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Stephen D. Herrmann and Karin A. Pfeiffer

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Karin A. Pfeiffer and Michael J. Wierenga

Participation in a sport is widely considered a valuable form of physical activity, especially for children and adolescents. In addition, many think that sport participation translates to future physical activity. However, limited research has examined the ability of youth sport to significantly contribute to meeting daily physical activity guidelines (60 min/day of moderate to vigorous physical activity) and whether the physical activity behaviors of youth sport participants will translate into future, habitual activity in both the short and the long term. In this paper, available research on the role of youth sport in the promotion of physical activity is evaluated. Two major questions are used to frame the discussion: How much physical activity do youth sport participants attain during games and practices, and does sport participation during childhood and adolescence translate into habitual physical activity in adulthood? This is followed by ideas for future research and preliminary recommendations for best practices or policies.

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Erin White, Jim Pivarnik, and Karin Pfeiffer

Background:

Approximately 10% of women engage in resistance training during pregnancy; however there is limited research on this activity. The purpose of this study was to examine associations between resistance training and adverse outcomes.

Methods:

Women completed an online survey and recalled their exercise habits during each trimester of their most recent pregnancy within the previous 5 years. Women also reported pregnancy and birth outcomes. Participants were then categorized into 3 groups based on leisure-time exercise: 1) Resistance + aerobic training (RTAE), 2) Aerobic exercise only (AE), and 3) no exercise (NE).

Results:

284 women completed the survey. Women in the RTAE group resistance trained on average 2.9 days/week for 27.3 minutes/session. The prevalences of hypertensive disorders (HD) and gestational diabetes mellitus (GDM) were significantly lower in the RTAE group when compared with the grouping of AE + NE women. Prepregnancy body mass index (BMI) was the strongest factor related to both GDM and HD. There was no difference in the risk of preterm labor, mode of delivery, or gestational age at delivery by exercise status.

Conclusions:

Our results suggest that women can safely engage in aerobic exercise and resistance training for muscular endurance 3 days/week for 30 minutes throughout gestation.

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Kimberly A. Clevenger, Karin A. Pfeiffer, and Cheryl A. Howe

Portable metabolic units (PMUs) are used to assess energy expenditure, with the assumption that physical activity level and enjoyment are unaffected due to the light weight and small size. Purpose: To assess differences in physical activity level and enjoyment while wearing and not wearing a PMU. Method: Youth (8–17 y; N = 73) played children’s games or active video games while wearing and not wearing a PMU (crossover design). Participants wore an accelerometer and heart rate monitor and responded to questions about enjoyment on a facial affective scale. A repeated-measures analysis of variance was used to determine if accelerometer measures, heart rate, or enjoyment differed between conditions overall and by sex and weight status. Results: Steps per minute were lower while wearing the PMU than not wearing the PMU (40 vs 44, P = .03). There was an interaction between PMU condition and weight status for enjoyment (P = .01), with overweight participants reporting less enjoyment when wearing the PMU compared with not wearing the PMU (72 vs 75 out of 100). Heart rate, vector magnitude, and counts per minute were not different. Conclusion: There may be psychosocial effects of wearing the PMU, specifically in overweight participants. Activity level was minimally affected, but the practical significance for research is still unknown.

Open access

Jourdin Barkman, Karin Pfeiffer, Allie Diltz, and Wei Peng

Background:

Replacing sedentary time with physical activity through new generation exergames (eg, XBOX Kinect) is a potential intervention strategy. The study’s purpose was to compare youth energy expenditure while playing different exergames in single- vs. multiplayer mode.

Methods:

Participants (26 male, 14 female) were 10 to 13 years old. They wore a portable metabolic analyzer while playing 4 XBOX Kinect games for 15 minutes each (2 single-, 2 multiplayer). Repeated-measures ANOVA (with Bonferroni correction) was used to examine player mode differences, controlling for age group, sex, weight status, and game.

Results:

There was a significant difference in energy expenditure between single player (mean = 15.4 ml/kg/min, SD = 4.5) and multiplayer mode (mean = 16.8 ml/kg/min, SD = 4.7). Overweight and obese participants (mean = 13.7 ml/kg/min, SD = 4.2) expended less energy than normal weight (mean = 17.8 ml/kg/min, SD = 4.5) during multiplayer mode (d = 0.93).

Conclusion:

Player mode, along with personal factors such as weight status, may be important to consider in energy expenditure during exergames.

Open access

Stewart G. Trost, Christopher C. Drovandi, and Karin Pfeiffer

Background:

Published energy cost data for children and adolescents are lacking. The purpose of this study was to measure and describe developmental trends in the energy cost of 12 physical activities commonly performed by youth.

Methods:

A mixed age cohort of 209 participants completed 12 standardized activity trials on 4 occasions over a 3-year period (baseline, 12-months, 24-months, and 36-months) while wearing a portable indirect calorimeter. Bayesian hierarchical regression was used to link growth curves from each age cohort into a single curve describing developmental trends in energy cost from age 6 to 18 years.

