Bone geometry in response to long-term tennis playing and its relationship with muscle volume : a quantitative magnetic resonance imaging study in tennis players

The benefit of impact-loading activity for bone strength depends on whether the additional bone mineral content (BMC) accrued at loaded sites is due to an increased bone size, volumetric bone mineral density (vBMD) or both. Using magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA), the aim of this study was to characterize the geometric changes of the dominant radius in response to long-term tennis playing and to assess the influence of muscle forces on bone tissue by investigating the muscle–bone relationship. Twenty tennis players (10 men and 10 women, mean age: 23.1 ± 4.7 years, with 14.3 ± 3.4 years of playing) were recruited. The total bone volume, cortical volume, sub-cortical volume and muscle volume were measured at both distal radii by MRI. BMC was assessed by DXA and was divided by the total bone volume to derive vBMD. Grip strength was evaluated with a dynamometer. Significant side-to-side differences (P < 0.0001) were found in muscle volume (+9.7%), grip strength (+13.3%), BMC (+13.5%), total bone volume (+10.3%) and sub-cortical volume (+20.6%), but not in cortical volume (+2.6%, ns). The asymmetry in total bone volume explained 75% of the variance in BMC asymmetry (P < 0.0001). vBMD was slightly higher on the dominant side (+3.3%, P < 0.05). Grip strength and muscle volume correlated with all bone variables (except vBMD) on both sides (r = 0.48–0.86, P < 0.05–0.0001) but the asymmetries in muscle parameters did not correlate with those in bone parameters. After adjustment for muscle volume or grip strength, BMC was still greater on the dominant side. This study showed that the greater BMC induced by long-term tennis playing at the dominant radius was associated to a marked increase in bone size and a slight improvement in volumetric BMD, thereby improving bone strength. In addition to the muscle contractions, other mechanical stimuli seemed to exert a direct effect on bone tissue, contributing to the specific bone response to tennis playing.

Contemporary PE reform in China : teachers' talk

Among the many changes occurring across Chinese society in the early phase of Y2K is the construction and implementation of a new physical education (PE) curriculum. Not unlike recent changes in Australia, New Zealand and the UK, this process has seen a heightening of the profile of health. Presented within a wider framework for making the school curriculum more relevant, PE is more closely aligned with China's emerging health concerns around young people. Foremost here are burgeoning social anxieties about decreased levels of physical activity, dietary practices, risk-taking tendencies, and a general decline of social cohesion/connection across the profile of contemporary youth. This paper reports on a study undertaken to explore the experiences of Chinese PE teachers as they engage with the new curriculum.

The data reveals a number of structural, personal and cultural factors that work against teachers taking up the opportunities presented in the new curriculum. Prominent here are; low professional status, an expanding generation gap, lack of training and the grip of deeply rooted cultural values. Juxtaposed against the like experiences of PE teachers in Australia and the UK the paper concludes with practical recommendations for nurturing curriculum change in China.

Effects of strength, flexibility and moderate intensity cardiovascular exercise on measures of fitness in sedentary women

The maintenance of functional physical fitness across the lifespan depends upon the presence or absence of disease, injury, and the level of habitual physical activity. The prevalence of sedentariness rises with increasing age culminating in 31% of elderly women being classified as leading a sedentary lifestyle. Exercise prescription that involves easily accomplished physical activity may result in the maintenance of mobility into old age through a reduction in the risk of premature death and disablement from cardiovascular disease and a reduction in the risk of falls and injuries from falls. It may be that short bouts of physical activity are more appealing to the sedentary and to those in full time employment than longer bouts, and it may be that short bouts of exercise, performed three times per day, can improve physical fitness. The purpose of this study was therefore to examine the problem: Does exercise session duration, initial cardiovascular fitness, and age group effect changes in functional physical fitness in sedentary women training for strength, flexibility and aerobic fitness? Twenty-three, sedentary women aged between 19 and 54 years who were employed at a major metropolitan hospital undertook six weeks of moderate intensity physical activity in one of two training groups. Participants were randomly allocated to either short duration (3 x 10 minute), or long duration (30 minute), exercise groups. The 3 x 10 minute group (n=13), participated in three, 10 minute sessions per day separated by at least 2 hours, 3 days per week. The 30 minute group (n=10), participated in three 30 minute sessions per week. The total amount of work was similar, with an average of 129 and 148 kcal training day for the 3 x 10 minute and 30 minute groups, respectively. The training program incorporated three walking and stair climbing courses for aerobic conditioning, a series of eleven static stretches for joint flexibility, and isotonic and isometric strength exercises for lower and upper body muscular strength. Measures of functional strength, functional flexibility and cardiovascular fitness were assessed prior to training, and immediately following the six week exercise program. A two way analysis of variance (Group x Time) was used to examine the effect of training and group on the dependent variables. The level of significance, 0.05 was adopted for all statistical tests. Mean hand grip strength showed for both groups no significant change over time for the 3 x 10 minute group (30.7kg to 31.7kg) and 30 minute group (30.2kg to 32.4kg). Leg strength showed a trend for improvement (p=0.098) in both the 3 x 10 minute and 30 minute training groups representing a 15% and 18% improvement, respectively. Combined right and left neck rotation significantly improved in the 3 x 10 minute group (82.8° to 92.0°) and 30 minute group (82.5° to 91.5°). Wrist flexion and extension improved significantly in 3 out of the 4 measurements. Left wrist flexion improved significantly by an average of 7.0% for the 3 x 10 minute and 4.9% for the 30 minute group. Right and left wrist extension improved significantly in the 3 x 10 minute and 30 minute training groups (5.9% and 6.8%, respectively). Hip and spine flexibility improved 3.4cm (35.2cm to 38.6cm) in the 3 x 10 minute group, and 6.6cm (37.4cm to 44.0cm) in the 30 minute group. There was a significant improvement in cardiovascular fitness for both groups representing a 22% improvement in the 3 x 10 minute group (27.2 to 33.2 ml kg min), and a 25% improvement in the 30 minute group (27.5 to 34.4 ml -kg min). No significant difference was shown in the degree of improvement in cardiovascular fitness over six weeks of training for subjects of either low or moderate initial aerobic fitness. Grip strength showed no significant changes over time for either the young-aged (19-35 years) or middle-aged (36-54 years) groups. Leg strength showed a trend for improvement (p=0.093) in the young-aged group (63.5kg to 71.9kg) and middle-aged group (69.3kg to 85.8kg). Neck rotation flexibility improved a similar amount in both the young and middle aged groups representing an improvement of 9.9° and 8.0° respectively. There was significant improvement in two of the four measures of wrist flexibility. Hip and spine flexibility was significantly greater in the young-aged group compared to the middle-aged group (38.5cm and 30.7cm, respectively). There was a significant improvement in hip and spine flexibility over the six week training program representing an increase in reach of 6.5cm for the young age group and 4.9cm for the older group. The middle-aged subjects had significantly lower cardiovascular fitness than their younger peers, scoring 22.8 and 30.7 ml -kg min, respectively. Cardiovascular fitness improved a similar amount in both age groups representing a significant improvement of 23.8% and 28.1% for the younger-aged and middle-aged subjects, respectively. The findings of this study suggest that short bouts of exercise may be equally as effective as longer bouts of exercise for improving the flexibility and cardiovascular components of functional physical fitness in sedentary young and middle aged women. Additionally short bouts of exercise may be more attractive than longer bouts of exercise for the beginning exerciser as they may more easily fit into the busy lifestyle encountered by many people in today's society. Sedentary young and middle-aged women should benefit from static flexibility exercises designed to improve and/or maintain functional flexibility and thus maintain mobility and reduce the incidence of muscular injury. Regular, brisk walking, incorporating some stair climbing, is likely to be beneficial in improving cardiovascular health and perhaps also in improving leg strength, thereby helping to improve and maintain functional physical fitness for both young and middle-aged sedentary women.

Ideal golf swing : an evaluation of its characteristics and the assumptions underlying its acquisition during coaching

The game of golf requires hitting a ball from a range of lies over a range of distances in environments that include many obstacles to be avoided. Each of these different golf shots arc designed to move the ball from the tee to the hole in the least number of strokes. However, the fundamental assumption that seems to underlie the coaching of golf, particularly to novice players, is that acquisition of an ideal basic golf swing is the most important outcome of coaching. Implicit in this view are three further assumptions. The first is that once this ideal basic golf swing is acquired by players, they are able to complete a game of golf in a competent manner even though this requires a range of different shots. The second is that there is a close correspondence between the quality of execution of any golf swing as judged in terms of this ideal swing, and the quality of outcome of the golf shot of which the swing is a part, as judged by where the ball comes to rest. The third assumption is that visual inspection of the golf swing by a coach can reveal inadequacies which can be remedied leading lo improved performance in the game of golf. The research reported in this thesis is an investigation of these assumptions. The rationale underlying coaching of golf was examined by reviewing the golf coaching literature (Chapter 1) and conducting a survey of professional golf coaches (Chapter 2). Results of the literature review and the survey indicated that the major emphasis of golf coaching of novices was on their acquiring what might be described as an ideal basic golf swing. This typically involved identifying components in sequence. Little emphasis was placed during this stage of coaching on what might be described as the complete action of a golf shot which involves hitting a ball to some target location. To examine the assumption that there was a close correspondence between the quality of execution of the golf swing and the quality of the outcome of a golf shot, two studies were conducted. In Chapter 3 the development of a 70-item checklist to be used to evaluate the quality of execution of a golf swing is reported. This checklist was based on a detailed behavioural analysis of the golf swing involving collaboration with relevant experts (i.e., golf coaches, biomechanist, kinesiologist), and information derived from a review of golf coaching materials. Development of the checklist was an iterative process in which earlier versions were used to evaluate sample golf swings, and problems identified during this lest process were used to improve the checklist. The final 70-item checklist comprised of a static component with three parts (left-hand grip; right-hand grip; stance) and a dynamic component with six parts (half backswing; full backswing; half downswing; ball contact; half followthrough; finish position). This version of the checklist was used in a study (reported in Chapter 4) of the relationship between the judged quality of execution of a golf swing and the outcome accuracy of a golf shot. Three groups of golfers with varying ability and experience were required to hit 50 balls with a 9-iron club to a target. Outcome accuracy for each shot was assessed in terms of the distance between the target and the resting location of the ball. Edited videotapes (showing only execution of the golf swing) of the five most, and five least accurate shots produced a sub-sample of these golfers (four professional players; four novice players) were subsequently viewed by three expert coaches. They independently rated using the checklist, the quality of execution of the 80 golf swings in random order without having information about the accuracy of any shot. As expected, the professional golfers completed more accurate golf shots than did the novices, and the golf swings completed by the professionals were rated more highly than those completed by the novices. However, for both groups of golfers the results indicated that there was no clear relationship between the rated quality of execution of golf swings and the outcome accuracy of the shots of which the swing were the initial part. Chapter 5 provides a summary and overview of the research reported in Chapter 1 to 4. It is argued that this research suggests a need for a change of emphasis in golf coaching away from consideration of the golf swing in isolation to consideration of the golf swing as part of a complete action. That is, the quality of execution of a golf swing should not be judged simply in relation to some ideal set of golf-swing components, but rather in relation to how well the completed swing (i.e., the golf shot) achieves the desired aim of propelling the ball from its present location to the target location.

Approaching responsivity : the Victorian Department of Justice and Indigenous Offenders

Offender rehabilitation has developed a stronghold on correctional practice in the past two decades. Further strengthening this grip have been three main  principles for effective practice; risk, needs and responsivity. This paper will focus on the responsivity principle, which dictates that effective rehabilitation involves consideration of an offender's cognitive behavioural characteristics and appropriate program delivery. In particular, this paper will analyse how this task has been approached by the Victorian Department of Justice in relation to  Indigenous offenders. Drawing on recent interviews with Justice staff, it will be  shown that Justice's approach to being responsive to the needs of Victorian Indigenous offenders is more complex than addressing cognitive behavioural characteristics and program delivery. It involves meaningful interactions that extend beyond the Department of Justice and Indigenous offenders to include Indigenous communities.

Transitions : experiences of women with type 1 diabetes : Turning points and transitions as experienced by young women with type 1 diabetes in Australia

The relationship among psychosocial stress, coping and metabolic control has a key effect on diabetes clinical outcomes and mental health. Life transitions are peak times of major change within personal and social contexts, which add stress affecting on peoples? problem solving. The thesis describes young women with Type 1 diabetes? perspectives of the problems encountered and how they managed them when they faced turning points and made life transitions. The study identified the women?s health concerns and factors that enhanced or hindered their ability to manage turning points and transitions. A substantive theory that comprised a problem of ?being in the grip of blood glucose levels? (BGLs) and a process termed ?creating stability? to manage life transitions was developed. The state of being in the grip of BGLs was associated with the impact of fluctuating BGLs; responses of other people to the womens? diabetes and the impact of diabetes on other people?s lives. The women managed these problems by engaging in social and psychological strategies helping them to stabilised their lives and feel more in control during life transitions.

Turning points and transitions : experiences of young women with Type 1 diabetes

This research explores young women with Type 1 diabetes' perspectives of the problems and how they manage them when facing turning points and making life transitions. The study presents a substantive theory of how the women tried to minimise the grip of blood glucose levels felt during transitions by creating stability in their lives.

I think it's a good idea, I just don't know how to do it : the struggle for PE reform in China

Among the many changes occurring across Chinese society in the early phase of Y2K is the construction and implementation of a new physical education (PE) curriculum. Not unlike recent changes in Australia, New Zealand and the UK, this process has seen a heightening of the emphasis on health. Presented within a wider framework for making the school curriculum more relevant, PE is more closely aligned with China’s emerging population health concerns around lifestyle practices of its youth. Foremost here are burgeoning social anxieties about decreased levels of physical activity, poor dietary practices, risk-taking tendencies, and a general shift in focus from ideology to skills.

This paper reports on a study undertaken to explore the perceptions of Chinese PE teachers and their engagement with the new PE & Health curriculum. The data reveals a number of structural, personal and cultural factors that work against PE teachers taking up the opportunities presented in the new curriculum. Prominent here are; low professional status, lack of resources, lack of training and the grip of deeply rooted cultural values.

Comparison of corticomotor excitability during visuomotor dynamic and static tasks

The human central nervous system (CNS) has the ability to modulate its activity during the performance of different movements. Recent evidence, however, suggests that the CNS can also modulate its activity in the same movement but with increased precision during a visuomotor static task. This study aimed to extend on these findings by using transcranial magnetic stimulation (TMS) to measure the CNS during the performance of two visuomotor dynamic tasks. Twelve volunteers participated in this study, performing two separate motor tasks. Study I (“Position Tracking”) involved participants to perform a visuomotor tracking task using a dial potentiometer and matching their response icon to the computer generated tracking icon whilst holding a pincer grip. Study II (“Force Tracking”) involved participants to perform a similar visuomotor tracking task by applying or releasing pressure against a fixed force transducer. Tasks were conducted at two speeds (“slow” being one tracking cycle in 10 s; and “fast” being two tracking cycles in 10 s) and compared to a visuomotor static task at a similar muscle contraction level. Results showed corticospinal changes with significant increases (p = 0.002) in excitability demonstrated during Study I (42.3 ± 16.8%) and Study II (56.3 ± 34.2%) slow speed tasks. Moreover, significant reduction in corticospinal inhibition was also observed during both tracking tasks at slow (59.3 ± 13.7%; p = 0.001) and fast speeds (31.9 ± 12.3%; p = 0.001). The findings may provide information on the underlying physiology during the early stages of motor skill acquisition.

