摘要:

For years, osteoporosis and cardiovascular disease were thought to be two independent  consequences  of  aging;  however,  mounting  evidence  supports an association between these diseases. Recently, a widespread class of cholesterol-lowering drugs known as statins have demonstrated (in rodents and cell cultures) the ability to induce bone formation. This finding is significant since current therapies are limited to the prevention or slowing down of bone loss rather than (enhancing/improving) bone formation. In humans, the ability of statins to generate new bone has not been consistent; however, several investigations have demonstrated a dramatic decrease in fracture risk. Although it has been proposed that statins induce new bone via increased bone morphogenetic protein-2, other conditions affected by statins such as dyslipidaemia, vascular calcification, endothelial dysfunction and impaired nitric oxide expression, may also contribute to the cardiovascular and bone health paradigm. Furthermore, the role of physical activity and its influence on cardiovascular and bone health, especially in postmenopausal women, may contribute to the discrepancy of findings in human data. In summary, it remains to be determined if statins contribute to bone health via improvements in vascular health or by pleiotropic properties unique to their pharmacology. This review provides information on our current understanding of the bone and cardiovascular association, as well as on novel areas of research to further our current understanding of these conditions.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Aging has been associated with a loss of muscle mass that is referred to as ‘sarcopenia’. This decrease in muscle tissue begins around the age of 50 years, but becomes more dramatic beyond the 60th year of life. Loss of muscle mass among the aged directly results in diminished muscle function. Decreased strength and power contribute to the high incidence of accidental falls observed among the elderly and can compromise quality of life. Moreover, sarcopenia has been linked to several chronic afflictions that are common among the aged, including osteoporosis, insulin resistance and arthritis. Loss of muscle fibre number is the principal cause of sarcopenia, although fibre atrophy – particularly among type II fibres – is also involved. Several physiological mechanisms have been implicated in the development of sarcopenia. Denervation results in the loss of motor units and thus, muscle fibres. A decrease in the production of anabolic hormones such as testosterone, growth hormone and insulin-like growth factor-1 impairs the capacity of skeletal muscle to incorporate amino acids and synthesise proteins. An increase in the release of catabolic agents, specifically interleukin-6, amplifies the rate of muscle wasting among the elderly. Given the demographic trends evident in most western societies, i.e. increased number of those considered aged, management interventions for sarcopenia must become a major goal of the healthcare profession.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

At international standard, sculling (two oars) and rowing (one oar) are competed on-water over 2000m. Race time is the critical measure of performance and is determined from mean skiff velocity during a race. Although a high proportion of race training is completed on-water, rowing ergometers are commonly used for performance testing, technique coaching, crew selection or for training during poor weather. Rowing biomechanics research has aimed to identify characteristics of successful sculling and sweep rowing strokes; however, biomechanical predictors of 2000m rowing performance are indistinct in the literature. If specific biomechanical parameters distinguish between ability levels and successful or unsuccessful techniques, these attributes can be considered when modifying technique or predicting future rowing performance. The kinematics and kinetics of the sculling and rowing movements have been described on ergometers, on-water and for novice and elite male and female rowers, but there is limited research on the ideal technique or how a rower’s anthropometry or boat set-up could help improve/optimise their rowing performance. Currently viewing the technique and providing verbal feedback is the primary tool used by a coach to help improve a rower’s technique and performance. The greater use of customised telemetered sensors on the rowing skiff can assist the coach and biomechanist with judging when performance (skiff velocity) improves with some form of intervention.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Rugby league is an international collision sport played at junior, amateur, semi-professional and professional levels. Due to the high numbers of physical collisions and tackles, musculoskeletal injuries are common. A large percentage of injuries result in long-term employment and study limitations, medical costs and loss of income. Review articles addressing the applied physiology of rugby league and common rugby league injuries have been published. However, both of these review articles have focused on the professional rugby league player. This review addresses the extent of the injury problem in rugby league in all levels of competition (i.e. junior, amateur, semi-professional and professional).The incidence of rugby league injuries typically increases as the playing level is increased. The majority of studies have shown that the head and neck is the most common site of match injuries in senior rugby league players, while knee injuries are the most common site of injury in junior rugby league players. Muscular injuries are the most common type of injury sustained by senior rugby league players, while junior rugby league players more commonly sustain fractures. Injuries are most commonly sustained in tackles, by the tackled player. Thigh and calf strains are the most common injuries sustained during rugby league training, while overexertion is the most common cause of training injuries. Player fatigue may influence the incidence of injury, with most sub-elite (amateur and semi-professional) rugby league injuries occurring in the second half of matches or the latter stages of training sessions. The majority of training injuries occur in the early stages of the season, while match injuries occur in the latter stages of the season, suggesting that changes in training and playing intensity may influence the incidence of injury in rugby league.Injury prevention studies are required to reduce the incidence, severity and cost of rugby league injuries. These injury prevention strategies could include coaching on defensive skills, correct tackling technique, correct falling technique and methods to minimise the absorption of impact forces in tackles. Game-specific attacking and defensive drills practised before and during fatigue may also encourage players to make appropriate decisions under fatigued conditions and apply learnt skills during the pressure of competitive matches. Further studies investigating risk factors for injury in junior and senior rugby league players, injuries sustained by specific playing positions and the influence of injuries on playing performance are warranted.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS