausal women (N = 64; mean [SD] age, 58.6 [3.6] y) were assessed for body composition via dual-energy x-ray absorptiometry, for physical activity via accelerometer (steps per day), and for physical function via Timed Up and Go, 30-second chair stand, and 6-minute walk. Leg strength was assessed using isokinetic dynamometry at 60° second. Leg power was assessed with the Nottingham Leg Extensor Power Rig. Muscle quality was calculated as (1) the ratio of leg strength at 60° second to upper leg lean mass and (2) the ratio of leg power to total lower body lean mass.
Regression analyses revealed the following: (1) age and muscle quality calculated with leg power are independently related to Timed Up and Go, explaining 12% and 11% of the variance, respectively (P < 0.05); (2) age and muscle quality calculated with leg strength are independently related to 30-second chair stand, explaining 12% and 10% of the variance, respectively (P < 0.05); and (3) number of medical conditions, muscle quality calculated with leg strength, steps per day, and adiposity are independent predictors of 6-minute walk, collectively explaining 51% of the variance.
In postmenopausal women, a more optimal body composition (including lower adiposity and higher lean mass) and higher levels of physical activity are associated with better physical function performance at midlife.
Menopause (New York, N.Y.) 03/2014; 21(10). DOI:10.1097/GME.0000000000000225 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background and objectives:
The prevalence of obesity and diabetes is increasing among children, adolescents, and adults. Although estimates of the efficacy of exercise training on fasting insulin and insulin resistance have been provided, for adults similar estimates have not been provided for youth. This systematic review and meta-analysis provides a quantitative estimate of the effectiveness of exercise training on fasting insulin and insulin resistance in children and adolescents.
Potential sources were limited to peer-reviewed articles published before June 25, 2013, and gathered from the PubMed, SPORTDiscus, Physical Education Index, and Web of Science online databases. Analysis was limited to randomized controlled trials by using combinations of the terms adolescent, child, pediatric, youth, exercise training, physical activity, diabetes, insulin, randomized trial, and randomized controlled trial. The authors assessed 546 sources, of which 4.4% (24 studies) were eligible for inclusion. Thirty-two effects were used to estimate the effect of exercise training on fasting insulin, with 15 effects measuring the effect on insulin resistance. Estimated effects were independently calculated by multiple authors, and conflicts were resolved before calculating the overall effect.
Based on the cumulative results from these studies, a small to moderate effect was found for exercise training on fasting insulin and improving insulin resistance in youth (Hedges' d effect size = 0.48 [95% confidence interval: 0.22-0.74], P < .001 and 0.31 [95% confidence interval: 0.06-0.56], P < .05, respectively).
These results support the use of exercise training in the prevention and treatment of type 2 diabetes.