Predicting VO2max in College-Aged Participants Using Cycle Ergometry and Perceived Functional Ability

The purpose of this study was to develop a multiple linear regression model to predict treadmill VO_2max scores using both exercise and non-exercise data. One hundred five college-aged participants (53 male, 52 female) successfully completed a submaximal cycle ergometer test and a maximal graded exercise test on a motorized treadmill. The submaximal cycle protocol required participants to achieve a steady-state heart rate equal to at least 70% of age-predicted maximum heart rate (220-age), while the maximal treadmill graded exercise test required participants to exercise to volitional fatigue. Relevant submaximal cycle ergometer test data included a mean (±SD) ending steady-state heart rate and ending workrate equal to 164.2 ± 13.0 bpm and 115.3 ± 27.0 watts, respectively. Relevant non-exercise data included a mean (±SD) body mass (kg), perceived functional ability score, and physical activity rating score of 74.2 ± 15.1, 15.7 ± 4.3, and 4.7 ± 2.1, respectively. Multiple linear regression was used to generate the following prediction of (R = .91, standard error of estimates (SEE) = 3.36 ml·kg^?1·min^?1): VO_2max = 54.513 + 9.752 (gender, 1 = male, 0 = female) – .297 (body mass, kg) + .739 (perceived functional ability, 2–26) + .077 (work rate, watts) – .072 (steady-state heart rate). Each predictor variable was statistically significant (p < .05) with beta weights for gender, body mass, perceived functional ability, exercise workrate, and steady-state heart rate equal to .594, –.544, .388, .305, and –.116, respectively. The predicted residual sums of squares (PRESS) statistics reflected minimal shrinkage (R_PRESS = .90, SEE_PRESS = 3.56 ml·kg^?1·min^?1) for the multiple linear regression model. In summary, the submaximal cycle ergometer protocol and accompanying prediction model yield relatively accurate VO_2max estimates in healthy college-aged participants using both exercise and non-exercise data.     

Cardiorespiratory fitness in urban adolescent girls: associations with race and pubertal status

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.     

Four weeks of running sprint interval training improves cardiorespiratory fitness in young and middle-aged adults

The purpose of this study was to determine the effectiveness of a 4-week running sprint interval training protocol to improve both aerobic and anaerobic fitness in middle-aged adults (40–50 years) as well as compare the adaptations to younger adults (20–30 years). Twenty-eight inactive participants – 14 young 20–30-year-olds (n = 7 males) and 14 middle-aged 40–50-year-olds (n = 5 males) – completed 4 weeks of running sprint interval training (4 to 6, 30-s “all-out” sprints on a curved, self-propelled treadmill separated by 4 min active recovery performed 3 times per week). Before and after training, all participants were assessed for maximal oxygen consumption (VO_2max), 2000 m time trial performance, and anaerobic performance on a single 30-s sprint. There were no interactions between group and time for any tested variable, although training improved relative VO_2max (young = 3.9, middle-aged = 5.2%; P < 0.04), time trial performance (young = 5.9, middle-aged = 8.2%; P < 0.001), peak sprint speed (young = 9.3, middle-aged = 2.2%; P < 0.001), and average sprint speed (young = 6.8, middle-aged = 11.6%; P < 0.001) in both young and middle-aged groups from pre- to post-training on the 30-s sprint test. The current study demonstrates that a 4-week running sprint interval training programme is equally effective at improving aerobic and anaerobic fitness in younger and middle-aged adults.     

优秀青少年运动员有氧运动能力项群特点

目的：通过分析上海地区不同项群优秀青少年有氧能力,寻找不同项群有氧能力特点。方法：选择上海市2003—2014年一线、二线运动员测试数据库,从中筛选88名16岁以上男性,年龄为（17.5±1.2）岁,103名15岁以上女性,年龄为（16.4±1.1）岁,均为国家二级以上运动员,对其最大摄氧量绝对值和相对值进行统计分析,使用单因素方差分析以及Z分值等方法比较不同性别各项群间有氧运动能力特点。结果：耐力项群最大摄氧量绝对值显著高于隔网对抗（P＜0.05）与格斗对抗（P＜0.01）。男性各项群间最大摄氧量相对值无显著差异;女性耐力项群最大摄氧量相对值显著高于同场对抗（P＜0.01）、隔网对抗（P＜0.01）与格斗对抗（P＜0.01）;女性同场对抗项群最大摄氧量相对值显著高于格斗对抗（P＜0.05）。结论：耐力项群最大摄氧量绝对值高于其他项群;体能主导类项群最大摄氧量相对值高于技能主导类项群;同场对抗项群最大摄氧量绝对值优于相对值,其余项群最大摄氧量相对值和绝对值同步。为科学训练提供有力数据支持,教练员可以结合项群有氧运动能力特点,判断运动员的有氧工作能力水平,从而针对性地制定训练计划,提高整体竞技水平。     

Development of 1-mile walk tests to estimate aerobic fitness in children

To examine the reliability and validity of 1-mile walk tests for estimation of aerobic fitness (VO_2max) in 10- to 13-year-old children and to cross-validate previously published equations. Participants (n = 61) walked 1-mile on two different days. Self-reported physical activity, demographic variables, and aerobic fitness were used in multiple regression analyses. Eight models were developed with various combinations of predictors. The recommended model for fitness testing in schools was: VO_2max = 120.702 + (4.114 × Sex [F = 0, M = 1]) – (2.918 × 1-mile Walk Time [min]) – (2.841 × Age), R = .73, standard error of estimate = 6.36 mL·kg^?1·min^?1. Cross-validation of previously published equations demonstrated lower correlations with measured VO_2max than the newly developed walk tests. Evidence of reliability and validity for 1-mile walk tests to estimate VO_2max in young children was provided. The model that included 1-mile walk time, age, and sex may be appropriate for youth fitness testing in physical education, particularly for unmotivated or overweight young children.     

Children's Activity Rating Scale (CARS): Description and Calibration

Abstract

A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO₂s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO₂s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml kg BW^?1 min^?1 (1 to 5.42 METS; 145% to 80.6% of VO₂max). Mean heart rates ranged from 89 to 183 b min^?1 for activities in Levels 1-5. VO₂s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discriminates between levels of energy expenditure, and can be used by trained observers to reliably evaluate physical activity and estimate energy expenditure of young children.     

Individualised training at different intensities,in untrained participants,results in similar physiological and performance benefits

This study compared effects of training at moderate, high, or a combination of the two intensities (mixed) on performance and physiological adaptations, when training durations were individualised. Untrained participants (n = 34) were assigned to a moderate, high, or mixed group. Maximal oxygen uptake (V?O_2max), power output at V?O_2max (MAP), time-to-exhaustion and gross efficiency were recorded before and after four weeks of cycling training (four times per week). The moderate group cycled at 60% MAP in blocks of 5 min with 1 min recovery, and training duration was individualised to 100% of pre-training time-to-exhaustion. The high group cycled at 100% MAP for 2 min with 3 min recovery, and training duration was set as the maximum number of repetitions completed in the first training session. The mixed group completed two moderate- and two high-intensity sessions each week, on alternate days. V?O_2max, MAP, and time-to-exhaustion increased after training (P < 0.05), but were not different between groups (P > 0.05). The mixed group improved their gross efficiency at 50% MAP more than the other two groups (P = 0.044) after training. When training is individualised for untrained participants, similar improvements in performance and physiological measures are found, despite marked differences in exercise intensity and total training duration.