Results:

For sedentary and light-intensity household chores, YOUTH METs (METy) remained stable or declined with age. In contrast, METy values associated with brisk walking, running, basketball, and dance increased with age.

Conclusions:

The reported energy costs for specific activities will contribute to efforts to update and expand the youth compendium.

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Felipe Lobelo, Marsha Dowda, Karin A. Pfeiffer, and Russell R. Pate

Background:

Few investigations have assessed in adolescent girls the cross-sectional and longitudinal associations between elevated exposure to electronic media (EM) and activity-related outcomes such as compliance with physical activity (PA) standards or cardiorespiratory fitness (CRF).

Methods:

Four-hundred thirty-seven white and African American girls were assessed at the 8th, 9th, and 12th grades. PA and EM (TV/video watching, electronic games, Internet use) were self-reported, and CRF was estimated using a cycle-ergometer test. Hi EM exposure was defined as ≥four 30-minute blocks/d.

Results:

8th-, 9th-, and 12th-grade girls in the Hi EM group showed lower compliance with PA standards and had lower CRF than the Low EM group (P ≤ .03). Girls reporting Hi EM exposure at 8th and 9th grades had lower vigorous PA and CRF levels at 12th grade than girls reporting less EM exposure (P ≤ .03).

Conclusion:

Girls reporting exposure to EM for 2 or more hours per day are more likely to exhibit and maintain low PA and CRF levels throughout adolescence. These results enhance the scientific basis for current public health recommendations to limit adolescent girls’ daily exposure to television, electronic games, and Internet use to a combined maximum of 2 hours.

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Heather M. Hayes, Joey C. Eisenmann, Karin Pfeiffer, and Joseph J. Carlson

Background:

The purpose of this study was to determine the independent and joint association of weight status and physical activity on resting blood pressure and C-reactive protein in children.

Methods:

Participants were 174 (71 males, 103 females) children (mean age = 10.5 ± 0.4 yrs). Physical activity was self-reported, body mass index was calculated from measured height and body mass, and blood pressure was measured according to standard procedures. A subset of 91 children had C-reactive protein measured by fingerstick blood sample. Four weight/physical activity groups were created by cross tabulation of weight status classification and physical activity level.

Results:

The prevalence of low physical activity (< 5 days/wk moderate-vigorous activity) did not differ between overweight and normal weight children (50%). Physical activity was not correlated with C-reactive protein (r = 0.01; P = 0.91) and C-reactive protein was not significantly different between physical activity groups (P = 0.87). Physical activity did not modify the difference in blood pressure or C-reactive protein within weight categories.

Conclusions:

Fatness (specifically overweight and obesity), but not physical activity, was shown to be associated with blood pressure and C-reactive protein levels in children. Physical activity did not attenuate blood pressure or C-reactive protein in overweight and obese children.

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John R. Sirard, Karin A. Pfeiffer, Marsha Dowda, and Russell R. Pate

The purpose of this study was to identify racial differences in physical activity (PA), fitness, and BMI in female 8th-grade sports participants and nonparticipants. Girls from 31 South Carolina middle schools (N = 1,903, 48% White; mean age = 13.6 ± 0.63) reported PA and previous year sports-team participation, completed a submaximal fitness test, and had height and weight measured. Sports team participation was positively associated with PA and negatively associated with television viewing and BMI, in a dose-response manner. Compared with Whites, African-Americans reported less PA and more television viewing, and had greater BMI scores. Whereas PA intervention programs that incorporate a sports-team component could benefit all girls, African-American girls could be specifically targeted because of their lower physical activity.

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Rebecca A. Schlaff, Claudia Holzman, Lanay M. Mudd, Karin A. Pfeiffer, and James M. Pivarnik

Background:

Little is known about how leisure-time physical activity (LTPA) influences gestational weight gain (GWG) among body mass index (BMI) categories. The purpose of this study was to examine the relationship between pregnancy LTPA and the proportion of normal, overweight, and obese women who meet GWG recommendations.

Methods:

Participants included 449 subcohort women from the Pregnancy Outcomes and Community Health (POUCH) study. LTPA was collapsed into 3 categories [(None, < 7.5 kcal/kg/wk (low), ≥ 7.5 kcal/kg/wk (recommended)]. GWG was categorized according to IOM recommendations (low, recommended, or excess). Chi-square and logistic regression analyses were used to evaluate relationships among LTPA, BMI, and GWG.

Results:

Overweight women were more likely to have high GWG vs. normal weight women (OR = 2.3, 95% CI 1.3–4.0). Obese women were more likely to experience low GWG (OR = 7.3, 95% CI 3.6–15.1; vs. normal and overweight women) or excess GWG (OR = 3.5, 95% CI 1.9–6.5; vs. normal weight women). LTPA did not vary by prepregnancy BMI category (P = .55) and was not related to GWG in any prepregnancy BMI category (P = .78).

Conclusions:

Regardless of prepregnancy BMI, LTPA did not affect a woman’s GWG according to IOM recommendations. Results may be due to LTPA not differing among BMI categories.