摘要:

The relationship between strength, exhibited by an athlete in both dynamic constant resistance and isokinetic exercise, and sprint performance was investigated in 12 wheelchair track athletes (32.2±9.3 years old, National Wheelchair Athletic Association functional classification ranging from II to V). Strength tests included a 1 repetition maximum (RM) bench press and an isokinetic arm compound movement (60°.sec‐1and 180o‐sec‐1). Times for a 40 and 100 m wheelchair sprint were also measured. A nonsignificant correlation was observed between the 40 or 100 m sprint time and the 1 RM bench press (r =‐0.38 and r =‐0.31) and between the 40 or 100 m sprint time and the arm compound movement both at a speed of 60°.Sec‐1(r =‐0.05 and r =‐0.16) and 180°.sec‐1(r =‐0.18 and r =‐0.11). Therefore, strength in the upper body musculature of the wheelchair athlete appears not to be a valid predictor of their wheelchair sprint speed. This finding emphasizes the importance of additional factors, such as racing technique, functional classification, and training experience affecting an athlete's wheelchair sprint performance.

ISSN:1057-8315    

DOI:10.1080/15438629409512014

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

摘要:

By means of noninvasive transthoracic impedance cardiography, the cardiovascular profile of two groups of male asymptomatic and glycometabolic‐compensated insulin‐dependent diabetics (IDD), one composed of five untrained patients (UD) and the other of five athletes trained for aerobic‐anaerobic sports (TD), was studied during a cycle ergometer progressive exercise up to a submaximal work rate corresponding to a heart rate (HR) of 130 beats/ min (W 130). At rest, although HR and arterial blood pressure were similar in the two groups, values for TD were higher than for UD in stroke volume (SI, +14%) and cardiac output (CI, +26%) index expressed per m2of body surface area, impedance‐derived cardiac work indicator (CWI, +24%), impedance‐derived heart mechanical efficiency indicator (HEI, +16%), impedance‐derived ventricle preload indicator (PLI, +12%), and those for TD were lower than for UD in impedance‐derived total peripheral resistance indicator (TPRI,‐24%) and impedance‐derived myocardial contractility indicator (MCI,‐25%). With respect to rest, at W 130 TD showed the following changes: SI, +9%; CI, +82%; CWI, +122%; HEI,‐3%; PLI, +5%; TPRI,‐65%; and MCI, +27%. UD showed: SI,‐6%; CI, +59%; CWI, +82%; HEI,‐20%; PLI,‐3%; TPRI,‐29%; and MCI,‐5%. It was concluded that in the asymptomatic IDD patient a sedentary habit may lead to subclinical left ventricle dysfunction. On the contrary, participation in competitive sports led to an increase in the physical capacity of the subjects and also reduced the risk of cardiomyopathy.

ISSN:1057-8315    

DOI:10.1080/15438629409512015

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study evaluated the reproducibility of four commonly utilized metabolic systems. The metabolic carts and associated electronic cycle ergometers were: (1) the Q‐PLEX I/Corival, (2) SensorMedics 2900/Ergometrics, (3) Medical Graphics Corporation (MGC) 2001/Mijnhardt, and (4) CPX/Medifit. Five individuals (mean age, 32 years; weight, 74 kg; height, 179 cm) experienced in graded exercise testing participated. Duplicate submaximal and maximal protocols were completed on separate days with all four systems. The submaximal power outputs averaged 85, 135, and 190 W and were each 4 minutes in duration. A maximal effort was achieved with a continuous ramp protocol (30 W/min) until exhaustion. All four systems demonstrated excellent reproducibility (usually 5% or less variation) for values reported during either submaximal or maximal exercise. These values were system dependent, however, as evident from a significant difference in submaximal and maximal pulmonary ventilation, oxygen consumption (VO2), carbon dioxide output, and respiratory exchange ratio between various systems. The average peak VO2varied by as much as 22% (45 to 55 ml‐kg‐min) among the systems. The group mean peak power output varied by as much as 39 W (296 to 335 W) among the cycle ergometers. Failure to measure a criterion pulmonary and metabolic functional capability will inevitably lead to the development of a divergent exercise prescription or training program in different locales using different equipment and will severely limit the interpretation and comparison of longitudinal or cross‐sectional studies.

ISSN:1057-8315    

DOI:10.1080/15438629409512016

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

摘要:

A Kofranyi‐Michaelis respirometer has been used to measure net energy expenditures in 16 women and 52 men undergoing rehabilitation following hemiplegia. Measurements were made during seated rest, standing, comfortable ambulation, and ascent and descent of a laboratory staircase. Because tasks were performed more slowly than in the able‐bodied, all data were expressed as net oxygen cost (ml/[kg.m]) relative to seated rest. Resting metabolism was slightly reduced by hemiplegia (3.1±0.7 and 3.4±0.7 ml/[kg‐min] in men and women, respectively). Stair climbing was performed with a low net mechanical efficiency (6 to 8%). The metabolic cost of ambulation was also high relative to the able‐bodied individual, particularly at slow speeds of walking. Above a pace of 40 m/min in women and 50 m/min in men, the energy cost was only 10 to 20% higher in some hemiplegics than in the able‐bodied, but because of age and disability, many of the subjects with hemiplegia could not attain such speeds. We conclude that although some apparent optimization of the energy cost of ambulation is due to a consideration of the gross rather than the net oxygen cost, a combination of age and disability holds many individuals with hemiplegia to a walking speed that is mechanically inefficient.

ISSN:1057-8315    

DOI:10.1080/15438629409512017

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

摘要:

Ultraviolet (UV) skin exposure was measured in a group of 21 marathon runners during the Barcelona and Madrid marathons. This was accomplished by means of a personal dosimeter attached to the runner's chest or back. At the same time, ambient UV irradiance and heat stress index were also measured by means of a spectroradiometer and a heat versus exertion monitor, respectively. The latter is an analog of the wet bulb globe temperature. The results showed that during the races the marathoners received a mean radiation of 10 and 4.5 of the minimal erythematous dose. In spite of this high UVB dose the runners did not show unwanted acute skin responses such as sunburn. Since marathon runners can be at high risk for skin cancer, the guidelines for protection of the skin from the American Cancer Society against UV radiation are highly recommended for this group of athletes.

ISSN:1057-8315    

DOI:10.1080/15438629409512018

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

摘要:

Immune responses measured at rest immediately or some hours after exercise training (some with and some without increase in maximal oxygen uptake) gave variable and sometimes conflicting results; therefore, no general conclusions can be drawn. On the other hand, most immune responses were either unchanged (immunoglobulin, T cells, CD4+, and natural killer activity) or decreased (blood properdin, neutrophil phagocytic activity, salivary lysozymes, brain immunoglobulin A and G, and liver B lymphocytes and phytohemagglutinin activity) during prolonged bed rest. Some data suggested that exercise training during bed rest may partially ameliorate the decreased functioning of the immune system. Exercise and change in body position, especially during prolonged bed rest with plasma fluid shifts and diuresis, may induce a change in plasma protein concentration and content, which can influence drug metabolism as well as immune function. Leukocytosis, accompanied by lymphopenia and a depressed lymphocyte response, occurs in astronauts on return to Earth from spaceflight; recovery may depend on time of exposure to microgravity. It is clear that the effect of drugs and exercise used as countermeasures for microgravity deconditioning should be evaluated for their effect on an astronaut's immune system to assure optimal health and performance on long‐duration space missions.

ISSN:1057-8315    

DOI:10.1080/15438629409512019

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629409512020

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor

ISSN:1057-8315    

DOI:10.1080/15438629409512013

出版商:Taylor&Francis Group    

年代:1994

数据来源: Taylor