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1.
Abstract

The ActiGraph activity monitors have developed and newer versions of the ActiGraph accelerometers (GT1M, GT3X and GT3X +) are now available, including changes in hardware and software compared to the old version (AM7164). This is problematic as most of the validation and calibration work includes the AM7164. The aims of the study were to validate the ActiGraph GT1M during level and graded walking and to assess the potential underestimation of physical activity during cycling. Data were obtained from 20 participants during treadmill walking and ergometer cycling. Energy expenditure was measured via indirect calorimetry and used as the criterion method. Activity counts were highly correlated with energy expenditure during level walking (R2 = 0.82) and graded walking at 5% and 8% (R2 = 0.82 and R2 = 0.67, respectively). There was no linear relationship between activity counts and energy expenditure during cycling. The average activity counts for all data points during cycling was 1,157 counts per minute (CPM) (SD = 974), and mean energy expenditure was 5.0 metabolic equivalents. The GT1M is a valid tool for assessing walking across a wide range of speeds and gradients. However, there is no relationship between activity counts and energy expenditure during cycling and physical activity is underestimated by ≈73% during cycling compared to walking.  相似文献   

2.
Abstract

The primary objective of this study was to examine the relationship between heart rate intensity and pedometer step counts in adolescents. To determine cardiorespiratory fitness, 106 participants (47 boys, 59 girls, mean age 14.2 years, s = 0.8) completed the Queen's College Step Test and were classified as having low, moderate or high cardiorespiratory fitness. Adolescents also completed a 10-min treadmill trial while wearing a pedometer and heart rate monitor. The participants were instructed to maintain their heart rate between 65 and 75% of their maximum heart rate while running or walking on a treadmill. A heart rate of 65–75% maximum was associated with 146 steps per minute (s = 22) in boys and 137 steps per minute (s = 22) in girls. Results of analysis of variance indicated that there was a main effect for level of fitness (F 2,102 = 9.36, P < 0.001). The correlation between mean steps per minute and estimated maximum oxygen consumption was statistically significant (r = 0.44, P < 0.001). The results from this study suggest that a step rate of 130 steps per minute is equal to 65–75% maximum heart rate in low-fit adolescents and achieving 130 steps per minute could be used as an initial goal to improve fitness.  相似文献   

3.
Abstract

Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake ([Vdot]O2) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and [Vdot]O2 were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 ± 2,390 kcal (750 ± 100 kcal · h?1) and 80,000 ± 18,000 kcal (500 ± 100 kcal · h?1) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 ± 1,160 kcal, resulting in an energy deficit of 9,590 ± 770 kcal. Body mass decreased in Study 1 (?2.3 ± 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (?2.3 ± 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.  相似文献   

4.
Abstract

The aim of this study was to evaluate the utility of the RT3 accelerometer in young children, compare its accuracy with heart rate monitoring, and develop an equation to predict energy expenditure from RT3 output. Forty-two volunteers (mean age 12.2 years, s = 1.1) exercised at two horizontal and graded walking speeds (4 and 6 km · h?1, 0% grade and 6% grade), and one horizontal running speed (8 km · h?1, 0% grade), on a treadmill. Energy expenditure and oxygen consumption ([Vdot]O2) served as the criterion measures. Comparison of RT3 estimates (counts and energy expenditure) demonstrated significant differences at 4, 6, and 8 km · h?1 on level ground (P < 0.01), while no significant differences were noted between horizontal and graded walking at 4 and 6 km · h?1. Correlation and regression analyses indicated no advantage of vector magnitude over the vertical plane (X) alone. A strong relationship between RT3 estimates and indirect calorimetry across all speeds was obtained (r = 0.633–0.850, P < 0.01). A child-specific prediction equation (adjusted R 2 = 0.753) was derived and cross-validated that offered a valid energy expenditure estimate for walking/running activities. Despite recognized limitations, the RT3 may be a useful tool for the assessment of children's physical activity during walking and running.  相似文献   