Association between changes in habitual physical activity and changes in bone density, muscle strength, and functional performance in elderly men and women

OBJECTIVES: To investigate the long-term effects of habitual physical activity on changes in musculoskeletal health, functional performance, and fracture risk in elderly men and women.

DESIGN: Ten-year prospective population-based study.

SETTING: Malmö-Sjöbo Prospective Study, Sweden.

PARTICIPANTS: Participants were 152 men and 206 women aged 50, 60, 70, and 80 who were followed for 10 years.

MEASUREMENTS: Distal radius bone mineral density (BMD) (single photon absorptiometry), upper limb muscle (grip) strength, balance, gait velocity, occupational and leisure-time activity, and fractures (interview-administered questionnaire) were reassessed after 10 years. Annual changes for all measures were compared between participants with varying habitual physical activity histories at baseline and follow-up: inactive–inactive (n=202), active–inactive (n=47), inactive–active (n=49), and active–active (n=60). Data for men and women were pooled, because there were no sex-by-activity group interactions. To detect possible differences in fracture incidence between the varying habitual activity groups, participants were classified into two activity groups based on their activity classification at baseline and follow-up: inactive:less active versus active:more active.

RESULTS: The annual rate of bone loss was 0.6% per year less in individuals classified as active at both time points than in those classified as inactive at both time points (P<.01). Similar results were observed for balance, but there was no effect of varying habitual activity on changes in muscle strength or gait velocity. There were also no differences in fracture incidence between individuals categorized as active:more active and those categorized as inactive:less active during the follow-up (adjusted hazard ratio=0.90, 95% confidence interval (CI)=0.42–1.90).

CONCLUSION: This study showed that elderly men and women who maintained a habitually active lifestyle over 10 years had lower bone loss and retained better balance than those who remained habitually inactive.

Empirical investigation of multi-tier ensembles for the detection of cardiac autonomic neuropathy using subsets of the Ewing Features

This article is devoted to an empirical investigation of per- formance of several new large multi-tier ensembles for the detection of cardiac autonomic neuropathy (CAN) in diabetes patients using subsets of the Ewing features. We used new data collected by the diabetes screening research initiative (DiScRi) project, which is more than ten times larger than the data set originally used by Ewing in the investigation of CAN. The results show that new multi-tier ensembles achieved better performance compared with the outcomes published in the literature previously. The best accuracy 97.74% of the detection of CAN has been achieved by the novel multi-tier combination of AdaBoost and Bagging, where AdaBoost is used at the top tier and Bagging is used at the middle tier, for the set consisting of the following four Ewing features: the deep breathing heart rate change, the Valsalva manoeuvre heart rate change, the hand grip blood pressure change and the lying to standing blood pressure change.

Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study

Background: 

Effectiveness of dual-task functional power training for preventing falls in older people: study protocol for a cluster randomised controlled trial

