Concurrent validation of the Actigraph gt3x+, Polar Active accelerometer, Omron HJ-720 and Yamax Digiwalker SW-701 pedometer step counts in lab-based and free-living settings.

Activity monitors are frequently used to assess activity in many settings. But as technology advances, so do the mechanisms used to estimate activity causing a continuous need to validate newly developed monitors. The purpose of this study was to examine the step count validity of the Yamax Digiwalker SW-701 pedometer (YX), Omron HJ-720 T pedometer (OP), Polar Active accelerometer (PAC) and Actigraph gt3x+ accelerometer (AG) under controlled and free-living conditions. Participants completed five stages of treadmill walking (n = 43) and a subset of these completed a 3-day free-living wear period (n = 37). Manually counted (MC) steps provided a criterion measure for treadmill walking, whereas the comparative measure during free-living was the YX. During treadmill walking, the OP was the most accurate monitor across all speeds (±1.1% of MC steps), while the PAC underestimated steps by 6.7-16.0% per stage. During free-living, the OP and AG counted 97.5% and 98.5% of YX steps, respectively. The PAC overestimated steps by 44.0%, or 5,265 steps per day. The Omron pedometer seems to provide the most reliable and valid estimate of steps taken, as it was the best performer under lab-based conditions and provided comparable results to the YX in free-living. Future studies should consider these monitors in additional populations and settings.

Measurement agreement between estimates of aerobic fitness in youth: the impact of body mass index.

PURPOSE: The purpose of this study was to examine the impact of body mass index (BMI) on the agreement between aerobic capacity estimates from different Progressive Aerobic Cardiorespiratory Endurance Run (PACER) equations and the Mile Run Test. METHOD: The agreement between 2 different tests of aerobic capacity was examined on a large data set from 2 suburban school districts (n = 1,686 youth in Grades 3-10). Difference estimates between the Mile Run Test and several PACER equations were computed, and residuals were examined using cluster analysis. The implication of the discrepancy between these tests was also examined using FITNESSGRAM health-related standards for BMI. Comparisons were made against corresponding estimates of peak oxygen consumption from the Mile run because this equation is more established. RESULTS: Results supported a 2-cluster solution. The discrepancy between tests was higher in participants with higher BMI scores (Z scores for residuals in this group ranged from -0.07 to 1.57). BMI was able to explain 30% to 34% of the disagreement between the Mile and different PACER equations of aerobic fitness. Classification analyses revealed that kappa scores were lower among PACER equations that do not include a BMI term (kappa = .12-.34 vs. .59-.81). Overall, the test-equating approach used in the Fitnessgram program to process PACER data had better agreement than alternative PACER equations that included BMI. CONCLUSION: The results support the inclusion of BMI in prediction equations used to estimate aerobic capacity from the PACER.

Relationship between socioeconomic status and physical fitness in junior high school students.

BACKGROUND: Research on physical fitness often regards socioeconomic status (SES) as a confounding factor. However, few studies investigate the impact of SES on fitness. This study investigated the impact of SES on physical fitness in both males and females, with an economic-based construct of SES. METHODS: The sample consisted of 954 6th, 7th, and 8th graders from a public, urban, Illinois middle school. The students participated in the FITNESSGRAM battery of fitness assessments as part of physical education. Descriptive statistics were calculated for height, weight, age, and sex. Students were grouped as high or low SES depending on whether they qualified for the federal free lunch program. A multivariate analysis of variance controlled for age and stratified by sex compared the raw scores from the fitness test for low and high SES students. Odds ratios stratified by sex were calculated for the likelihood of not achieving the FITNESSGRAM Healthy Fitness Zone standards among SES groups. RESULTS: Girls of the low SES group had significantly lower scores on the FITNESSGRAM assessments and were significantly less likely to achieve Healthy Fitness Zone status than the girls from the high SES groups. For boys, SES was a significant main effect for body composition but not for the other fitness tests conducted. CONCLUSION: SES is related to physical fitness in girls but not in boys. A potential explanation for this is that boys are more likely to engage in vigorous leisure time activity regardless of SES than girls.

Physical fitness and academic performance in middle school students.

AIM: The purpose of this study was to determine whether physical fitness is linked to academic success in middle school students. METHODS: The FITNESSGRAM test battery assessed students (n = 838) in the five components of health-related fitness. The Illinois Standardized Achievement Test (ISAT) was used to assess academic achievement in reading and math. RESULTS: The largest correlations were seen for aerobic fitness and muscular endurance (ranging from 0.12 to 0.27, all p < 0.05). Boys in the Healthy Fitness Zone (HFZ) for aerobic fitness or muscular endurance were 2.5-3 times more likely to pass their math or reading exams. Girls in the HFZ for aerobic fitness were approximately 2-4 times as likely to meet or exceed reading and math test standards. CONCLUSIONS: Aerobic capacity and muscular endurance seem to positively affect academic achievement in middle school students.