5.
Purpose: The purpose of this study was to determine the reliability of cardiorespiratory and pelvic kinematic responses to simulated horseback riding (SHBR) and to characterize responses to SHBR relative to walking in apparently healthy children. Method: Fifteen healthy children (Mage = 9.5 ± 2.6 years) completed SHBR on a commercially available simulator at low intensity (0.27 Hz) and high intensity (0.65 Hz) during 3 sessions on different occasions. Heart rate (HR), blood pressure, and respiratory gases were measured at rest and during steady-state exercise at both intensities. Pelvic displacement was measured during steady-state exercise. Rate of energy expenditure, mean arterial pressure, and rate pressure product (RPP) were calculated. Participants also walked on a treadmill for 26.8 m/min to 80.5 m/min in 13.4-m/min increments at 0% grade during 1 session to compare cardiorespiratory responses with those of SHBR. Results: Physiological variables across all 3 SHBR sessions were similar at both intensities (p>.05 for all). Intraclass correlation coefficients (ICCs) and coefficients of variation indicate good to modest reliability of cardiorespiratory measures during SHBR (ICCs = .542–.996 for oxygen consumption, energy expenditure, and RPP). Cardiorespiratory variables, except for HR, were 2% to 19% greater, and pelvic displacement was up to 37% greater with high-intensity riding. Treadmill walking at all speeds elicited greater physiological responses compared with SHBR (p < .05). Conclusion: Cardiorespiratory responses and pelvic kinematics are reproducible with SHBR in young children, and these responses were lower than those elicited by slow treadmill walking.  相似文献   

6.
ABSTRACT

No study has investigated secular changes in both total steps and moderate-to-vigorous physical activity (MVPA) among Japanese children. This study examined the secular changes of total steps and MVPA among fourth-grade students in Japan in 2003/2004 and 2016/2017. It was performed at a school in Okayama Prefecture in Japan. A total of 452 participants (226 boys and 226 girls; mean age, 9.6 ± 0.5 years) participated in the study. We measured total steps and MVPA of the participants by using the same methods in 2003/2004 and 2016/2017. An uniaxial accelerometer was used to measure total steps and MVPA. On weekdays and weekends, the total steps and MVPA were lowered by approximately 1,000–3,000 steps/day and 10 min/day, respectively, in boys and by 1,000 steps/day and 5 min/day, respectively, in girls in 2016/2017 in comparison to 2003/2004. In both boys and girls, the percentage of children meeting 60 minutes/day of MVPA decreased in 2016/2017(weekdays: boys 21.8%, girls 6.0%; weekends: boys 3.8%, girls 4.1%) compared with 2003/2004 (weekdays: boys 48.2%, girls 11.6%; weekends: boys 7.8%, girls 7.6%). In conclusion, the results demonstrated that total steps and MVPA of fourth-grade students in Japan were lower in 2016/2017 than in 2003/2004.  相似文献   

7.
Abstract

Third and fourth grade boys (n = 422) and girls (n = 390) in four Texas elementary schools reported their participation in moderate to vigorous physical activities (MVPAs) over a 3-day period. Students were surveyed during class on successive days. On a subsample (n = 44), the agreement between reported and observed physical activities during physical education or recess was 86.3%. Running, walking fast, games and sports, and bicycling accounted for 70% of Total MVPAs. Of Total MVPAs reported, 47.0% for boys and 44.6% for girls were 10 min or longer in duration (LMVPA). The average number of LMVPAs per day was 1.7 for both boys and girls. Students reported significantly more occurrences of LMVPAs out of school than during school. Significant interaction between grade and gender indicated that third grade boys reported more Total MVPAs and LMVPAs than third grade girls, but fourth grade boys reported fewer Total MVPAs and LMVPAs than fourth grade girls. During the 3-day reporting period, 12.3% of boys and 13.3% of girls reported no LMVPAs, and 35.6% of boys and girls reported fewer than one LMVPAs per day. While the majority of children reported obtaining at least some activity daily, a substantial proportion of children in this sample reported fewer than one LMVPA daily, indicating that many children may not be obtaining adequate amounts of physical activity.  相似文献   

8.
Abstract

The aims of this study were to describe the prevalence of dance participation in U.S. adolescents and to estimate the contribution of dance to total moderate-to-vigorous physical activity (MVPA). The sample was composed of 3,598 adolescents from the 2003–06 National Health and Nutrition Examination Survey. Youth reported frequency and duration of physical activities performed in the past month. Dance participation prevalence was calculated; among those who reported dance, its contribution to total MVPA was estimated. The prevalence of dance was much higher in girls (34.8%) than boys (8.4%). Girls had a greater contribution of dance to total MVPA (39.3%) than boys (23.0%). Dance is a prevalent form of physical activity among girls, and it accounts for a substantial fraction of their total MVPA.  相似文献   

9.
This study examined the validity of the Actical accelerometer step count and energy expenditure (EE) functions in healthy young adults. Forty-three participants participated in study 1. Actical step counts were compared to actual steps taken during a 200 m walk around an indoor track at self-selected pace and during treadmill walking at different speeds (0.894, 1.56 and 2.01 m · s–1) for 5 min. The Actical was also compared to three pedometers. For study 2, 15 participants from study 1 walked on a treadmill at their predetermined self-selected pace for 15 min. Actical EE was compared to EE measured by indirect calorimetry. One-way analysis of variance and t-tests were used to examine differences. There were no statistical difference between Actical steps and actual steps in self-selected pace walking and during treadmill walking at moderate and fast speeds. During treadmill walking at slow speed, the Actical step counts significantly under predicted actual steps taken. For study 2, there was no statistical difference between measured EE and Actical-recorded EE. The Actical provides valid estimates of step counts at self-selected pace and walking at constant speeds of 1.56 and 2.01 m · s–1. The Actical underestimates EE of walking at constants speeds ≥1.38 m · s–1.  相似文献   

10.
Abstract

The purpose of this study was to establish whether an accumulated brisk walking programme, performed during the school day, is effective in changing body composition in primary school children aged 5–11 years. Altogether, 152 participants (79 boys and 73 girls) took part in this repeated-measures intervention study, divided into groups of walkers and controls. The walkers took part in the intervention during school time, which involved brisk walking around the school grounds for 15 min in the morning and afternoon, at least three times a week for 15 weeks. This represented an additional 90 min of moderate physical activity per week. The controls undertook their usual school day activities. Pre- and post-intervention anthropometric and body composition measures were taken. Body fat (?1.95 ± 2.6%) and fat mass (?0.49 ± 1.0 kg) were significantly reduced in the walkers after the intervention, whereas the controls showed no significant changes in these measures. Our results show that regular accumulated bouts of brisk walking during the school day can positively affect body composition in primary school children.  相似文献   

11.
ABSTRACT

Childhood physical fitness relative to adult health outcomes coupled with scant longitudinal research indicates that tracking of fitness components throughout childhood/adolescence is imperative. The study examined the stability/tracking of 9 measures of fitness for boys and girls at 5 points throughout childhood/adolescence. Tracking coefficients between individual fitness measures at various age comparisons were calculated. Using a sample with recorded data at 4 time-points, tertiles (high, moderate, low) were calculated for each fitness measure for boys and girls. Stability of fitness measures was calculated. Boys outperformed girls on fitness measures at most time points. Significantly low to moderately high tracking coefficients for each fitness measure at all time points for boys (r = .21-.79) and girls (r = .23-.89) were found. Tertile ratings remained stable across the 4 time-points. Findings highlight the importance of developing healthy fitness behaviors early in life and the significance of intervention during adolescence in low-fit youth.  相似文献   

12.
Abstract

The purpose of this study was to compare the physiological responses of Nordic walking on a specially designed treadmill and Nordic walking on a level over-ground surface. Thirteen participants completed three 1-h Nordic walking training sessions. Following the training sessions, each participant performed two 1600-m over-ground Nordic walking trials at a self-selected pace. Each participant then completed two 1600-m Nordic walking treadmill trials on a Hammer Nordic Walking XTR Treadmill®, at the mean walking speed of their two over-ground Nordic walking trials. Breath-by-breath analysis of oxygen uptake ([Vdot]O2) and heart rate was performed during each trial. Caloric expenditure was calculated using the [Vdot]O2. Rating of perceived exertion (RPE) was assessed at the end of each trial. We found no significant differences in physiological variables collected during the two over-ground Nordic walking trials or the two treadmill Nordic walking trials. Mean walking speed was 106.96±11.49 m · min?1. Mean heart rate during treadmill walking (99±13 beats · min?1) was 22% lower than that during the over-ground condition (126±17 beats · min?1). Mean [Vdot]O2 and mean caloric expenditure were also lower during treadmill walking (15.18±3.81 ml · min?1 · kg?1, 0.08±0.02 kcal · min?1 · kg?1) than over-ground walking (24.16±4.89 ml · min?1 · kg?1, 0.12±0.02 kcal · min?1 · kg?1). Analysis of variance demonstrated that all variables were significantly higher during over-ground Nordic walking (P<0.001). A Mann-Whitney U-test demonstrated that the RPE for over-ground Nordic walking was greater than that for treadmill Nordic walking (P=0.02). Thus over-ground Nordic walking created a greater physiological stress than treadmill Nordic walking performed at the same speed and distance. The reason for this difference may have been the relatively narrow walking and poling decks on the treadmill, which made it difficult for the participants to place their poles correctly and maintain a consistent walking pattern. This would decrease the contribution of the arm muscles to overall oxygen consumption. In conclusion, the Hammer Nordic Walking XTR Treadmill® does not replicate the physiological stress of over-ground Nordic walking. Increasing the width of the decks could eliminate the discrepancy.  相似文献   

13.
This study establishes tri-axial activity count (AC) cut-points for the GT3X+ accelerometer to classify physical activity intensity in overweight and obese adults. Further, we examined the accuracy of established and novel energy expenditure (EE) prediction equations based on AC and other metrics. Part 1: Twenty overweight or obese adults completed a 30 minute incremental treadmill walking protocol. Heart rate (HR), EE, and AC were measured using the GT3X+ accelerometer. Part 2: Ten overweight and obese adults conducted a self-paced external walk during which EE, AC, and HR were measured. Established equations (Freedson et al., 1998; Sasaki et al., 2011) overestimated EE by 40% and 31%, respectively (p < .01). Novel gender-specific prediction equations provided good estimates of EE during treadmill and outdoor walking (standard error of the estimate = .91 and .65, respectively). We propose new cut-points and prediction equations to estimate EE using the GT3X+ tri-axial accelerometer in overweight and obese adults.  相似文献   

14.
Aim: The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers.

Methods: Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h?1, where race walking economy (ml·kg?1·km?1) and spatiotemporal gait variables were analysed at different speeds.

Results: 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05).

Conclusion: According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.  相似文献   

15.
This study assessed the effectiveness of a 6-week, high-intensity, games-based intervention on physiological and anthropometric indices of health, in normal weight (n = 26; 32.5 ± 8.9 kg) and obese (n = 29; 49.3 ± 8.9 kg) children (n = 32 boys, 23 girls), aged 8–10 years. Children were randomised into an exercise or control group. The exercise group participated in a twice-weekly, 40 min active games intervention, alongside their usual school physical education classes. The control group did not take part in the intervention. Before and after the intervention, participants completed both a maximal and submaximal graded exercise test. The submaximal exercise test comprised of a 6 min, moderate- and 6 min heavy-intensity bout, interspersed with a 5 min recovery. The exercise group demonstrated improvements in maximal oxygen uptake (51.4 ± 8.5 vs 54.3 ± 9.6 ml · kg?1 · min?1) and peak running speed (11.3 ± 1.6 vs 11.9 ± 1.6 km · h?1), and a reduction in the oxygen cost of submaximal exercise between assessments (P < .05). A decrease in waist circumference and increase in muscle mass were observed between assessments for the obese participants randomised to the intervention (both P < .05). This study demonstrates that a short-term, high-intensity games intervention may elicit positive changes in physiological and anthropometric indices of health in normal weight and obese children.  相似文献   