BACKGROUND: Falls are a major public health concern with at least one third of people aged 65 years and over falling at least once per year, and half of these will fall repeatedly, which can lead to injury, pain, loss of function and independence, reduced quality of life and even death. Although the causes of falls are varied and complex, the age-related loss in muscle power has emerged as a useful predictor of disability and falls in older people. In this population, the requirements to produce explosive and rapid movements often occurs whilst simultaneously performing other attention-demanding cognitive or motor tasks, such as walking while talking or carrying an object. The primary aim of this study is to determine whether dual-task functional power training (DT-FPT) can reduce the rate of falls in community-dwelling older people. METHODS/DESIGN: The study design is an 18-month cluster randomised controlled trial in which 280 adults aged ≥65 years residing in retirement villages, who are at increased risk of falling, will be randomly allocated to: 1) an exercise programme involving DT-FPT, or 2) a usual care control group. The intervention is divided into 3 distinct phases: 6 months of supervised DT-FPT, a 6-month 'step down' maintenance programme, and a 6-month follow-up. The primary outcome will be the number of falls after 6, 12 and 18 months. Secondary outcomes will include: lower extremity muscle power and strength, grip strength, functional assessments of gait, reaction time and dynamic balance under single- and dual-task conditions, activities of daily living, quality of life, cognitive function and falls-related self-efficacy. We will also evaluate the cost-effectiveness of the programme for preventing falls. DISCUSSION: The study offers a novel approach that may guide the development and implementation of future community-based falls prevention programmes that specifically focus on optimising muscle power and dual-task performance to reduce falls risk under 'real life' conditions in older adults. In addition, the 'step down' programme will provide new information about the efficacy of a less intensive maintenance programme for reducing the risk of falls over an extended period. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613001161718 . Date registered 23 October 2013.

Progressive adaptation in physical activity and neuromuscular performance during 520d confinement

To understand whether prolonged confinement results in reductions in physical activity and adaptation in the musculoskeletal system, six subjects were measured during 520 d isolation in the Mars500 study. We tested the hypothesis that physical activity reduces in prolonged confinement and that this would be associated with decrements of neuromuscular performance. Physical activity, as measured by average acceleration of the body's center of mass ("activity temperature") using the actibelt® device, decreased progressively over the course of isolation (p<0.00001). Concurrently, countermovement jump power and single-leg hop force decreased during isolation (p<0.001) whilst grip force did not change (p≥0.14). Similar to other models of inactivity, greater decrements of neuromuscular performance occurred in the lower-limb than in the upper-limb. Subject motivational state increased non-significantly (p = 0.20) during isolation, suggesting reductions in lower-limb neuromuscular performance were unrelated to motivation. Overall, we conclude that prolonged confinement is a form of physical inactivity and is associated with adaptation in the neuromuscular system.

Bone density and neuromuscular function in older competitive athletes depend on running distance

UNLABELLED: Individuals who are involved in explosive sport types, such as 100-m sprints and long jump, have greater bone density, leg muscle size, jumping height and grip strength than individuals involved in long-distance running. INTRODUCTION: The purpose of this study is to examine the relationship between different types of physical activity with bone, lean mass and neuromuscular performance in older individuals. METHODS: We examined short- (n = 50), middle- (n = 19) and long-distance (n = 109) athletes at the 15th European Masters Championships in Poznań, Poland. Dual X-ray absorptiometry was used to measure areal bone mineral density (aBMD) and lean tissue mass. Maximal countermovement jump, multiple one-leg hopping and maximal grip force tests were performed. RESULTS: Short-distance athletes showed significantly higher aBMD at the legs, hip, lumbar spine and trunk compared to long-distance athletes (p ≤ 0.0012). Countermovement jump performance, hop force, grip force, leg lean mass and arm lean mass were greater in short-distance athletes (p ≤ 0.027). A similar pattern was seen in middle-distance athletes who typically showed higher aBMD and better neuromuscular performance than long-distance athletes, but lower in magnitude than short-distance athletes. In all athletes, aBMD was the same or higher than the expected age-adjusted population mean at the lumbar spine, hip and whole body. This effect was greater in the short- and middle-distance athletes. CONCLUSIONS: The stepwise relation between short-, middle- and long-distance athletes on bone suggests that the higher-impact loading protocols in short-distance disciplines are more effective in promoting aBMD. The regional effect on bone, with the differences between the groups being most marked at load-bearing regions (legs, hip, spine and trunk) rather than non-load-bearing regions, is further evidence in support of the idea that bone adaptation to exercise is dependent upon the local loading environment, rather than as part of a systemic effect.