汽车整车检测课程与资源库库建设探究     

刘志明 《大众科技》2013,(8):122-123

汽车整车检测课程建设过程中,通过教学模式创新、改革教学内容、方法和手段,促进优质教学资源开发和利用,促进品牌课程的形成及教学质量的提高,从而培养出符合社会需要的实用型技能人才。  相似文献   

Biomechanical response to systematic changes in impact interface cushioning properties while performing a tennis-specific movement     

Victoria Stiles  Sharon Dixon 《Journal of sports sciences》2013,31(11):1229-1239

Abstract

It is currently not known whether human responses across typical sports surfaces are dependent on cushioning or frictional properties of the interface. The present study assessed systematic changes in surface cushioning (baseline acrylic, rubber, thin foam, and thick foam) as participants performed tennis running forehand foot plants wearing a basic neutral shoe (plimsolls). It was hypothesized that systematic decreases in peak rates of loading, heel pressures, and perceived hardness would be yielded as surface cushioning increased (impact test device). A common acrylic top surface provided consistent frictional properties across surfaces. Kinetics (AMTI, 960 Hz and Footscan Pressure Insoles, 500 Hz), kinematics (Peak MOTUS, 120 Hz), and cushioning perception were assessed. Peak and mean loading rates of vertical ground reaction force, peak horizontal force, peak heel pressure, and rates of loading demonstrated significant correlations (P < 0.05) with the participants' perceived levels of cushioning and matched mechanical rankings of surface cushioning. In contrast, peak impact force was lowest on the least cushioned surface. Kinematic responses were not significantly different between surfaces. Present evidence supports ‘‘peak rate of loading'' as a more suitable indicator of surface cushioning than peak impact force. Although cautionary, biomechanical support is also provided for mechanical methods of surface cushioning assessment.  相似文献   

America's Cup yacht racing: Race analysis and physical characteristics of the athletes     

Vernon Neville  Julian Calefato  Cristina Pérez-Encinas  Enrique Rodilla-Sala  Sergio Rada-Ruiz  Paul Dorochenko 《Journal of sports sciences》2013,31(9):915-923

Abstract

The America's Cup is the oldest competing trophy in sport, yet little is known of the nature and intensity of racing or the physical characteristics of the athletes. In this study, aspects of the physical demands of America's Cup yacht racing were analysed, including the intensity of exercise and activity pattern of “grinding”. Anthropometric data were collected from 92 professional male America's Cup sailors, and fitness data from a top-4 and a lower-7 ranking team during the 32nd America's Cup. Over the 135 races, mean race duration was 82 min (s = 9), with 20 tacks (s = 10) and 8 gybes (s = 3) per race. Grinding bouts were 5.5 s (s = 5.4; range: 2.2–66.3) long, with 143 exercise bouts per race and an exercise-to-rest ratio of 1:6. Mean and peak heart rate was 64% and 92% of maximum for all positions, with bowmen highest (71% and 96%). Grinders were taller, heavier, and stronger than all other positions. Body fat was similar between positions (13%, s = 4). The higher-standard team was stronger and had greater strength endurance, which probably contributed to their quicker manoeuvres. Intensity of exercise was dependent on the similarity of competing boats and the role of the athlete. The short duration and intermittent nature of grinding is indicative of predominantly anaerobic energy provision.  相似文献   

A comparison of ratio and allometric scaling methods for normalizing power and strength in elite rugby union players     

Blair T. Crewther  Nicholas Gill  Robert P. Weatherby  Tim Lowe 《Journal of sports sciences》2013,31(14):1575-1580

Abstract

In this study, we compared the effectiveness of ratio and allometric scaling for normalizing power and strength in elite male rugby union players. Rugby union forwards (n = 18) and backs (n = 20) were assessed for squat jump and bench throw peak power, and box squat and bench press one-repetition maximum strength. The performance data for the forwards and backs were compared using ratio (P/BM) and allometric scaling (P/BM^b ), where P represents performance, BM is body mass in kilograms, and b is a power exponent. A proposed allometric exponent (0.67) and exponents (±95% confidence intervals) derived for the box squat (0.33 ± 0.31), bench press (0.45 ± 0.30), bench throw (0.46 ± 0.36), and squat jump (0.64 ± 0.31) exercises were used. In general, the absolute expression of power and strength was superior for the heavier forwards, but after ratio scaling these performance measures then favoured the lighter backs. There were no performance differences between the forwards and backs after allometric scaling using either the proposed or the derived exponents. Thus, allometric scaling may provide a more effective method for normalizing power and strength in elite athletes when body size is a confounding variable.  相似文献   

Can more than one incremental cycling test be performed within one day?     

《European Journal of Sport Science》2013,13(5):459-467

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Bunny Hill or Black Diamond: Differences in Advanced Course‐Taking in College as a Function of Cognitive Ability and High School GPA     

Oren R. Shewach  Kyle D. McNeal  Nathan R. Kuncel  Paul R. Sackett 《Educational Measurement》2019,38(1):25-35

College students commonly have considerable course choice, and they can differ substantially in the proportion of their coursework taken at an advanced level. While advanced coursework is generally viewed as a desirable component of a student's education, research has rarely explored differences in student course‐taking patterns as a measure of academic success in college. We examined the relationship between the SAT, high school grade point average (HSGPA), and the amount of advanced coursework taken in a sample of 62 colleges and 188,985 students. We found that both the SAT and HSGPA predict enrollment in advanced courses, even after controlling for advanced placement (AP) credits and demographic variables. The SAT subtests of Critical Reading, Writing, and Math displayed differential relationships with advanced course‐taking dependent on student major. Gender and race/ethnicity were also related to advanced course‐taking, with women taking more advanced courses in all major categories except for science, technology, engineering, and mathematics (STEM) where they took fewer, even after controlling for other variables. Socioeconomic status had a negligible relationship with advanced course‐taking. This research broadens our understanding of academic achievement in college and the goals of admissions in higher education.  相似文献   

Prediction of peak V˙O2 in Children and Adolescents With HIV From an Incremental Cycle Ergometer Test     

Luiz Rodrigo Augustemak de Lima  Diego Augusto Santos Silva  Paulo Cesar do Nascimento Salvador  Carlos Alencar Souza Alves Junior  Priscila Custódio Martins  João Antônio Chula de Castro 《Research quarterly for exercise and sport》2019,90(2):163-171

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The 3-minute all-out cycling test is sensitive to changes in cadence using the Lode Excalibur Sport ergometer     

James Wright  Stewart Bruce-Low  Simon A. Jobson 《Journal of sports sciences》2019,37(2):156-162

This study investigated the effect cadence has on the estimation of critical power (CP) and the finite work capacity (W?) during the 3-minute all-out cycling test. Ten participants completed 8 tests: 1) an incremental test to calculate gas exchange threshold (GET), maximal aerobic power (MAP) and peak oxygen uptake (V?O_2peak), 2–4) three time-to-exhaustion tests at 80, 100 and 105% MAP to calculate CP and W?, 5–7) four 3-minute all-out tests to calculate end power (EP) and work done above EP (WEP) using cadences ranging from preferred ?5 to preferred +10 rev·min^?1 to set the fixed resistance. Significant differences were seen between CP and EP-preferred (267.5 ± 22.6 W vs. 296.6 ± 26.1 W, P < 0.001), CP and EP?5 (267.5 ± 22.6 W vs. 303.6 ± 24.0 W, P < 0.001) and between CP and EP+5 (267.5 ± 22.6 W vs. 290.0 ± 28.0 W, P = 0.002). No significant differences were seen between CP and EP+10 (267.5 ± 22.6 W vs. 278.1 ± 30.9 W, P = 0.331). Significant differences were seen between W? and WEP at all tested fixed resistances. EP is reduced when cycling at higher than preferred cadences, providing better estimates of CP.  相似文献   

Validity of equations for estimating aerobic fitness in Mexican youth     

César Iván Ayala-Guzmán 《Journal of sports sciences》2019,37(16):1884-1891

The purpose of this study was to evaluate the validity of prediction equations for estimating maximal oxygen uptake (VO_2peak) based on the PACER test and different adiposity indicators in Mexican youth. A convenience sample of youth aged 9–18 years from schools in Mexico City was recruited. VO_2peak was evaluated with a laboratory exercise test on a treadmill and using a gas analyser and with the 20-m PACER test guidelines. The sample was randomly divided to develop new equations (n = 220) and to evaluate their validity (n = 106). Prediction equations of VO_2peak were developed using multiple linear regression models. The adiposity indicators were BMI, waist circumference and body fat. The validity of the new and previously published equations was evaluated based on linear regression models, intra-class coefficient, Akaike’s information criterion, mean absolute percentage error and Bland-Altman graphs. Equations with waist circumference and body fat performed better than those with BMI and without any anthropometric indicator. The accuracy of the developed equations (R² = 57.0%–59.50%) was higher than that of previously published equations (R² = 24.1%–56.0%). The new equations had lower bias in estimating VO_2peak. In Mexican youth, the estimation of VO_2peak from the 20-m PACER test is more accurate after including waist circumference or body fat than with BMI.  相似文献   

Predicting Freshman Grade‐Point Average from Test Scores: Effects of Variation Within and Between High Schools          下载免费PDF全文

D. Koretz  M. Langi 《Educational Measurement》2018,37(2):9-19

Most studies predicting college performance from high‐school grade point average (HSGPA) and college admissions test scores use single‐level regression models that conflate relationships within and between high schools. Because grading standards vary among high schools, these relationships are likely to differ within and between schools. We used two‐level regression models to predict freshman grade point average from HSGPA and scores on both college admissions and state tests. When HSGPA and scores are considered together, HSGPA predicts more strongly within high schools than between, as expected in the light of variations in grading standards. In contrast, test scores, particularly mathematics scores, predict more strongly between schools than within. Within‐school variation in mathematics scores has no net predictive value, but between‐school variation is substantially predictive. Whereas other studies have shown that adding test scores to HSGPA yields only a minor improvement in aggregate prediction, our findings suggest that a potentially more important effect of admissions tests is statistical moderation, that is, partially offsetting differences in grading standards across high schools.  相似文献