Physical activity patterns of Singapore school children aged 9–10 years were assessed by continuous heart rate monitoring. Fifty boys and 64 girls were monitored for three 14-hour periods during normal school days. In addition, 43 boys and 53 girls were monitored for 14 hours on a Saturday. Only 13 children (11.4%) experienced a daily 10-min period of continuous activity at a heart rate ≥140 bpm. Twenty percent of the boys and more than 50% of the girls never achieved a single 10-minute period ≥140 bpm. Boys achieved more periods of moderately intense activity (p < .01) than girls on weekdays. Lean girls were more active (p < .05) than the obese girls during weekdays. No differences were detected between activity levels on weekdays or on Saturday. The results indicate that Singapore school children in general rarely experience the quantity or quality of physical activity needed for maintenance and development of cardiovascular health and cardiopulmonary fitness.
Helen Gilbey and Malcolm Gilbey
Karen L. Moy, Robert K. Scragg, Grant McLean and Harriette Carr
This study validated the short- and long-form New Zealand Physical Activity Questionnaires (NZPAQ-SF and NZPAQ-LF) against heart-rate monitoring (HRM) with individual calibration.
A multiethnic sample (N = 180), age 19 to 86 y, underwent HRM for 3 consecutive days while simultaneously completing physical activity (PA) logs.
Both NZPAQs showed significant (p < .001) correlations to HRM data for brisk walking (r = .27–.43), vigorous-intensity PA (r = .27–.35), and total PA (r = .25; 95% CI, 0.10-0.40), whereas moderate-intensity PA was substantially overreported (mean = 157-199 min). Although the NZPAQ-LF performed better for brisk walking and vigorous-intensity PA, the NZPAQs were strongly correlated (r = .61 and r = .52, respectively, p < .0001). European/Other participants demonstrated the most accurate PA recall of total PA on both NZPAQs (r = .36−.41, p < .01).
The NZPAQs are acceptable instruments for measuring adult PA levels and produce similar results. Substituting culturally specific examples of PAs on the NZPAQs and their accompanying show cards could potentially improve PA recall for Maori and Pacific people.
Steven Gastinger, Guillaume Nicolas, Anthony Sorel, Hamid Sefati and Jacques Prioux
The aim of this article was to compare 2 portable devices (a heart-rate monitor and an electromagnetic-coil system) that evaluate 2 different physiological parameters—heart rate (HR) and ventilation (VE)—with the objective of estimating energy expenditure (EE). The authors set out to prove that VE is a more pertinent setting than HR to estimate EE during light to moderate activities (sitting and standing at rest and walking at 4, 5, and 6 km/hr). Eleven healthy men were recruited to take part in this study (27.6 ± 5.4 yr, 73.7 ± 9.7 kg). The authors determined the relationships between HR and EE and between VE and EE during light to moderate activities. They compared EE measured by indirect calorimetry (EEREF) with EE estimated by HR monitor (EEHR) and EE estimated by electromagnetic coils (EEMAG) in upright sitting and standing positions and during walking exercises. They compared EEREF with EEHR and EEMAG. The results showed no significant difference between the values of EEREF and EEMAG. However, they showed several significant differences between the values of EEREF and EEHR (for standing at rest and walking at 5 and 6 km/hr). These results showed that the electromagnetic-coil system seems to be more accurate than the HR monitor to estimate EE at rest and during exercise. Taking into consideration these results, it would be interesting to associate the parameters VE and HR to estimate EE. Furthermore, a new version of the electromagnetic-coil device was recently developed and provides the possibility to perform measurement under daily life conditions.
Linda E. Kelly
Physical activity levels of 40 American children, 9–10 years old, were assessed by 12-hrs of continuous heart rate monitoring over the 7 different days of the week. Most participants (92.5%) accumulated 30 min of moderate physical activity on most days of the week. A little more than half (52.5%) reached this level for 7 days of the week. Less than one third (27.5%) accrued the greater health benefits of physical activity by being active for 30 sustained minutes 3 times per week. A slightly larger percentage (35%) obtained 30 min in 10-min or greater sustained bouts 5 or more days of the week. Boys (95.2%) were 6.4% more active in accumulating 30 min or more on most days of the week than girls (88.9%). Boys (40.8%) also obtained 30 min of physical activity in sustained bouts of 10-min or greater at a higher percentage than girls (27.7%).
Andreas Wolff Hansen, Inger Dahl-Petersen, Jørn Wulff Helge, Søren Brage, Morten Grønbæk and Trine Flensborg-Madsen
The International Physical Activity Questionnaire (IPAQ) is commonly used in surveys, but reliability and validity has not been established in the Danish population.
Among participants in the Danish Health Examination survey 2007–2008, 142 healthy participants (45% men) wore a unit that combined accelerometry and heart rate monitoring (Acc+HR) for 7 consecutive days and then completed the IPAQ. Background data were obtained from the survey. Physical activity energy expenditure (PAEE) and time in moderate, vigorous, and sedentary intensity levels were derived from the IPAQ and compared with estimates from Acc+HR using Spearman’s correlation coefficients and Bland-Altman plots. Repeatability of the IPAQ was also assessed.
PAEE from the 2 methods was significantly positively correlated (0.29 and 0.49; P = 0.02 and P < 0.001; for women and men, respectively). Men significantly overestimated PAEE by IPAQ (56.2 vs 45.3 kJ/kg/day, IPAQ: Acc+HR, P < .01), while the difference was nonsignificant for women (40.8 vs 44.4 kJ/kg/day). Bland-Altman plots showed that the IPAQ overestimated PAEE, moderate, and vigorous activity without systematic error. Reliability of the IPAQ was moderate to high for all domains and intensities (total PAEE intraclass correlation coefficient = 0.58).
This Danish Internet-based version of the long IPAQ had modest validity and reliability when assessing PAEE at population level.
Douglas A. Haines and Mark E. Raizenne
Models to indirectly estimate minute ventilation (V̇E) from heart rate (HR) monitored during normal activity were developed. VE-to-HR relationships were established from V̇E and HR measured in a graded cycle ergometer test performed by 99 girls, 7-14 years of age. The regression In V̇E = a + (b × HR) was a better predictor of V̇E, when individually determined, than were generalized prediction equations. V̇E, estimated by applying individual VE-to-HR regressions to HR monitored over 10 daytime hours, ranged between 11.5 and 14.5 L·min−1. This is a practical method of estimating V̇E, but further validation of the relationships with HR under various modes of exercise are necessary to improve the prediction in everyday settings.
Brad Strand and Steve Reeder
Jorge Cañete García-Prieto, Vicente Martinez-Vizcaino, Antonio García-Hermoso, Mairena Sánchez-López, Natalia Arias-Palencia, Juan Fernando Ortega Fonseca and Ricardo Mora-Rodriguez
The aim of this study was to examine the energy expenditure (EE) measured using indirect calorimetry (IC) during playground games and to assess the validity of heart rate (HR) and accelerometry counts as indirect indicators of EE in children´s physical activity games. 32 primary school children (9.9 ± 0.6 years old, 19.8 ± 4.9 kg · m-2 BMI and 37.6 ± 7.2 ml · kg-1 · min-1 VO2max). Indirect calorimetry (IC), accelerometry and HR data were simultaneously collected for each child during a 90 min session of 30 playground games. Thirty-eight sessions were recorded in 32 different children. Each game was recorded at least in three occasions in other three children. The intersubject coefficient of variation within a game was 27% for IC, 37% for accelerometry and 13% for HR. The overall mean EE in the games was 4.2 ± 1.4 kcals · min-1 per game, totaling to 375 ± 122 kcals/per 90 min/session. The correlation coefficient between indirect calorimetry and accelerometer counts was 0.48 (p = .026) for endurance games and 0.21 (p = .574) for strength games. The correlation coefficient between indirect calorimetry and HR was 0.71 (p = .032) for endurance games and 0.48 (p = .026) for strength games. Our data indicate that both accelerometer and HR monitors are useful devices for estimating EE during endurance games, but only HR monitors estimates are accurate for endurance games.
Peter Collins, Yahya Al-Nakeeb and Mark Lyons
Active school commuting is widely regarded as a key opportunity for youth to participate in physical activity (PA). However, the accurate measurement of the commute home from school and its contribution to total free-living moderateto- vigorous PA (MVPA) is relatively unexplored.
Seventy-five adolescents (38 males, 37 females) wore an integrated GPS and heart rate device during after-school hours for 4 consecutive weekdays.
Active commuters were significantly more active (11.72 minutes MVPA) than passive commuters (3.5 minutes MVPA) during their commute home from school (P = .001). The commute home of walkers and cyclists on average contributed 35% of their total free-living PA. However, there was no significant difference in the overall free-living PA levels of passive and active commuters (P > .05). A total 92.7% of the youth living within 1.5 miles of the school actively commuted, compared with 16.7% of the youth who lived further away. Socioeconomic differences in commuting patterns were also evident.
The findings highlighted the significant proportion of total free-living PA that was attributed to active commuting home from school. The study demonstrates the usefulness of utilizing GPS and heart rate data to accurately track young people’s after-school PA. Demographic influences and implications for future research are discussed.
Martin Buchheit, Yannick Cholley and Philippe Lambert
To examine in elite soccer players after traveling across 6 time zones some psychometric and physiological responses to a competitive camp in the heat.
Data from 12 elite professional players (24.6 ± 5.3 y) were analyzed. They participated in an 8-d preseason summer training camp in Asia (heat index 34.9°C ± 2.4°C). Players’ activity was collected during all training sessions and the friendly game using 15-Hz GPS. Perceived training/playing load was estimated using session rating of perceived exertion (RPE) and training/match duration. Psychometric measures of wellness were collected on awakening before, during, and after the camp using simple questionnaires. Heart-rate (HR) response to a submaximal 4-min run (12 km/h) and the ratio between velocity and force-load (accelerometer-derived measure, a marker of neuromuscular efficiency) response to four ~60-m runs (22–24 km/h) were collected before, at the end of, and after the camp.
After a large increase, the RPE:m/min ratio decreased substantially throughout the camp. There were possible small increases in perceived fatigue and small decreases in subjective sleep quality on the 6th day. There were also likely moderate (~3%) decreases in HR response to the submaximal run, both at the end of and after the camp, which were contemporary to possible small (~8%) and most likely moderate (~19%) improvements in neuromuscular efficiency, respectively.
Despite transient increases in fatigue and reduced subjective sleep quality by the end of the camp, these elite players showed clear signs of heat acclimatization that were associated with improved cardiovascular fitness and neuromuscular running efficiency.