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1.
Manoeuvring a motorcycle at high-speed in official competition has been shown to expose riders to substantial and complex physiological and psychological demands, however few studies have analysed the physical load experienced by professional racers. This study aimed to quantify the physical stress experienced by riders and explore relationships between performance related variables (i.e. crashes). Performance and braking data were collected from official race reports from 2013 to 2015 of the top class of the FIM Road Racing Grand Prix World Championship. Top-level riders are exposed to a considerable volume (175 ± 42 brakes and 372 ± 48 leans to corner per race) of high intensity actions (>40% of brakes initiated at speeds higher than 260 km.h?1, and 13.2% over 300 km.h?1), where 1 out of every 4 braking actions generated inertial stresses greater than 10 m.s?2. Furthermore, the mean speed across competitions increased over the years (from 161.7 ± 6 km.h?1 to 164.5 ± 6 km.h?1), however no clear relationships between the amount of crashes and competition-related factors were found. Given the findings it would seem that riders could benefit from strength training specifically designed to prepare the body to counteract the repetitive inertial stresses of racing.  相似文献   

2.
Abstract

Physical fitness performance is an important health correlate yet is often unrelated to sedentary behaviour in early adolescence. In this study, we examined the association of sedentary behaviour (i.e. screen time) with weight-related health markers and blood pressure, after controlling for cardiorespiratory fitness performance. American middle school students (N = 153, 56% females) aged 11–15 years (mean 12.6 years, s = 0.5) completed assessments of cardiorespiratory fitness performance, screen time, weight status (BMI percentile, waist-to-height ratio), and blood pressure. Multivariate analysis of covariance, controlling for cardiorespiratory fitness performance, found those who met the daily recommendation of 2 h or less of screen time (n = 36, 23.5%) had significantly lower BMI (p < 0.05) and systolic blood pressure (p < 0.01) compared with those who exceeded this recommendation. Findings suggest specific intervention programmes may be designed to target both cardiorespiratory fitness and sedentary behaviours to maximize early adolescent health because these behaviours are likely to have unique and independent effects on youth health markers.  相似文献   

3.
Abstract

Although motorcycling performance strongly depends on the characteristics of the motorcycles and capabilities of the riders, little information is available on the physiological profiles of riders. The aim of this study was to evaluate the physical load of official international men's road-race motorcycling competitions. Data were obtained from 34 male riders during the 2005 European Road-Race Motorcycling Championship (categories classified by size of engine: 125 GP, 250 GP, and 600 cc) during free practices, qualifying sessions, and official races. Participants' heart rates were recorded and blood lactate concentrations determined. During races, heart rates were most often above 90% of maximum heart rate (frequency of occurrence: 125 GP = 92.9%, s = 5.3; 250 GP = 93.6%, s = 7.3; 600 cc = 93.2%, s = 10.2). The heart rate distribution during riding showed main effects between phases of competition, engine sizes, and different portions of the race (P < 0.001). No difference was observed between riders on and not on the podium at the end of the race. Peak blood lactate concentrations after the qualifying sessions (5.2 mmol · l?1, s = 1.2) and official races (6.0 mmol · l?1, s = 2.1) were higher (P < 0.001) than at baseline. The present results show that road-race motorcycling imposes a high load on the riders, who should possess adequate fitness to maintain high-speed rides and minimize the effects of fatigue during competition.  相似文献   

4.
The rim width of cross-country mountain bike wheel sets has increased in recent years, but the effect of this increase on performance remains unknown. The aim of this study was to analyse the influence of rim width on rolling resistance and off-road speed. We compared 3 tubeless wheel sets: 25 mm inner width as baseline, 30 mm width with the same tyre stiffness, and 30 mm width with the same tyre pressure. Three riders conducted 75 rolling resistance tests for each wheel set on a cross-country course. We determined rolling resistance using the virtual elevation method and calculated off-road speeds for flat and uphill conditions using a mathematical model. Baseline rolling resistance (Cr) was 0.0298, 90% CI [0.0286, 0.0310], which decreased by 1.4%, [0.7, 2.2] with the wider rim and the same tyre stiffness and increased by 0.9%, [0.1, 1.6] with the wider rim and the same tyre pressure. The corresponding effects on off-road speed were most likely trivial (0.0% to 0.7% faster and 0.1% to 0.6% slower, respectively). Because the effect of rim width on off-road speed seems negligible, athletes should choose the rim width that offers the best bike handling and should experiment with low tyre pressures.  相似文献   

5.
ABSTRACT

This study examined the associations between socioeconomic status (SES) and musculoskeletal (MSF) and cardiorespiratory fitness (CRF) in youth. The sample consisted of boys and girls between 3-15 years. SES was categorized utilizing family-income-to-poverty ratio (FIPR). All analyses were standardized for age and sex. For each test of physical fitness, SES was used to estimate mean fitness test percentile and 95% confidence intervals, controlling for race/ethnicity and physical activity. Odds ratios were calculated for the likelihood of having low fitness by SES category. In general, the high SES group had a better composite MSF, body composition, and CRF profiles than low and moderate SES groups. Statistically significant differences were identified for relative grip strength, plank, body mass index, and cardiovascular endurance time (all p < 0.05). Additionally, the odds of low/poor MSF fitness were 1.7 and 1.6 times higher in the low and moderate SES groups (respectively) compared to the children from high SES families. The moderate SES group had an odds of poor CRF 1.6 times higher than the high SES group as well. Children and adolescents from high SES families tend to have higher mean fitness and were less likely to have low/poor fitness.  相似文献   

6.
Abstract

The purpose of this cross-sectional study was to examine the relationship between objectively measured physical activity, sedentary time, and cardiorespiratory fitness in a diverse sample of youth. Participants were recruited from three middle schools and completed assessments of height, weight, cardiorespiratory fitness, and wore an accelerometer for a minimum of four days. Hierarchical general linear models controlling for age, body mass index (BMI) percentile, and sex were used to evaluate the association of time (minutes per day) spent sedentary, and in moderate physical activity and vigorous physical activity with cardiorespiratory fitness (i.e., heart rate response [beats per minute], dependent variable). Results indicated age (β = –0.16, P < 0.05), BMI percentile (β = 0.33, P <0.05), being male (β = 0.17, P < 0.05), sedentary time (β = 0.11, P <0.05), moderate (β = –0.03, P > 0.05) and vigorous (β = –0.22, P < 0.05) physical activity explained 29% of the variance in cardiorespiratory fitness. Evaluation of fitness among high sedentary/high vigorous, high sedentary/low vigorous, low sedentary/low vigorous, and low sedentary/high vigorous groups (defined by the median split) showed that high levels of vigorous activity removed the detrimental effect of high levels of sedentary time on cardiorespiratory fitness. These analyses suggest that the negative impact of sedentary time can be mitigated by engaging in vigorous activity.  相似文献   

7.
The purpose of this study was to investigate the tracking of gross motor coordination (GMC) and to profile children at 6 years of age who consistently showed higher stability patterns in different levels of GMC. The participants were 245 children (123 boys and 122 girls) who were assessed longitudinally from 6 to 9 years of age. GMC was assessed using the Korperkoordinationtest fur Kinder (KTK) test battery. Anthropometry, physical activity, and health- and performance-related physical fitness were also measured. Cohen’s kappa (κ) was used to estimate tracking. Tracking was poor for all GMC tests (0.17 ≤ κ ≤ 0.38) and moderate for the GMC motor quotient (MQ) in both boys and girls (0.44 ≤ κ ≤ 0.45). Instability at the extremes was low in GMC tests and negligible for MQ. Children who consistently showed high GMC levels during the 4 years of follow-up were lighter, had lower body mass index and subcutaneous fat, and showed higher scores in physical fitness tests at 6 years of age than those who consistently had low GMC levels. In conclusion, GMC showed low-to-moderate tracking over time in childhood. However, children who consistently demonstrated high GMC levels over time had healthier profiles at 6 years of age.  相似文献   

