Physical activity,physiological, and psychomotor performance: a study of variously active older adult men

This research examined varying levels of physical activity and psychomotor and physiological function in variously active older men. Very active moderately active, and low active participants were tested on simple (SRT) and choice reaction time (CRT), coincidence-anticipation timing (CAT), and VO2max. No significant differences for age or height were found, although percentage of fat, and weight were statistically different. Active groups were leaner and lighter. VO2max was significantly different between groups, as physically active groups yielded geater values. SRT and CAT also yielded significantly different results with more active participants showing better performance. No between-groups significant differences resulted for CRT. Generally, increased levels of physical activity were related to superior physiological outcomes and improved psychomotor peformance.     

Science and cycling: current knowledge and future directions for research

In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( > 4 km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1 km time-trial), an 'all out' effort from the start is advised to 'save' time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.     

The creation of prehistoric man. Aimé Rutot and the Eolith controversy, 1900-1920

Although he died in obscurity, the Belgian museum conservator Aimé Rutot (1847-1933) was one of the most famous European archaeologists between 1900 and 1920. The focus of his scientific interest was stone flints, which he claimed to be the oldest known human tools, so-called eoliths. Skeptics maintained that the flints showed no marks of human workmanship, but Rutot nevertheless managed to spread his "Eolithic theory" in an important part of the scientific community. This essay demonstrates how material objects--series of stone flints and sets of statues that purported to reconstruct prehistoric "races"--were given scientific meaning by Rutot. Rutot diffused his ideas by disseminating his stones and statues, thus enlarging his networks of influence. For a time he managed to be at the material center of a trade network as well as at the intellectual center of archaeological debate. The essay shows how Rutot achieved this status and how he eventually fell from favor among serious scientists.     

航空和社会

飞机是否飞得太高了?这个不必回答、只是为了加强印象的反问句表明这样一种关切:今天飞机的航线并不象从前的商业和旅行的非常大的交通干线——沙漠和海洋——一样,也许不会对航线通过的国家的民族和文化产生相对来说较深远的影响。诚然,飞机用于空中运输正在不断地使地球变小,而飞机用于空中作业,创造了许多人道主义的或科学上的奇迹。“但是”,作者问道,“飞机是否深入到了人的内心世界?是否改变了人的心理活动或丰富了人的文化生活?”     

Impaired motor control after sport-related concussion could increase risk for musculoskeletal injury: Implications for clinical management and rehabilitation

This review presents a conceptual framework and supporting evidence that links impaired motor control after sport-related concussion(SRC)to increased risk for musculoskeletal injury.Multiple studies have found that athletes who are post-SRC have higher risk for musculoskeletal injury compared to their counterparts.A small body of research suggests that impairments in motor control are associated with musculoskeletal injury risk.Motor control involves the perception and processing of sensory information and subsequent coordination of motor output within the central nervous system to perform a motor task.Motor control is inclusive of motor planning and motor learning.If sensory information is not accurately perceived or there is interference with sensory information processing and cognition,motor function will be altered,and an athlete may become vulnerable to injury during sport participation.Athletes with SRC show neuroanatomic and neurophysiological changes relevant to motor control even after meeting return to sport criteria,including a normal neurological examination,resolution of symptoms,and return to baseline function on traditional concussion testing.In conjunction,altered motor function is demonstrated after SRC in muscle activation and force production,movement patterns,balance/postural stability,and motor task performance,especially performance of a motor task paired with a cognitive task(i.e.,dual-task condition).The clinical implications of this conceptual framework include a need to intentionally address motor control impairments after SRC to mitigate musculoskeletal injury risk and to monitor motor control as the athlete progresses through the return to sport continuum.     

格拉斯梅——华滋华斯的故乡

如今,已经没有人“象飘浮的云彩一般”,在华滋华斯故乡的村中独自徘徊了。每年,数以万计的仰慕华滋华斯盛名的人群来到他的墓前凭吊,追念这位将湖区精华尽收笔下的诗人。     

运动员使用促合成代谢类固醇的益处和害处

自1950年以来,用促合成代谢药物做实验的运动员愈来愈多了。这些药物能促进组织生长,因此推测也能促进肌肉增长,从而增加运动员的力量。在这些促合成代谢药物中,最常滥用的是促合成代谢雄性激素类固醇,即雄性激素、睾丸酮及其人工合成类似物,它们不是以针剂形式注射,就是以片剂形式口服,除促合成代谢作用之外,这些类固醇还具有男性化(masculinizing)效应,促合成代谢雄性类固醇是本综述的焦点。从化验报告得知,生长激素和人绒毛膜促性腺激素正越来越多地被国家级和世界级运动虽使用。可能运动员开始实验促合成代谢类固醇—雌性激素为时不长,这是与女性激素相似的化合物(在饲养家畜时,雄     

无氧代谢在田径运动中的重要性

<正> 一、引言肌肉运用能量的唯一形式是三磷酸腺苷分子合成的化学能。在人体所有的活动中,其能量的来源是通过有氧代谢和无氧代谢二个不同性质的过程中获得的。本文主要是叙述无氧能量产生的过程,并检验它在不同情况下对完成工作所起的作用。有氧代谢和无氧代谢在不同项目中对总能量的影响见(表一)。     

Effective conditioning of female soccer players

We compared the efficacy of three physical conditioning programmes provided over a 12 week period (24 h in total) on selected anthropometric and physical fitness parameters in female soccer players. Two of the groups received physical conditioning training in accordance with speed, agility and quickness (SAQ); one group used specialized resistance and speed development SAQ equipment (equipment group; n = 12), while the other group used traditional soccer coaching equipment (non-equipment group; n = 12). A third group received their regular fitness sessions (active control group; n = 12). All three interventions decreased (P < 0.001) the participants' body mass index (-3.7%) and fat percentage (-1.7%), and increased their flexibility (+14.7%) and maximal aerobic capacity (VO2max) (+18.4%). The participants in the equipment and non-equipment conditioning groups showed significantly (P < 0.005) greater benefits from their training programme than those in the active control group by performing significantly better on the sprint to fatigue (-11.6% for both the equipment and non-equipment groups versus -6.2% for the active control group), 25 m sprint (-4.4% vs -0.7%), left (-4.5% vs -1.0%) and right (-4.0% vs -1.4%) side agility, and vertical (+18.5% vs +4.8%) and horizontal (+7.7% vs +1.6%) power tests. Some of these differences in improvements in physical fitness between the equipment and non-equipment conditioning groups on the one hand and the active control group on the other hand were probably due to the specificity of the training programmes. It was concluded that SAQ training principles appear to be effective in the physical conditioning of female soccer players. Moreover, these principles can be implemented during whole team training sessions without the need for specialized SAQ equipment. Finally, more research is required to establish the relationship between physical fitness and soccer performance as well as the principles underlying the improvements seen through the implementation of SAQ training programmes.