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181.
Michael Clemens Rumpf John Cronin Jonathan Oliver Michael Hughes 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):256-263
The purpose of this study was to quantify the reliability of kinematic and kinetic variables using a sample of pre-peak-height-velocity (PHV) male athletes sprinting on a non-motorised treadmill. Following variables were measured and their normative data presented, average and peak velocity, average and peak power, average and peak horizontal force, average and peak vertical force, average step frequency, average step length, average work. Twenty-five participants performed three 5-s all-out sprints from a standing split start on a non-motorised treadmill on three separate occasions. Per cent change in the means (-3.66 to 3.35%) and coefficients of variation (0.56–7.81%) were thought reliable for all variables. However, average step rate, average horizontal force and average vertical force did not meet the standards (≥0.70) set for acceptable intraclass correlation coefficients (ICC). Due to the homogeneous group, it was expected to receive low ICC values. Therefore, youth sprinting performance can be tested reliably on a non-motorised treadmill, especially if the per cent change in the mean and CV are deemed the important reliability measures. Normative data are given for the participant’s age as well as their maturity level for kinematic and kinetic variables. 相似文献
182.
Road criterium and track bicycle racing occur at high speeds, demand repeated high power outputs, last 10–90?min, and offer little chance for recovery after the event. Consecutive evenings of criterium and track racing are respectively known as speed-week or six-day events and take place in evening hours over the course of a week. Given the schedule and timing of these competitions, return to homeostasis can be compromised. No recommendations exist on how to optimize recovery for cyclists participating in these types of repeated evening competitions. Criterium and track cyclists spend considerable time, near and above the individual lactate threshold and therefore mostly utilize carbohydrate as their chief energy substrate. Henceforth, pre – and post-race nutrition and hydration is examined and recommendations are brought forward for carbohydrate, protein, and fluid intake. As evening high-intensity exercise perturbs sleep, strategies to optimize sleep are discussed and recommendations for an optimal sleep environment are given. Active recovery is examined, and the benefits of a short duration low intensity exercise reviewed. Passive recovery methods such as compression garments and cold water immersion are recommended, while evidence for massage, pneumatic compression devices, and neuromuscular electrical stimulation is still lacking. Optimizing recovery strategies will facilitate a return to the resting state following strenuous night competition. 相似文献
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Michael E. Gluck 《Research Policy》1987,16(6)
Growth in the industrial support of university research in the life sciences and more specifically in biotechnology has raised questions concerning its effects, both positive and negative, on the educational experiences of graduate students and post-doctoral fellows. A survey of 693 graduate students and post-doctoral fellows at six research intensive universities in the United States reveals that 19 percent of the responding students and fellows receive direct industry support for their research or training and that another 15 percent work with faculty advisors supported by industrial funds. On average students and fellows in this sample believe that the benefits of relationships with private firms outweigh the risks. In addition, students funded by private firms are more likely than those without industry connections to report patents resulting from their research. No relationship is found between industry support and young scientists' career plans or their rating of the quality of their educational experiences. However, the data suggest the existence of some risks: industry support is associated with fewer or delayed publications, inhibition of scientific communication on the part of some trainees, and some restrictions on students' and fellows' research. In a few cases, students are supported by funds from companies in which faculty advisors hold equity, a situation that creates potential conflicts of interest for students' mentors. To protect students, university administrators must monitor the relationships with industry that give rise to these potential problems. Future research into industrial support of research and training is needed to extend these results. 相似文献
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Michael J Shoemaker Heather Hurt Leah Arndt 《Cardiopulmonary Physical Therapy Journal》2008,19(3):75-83
Purpose: To conduct a systematic review of the evidence regarding the efficacy of exercise training in the management of cystic fibrosis (CF).Methods: Articles were found by searching PEDRO, MEDLINE, and CINAHL databases. Included articles involved exercise-related interventions for long-term adaptations (ie, not acute effects of exercise). Articles were excluded if the language was other than English or if other non-exercise interventions were used. Date of publication was not a factor for exclusion. Two independent reviewers evaluated the included articles using Sackett''s levels of evidence and select scoring criteria.Results: Twelve articles were eligible for inclusion. Interventions studied included various aspects of exercise training: anaerobic, aerobic, or resistance training. Study end-points included pulmonary function, aerobic capacity, strength, and health-related quality of life (HRQL).Conclusions: Exercise training in individuals with CF is beneficial, with aerobic and resistance training having the greatest support in the literature for improved aerobic capacity and strength, respectively. Exercise training does not appear to have an effect of improving pulmonary function, but may have a preservation effect. Strong conclusions about improvement in HQRL from exercise training cannot be made. However, greater consistency in measuring this outcome is needed in future trials. There is a paucity of evidence regarding the role of exercise training in reducing hospitalization and health care utilization, and questions raised by this review should be considered in the design of future trials.Key Words: cystic fibrosis, aerobic exercise, review 相似文献
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The purpose of this study was to compare measures of body size in two samples of youth baseball players with normative data from the United States National Center for Health Statistics (NCHS) growth charts. One sample of youth baseball players participated in a local little league. The second sample of youth baseball players were members of eight of the twelve teams participating in the 1995 Dixie Youth World Series. Normative data for the United States (NCHS) were used as comparative data. Two trained anthropometrists measured standing height, sitting height, lower limb height, upper limb length, arm girth, calf girth, tricep skinfold, and abdomen skinfold on all participants. In both samples, pitchers, short stops, and first basemen were a more highly skilled group and exhibited larger body size (greater standing height, sitting height, lower limb height, upper limb length) than children who played at other positions. The standing height of local little league players was similar to the median of reference data at ages 7, 8, and 9 years. The standing height and weight of skilled players in both samples approximated the 75th percentile for standing height and weight at ages 10, 11, 12, and 13 years. The results suggest that baseball players exhibit larger body size than the normal population at young ages. Body size may be an important criterion used by coaches to select and assign young players to certain positions. 相似文献