8.
Abstract

This research compares the prevalence of hypertension in a group of adult masters swimmers with an age and sex matched cohort from the 2008 NHANES (National Health and Nutrition Examination Survey), used to represent the general population in the United States. Masters swimmer data were obtained from a one-time survey of all United States Masters Swimming (USMS) members. Both datasets included demographics, drug therapy, diseases and health status. Characteristics of swimming sessions as well as perceptions of impact of medications on exercise were also collected from the USMS respondents. Of 1346 completed surveys from USMS respondents, 15.8% self-identified as having hypertension while 36.2% participants in the NHANES survey suffered from hypertension (P < 0.001). The two groups were well matched for age and gender but the USMS group was primarily Caucasian, higher income, higher education, and reported higher health status. In the USMS group, not only was hypertension less prevalent but those who suffered from hypertension took fewer medications (P = 0.04) to manage their hypertension than in the NHANES group. Additionally, The USMS group suffering from hypertension considered themselves healthier (P < 0.001) than the NHANES group.  相似文献   

9.
Purpose: This study aimed to investigate the relationship between fundamental movement skills (FMS) and markers of health among a cohort of Irish primary school children. Methods: Participants (N = 296, mean age: 7.99 ± 2.02 years) were senior infant (n = 149, mean age: 6.02 ± 0.39 years) and 4th class (n = 147, mean age: 9.97 ± 0.40 years) students from three primary schools in Cork, Ireland. FMS proficiency (TGMD-2) and markers of health (BMI percentile, waist circumference percentile, blood pressure percentiles, resting heart rate, cardiorespiratory fitness, objectively measured physical activity; PA) measurements were recorded. Correlation and hierarchical stepwise multiple linear regression analyses were conducted to investigate the relationship between FMS and markers of health. Results: A small, positive relationship was found between FMS (Gross Motor Quotient; GMQ) and cardiorespiratory fitness with small negative correlations between GMQ and 550 m time SDS among 6-year-olds (r(129) = ?.286, p < .05) and 10-year-olds (r(132) = ?.340, p < .05). A moderate, positive correlation was found between GMQ and light PA (r(71) = .400, p < .05). Small positive correlations were revealed between GMQ and moderate PA (r(71) = .259, p < .05) and between GMQ and total PA (r(71) = .355, p < .05). After adjusting for age, sex, the interaction effect of age and sex, and school attended, FMS explained 15.9% and 24.8% of the variance in 550 m time SDS among 6- and 10-year-olds, respectively, and 6% and 6.5% of the variance in light PA and moderate PA, respectively. After adjusting for age and sex, FMS explained 11.6% of the variance in total PA. Conclusion: A wide range of FMS is important for children’s cardiorespiratory fitness and PA.  相似文献   

10.
The purpose of this study was to examine the ability of international normative centiles for the 20 m shuttle run test (20mSRT) to identify youth at increased cardiometabolic risk. This was a cross-sectional study involving 961 children aged 10–17 years (53% girls) from the United Kingdom. Receiver operating characteristic (ROC) curves determined the discriminatory ability of cardiorespiratory fitness percentiles for predicting increased cardiometabolic risk. ROC analysis demonstrated a significant but poor discriminatory accuracy of cardiorespiratory fitness in identifying low/high cardiometabolic risk in girls (AUC = 0.58, 95% CI: 0.54–0.63; p = 0.04), and in boys (AUC = 0.59, 95% CI: 0.54–0.63; p = 0.03). The cardiorespiratory fitness cut-off associated with high cardiometabolic risk was the 55th percentile (sensitivity = 33.3%; specificity = 84.5%) in girls and the 60th percentile (sensitivity = 42.9%; specificity = 73.6%) in boys. These 20mSRT percentile thresholds can be used to identify children and adolescents who may benefit from lifestyle intervention. Nonetheless, further work involving different populations and cardiometabolic risk scores comprising of different variables are needed to confirm our initial findings.  相似文献   

11.
Abstract

This study aimed to produce age- and sex-specific physical fitness reference data for Portuguese youth; to report the prevalence of youth in the healthy zone of physical fitness according to the FITNESSGRAM® criteria; to verify the agreement between the Portuguese physical fitness percentiles and the FITNESSGRAM® healthy zones. In 2008, 22,048 Portuguese children and adolescents (10–18 years) were evaluated. Physical fitness (curl-ups, push-ups, 20-m shuttle run and modified-back-saver-sit-and-reach tests) was evaluated using the FITNESSGRAM® Test Battery 8.0. Smoothed percentile curves were estimated using Cole’s LMS method. Boys consistently outperformed girls in every physical fitness test, except for the modified-back-saver-sit-and-reach tests. In both sexes and for all physical fitness tests, higher percentile values were observed at older ages. The 50th percentile of all physical fitness tests had the highest accuracy to discriminate between under healthy zone and healthy zone of the FITNESSGRAM®. Portuguese schools and physical education teachers may considerer the 50th percentile for age and sex or the FITNESSGRAM® criteria for classifying participants in the healthy zone as acceptable cut-offs, above which youth should be considered fit. These reference values can be used as normative data and for baseline values for subsequent surveillance of the physical fitness of Portuguese youth.  相似文献   

12.
Abstract

The purpose of this study was to compare fitness levels of children participating in a movement education (ME) program to Illinois fitness norms (control group). The AAHPERD Health-Related Fitness test was administered to children ages 7 through 12 during May in each of the three years, 1980–83. The skinfold measures showed that the ME children had more skinfold thickness regardless of age and gender. Scores for sit-ups and sit and reach over the three years for ME children showed that the 9- and 11-year-old ME males had more abdominal strength and 11- and 12-year-old ME females, less flexibility. Times in the mile run indicated that ME children were slower than the control group. Reference scores at the 50th and 25th percentile on the Illinois norm tables were located for each fitness measurement. These references were then used to determine the percentage of ME children who fell at or above the 50th percentile and at or below the 25th percentile. Data indicated that ME children need remediation in cardiovascular activity and reduction in subcutaneous fat.  相似文献   

13.
Physical activity (PA) promotes health in obese youth and is an important adjunct to medical weight management. Access to structured fitness programmes for obese, low-income youth is limited and potential benefits of such programmes are poorly understood. We describe an urban afterschool fitness programme for obese youth and participants’ changes in fitness and body composition. A case series of 30 youth (age: 11.5 ± 2.5 years) with BMI ≥95th percentile and physician referral received a 24-wk programme scholarship. The programme, offered 4 times a week for 90-min.session, included aerobic, strength, and self-organised PA. Primary outcomes, measured at baseline (BL) time 1 (4–8 wk) and time 2 (12–16 wk) were BMI, per cent body fat (%BF), fat-free mass (FFM), heart rate during a treadmill test, and muscular strength (one repetition maximum (1RM)) and endurance (reps at 70% of 1RM) on the leg press (LP) and chest press (CP). Average participation was 1.5 ± 0.6 visits per week for 18.7 ± 6.5 weeks. Between BL and time 2, LP and CP 1RM and endurance significantly improved (P < 0.05). Additionally, there was a significant interaction for %BF with boys losing 5.2% (P > 0.05) while girls lost 0% (>0.05). Obese youth attending an urban fitness programme for at least three months improved strength and body composition, but average attendance was below planned levels.  相似文献   

14.
We analyzed data from the National School Population Fitness Survey (Reiff et al., 1986) and data collected by the authors of the original study to assess the fitness of American children and youth based on the results of additional analyses. We then compared the numbers of children and youth meeting norm-referenced standards to numbers meeting recently adopted criterion-referenced health (CRH) standards for individual test items in the FITNESSGRAM (Institute for Aerobics Research, 1987) and AAHPERD Physical Best (AAHPERD, 1988) test batteries. The number of children and youth meeting CRH standards for multiple items in a test battery was also determined. Finally, data were analyzed to determine if changes in fitness have occurred among American children and youth over recent decades. Our results suggest that, with the exception of measures of arm and shoulder girdle strength/endurance, more children and youth meet criterion-referenced health standards than norm-referenced standards (50th percentile) and the majority of American children and youth meet CRH standards for individual test items. However, the majority of American children and youth cannot meet the CRH standards for a battery of items for either of the two batteries studied. A second look at decade to decade comparisons of fitness produced evidence that questions the idea that youth are less fit now than in previous years.  相似文献   

15.
Abstract

We analyzed data from the National School Population Fitness Survey (Reiff et al., 1986) and data collected by the authors of the original study to assess the fitness of American children and youth based on the results of additional analyses. We then compared the numbers of children and youth meeting norm-referenced standards to numbers meeting recently adopted criterion-referenced health (CRH) standards for individual test items in the Fitnessgram (Institute for Aerobics Research, 1987) and AAHPERD Physical Best (AAHPERD, 1988) test batteries. The number of children and youth meeting CRH standards for multiple items in a test battery was also determined. Finally, data were analyzed to determine if changes in fitness have occurred among American children and youth over recent decades. Our results suggest that, with the exception of measures of arm and shoulder girdle strength!endurance, more children and youth meet criterion-referenced health standards than norm-referenced standards (50th percentile) and the majority of American children and youth meet CRH standards for individual test items. However, the majority of American children and youth cannot meet the CRH standards for a battery of items for either of the two batteries studied. A second look at decade to decade comparisons of fitness produced evidence that questions the idea that youth are less fit now than in previous years.  相似文献   

16.
ABSTRACT

Cross-sectional study aimed to analyse differences in cognitive performance across fitness components categories (cardiorespiratory fitness [CRF], speed-agility and muscular fitness [MF]) and weight status in children, and to determine whether physical fitness mediates the association between body mass index (BMI) and cognitive performance. Fitness components and BMI were measured using standard procedures in 630 children aged 5-to-7 years from the provinces of Cuenca and Ciudad Real, Spain. BADyG was used to assess cognitive performance. We used ANCOVA models to test mean differences in cognition scores by BMI and fitness categories. Hayes’s PROCESS macro was used for mediation analyses. Children with normal weight scored better in spatial factor and general intelligence than their overweight/obese peers (p < 0.05), but differences were attenuated when controlling for CRF (p > 0.05). Children with better results in CRF and speed-agility scored better in all cognitive dimensions even after controlling for BMI (p < 0.05). Similarly, children with high MF obtained better scores in verbal factor (p < 0.05). All fitness components acted as mediators of the relationship between BMI and general intelligence (p < 0.05). These findings highlight the crucial role of fitness in minimising the negative effect of excess weight on children’s cognition.

Abbreviations: BMI: Body mass index; CRF: Cardiorespiratory fitness; MF: Muscular fitness; BADyG E1: Battery of general and differential aptitudes; SES: Socioeconomic status; SD: Standard deviation; IE: Indirect effect  相似文献   

17.
Cardiorespiratory fitness affords health benefits to youth. Among females, weight-relative fitness declines during puberty and is lower among African American (AA) than Caucasian girls. Data indicate racial differences in pubertal timing and tempo, yet the interactive influence of puberty and race on fitness, and the role of physical activity (PA) in these associations have not been examined. Thus, independent and interactive associations of race and pubertal development with fitness in adolescent girls, controlling for PA were examined. Girls in grades 5–8 (n = 1011; Caucasian = 25.2%, AA = 52.3%, Other Race group = 22.5%) completed the Pubertal Development Scale (pubertal stage assessment) and Fitnessgram® Progressive Aerobic Cardiovascular Endurance Run (PACER) test (cardiorespiratory fitness assessment). PA was assessed by accelerometry. Bivariate and multivariate analyses were used to examine associations among race, pubertal stage and fitness, controlling for vigorous PA, AA, and pubertally advanced girls demonstrated lower fitness than Caucasian and less mature counterparts. Puberty and race remained significantly associated with fitness after controlling for vigorous PA. The interaction effect of race and puberty on fitness was non-significant. The pubertal influence on fitness is observed among AA adolescents. Associations between fitness and race/puberty appear to be independent of each other and vigorous PA. Pubertally advanced AA girls represent a priority group for fitness interventions.  相似文献   

18.
The study aimed to explore how weight changes from childhood to adolescence influenced the performances of physical fitness. The participants (N = 115) were pre-tested when they were in kindergarten, first, or second grades (mean age = 7.25). The same participants were post-tested again after 6 years. The President’s Challenge test battery was used in the study. A repeated measure multivariate analysis of variance (MANOVA) was conducted to examine the effects of time and body mass index (BMI) change on participants’ fitness performances. Results showed that participants who maintained normal weight made greater improvements in the performances of sit-ups, flexed-arm hang, and shuttle run tests than those who became or maintained overweight/obese weight status. Additionally, children who maintained normal weight were 6.21 times more likely to achieve healthy fitness zone (HFZ) standards for the 1-mile run post-test. The findings highlight the importance of maintaining normal body weight during elementary school years in achieving better physical fitness.  相似文献   

19.
ABSTRACT

Purpose: This study examined the test-retest reliability and feasibility of select fitness assessments in 7–12 year old children on the autism spectrum. Method: Participants (N = 14; n = 1 female; Mage = 9.5 ± 1.7 years) completed 7 fitness assessments, administered in a random order, on two occasions: Bruce protocol; Modified 6-minute walk test (M6MWT); Wingate anaerobic cycling test; muscle power sprint test (MPST); sit & reach; standing long jump; and grip strength. Intraclass correlations (two-way mixed with absolute agreement) were computed to examine test-retest reliability. Feasibility was assessed by questionnaire following the first administration of each test. Results: The Wingate (ICC = .956), standing long jump (ICC = .925), grip strength (ICC = .913), and sit and reach (ICC = .829) tests demonstrated good- to- excellent reliability, while the Bruce protocol (ICC = .811), M6MWT (ICC = .510), and MPST (ICC = .703) demonstrated moderate- to- good reliability based on the 95% confidence intervals of the ICC. All tests demonstrated assessor-rated feasibility scores of 70/100 or higher and child-rated feasibility scores of 66/100 or higher. Conclusion: The results demonstrate moderate- to excellent test-retest reliability for select fitness tests. Short, single-instruction (e.g., standing long jump) tests may be more reliable than lengthier assessments (e.g., M6MWT) in this population. Implications of this work include the ability of practitioners and researchers to feasibly and reliably measure the fitness of school-aged children on the autism spectrum for ongoing health and behavioural monitoring and intervention purposes.  相似文献   

20.
This study aimed to analyse the association between socioeconomic status (SES) and fatness and fitness in preschoolers. 2,638 preschoolers (3–5 years old; 47.2% girls) participated. SES was estimated from the parental educational and occupational levels, and the marital status. Fatness was assessed by body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR). Physical fitness components were assessed using the PREFIT battery. Preschoolers whose parents had higher educational levels had lower fatness (P < 0.05). BMI significantly differed across occupational levels of each parent (P < 0.05) and WHtR across paternal levels (P = 0.004). Musculoskeletal fitness was different across any SES factor (P < 0.05), except handgrip across paternal occupational levels (P ≥ 0.05). Preschoolers with high paternal occupation had higher speed/agility (P = 0.005), and those with high or low maternal education had higher VO2max (P = 0.046). Odds of being obese and having low musculoskeletal fitness was lower as SES was higher (P < 0.05). Those with married parents had higher cardiorespiratory fitness than single-parent ones (P = 0.010). School-based interventions should be aware of that children with low SES are at a higher risk of obesity and low fitness already in the first years of life.  相似文献   

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