Effects of long-term tennis playing on the muscle-bone relationship in the dominant and non-dominant forearms

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81 - 0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.

Muscle activation is enhanced with multi- and uni-articular bilateral versus unilateral contractions

Ten resistance trained (RT) and 6 non-resistance trained (NRT) subjects were used to determine differences in quadriceps activation between isometric single and double knee extensions and squat contractions. Greater inactivation, as measured by the interpolated twitch technique, was recorded with single (RT: 16.5%, NRT: 17.6%) than double leg extensions (RT: 8.4%, NRT: 13.4%) or squats (RT: 4.03%, NRT: 1.7%). There was no significant difference between the maximum voluntary contraction (MVC) force of the dominant leg during single and double leg extensions. However, in NRT subjects, the contralateral or non-dominant leg during double leg extensions exhibited significantly less force than the dominant leg (715.9 vs 566.9 N). This deficit may be due to a lesser reliance on the non-dominant limb. The contractions of multiple lower body muscle groups enhanced the activation of the dominant quadriceps. Greater levels of activation may be necessary to cope with the stabilization necessary for bilateral and multi-articular contractions.

The contribution of upper limb and total body movement to adolescents’ energy expenditure whilst playing Nintendo Wii

Little research documents the contribution of upper limb and total body movement to energy expenditure (EE) during active video gaming. To address this, EE, heart rate (HR), and, upper limb and total body movement were assessed in 11- to 17-year-old adolescents whilst playing three active (Nintendo Wii) and one sedentary (XBOX 360) video games. Non-dominant upper limb activity, EE and HR were significantly greater during Wii Sports boxing [mean 267.2 (SD 115.8) J kg−1 min−1; 136.7 (24.5) beats min−1] than tennis or bowling (P ≤ 0.044). For all active games hip activity best predicted EE (R 2 ≥ 0.53), with two-measure models of HR and single-site activity data, and multi-site activity data, similarly explaining the variance in EE (R 2 ≥ 0.64). The physiological cost of upper-body orientated active video games increased when movement of both upper limbs was encouraged. Improvements in EE explanatory power provide support for multi-site activity monitoring during unique, non-ambulatory activities.

Formation of cortical plasticity in older adults following tDCS and motor training

Neurodegeneration accompanies the process of natural aging, reducing the ability to perform functional daily activities. Transcranial direct current stimulation (tDCS) alters neuronal excitability and motor performance; however its beneficial effect on the induction of primary motor cortex (M1) plasticity in older adults is unclear. Moreover, little is known as to whether the tDCS electrode arrangement differentially affects M1 plasticity and motor performance in this population. In a double-blinded, cross-over trial, we compared unilateral, bilateral and sham tDCS combined with visuomotor tracking, on M1 plasticity and motor performance of the non-dominant upper limb, immediately post and 30 min following stimulation. We found (a) unilateral and bilateral tDCS decreased tracking error by 12–22% at both time points; with sham decreasing tracking error by 10% at 30 min only, (b) at both time points, motor evoked potentials (MEPs) were facilitated (38–54%) and short-interval intracortical inhibition was released (21–36%) for unilateral and bilateral conditions relative to sham, (c) there were no differences between unilateral and bilateral conditions for any measure. These findings suggest that tDCS modulated elements of M1 plasticity, which improved motor performance irrespective of the electrode arrangement. The results provide preliminary evidence indicating that tDCS is a safe non-invasive tool to preserve or improve neurological function and motor control in older adults.

The Influence of Task Characteristics on the Intermanual Asymmetry of Motor Overflow

The two studies reported here were designed to test the proposition that greater motor overflow occurs when movements are performed by the non-dominant hand. Unlike previous studies using normal adults, the task in these studies did not require force production. In the first study, a group of 19 right-handed participants performed unweighted finger lifting. That the frequency of motor overflow occurrence was the same regardless of which hand performed the task, did not support findings from other studies where tasks involving force production resulted in more overflow when performed by the non-dominant hand. To investigate further the influence of task characteristics on motor overflow occurrence, in the second study participants were required to remember and reproduce a prescribed sequence of four finger lifts. Left- and right-handed participants ( N =30) performed both single and sequenced finger lifting. The relative frequency of motor overflow (unintended lifts of fingers of the passive hand) was compared between hand preference groups, active hand and task type (single/sequenced). Contrary to the expectation that motor overflow would be greater for the sequenced finger lifting task, overflow was exhibited with a significantly greater frequency on single finger lifting. This finding indicates that task characteristics influence the pattern of overflow occurrence in normal adults. The task used in this study did not involve force production and did not result in an intermanual asymmetry of motor overflow. This contrasts with findings from other studies requiring adults to exert forces where greater overflow occurred when the non-dominant hand was active. However, this study confirms previous findings which show that left-handers produce greater overflow compared to right-handers regardless of the task being performed and the hand performing the task.