Field evaluation of the new FITNESSGRAM® criterion-referenced standards.

BACKGROUND: The Cooper Institute established new criterion-referenced standards for the body composition and cardiovascular fitness standards for the FITNESSGRAM(®) program. PURPOSE: The purpose of this study was to evaluate differences in the achievement of standards and classification agreement between the old and new standards. METHODS: Fitness data were collected during the 2009-2010 school year from 1686 youth (grades 3-12) from six schools (two districts) in a small Midwestern town. Data analyses were completed during the 2010 and 2011 school year. Descriptive statistics were computed to determine the percentage of students classified into the various fitness classifications using both the old and new standards. Classification agreement was examined for alternative tests of cardiovascular fitness (Progressive Aerobic Cardiovascular Endurance Run [PACER] and 1-mile run) and body composition (skinfold determination of body fat and BMI) using both the old and new standards. RESULTS: The descriptive results reveal important age and gender differences in reported levels of fitness levels in school-aged youth. For body composition, the percentage of youth achieving the healthy fitness zone (HFZ) was about 10% lower with the new standards than the old ones. For aerobic capacity, a larger percentage of young boys and a smaller percentage of older boys achieved the new HFZ for aerobic capacity. However, a smaller percentage of girls achieved the new HFZ at all ages. The use of test-equating in the revised standards led to significant improvements in the classification agreement between 1-mile run and the PACER. CONCLUSIONS: The large data set provided a useful sample to examine the impact of the new fitness standards on the documentation of youth fitness levels in schools. The new standards address a number of measurement issues with the old standards and provide a more appropriate way to evaluate levels of health-related fitness in youth.

Physiologic and metabolic responses to a continuous functional resistance exercise workout.

The purpose of this study was to evaluate the physiologic and perceptual responses to a continuous functional exercise workout. Ten men and 10 women (21.2 +/- 2.4 and 21.0 +/- 1.5 years) completed a maximal oxygen uptake test, strength test, and body composition analysis. Subjects then participated in 3 familiarization sessions, during which they followed a videotaped routine that consisted of a series of functional resistance exercises performed in a continuous manner. Subjects performed the same routine in a final session, during which VO2, VCO2, respiratory exchange ratio (RER), RPE, and heart rate were measured and blood samples were taken and analyzed for blood lactic acid concentration. Descriptive statistics were calculated for RPE, RER, blood lactic acid concentration, energy expenditure, and absolute and relative oxygen uptake and heart rate. Energy expenditure was calculated using VO2 and RER. Independent t-tests were used to examine differences between men and women for oxygen consumption, weight lifted, and energy expenditure during the workout. Subjects had a mean VO2 of 27.8 ml.kg.min (51% of VO2 peak and 47.8% of VO2 reserve), a mean heart rate of 156 bpm (83% of maximum heart rate), and a mean RER of 0.91. The mean RPE was 5.9, and the mean difference between pre and post lactic acid concentration was 2.5 mmol.L. The mean total caloric expenditure was 289 kcal. Men lifted significantly heavier weights and expended more total calories than women. Caloric expenditure (kcal x kg x min), VO2, and weight lifted were similar between men and women when expressed relatively. Performing dynamic functional exercises in a continuous manner resulted in energy expenditure values, but not relative VO2 values, that meet the American College of Sports Medicine recommendations.

Heart rates of high school physical education students during team sports, individual sports, and fitness activities.

This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 +/- 24 beats per minute [bpm]) compared to team (118 +/- 24 bpm) or individual (114 +/- 18) activities. Similar results occurred for the percentage of activity time spent within a target heart rate zone (fitness 81.7 +/- 15.9%, individual 68.4 +/- 30.5%, and team 60.6 +/- 30.5%). Boys attained higher heart rates during team activities, while female students had higher rates during individual activities indicating male and female adolescents respond differently to activity types. The highest mean heart rates were observed during fitness activities.

Effect of exercise-induced changes in residual lung volume on the determination of body composition.

The transient increase in residual lung volume (RV) as a result of exercise has been well documented. An accurate assessment of exercise-induced RV would be important when hydrostatic weighing (HW) is performed after exercise. The purpose of this study was to determine whether accurate HW measures could be performed after exercise when changes in RV are measured. Subjects (n = 32) performed pulmonary function (vital capacity [VC]-estimated RV), oxygen dilution-determined RV, and HW measures before and after either a maximal treadmill test (n = 16) or seated rest (n = 16). Two-way analysis of variance (p