16.
ABSTRACT

We compared cardiometabolic demand and post-exercise enjoyment between continuous walking (CW) and time- and intensity-matched interval walking (IW) in insufficiently active adults. Sixteen individuals (13 females and three males, age 25.3 ± 11.1 years) completed one CW and one IW session lasting 30 min in a randomised-counterbalanced design. For CW, participants walked at a mean intensity of 65–70% predicted maximum heart rate (HRmax). For IW, participants alternated between 3 min at 80% HRmax and 2 min at 50% HRmax. Expired gas was measured throughout each protocol. Participants rated post-exercise enjoyment following each protocol. Mean HR and V˙O2 showed small positive differences in IW vs. CW (2, 95%CL 0, 4 beat.min?1; d = 0.23, 95%CL 0.06, 0.41 and 1.4, 95%CL 1.2 ml.kg?1.min?1, d = 0.36, 95%CL 0.05, 0.65, respectively). There was a medium positive difference in overall kcal expenditure in IW vs. CW (25, 95%CL 7 kcal, d = 0.58, 95%CL 0.33, 0.82). Post-exercise enjoyment was moderately greater following IW vs. CW (9.1, 95%CL 1.4, 16.8 AU, d = 0.62, 95%CL 0.06, 0.90), with 75% of participants reporting IW as more enjoyable. Interval walking elicits meaningfully greater energy expenditure and is more enjoyable than CW in insufficiently active, healthy adults.  相似文献   

17.
Objectives: To analyse the associations between high screen time and overweight, poor dietary habits and physical activity in adolescents according to sex. Methods: The study comprised 515 boys and 716 girls aged 14–17 years from Londrina, Brazil. Nutritional status (normal weight or overweight/obese) was assessed by calculating the body mass index. Eating habits and time spent in physical activity were reported using a questionnaire. The measurement of screen time considered the time spent watching television, using a computer and playing video games during a normal week. Associations between high screen time and dependent variables (nutritional status, eating habits and physical activity levels) were assessed by binary logistic regression, adjusted for sociodemographic and lifestyle variables. Results: Most adolescents (93.8% of boys and 87.2% of girls) spent more than 2 hours per day in screen-time activities. After adjustments, an increasing trend in the prevalence of overweight and physical inactivity with increasing time spent on screen activities was observed for both sexes. Screen times of >4 hours/day compared with <2 hours/day were associated with physical inactivity, low consumption of vegetables and high consumption of sweets only in girls and the consumption of soft drinks in both sexes. Conclusions: The frequency of overweight and physical inactivity increased with increasing screen time in a trending manner and independently of the main confounders. The relationship between high screen time and poor eating habits was particularly relevant for adolescent girls.  相似文献   

18.
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19.
This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg?1 · h?1 (before school time) to 0.62 kcal · kg?1 · h?1 (physical education class) in boys and ?0.39 kcal · kg?1 · h?1 (transportation from school) to 0.37 kcal · kg?1 · hour?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols.  相似文献   

20.
Purpose: A relationship exists between attitudes toward physical education and future physical activity. The purpose of this study was to examine changes in attitude toward physical education as students progressed from upper elementary school (Grade 4) through middle school (Grade 8). Method: Three cohorts of students (Cohort 1, Grades 4–6, n = 96; Cohort 2, Grades 5–7, n = 71; and Cohort 3, Grades 6–8, n = 73) were each followed for 3 years to examine changes in attitudes toward physical education. Results: After an initial increase from Grade 4 to Grade 5, a significant decrease was observed from Grades 5 to 8 in students’ positive attitudes toward physical education, with a faster rate of change for girls than boys. Conclusion: This longitudinal study provides further insights regarding the attitudes of students as they progress from Grade 4 to Grade 8 and expands on previous findings identifying decreasing positive attitudes toward physical education as students age, particularly for girls. The results provide evidence to support targeted interventions.  相似文献   

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