TMS stimulus-response asymmetry in left- and right handed individuals

There have been inconsistencies in the literature regarding asymmetrical neural control and results of experiments using TMS techniques. Therefore, the aim of this study was to further our understanding of the neural relationships that may underlie performance asymmetry with respect to the distal muscles of the hand using a TMS stimulus–response curve technique. Twenty-four male subjects (12 right handed, 12 left handed) participated in a TMS stimulus–response (S–R) curve trial. Focal TMS was applied over the motor cortex to find the optimal position for the first dorsal interossei muscle and to determine rest threshold (RTh). Seven TMS intensities ranging from 90 to 150 % of RTh were delivered in 10 % increments. One single TMS block consisted of 16 stimuli at each intensity. Peak-to-peak amplitudes were measured and the S–R curve generated. In right-handed subjects, the mean difference in slopes between the right and left hand was −0.011 ± 0.03, while the mean difference between hands in left-handed subjects was −0.049 ± 0.08. Left-handed normalized data in right handers displayed a mean of 1.616 ± 1.019 (two-tailed t test p < 0.05). The left-handed group showed a significant change in the normalized slope as indicated by a mean of 1.693 ± 0.149 (two-tailed t test p < 0.00006). The results found in this study reinforce previous work which suggests that there is an asymmetry in neural drive that exists in both left- and right-handed individuals. However, the results show that the non-dominant motor hemisphere displays a greater amount of excitability than the dominant, which goes against the conventional dogma. This asymmetry indicates that the non-dominant hemisphere may have a higher level of excitation or a lower level of inhibition for both groups of participants.

A possible anatomical and biomechanical explanation of the 10% rule used in the clinical assessment of prehensile hand movements and handed dominance

Abstract
A current doctrine in the dynamometric approach to determine lateralization of hand function states that in 10% of cases, the non-dominant hand will be stronger than the dominant hand. In this study, a novel MRI based modelling approach was applied to the first dorsal introsseus muscle (FDI), to determine whether the 10% rule may be applied to the FDI and may be partially explained by the arrangement of the anatomical components of the FDI.

Methods
Initially the force generated by the thumb segment during an isometric pushing task in the horizontal plane was measured from 25 strongly right-handed young males. Nine of these participants then had structural magnetic resonance imaging (sMRI) of the thumb and index osseous compartment. A modelling technique was developed to extract the muscle data and quantify the muscle line of action onto to the first metacarpal bone segment in order to quantify the muscle force at the point of momentary rotation – equilibrium.

Results
Eight of 25 subjects exhibited stronger force from the left hand. Six out of nine subjects from the MRI possessed significantly greater angles of attachment of the index osseous compartment on the left (non-dominant) hand. These six subjects also generated greater maximal isometric forces from the FDI of the left side. There was a significantly greater muscle volume for the right FDI muscle as compared to the left as measured from the reconstructed MRI slice data.

Conclusions
The calculated force produced by the muscle is related to the angle of attachment of the muscle to bone in the index osseous compartment. The MRI findings indicate that the 10% rule may be anatomically and biomechanically explained.

The patient experience of a peripherally inserted central catheter (PICC): A qualitative descriptive study.

UNLABELLED: Abstract Aim: To investigate the patient experience of Peripherally Inserted Central Catheter (PICC) insertion, the significance of arm choice and the impact of the device on activities of daily living. BACKGROUND: Arm choice for PICC insertion is often determined by PICC nurses with little input from consumers. There are few studies that have investigated the patient experience of living with a PICC and none that have examined the impact of arm choice from the consumer's perspective. METHOD: Participants were recruited in a hospital whilst they waited for PICC insertion. A purposeful sampling approach was used to select participants based on diagnosis types. Semi-structured telephone interviews were conducted November 2012-August 2013. Transcripts of the interviews were analysed using thematic analysis. FINDINGS: Ten participants were interviewed. Four themes were identified: (i) apprehension/adaptation/acceptance, (ii) impact of treatment, (iii) asking questions (trusting doctors) and (iv) freedom. Although initially apprehensive, participants adapted to the PICC and came to accept that the device allowed convenient access for treatment. This allowed them the freedom to receive treatment at home. The use of the dominant or non-dominant arm for PICC insertion had marginal impact on activities of daily living for participants. Auxiliary factors such as the infusion pump had a significant impact for those who received outpatient treatment. For those participants who did not understand the procedure, many did not seek clarification and trusted medical and nursing staff to make decisions for them. CONCLUSION: Nurses should involve consumers in clinical decision-making and provide individualised information and support that facilitates adaptation for patients living with a PICC.

Asymmetry in volume between dominant and nondominant upper limbs in young tennis players

This study aimed at demonstrating the asymmetry in volume between the dominant and nondominant upper limbs in tennis players, controlled for maturity status. Upper limb volumes on both sides were calculated in 72 tennis players and 84 control subjects, using the truncated cone method. The participants’ maturity status was determined using the predicted age at peak height velocity (PHV). The results showed significant larger side-to-side asymmetry in volume in tennis groups than
in control groups. These findings suggested that, even before PHV, specific-sport adaptations occurred in the dominant upper limb in tennis players.

Homophobic bullying and human rights : non-deficit approaches in queer youth wellbeing policy and practice

This chapter is concerned with ways for improving the capacity of school communities to provide queer young people with stimulating educational experiences that productively engage with the realities of their lives and which promote and enhance their wellbeing. By "queer" or "LBGTI" I mean to refer to all of those young people who do not conform to prevailing expectations regarding gender and sexual identity and behaviours, those young people who may be lesbian,gay, bisexual, transgender or intersexual (lGBTI), as well as all of those young people who have an association with gender and sexual diversity (for example, the straight fey boy who gets called a poofta; the teenage girl with lesbian parents, etc.). Methodologically, this chapter draws on a tradition of Foucauldian cultural analysis which acknowledges that gender and sexual identities are not stable or fixed, but that they are generated by influential discourses (e.g. my identity as a "man" in Melbourne today is mediated by contemporary discourses of masculinity, of Australianness, of class and so on) (for example, see Foucault 1984, 1990, 1992 and 1998).

This chapter argues that conventional approaches to school improvement for queer students normally focus on strategies for reducing the victimisation of teenage homosexuals, and that such strategies rely on dominant discourses of safety and bullying. I examine a recent example of this policy approach and use it as a starting point for considering the benefits and the constraints of a victim-based approach to queer youth wellbeing policy. The chapter then moves into a discussion about the recent introduction of human rights legislation in Victoria and how this can assist a move in policy and practice towards a more positive and diffuse engagement with gender and sexual diversity.

Re-framing the riot : journalism, creative non-fiction and telling the story of Australia's black history

On 19 November 2004, an Aboriginal man was arrested on Palm Island, off the coast of Townsville in northern Queensland. He was taken to the local watch house on a drunk and disorderly charge. An hour later, he lay dead on a cell floor. His liver, an autopsy showed, had been split in half and his spleen ruptured. But when that autopsy report also found that Mulrunji Doomadgee’s severe injuries were not caused by force, the Palm Island Indigenous community, enraged and grief-stricken, went looking for payback.

The Palm Island “riots” ensured that this Aboriginal death in custody made international news headlines where others barely got a mention, if at all (Hollinsworth, 2005). The ensuing Coronial Inquest and criminal prosecution of the arresting Queensland police officer, Chris Hurley, also were covered consistently by the news media. Senior Sergeant Hurley has, however, so far escaped punishment and the Queensland media’s most recent report of the case was to tell how the Qld Police Union now funds a legal bid to clear his name. Meanwhile, little is heard in the news media of the Doomadgee family, the Palm Island community, or of other deaths in custody occurring steadily through the 18 years since the Royal Commission that was supposed to implement a raft of preventative recommendations.

While the news media’s framing of these issues has most often followed historically predictable and ultimately racist lines, a work of creative non-fiction tells the story with warranted complexity and power. Chloe Hooper’s The Tall Man: Death and Life on Palm Island documents Cameron Doomadgee’s death, the riots, and the ensuing legal farce from the front row. Hooper, in the tradition of Truman Capote, arrived at Palm Island as a white writer from a big city. But by “walking the talk” – being with the Doomadgee family and their community through the hearings and after, Hooper was given extraordinary access to community, history, and significant cultural nuance barely identified by, let alone understood by, non-Indigenous readers.

By focussing on Hooper’s experience with sources and court reporting, compared with some print media coverage, this paper will consider the comparative roles of journalism and creative non-fiction in re-framing the Palm Island “riot”. It will suggest that Hooper’s work subverts some dominant (and racist) news media representations of Australian Indigenous peoples through its use of source relationships in an extended narrative structure.

Client-reported reasons for non-engagement in drug and alcohol treatment

Introduction and Aims.To examine client-reported reasons for missed early appointments at a drug and alcohol treatment service and to compare characteristics of those who missed appointments with those who attended. Design and Methods. Clients who missed a first or second appointment between 1 May and 31 August 2007 at a public community-based outpatient treatment facility were invited to participate in a semistructured telephone interview.This consisted of an open-ended question asking the reason(s) for nonattendance, followed by a questionnaire of items for therapeutic alliance and service satisfaction, perceived impact of substance use and previous treatment experience, mostly rated on Likert scales. Database information on demographic and clinical variables was gathered for all clients who were accepted for treatment within the study time frame. Characteristics of those who missed a first or second appointment (n = 66) were compared with those who attended at least their first two appointments (n = 97). Results. Of clients who missed their appointments, 80.6% provided reasons for nonattendance, which included extraneous factors (50.0%), service shortcomings (29.7%), no further need for service (16.2%) and motivational ambivalence (4.1%). They generally had high ratings of therapeutic alliance and service satisfaction and identified their substance use as having a negative impact on their lives. Clients who missed appointments were more likely to be male, unmarried and have a history of polysubstance use. Discussion and Conclusions. Extraneous issues relating to the client may be a dominant obstacle in early treatment engagement. Efforts to overcome these issues may therefore improve early engagement.

Reduction in corticospinal inhibition in the trained and untrained limb following unilateral leg strength training

This study used transcranial magnetic stimulation to measure the corticospinal responses following 8 weeks of unilateral leg strength training. Eighteen healthy, non-strength trained participants (14 male, 4 female; 18–35 years of age) were matched for age, gender, and pre-training strength; and assigned to a training or control group. The trained group participated in unilateral horizontal leg press strength training, progressively overloaded and wave periodised, thrice per week for 8 weeks. Testing occurred prior to the intervention, at the end of 4 weeks and at the completion of training at 8 weeks. Participants were tested in both legs for one repetition maximum strength, muscle thickness, maximal electromyography (EMG) activity, and corticospinal excitability and inhibition. No changes were observed in muscle thickness in either leg. The trained leg showed an increase in strength of 21.2% (P = 0.001) and 29.0% (P = 0.007, compared to pre-testing) whilst the untrained contralateral leg showed 17.4% (P = 0.01) and 20.4% (P = 0.004, compared to pre-testing) increases in strength at 4 and 8 weeks, respectively. EMG and corticospinal excitability did not change; however, corticospinal inhibition was significantly reduced by 17.7 ms (P = 0.003) and 17.3 ms (P = 0.001) at 4 and 8 weeks, respectively, in the trained leg, and 25.1 ms (P = 0.001) and 20.8 ms (P = 0.001) at 4 and 8 weeks, respectively, in the contralateral untrained leg. This data support the theory of corticospinal adaptations underpinning cross-education gains in the lower limbs following unilateral strength training.

Monitoring food and non-alcoholic beverage promotions to children

Food and non-alcoholic beverage marketing is recognized as an important factor influencing food choices related to non-communicable diseases. The monitoring of populations' exposure to food and non-alcoholic beverage promotions, and the content of these promotions, is necessary to generate evidence to understand the extent of the problem, and to determine appropriate and effective policy responses. A review of studies measuring the nature and extent of exposure to food promotions was conducted to identify approaches to monitoring food promotions via dominant media platforms. A step-wise approach, comprising ‘minimal’, ‘expanded’ and ‘optimal’ monitoring activities, was designed. This approach can be used to assess the frequency and level of exposure of population groups (especially children) to food promotions, the persuasive power of techniques used in promotional communications (power of promotions) and the nutritional composition of promoted food products. Detailed procedures for data sampling, data collection and data analysis for a range of media types are presented, as well as quantifiable measurement indicators for assessing exposure to and power of food and non-alcoholic beverage promotions. The proposed framework supports the development of a consistent system for monitoring food and non-alcoholic beverage promotions for comparison between countries and over time.