16 research outputs found
Reliability of DXA for the measurement of total and regional body composition in elite soccer players
No full textReliability of DXA for the measurement of total and regional body composition in elite soccer players
Fanchini M, Guido Rillo, Mattias Bruni, Carwyn Sharp
AS Roma Football Club, Roma, ITA
University of Verona, Faculty of Exercise and Sport Science, ITA;
INTRODUCTION
Dual-energy X-ray absorptiometry (DXA) is widely used for the assessment of total and regional body composition. Acquisition of the data can be done automatically with the in-built software however the software may under/overestimate regional parameters (i.e. legs). As such, the data may also be acquired by operator manual adjustment of the regions-of-interest (ROI) but the experience of the operator may influence the accuracy and reliability. In elite football monitoring leg muscle mass is relevant therefore operator adjustment may be required. The aim of this study was to examine the reliability of total and regional body composition when comparing automatic and manual ROI assessment performed by operators with different experience levels.
METHODS
Twenty-four elite soccer players (age 18 ± 1 yrs; height 179 ± 5 cm; body mass 72 ± 5 kg) from an Italian Serie-A team participated in a test-retest study. Tests were performed with Lunar iDXA (GE Healthcare Lunar, Madison, USA) and examined with in-built software (enCORE 17, GE Medical Systems Ultrasound & Primary Care Diagnostics, USA) on two different days. Total body fat mass (FM) and free fat mass (FFM) were examined as total body composition, and free fat mass of right and left legs (FFMR and FFML) were examined as regional body composition parameters. ROI were determined automatically (AROI) and by two operators with low and high experience (Low1 and High1). After two weeks, the operators were asked to do the analysis again (Low2 and High2) on the same images. Reliability was examined as Typical Error of Measurement (expressed as percentage, TEM) and Intraclass Correlation Coefficient (ICC).
RESULTS
The values were within the range 9.7-10.2 kg for FM, 58.8-59.5 kg for FFM, 10.3-12.8 kg for FFMR and 10.2-12.7 kg for FFML. The TEMs were within the range 2.0-2.4% for FM and 0.8-0.9% for FFM for all the assessment. The TEMs for FFMR were 1.4, 4.1, 1.2, 1.6, 1.3 % for AROI, Low1, High1, Low2 and High2 respectively. The TEMs for FFML were 2.0, 3.9, 1.1, 1.3, 1.1 % for AROI, Low1, High1, Low2 and High2 respectively. Low1 showed higher values of TEM for FFMR and FFML.
The ICC were within the range 0.99-1.00 for FM, 0.82-0.98 for FFMR, 0.83-0.98 for FFML and 0.99 for FFM.
DISCUSSION
The reliability of total and regional body parameters found in the present group of elite soccer players was similar to the values reported in the literature (1, 2). No significant difference was found between reliability parameters in FM, FFM however the lowest reliability found in Low1 in FFMR and FFML suggested the low experience of the operator have influenced the DXA results in his first assessment. Even if operators are familiarized with ROI customization they need experience to provide reliable outcomes.
1. Hart NH, Nimphius S, Spiteri T, Cochrane JL, Newton RU. J Sports Sci Med, 2015, 14, 620-626
2. Bilsborough JC, Greenway K, Opar D, Livingstone S, Cordy J, Coutts AJ. J Sports Sci, 2014, 19, 1821-
Do non-contact injuries occur during high-speed running in elite football? Preliminary results from a new GPS and video-based method
No full textObjectivesUnderstanding how injuries occur (inciting circumstances) is useful for developing etiological hypotheses and prevention strategies that can be tested. The aims of this study were 1) to evaluate the feasibility of a method combining video and GPS data to estimate the speed and acceleration of activities leading to injuries; 2) to use this method to analyse the inciting circumstances leading to non-contact injuries in football players.DesignRetrospective descriptive study.MethodsData collected from 46 elite players over three seasons are included. Training and matches were video recorded and external load measures were collected through Catapult Vector S7 GPS. Injury nciting circumstances were analysed through GPS measures and visual inspection.ResultsIn total 34 non-contact injuries were analysed. Sixteen out of the seventeen hamstring injuries occurred when players were running for (median and IQR) 16.75 m (8.42–26.65 m), achieved a peak speed of 29.28 km·h−1 (26.61–31.13 km·h−1) which corresponded to 87.55% of players' maximal speed (78.5% - 89.75%). Of the three adductor injuries, one occurred while the player was decelerating without the ball, one injury occurred while the player was accelerating and controlling the ball at knee level, and one injury occurred while the player was performing an instep kick. Two quadriceps injuries occurred while the players were kicking either while walking or while running.ConclusionsFrom the preliminary results reported in this study most hamstring injuries occurred when players ran > 25 km·h−1 and above 80% of their maximal speed. This study suggests that this novel approach can allow a detailed and standardised analysis of injury inciting circumstances
The response of intracellular signaling and muscle-protein metabolism to nutrition and exercise
No full textIn recent years, a body of literature examining the response of muscle-protein metabolism to exercise and nutrition has arisen. Developments in methods, especially stable isotopic tracer methodology, have allowed much information to be gathered in vivo in humans. The metabolic mechanism behind increased muscle mass requires that muscle-protein synthesis exceeds breakdown, i.e., net muscle-protein synthesis. Increased net muscle-protein balance may occur due to exercise, but net synthesis may occur only with the addition of nutrients, particularly a source of amino acids. The major impact of increased amino acid availability on net muscle-protein balance is due to stimulation of muscle-protein synthesis and less to inhibition of muscle-protein breakdown. Amino acids seem to stimulate muscle-protein synthesis, not only by mass action, i.e., providing substrate, but also as signals for initiation of protein synthesis. Stimulation of muscle-protein synthesis by amino acid ingestion may be linked to increased intracellular amino acid levels and/or to changing amino acid levels in the blood. Carbohydrate ingestion, most likely through the action of insulin, also may play a role in the response of muscle to exercise and nutrition. There is very little research in humans in vivo on the intracellular signaling that is linked to muscle-protein synthesis. It is clear that intracellular signaling responds to both insulin and amino acids, but the interactions with exercise are not well known; however, the details of the pathways have only just begun to be investigated, especially in humans. Delineation of these pathways is complicated, and there is little doubt that multiple intracellular signaling pathways with several levels of communication are involved in the hypertrophy process in response to nutrition and exercise. A systematic investigation of the relationship of the signaling to insulin and amino acids combined with exercise will provide important information, especially for populations vulnerable to muscle loss
The effect of branched-chain amino acid supplementation Rebuild II [TM], on cortisol levels in healthy resistance trained males
No full textComputer-mediated communication [CMC] is beginning to be used more frequently in traditional classrooms. A group of physical chemistry professors have developed Physical Chemistry On-Line [PCOL] modules designed to augment in-class instruction and engage students at geographically dispersed institutions in activities to help them learn physical chemistry concepts. These modules use context-rich scenarios with a guided-inquiry approach, and the WWW and e-mail for information distribution and communication. This allows for intra- and inter-institutional collaboration between module participants. Three modules implemented during the Fall 2000 term are evaluated in this study. In order to assess the effectiveness of PCOL, each student completed a pre-module and post-module survey, pre-module and post-module content questions, and participated in an online discussion group. The primary focus of this analysis was to determine the student's: 1) perception of on-line activities, 2) perception of on-line interactions, and 3) use of computers.Thesis (M.S.)School of Physical Educatio
Males Coaching Female Athletes
No full textThe author Mariah Burton-Nelson (2002) revealed that, as an adolescent athlete, she was the victim of sexual harassment and statutory rape perpetrated by her coach...Burton-Nelson's honesty provides a launching pad for this chapter, because it exhibits two important factors about the male coach-female athlete relationship. The first, that male coaches have been perpetrators of sexual harassment and abuse against female athletes of all ages, has been widely researched. The second, that consensual sexual relationships have occurred between adult coaches and adult athletes, has largely been ignored in the sports ethics literature
Dark chocolate intake positively modulates gut permeability in elite football athletes. A randomized controlled study
No full text: Gut barrier disruption can lead to enhanced intestinal permeability, which allows endotoxins, pathogens, and other proinflammatory substances to move through the intestinal barrier into circulation. Intense exercise over a prolonged period increases intestinal permeability, which can be further worsened by the increased production of reactive oxygen species (ROS) and pro-inflammatory cytokines. The aim of this study was to assess the degree of intestinal permeability in elite football players and to exploit the effect of cocoa polyphenols on intestinal permeability induced by intensive physical exercise. Biomarkers of intestinal permeability, such as circulating levels of zonulin, a modulator of tight junctions, occludin, a tight junction protein, and LPS translocation, were evaluated in 24 elite football players and 23 amateur athletes. Moreover, 24 elite football players were randomly assigned to either a dark chocolate (>85% cocoa) intake (n = 12) or a control group (n = 12) for 30 days in a randomized controlled trial. Biochemical analyses were performed at baseline and after 30 days of chocolate intake. Compared to amateur athletes, elite football players showed increased intestinal permeability as indicated by higher levels of zonulin, occludin, and LPS. After 30 days of dark chocolate intake, decreased intestinal permeability was found in elite athletes consuming dark chocolate. In the control group, no changes were observed. In vitro, polyphenol extracts significantly improved intestinal damage in the human intestinal mucosa cell line Caco-2. These results indicate that chronic supplementation with dark chocolate as a rich source of polyphenols positively modulates exercise-induced intestinal damage in elite football athletes
Exer-Genie(Registered Trademark) Exercise Device Hardware Evaluation
No full textAn engineering evaluation was performed on the ExerGenie(r) exercise device to quantify its capabilities and limitations to address questions from the Constellation Program. Three subjects performed rowing and circuit training sessions to assess the suitability of the device for aerobic exercise. Three subjects performed a resistive exercise session to assess the suitability of the device for resistive exercise. Since 1 subject performed both aerobic and resistive exercise sessions, a total of 5 subjects participated
Hardware Evaluation of the Horizontal Exercise Fixture with Weight Stack
No full textHEF with weight stack seems to be a very sturdy and reliable exercise device that should function well in a bed rest training setting. A few improvements should be made to both the hardware and software to improve usage efficiency, but largely, this evaluation has demonstrated HEF's robustness. The hardware offers loading to muscles, bones, and joints, potentially sufficient to mitigate the loss of muscle mass and bone mineral density during long-duration bed rest campaigns. With some minor modifications, the HEF with weight stack equipment provides the best currently available means of performing squat, heel raise, prone row, bench press, and hip flexion/extension exercise in a supine orientation
Ancillary care duties: the demands of justice
No full textAncillary care is care that research participants need that is not essential to make the research safe or scientifically valid and is not needed to remedy injuries that eventuate as a result of the research project itself. Ancillary care duties have recently been defended on the grounds of beneficence, entrustment, utility and consent. Justice has also been mentioned as a possible basis of ancillary care duties, but little attention has been paid to this approach. In this paper, the author seeks to rectify this omission by arguing that ancillary care duties can be based on a principle of justice as rectification
