摘要:

Reliability refers to the reproducibility of values of a test, assay or other measurement in repeated trials on the same individuals. Better reliability implies better precision of single measurements and better tracking of changes in measurements in research or practical settings. The main measures of reliability are within-subject random variation, systematic change in the mean, and retest correlation. A simple, adaptable form of within-subject variation is the typical (standard) error of measurement: the standard deviation of an individual’s repeated measurements. For many measurements in sports medicine and science, the typical error is best expressed as a coefficient of variation (percentage of the mean). A biased, more limited form of within-subject variation is the limits of agreement: the 95% likely range of change of an individual’s measurements between 2 trials. Systematic changes in the mean of a measure between consecutive trials represent such effects as learning, motivation or fatigue; these changes need to be eliminated from estimates of within-subject variation. Retest correlation is difficult to interpret, mainly because its value is sensitive to the heterogeneity of the sample of participants. Uses of reliability include decision-making when monitoring individuals, comparison of tests or equipment, estimation of sample size in experiments and estimation of the magnitude of individual differences in the response to a treatment. Reasonable precision for estimates of reliability requires approximately 50 study participants and at least 3 trials. Studies aimed at assessing variation in reliability between tests or equipment require complex designs and analyses that researchers seldom perform correctly. A wider understanding of reliability and adoption of the typical error as the standard measure of reliability would improve the assessment of tests and equipment in our disciplines.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Recent research has resulted in a number of recommended changes in how fitness professionals should prescribe target workloads and calculate the energy cost of exercise. The principal changes are in the use of oxygen consumption reserve (V-dot2R) as an alternative to percentage of maximal oxygen consumption (V-dot2max) for prescribing exercise intensity, the use of net V-dot2rather than gross V-dot2for the calculation of caloric expenditure during exercise, and a modification of the American College of Sports Medicine (ACSM) equation for calculating the oxygen cost of leg cycle ergometry. The V-dot2R method of prescribing exercise workloads is similar to the heart rate reserve (HRR) method of prescribing target heart rates, i.e. the target workload is established at a given percentage of the difference between maximal and resting V-dot2. Several recent studies have shown that there is a discrepancy between the exercise intensity at given percentages of HRR and V-dot2max, but that HRR and V-dot2R yield equivalent exercise intensities. The use of V-dot2R in exercise prescription provides more accurate target workloads, especially for individuals with a low fitness level. Net V-dot2during exercise is that amount above resting V-dot2due to the exercise itself. A recent recommendation is to employ net V-dot2in the calculation of the caloric expenditure during exercise, so as not to overestimate potential bodyweight loss. Several recent studies of leg cycling ergometry have yielded equations for the estimation of V-dot2that include a term for unloaded cycling, i.e. the oxygen cost of moving the legs against zero resistance. The equations from these studies provide more accurate estimations of cycling V-dot2than the existing ACSM equation, and a new standardised equation has been developed and adopted by the ACSM. The new equation is especially useful for improving the accuracy of V-dot2estimates during low intensity leg cycle ergometry. The ACSM equation for bench stepping has also been modified to include a term for resting metabolism.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Historically, the protocol used for exercise testing has been based on tradition, convenience or both. In the 1990s, a considerable amount of research has focused on the effect of the exercise protocol on test performance, including exercise tolerance, diagnostic accuracy, gas exchange patterns and the accuracy with which oxygen uptake (V-dot2) is predicted from the work rate. Studies have suggested that protocols which contain large and/or unequal increments in work cause a disruption in the normal linear relation between V-dot2and work rate, leading to an overprediction of metabolic equivalents. Other studies have demonstrated that such protocols can mask the salutary effects of an intervention, and some have suggested that the protocol design can influence the diagnostic performance of the test. Guidelines published by major organisations have therefore suggested that the protocol be individualised based on the patient being tested and the purpose of the test. The ramp approach to exercise testing has recently been advocated because it facilitates recommendations made in these guidelines. This article reviews these issues and discusses the evolution of ramp testing which has occurred in the 1990s.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

The heart rate deflection point (HRDP) is a downward or upward change from the linear HR-work relationship evinced during progressive incremental exercise testing. The HRDP is reported to be coincident with the anaerobic threshold. In 1982, Conconi and colleagues suggested that this phenomenon could be used as a noninvasive method to assess the anaerobic threshold. These researchers developed a field test to assess the HRDP, which has become popularised as the ‘Conconi test’. Concepts used to define and assess the anaerobic threshold as well as methodological procedures used to determine the HRDP are diverse in the literature and have contributed to controversy surrounding the HRDP concept. Although the HRDP may be assessed in either field or laboratory settings, the degree of HR deflection is highly dependent upon the type of protocol used. The validity of HRDP to assess the anaerobic threshold is uncertain, although a high degree of relationship exists between HRDP and the second lactate turnpoint. The HRDP appears to be reliable when a positive identification is made; however, not all studies report 100% reproducibility. Although the physiological mechanisms explaining the HRDP are unresolved, a relationship exists between the degree and direction of HRDP and left ventricular function. The HRDP has potential to be used for training regulation purposes. Clinically, it may be incorporated to set exercise intensity parameters for cardiac rehabilitation.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

During exercise, healthy individuals are able to maintain arterial oxygenation, whereas highly-trained endurance athletes may exhibit an exercise-induced arterial hypoxaemia (EIAH) that seems to reflect a gas exchange abnormality. The effects of EIAH are currently debated, and different hypotheses have been proposed to explain its pathophysiology. For moderate exercise, it appears that a relative hypoventilation induced by endurance training is involved. For high-intensity exercise, ventilation/perfusion (VA/Q) mismatching and/or diffusion limitation are thought to occur. The causes of this diffusion limitation are still under debate, with hypotheses being capillary blood volume changes and interstitial pulmonary oedema. Moreover, histamine is released during exercise in individuals exhibiting EIAH, and questions persist as to its relationship with EIAH and its contribution to interstitial pulmonary oedema. Further investigations are needed to better understand the mechanisms involved and to determine the long term consequences of repetitive hypoxaemia in highly trained endurance athletes.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

A major disaster was encountered at the 1997 Maccabiah Games in Israel. As the Australian team was about to enter the main stadium for the opening ceremony, a pedestrian bridge they were crossing collapsed, killing 4 athletes and injuring many others. The aim of this paper is to establish the rates, types and anatomical locations of musculoskeletal injuries incurred by members of the Australian Maccabiah Games team, with particular reference to the impact of the bridge collapse. In total, the 410 members of the team (360 athletes and coaches and 50 team officials) reported 166 injuries from their participation in sport and 30 musculoskeletal injuries associated with the collapse of the bridge. The most common sports-related injuries were sprains and strains to the hip/thigh, lumbar spine and ankle/foot regions, while the bridge collapse resulted in, most commonly, sprains and contusions to the hip/thigh, knee, lower leg and ankle/foot regions. In addition, team members incurred many medical and psychological conditions. This paper makes several recommendations for sports medicine staff based on the experience of this significant sport disaster.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS