Showing papers in "International Journal of Sports Medicine in 2017"

Standards for Ethics in Sport and Exercise Science Research: 2018 Update

Abstract: For publication in the International Journal of Sports Medicine (IJSM), studies involving human participants or animals must have been conducted in accordance with recognised ethical standards and national/international laws. At the very first stage of paper submission, authors are required to adhere to these and all other relevant standards and laws. In the 21st Century, research opportunities, approaches and environments are in a continual state of flux, and this is also the case for the associated ethical issues. In the original 2009 IJSM editorial [2], we described the ethical considerations embedded into national/international laws and provided specific guidance on the ethical issues which commonly arise in Sports Medicine research. In 2011, this information was updated to recognise the ethical principles of other professional associations and treaties when conducting research involving human participants [3]. Additional information was also provided on the use of Laboratory Animals in research, and on the links between sample size and research ethics. In the second update, published in 2013, we elaborated on the ethical issues relating to the investigation of doping agents; the use of animals for answering research questions that appear to be solely focussed on the enhancement of athletic performance; and sample size in the context of the burden to individual research participants [4]. In 2015, we updated some of the guidelines to account for the changes made to the Declaration of Helsinki in 2013, covered the use of social media in research, provided guidance on how researchers can feed back their incidental and pertinent findings to research participants, covered some of the issues relating to studies involving children, and outlined the difference between a full and pilot study in terms of desired number of participants [5]. In this, our new update for 2018 onwards, we provide the following revisions and additions, labelled with the word “Update” in bold text at various points in this paper; ▪ Clarification of the issues surrounding the use of a gatekeeper for accessing personal information on participants. ▪ Clarification of some of the requirements for research with participants who are either too young to give a valid consent (under relevant local Statute) themselves and/or who lack the mental capacity to give an informed consent. ▪ Clarification of the expectations for the presentation and content of information given to facilitate informed consent/ assent. ▪ Highlighting of the obligation to breach confidentiality in certain circumstances and the importance of communicating all relevant process to the potential participant. ▪ Clarification on the use of person identifiable information including a reminder of the upcoming (May 2018) changes to legislation governing how personal data may be accessed and processed in research in the European Union (https://www. eugdpr.org/). ▪ Provision of advice surrounding the increasing calls for open access data, including the resulting data storage issues. ▪ Update on the ethical and legal considerations involved in secondary analysis (retrospective data) studies. ▪ Clarification on the use of placebos in research. ▪ Coverage of the expectations for studies that involve participant deception (i. e. where fully informed consent is not obtained in advance of participation). ▪ Elaboration of the sample size issues relevant to research ethics. Harriss DJ et al. Standards for Ethics in ... Int J Sports Med 2017; 00: 00–00

Velocity Loss as a Variable for Monitoring Resistance Exercise.

Abstract: This study aimed to analyze: 1) the pattern of repetition velocity decline during a single set to failure against different submaximal loads (50–85% 1RM) in the bench press exercise; and 2) the reliability of the percentage of performed repetitions, with respect to the maximum possible number that can be completed, when different magnitudes of velocity loss have been reached within each set. Twenty-two men performed 8 tests of maximum number of repetitions (MNR) against loads of 50–55–60–65–70–75–80–85% 1RM, in random order, every 6–7 days. Another 28 men performed 2 separate MNR tests against 60% 1RM. A very close relationship was found between the relative loss of velocity in a set and the percentage of performed repetitions. This relationship was very similar for all loads, but particularly for 50–70% 1RM, even though the number of repetitions completed at each load was significantly different. Moreover, the percentage of performed repetitions for a given velocity loss showed a high absolute reliability. Equations to predict the percentage of performed repetitions from relative velocity loss are provided. By monitoring repetition velocity and using these equations, one can estimate, with considerable precision, how many repetitions are left in reserve in a bench press exercise set.

Relative Age, Maturation and Physical Biases on Position Allocation in Elite-Youth Soccer

Abstract: This study assessed the contribution of relative age, anthropometry, maturation, and physical fitness characteristics on soccer playing position (goalkeeper [GK], central-defender [CD], lateral-defender [LD], central-midfield [CM], lateral-midfielder [LM], and forward [FWD]) for 465 elite-youth players (U13–U18’s). U13–14 CD were relatively older than LD and CM (likely small effects). CD and GK were generally taller and heavier (likely small to very-likely moderate effects) than other players at each developmental stage and were advanced maturers at U13–14 (very-likely small to likely moderate effects). GK had inferior agility (very-likely small to likely moderate effects), endurance (very-likely small to likely moderate effects), and sprint capacities (likely small-moderate effects) vs. outfield positions at U13–14, but deficits in anaerobic phenotypes were diminished in U15–16 and U17–18. Position specific fitness characteristics were distinguished at U15–16 (likely small) and U17–18 (likely moderate), where LM were faster than their central counterparts. In summary, relative age, maturation and anthropometric characteristics appear to bias the allocation of players into key defensive roles from an early development stage, whereas position-specific physical attributes do not become apparent until the latter stages of talent development in outfield players. Given the inter-individual trajectories of physical development according to biological maturation, playing position allocation might be considered ‘plastic’ by selectors, until complete-maturity is achieved.

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling.

Abstract: The aim of this study was to compare the accuracy among a high number of current mobile cycling power meters used by elite and recreational cyclists against a first principle-based mathematical model of treadmill cycling. 54 power meters from 9 manufacturers used by 32 cyclists were calibrated. While the cyclist coasted downhill on a motorised treadmill, a back-pulling system was adjusted to counter the downhill force. The system was then loaded 3 times with 4 different masses while the cyclist pedalled to keep his position. The mean deviation (trueness) to the model and coefficient of variation (precision) were analysed. The mean deviations of the power meters were –0.9±3.2% (mean±SD) with 6 power meters deviating by more than±5%. The coefficients of variation of the power meters were 1.2±0.9% (mean±SD), with Stages varying more than SRM (p

Performance Factors in a Mountain Ultramarathon

Abstract: This study aimed to determine mountain ultra-marathon (MUM) performance factors in a large group of endurance mountain runners. Maximal aerobic speed (MAS) was assessed one week prior to the MUM. The level and graded (10%) energy cost of running, stiffness, knee extensors force (KEf), and jump height on a counter movement jump (CMJ) were measured in 24 male ultra runners before (pre) and immediately after (post) the Interlacs Trail (75 km and 3 930/3 700 m d+/d-). Performance time was correlated with MAS (r=- 0.74, p<0.001), fraction of MAS (FMAS) sustained (r=- 0.89, p<0.001), KEf (r=- 0.51, p<0.05), and KEf loss (r=- 0.51, p<0.05). A multiple regression analysis was performed using performance time in minutes (T) and the calculated individual characteristics, resulting in T=- 11.852×FMAS-37.195×MAS-0.118×KEf+2090.581 (R2=0.98, with 95% confidence interval). Contrary to expectations, performance was neither correlated to the level or uphill energy cost of running nor to the changes of these costs post-MUM. To perform in a MUM, training should take into account muscle strength of the KE, MAS and FMAS.

Multiple Measures are Needed to Quantify Training Loads in Professional Rugby League

Abstract: This study aims to investigate the effect of training mode (conditioning and skills) on multivariate training load relationships in professional rugby league via principal component analysis. Four measures of training load (internal: heart rate exertion index, session rating of perceived exertion; external: PlayerLoad™, individualised high-speed distance) were collected from 23 professional male rugby league players over the course of one 12 wk preseason period. Training was categorised by mode (skills or conditioning) and then subjected to a principal component analysis. Extraction criteria were set at an eigenvalue of greater than 1. Modes that extracted more than 1 principal component were subject to a varimax rotation. Skills extracted 1 principal component, explaining 57% of the variance. Conditioning extracted 2 principal components (1st: internal; 2nd: external), explaining 85% of the variance. The presence of multiple training load dimensions (principal components) during conditioning training provides further evidence of the influence of training mode on the ability of individual measures of external or internal training load to capture training variance. Consequently, a combination of internal and external training-load measures is required during certain training modes.

Whole-body Cryotherapy as a Recovery Technique after Exercise: A Review of the Literature.

Abstract: This review aims to evaluate the current body of literature investigating the effect of whole body cryotherapy on recovery after exercise. A systematic search was conducted to investigate the effect of whole body cryotherapy (WBC, exposure to temperatures between −110 to −190°C) on markers of recovery after damaging exercise in healthy, physically active subjects. Of the 16 eligible articles extracted, ten induced muscle damage using controlled exercise in a laboratory setting, while six induced damage during sport-specific training. Results indicated that muscle pain was reduced in 80% of studies following WBC. Two applied studies found recovery of athletic capacity and performance with WBC improved, variables of this nature were also improved in 71% of studies using controlled exercise. Further benefits of WBC treatment included reduction of systemic inflammation and lower concentrations of markers for muscle cell damage. These results suggest that WBC may improve recovery from muscle damage, with multiple exposures more consistently exhibiting improvements in recovery from pain, loss of muscle function, and markers of inflammation and damage. The diversity in muscle damage protocols, exposure timing with regards to exercise, as well as temperatures, duration and frequencies of exposure, make specific recommendations preliminary at present.

Is lower hip range of motion a risk factor for groin pain in athletes? : A systematic review with clinical applications

Abstract: BACKGROUND: Whether hip range of motion (ROM) is a risk factor for groin pain in athletes is not known OBJECTIVES: To systematically review the relationship between hip ROM and groin pain in athletes in cross-sectional/case-control and prospective studies STUDY DESIGN: Systematic review, prospectively registered (PROSPERO) according to PRISMA guidelines METHODS: Pubmed, Embase, CINAHL and SPORTDiscus were systematically searched up to December 2015 Two authors performed study selection, data extraction/analysis, quality assessment (Critical Appraisal Skills Programme) and strength of evidence synthesis RESULTS: We identified seven prospective and four case-control studies The total quality score ranged from 29% to 92% Heterogeneity in groin pain classification, injury definitions and physical assessment precluded data pooling There was strong evidence that total rotation of both hips below 85° measured at the pre-season screening was a risk factor for groin pain development Strong evidence suggested that internal rotation, abduction and extension were not associated with the risk or presence of groin pain CONCLUSION: Total hip ROM is the factor most consistently related to groin pain in athletes Screening for hip ROM is unlikely to correctly identify an athlete at risk of developing groin pain because of the small ROM differences found and poor ROM measurement properties

Urinary Incontinence in Physically Active Young Women: Prevalence and Related Factors

Abstract: This cross-sectional survey aims to (1) verify the prevalence of urinary incontinence and its impact on the quality of life among nulliparous fit women, and to (2) analyze whether urinary incontinence is influenced by the intensity of the sport (high- vs. low-impact) or by the volume of physical activity (minutes per week) performed. Two hundred forty-five nulliparous women (18–40 years) completed the International Consultation on Incontinence Questionnaire-Short Form, the Kings Health Questionnaire and a questionnaire regarding demographic and training variables. Overall 22.9% of the participants self-reported urinary incontinence, and among them, 60.7% had stress urinary incontinence. Incontinent women demonstrated worse quality of life than continent females (p=0.000). Women practicing high-impact sports presented higher frequency in loss of urine than those practicing low-impact sports (p=0.004). Regardless the intensity of the sport, the volume of exercise showed positive association with the frequency of loss of urine (p=0.005, r=0.475). In conclusion, almost one fourth of the women enrolled in this study reported symptoms of urinary incontinence and worse quality of life than those who were continent. Women who practice high-impact sports or who have higher volume of training should be aware of the symptoms associated with pelvic floor dysfunction, since they seem to predispose to urine leakage.

The Cardiovascular and Perceptual Response to Very Low Load Blood Flow Restricted Exercise.

Abstract: This study sought to compare cardiovascular and perceptual responses to blood flow restriction (BFR) exercise using various pressure and load combinations. Fourteen participants completed four sets of BFR elbow flexion using 10, 15 and 20% 1RM with 40 and 80% arterial occlusion pressure (AOP). AOP was measured before and after exercise. Perceived exertion (RPE) and discomfort were assessed before exercise and after each set. Data presented as mean (95% CI), except for RPE and discomfort: 25th, 50th, 75th percentiles. AOP increased post-exercise (p

Effects of Plyometric Training on Physical Fitness in Prepuberal Soccer Athletes.

Abstract: This study aimed at examining the effects of plyometric training on stable (SPT) vs. unstable (UPT) surfaces on physical fitness in prepuberal soccer players. Male athletes were randomly assigned to SPT (n=18; age=12.7±0.2 years) or UPT (n=16; age=12.2±0.5 years). Both groups conducted 3 regular soccer training sessions per week combined with either 2 SPT or UPT sessions. Assessment of jumping ability (countermovement jump [CMJ], and standing long jump [SLJ]), speed (10-m, 20-m, 30-m sprint), agility (Illinois agility test [IAT]), and balance (stable [SSBT], unstable [USBT] stork balance test; stable [SYBT], unstable [UYBT] Y balance test) was conducted pre-and post-training. An ANCOVA model was used to test for between-group differences (SPT vs. UPT) at post-test using baseline values as covariates. No significant differences were found for CMJ height (p>0.05, d=0.54), SLJ (p>0.05; d=0.81), 10-m, 20-m, and 30-m sprint performances (p>0.05, d=0.00–0.24), IAT (p>0.05, d=0.48), and dynamic balance (SYBT and UYBT, both p>0.05, d=0.39, 0.08, respectively). Statistically significant between-group differences were detected for the USBT (p

The Force-Velocity Relationship in Older People: Reliability and Validity of a Systematic Procedure

Abstract: This study compared the reliability and validity of different protocols evaluating the force-velocity (F-V) relationship and muscle power in older adults. Thirty-one older men and women (75.8±4.7 years) underwent two F-V tests by collecting the mean and peak force and velocity data exerted against increasing loads until one repetition maximum (1RM) was achieved in the leg press exercise. Two attempts per load were performed, with a third attempt when F-V points deviated from the linear F-V regression equation. Then, the subjects performed 2×3 repetitions at 60% 1RM to compare purely concentric and eccentric-concentric repetitions. The Short Physical Performance Battery was conducted to assess the validity of the different protocols. Significant differences were found in maximal power (Pmax) between mean and peak values and between protocols differing in the number of attempts per load (p 3), was significantly more reliable (Pmax: CV=2.6%; ICC=0.99) than the other alternatives. Mean values were also observed to be more associated with physical function than peak values (R2=0.34 and 0.15, respectively; p

Effects of HRV-Guided vs. Predetermined Block Training on Performance, HRV and Serum Hormones.

Abstract: The aim of this study was to compare heart rate variability -guided (HRVG) and predetermined (PD) block periodization of high intensity aerobic training (HIT) Endurance performance, neuromuscular performance, heart rate variability (HRV) and serum hormone concentrations were measured before, in the middle and after the 8-week training period in 24 endurance trained males Both groups improved significantly maximal treadmill velocity (Vmax) (p

Maximal Fat Oxidation is Related to Performance in an Ironman Triathlon.

Abstract: The aim of the present study was to investigate the relationship between maximal fat oxidation rate (MFO) measured during a progressive exercise test on a cycle ergometer and ultra-endurance performance. 61 male ironman athletes (age: 35±1 yrs. [23–47 yrs.], with a BMI of 23.6±0.3 kg/m2 [20.0–30.1 kg/m2], a body fat percentage of 16.7±0.7% [8.4–30.7%] and a VO2peak of 58.7±0.7 ml/min/kg [43.9–72.5 ml/min/kg] SEM [Range]) were tested in the laboratory between 25 and 4 days prior to the ultra-endurance event, 2016 Ironman Copenhagen. Simple bivariate analyses revealed significant negative correlations between race time and MFO (r2=0.12, p 9 h). Furthermore, we demonstrate that 50% of the variation in Ironman triathlon race time can be explained by peak oxygen uptake and maximal fat oxidation.

Foot Strike Patterns Differ Between Children and Adolescents Growing up Barefoot vs. Shod.

Abstract: Effects of early and permanent footwear use are not well understood. The aim of this study was to investigate the effects of habituation to footwear on foot strike patterns of children and adolescents. Healthy habitually barefoot and shod participants (aged 6–18 years) from South Africa (n=288) and Germany (n=390) performed multiple 20-m jogging and running trials with and without shoes. Each foot strike was captured using a high-speed camera to determine a rearfoot or non-rearfoot strike. The probability of a rearfoot strike in both cohorts and each age was analyzed by using a mixed-effects logistic regression adjusted for possible confounders. Habitually barefoot children showed a higher probability of using rearfoot strikes than habitually shod children (p

Contributions of Hamstring Stiffness to Straight-Leg-Raise and Sit-and-Reach Test Scores.

Abstract: The passive straight-leg-raise (PSLR) and the sit-and-reach (SR) tests have been widely used to assess hamstring extensibility. However, it remains unclear to what extent hamstring stiffness (a measure of material properties) contributes to PSLR and SR test scores. Therefore, we aimed to clarify the relationship between hamstring stiffness and PSLR and SR scores using ultrasound shear wave elastography. Ninety-eight healthy subjects completed the study. Each subject completed PSLR testing, and classic and modified SR testing of the right leg. Muscle shear modulus of the biceps femoris, semitendinosus, and semimembranosus was quantified as an index of muscle stiffness. The relationships between shear modulus of each muscle and PSLR or SR scores were calculated using Pearson’s product-moment correlation coefficients. Shear modulus of the semitendinosus and semimembranosus showed negative correlations with the two PSLR and two SR scores (absolute r value≤0.484). Shear modulus of the biceps femoris was significantly correlated with the PSLR score determined by the examiner and the modified SR score (absolute r value≤0.308). The present findings suggest that PSLR and SR test scores are strongly influenced by factors other than hamstring stiffness and therefore might not accurately evaluate hamstring stiffness.

Functional Screening Tests: Interrelationships and Ability to Predict Vertical Jump Performance.

Abstract: There are several methods used in sports science to identify asymmetries in athletes, given their purported relevance to injury prevention and performance optimization. We aimed to verify whether asymmetries provided by isokinetic assessments, jump tests, and tensiomyography (TMG) are associated with each other, and whether their respective functional indices are related to jumping ability. TMG parameters, unilateral and bilateral squat-jump (SJ) and countermovement-jump (CMJ) performances, and peak torque in knee-extension and flexion with angular velocities of 60o/s and 300o/s for twenty-four soccer players were retained for analyses. Asymmetry was detected by examining the percentage difference between dominant and non-dominant legs. The median-split technique was used to identify the best and worst performers in SJ and CMJ tests. Results revealed that the asymmetries detected in the three different methods were not interrelated. Curiously, better performances in SJ and CMJ tests were associated with higher asymmetry levels. Furthermore, only the knee-extension peak torque at both angular velocities was correlated moderately to largely (r=0.48-0.66) with jump performance. Despite their recognized ability to predict the risk of injury, the absence of interrelationships between TMG, isokinetic tests, and unilateral jumps precludes their single use as a unique functional screening diagnostic. Finally, and very importantly, lower-limb asymmetry is not necessarily related to impaired vertical jump performance in soccer players.

Training Effects of the FIFA 11+ and Harmoknee on Several Neuromuscular Parameters of Physical Performance Measures.

Abstract: The main purpose of this study was to analyse the training effects of the FIFA 11+ and Harmoknee on several parameters of physical performance measures in youth amateur football players. 41 adolescent players were randomised within each team into 2 groups (team 1: control vs. FIFA 11+; team 2: control vs. Harmoknee). The FIFA 11+ and Harmoknee groups performed the program 3 times a week for 4 weeks; the control groups completed their usual warm-up routines. 13 physical performance measures (joint range of motion, dynamic postural control, single legged hop limb symmetry, sprint time, jumping height and agility) were assessed. All physical performance parameters were compared via a magnitude-based inference analysis. Significant between-group differences (in favour of the FIFA 11+ players) were found for dynamic postural control (anterior [2.5%] and posteromedial [7.2%] distances), single legged hop limb symmetry (side-to-side symmetry during a triple hop test [8.3%]), 10 (8.4%) and 20 (1.8%) m sprint times and jumping height (9.1%) neuromuscular outcomes. For the Harmoknee, significant differences (in comparison to its paired control group) were found only for 10 (2.7%) and 20 (2.9%) m sprint times and jumping height (9.7%). Therefore, the main findings of this study suggest exchanging traditional warm-up programmes for the FIFA 11+ in male youth soccer players based on its superior effects on some neuromuscular parameters (sprinting, jumping and stability) of physical performance.

Association of Step Width with Accelerated Sprinting Performance and Ground Reaction Force.

Abstract: This study aimed to describe changes in step width (SW) during accelerated sprinting, and to clarify the relationship of SW with sprinting performance and ground reaction forces. 17 male athletes performed maximal-effort 60 m sprints. The SW and other spatiotemporal variables, as well as ground reaction impulses, over a 52 m distance were calculated. Average values for each 4 steps during acceleration were calculated to examine relationships among variables in different sections. The SW rapidly decreased up to the 13th step and slightly afterward during accelerated sprinting, showing a bilinear phase profile. The ratio of SW to the stature was significantly correlated with running speed based on average values over the 52 m distance and in the 9th–12th step section during accelerated sprinting. The SW ratio positively correlated with medial, lateral and mediolateral impulses in all step sections, except for medial impulse in the 17th–20th step section. These results indicate the importance of wider SW for better sprinting performance, especially in the 9th–12th step section. Moreover, the wider SW was associated with larger medial impulse and smaller lateral impulse, suggesting that a wide SW contributes to the production of greater mediolateral body velocity during accelerated sprinting.

Energy Systems Contribution in the Running-based Anaerobic Sprint Test.

Abstract: The aims of the present study were to verify the contributions of the energy systems during repeated sprints with a short recovery time and the associations of the time- and power-performance of repeated sprints with energetic contributions and aerobic and anaerobic variables. 13 healthy men performed the running-based anaerobic sprint test (RAST) followed by an incremental protocol for lactate minimum intensity determination. During the RAST, the net energy system was estimated using the oxygen consumption and the blood lactate responses. The relative contributions of oxidative phosphorylation, glycolytic, and phosphagen pathways were 38, 34, and 28%, respectively. The contribution of the oxidative pathway increased significantly during RAST especially from the third sprint, at the same time that power- and time-performances decreases significantly. The phosphagen pathway was associated with power-performance (peak power=432±107 W, r=0.65; mean power=325±80 W, r=0.65; minimum power=241±77 W, r=0.57; force impulse=1 846±478 N·s, r=0.74; p +0.65; p 0.58; p

Dynamic Expression and the Role of BDNF in Exercise-induced Skeletal Muscle Regeneration.

Abstract: Brain-derived neurotrophic factor (BDNF) is a myokine. However, its role in skeletal muscle has not been well elucidated. In this study, we aimed to investigate its expression profile in skeletal muscle following downhill running and to explore its functions. Male Sprague Dawley rats were assigned to sedentary and downhill running groups. Tail vein blood, total mRNA and protein from soleus muscle was obtained from rats at different time points post-exercise (1d, 3d, 5d, 7d and 14d). We found a significant elevation of BDNF mRNA level 5d and 7d post-exercise (p

Forced Retirement from Professional Rugby Union is Associated with Symptoms of Distress.

Abstract: Rugby has a higher injury burden than other popular sports, such as football Athletes who are forced to retire as a result of injury are associated with poor mental health With its high injury burden, professional rugby players might be at risk of mental health conditions associated with injury-related forced retirement This study aimed to compare mental health between former professional rugby players who were and weren't forced to retire A questionnaire including the 4DSQ (distress), GHQ-12 (anxiety/depression), PROMIS short-form (sleep disturbance) and AUDIT-C (alcohol misuse) was completed by retired professional players from Ireland, France and South Africa The questionnaire asked players whether or not they were forced to retire, as well as the reason for retirement Players forced to retire were more than twice as likely to report symptoms of distress in comparison to those that retired voluntarily (odds ratio: 21, 95% confidence interval: 12-36, p<0001) None of the other mental health measures (anxiety/depression, sleep disturbance or alcohol misuse) were associated with forced retirement In conclusion, rugby players that were forced to retire may require support structures and longitudinal monitoring Future studies should begin monitoring players during their careers to accurately assess the effect of retirement on mental health

Thermoregulatory responses during competitive wheelchair rugby match play

Abstract: The purpose of this study was to determine whether a player’s physical impairment or activity profile was related to the amount of thermal strain experienced during wheelchair rugby match play. 17 elite wheelchair rugby players played a competitive match, whilst activity profiles, measures of core and skin temperature, heart rate and perceptual responses were taken. Players were divided into 2 groups depending on their physical impairment: players with a cervical spinal cord injury, (n=10) or non-spinal related physical impairment (n=7). Total distance was lower (4 842±324 vs. 5 541±316 m, p

Effect of Melatonin Supplementation on Antioxidant Status and DNA Damage in High Intensity Trained Athletes

Abstract: The aim of the study was to evaluate the effect of melatonin supplementation on antioxidant capacity and DNA damage in high intensity interval training (HIIT) athletes. A 2-week randomised, double-blinded, placebo-controlled trial with two groups was conducted. Placebo (PG) and melatonin (MG) (20 mg/d) athletes were monitored over a two-week period of HIIT and strength training. The total antioxidant capacity (TAC) and the glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were analysed in blood samples. DNA damage was measured in isolated lymphocytes by comet assay prior to and immediately after exercise. The supplementation increased plasma melatonin levels in the melatonin-treated group (p

MR Spectroscopy Findings in Retired Professional Rugby League Players.

Abstract: The aim of this study was to examine brain neurometabolite concentrations in retired rugby league players who had a history of numerous self-reported concussions. Participants were 16 retired professional rugby league players (ages 30-45 years) with an extensive history of concussion and participation in contact sports, and 16 age- and education-matched controls who had no history of neurotrauma or participation in contact sports. All completed a clinical interview, psychological and cognitive testing, and magnetic resonance spectroscopy (MRS) investigation. MRS voxels were placed in posterior cingulate grey matter and parietal white matter. Neurometabolite concentrations were quantified using LCModel. It was hypothesized that retired athletes would differ on N-acetyl aspartate, myo-inositol, choline, glutamate, and glutathione. Retired players had significantly lower concentrations of grey matter glutathione (p=0.02, d=0.91). They did not significantly differ in concentrations of other neurometabolites. There were no significant differences between groups on measures of depression, anxiety, or cognitive functioning. The retired athletes reported significantly greater alcohol use (p<0.01; Cohen's d=1.49), and they had worse manual dexterity using their non-dominant hand (p=0.03; d=1.08). These preliminary findings suggest that MRS might be modestly sensitive to biochemical differences in athletes after their athletic careers have ended in the absence of clinical differences in cognitive performance and self-reported psychological functioning.

Prevalence of Urinary Incontinence in Females Performing High-Impact Exercises.

Abstract: The aim of this cross-sectional study was to monitor the prevalence of symptoms of stress (SUI) and mixed urinary incontinence (MUI) in sportswomen performing high-impact exercises. A further objective was to compare the symptoms of urinary incontinence (UI) and quality of life in sportswomen. We used the International Consultation on Incontinence Questionnaire (ICIQ-SF), the Overactive Bladder Questionnaire (OAB-q), the Urinary Incontinence Quality of Life Scale (I-QOL) and the International Physical Activity Questionnaire (IPAQ), short version. The group consisted of 503 sportswomen with a mean age of 21.1±3.6. The response rate was 71.15%. ICIQ-SF results confirmed mild difficulties with urine leakage in 72 (14.3%) sportswomen. Urinary leakage was not noted in 431 (85.7%) sportswomen. The OAB-q and I-QOL showed a significant difference, with pronounced symptoms of UUI and worse QOL in the group of sportswomen with urine leakage (p<0.000). The I-QOL recorded significantly worse parameters in the group of sportswomen with urine leakage (p<0.000). Prevalence of SUI was found in 68 (13.52%), and MUI was found in 4 (0.80%) sportswomen. Every seventh sportswoman (14.3%) in the study group had reported problems with UI when practising high-impact sporting activities, with a negative impact on QOL.

Jump Squat is More Related to Sprinting and Jumping Abilities than Olympic Push Press.

Abstract: The aim of this study was to test the relationships between jump squat (JS) and Olympic push press (OPP) power outputs and performance in sprint, squat jump (SJ), countermovement jump (CMJ) and change of direction (COD) speed tests in elite soccer players. 27 athletes performed a maximum power load test to determine their bar mean propulsive power (MPP) and bar mean propulsive velocity (MPV) in the JS and OPP exercises. Magnitude-based inference was used to compare the exercises. The MPV was almost certainly higher in the OPP than in the JS. The MPP relative to body mass (MPP REL) was possibly higher in the OPP. Only the JS MPP REL presented very large correlations with linear speed (r>0.7, for speed in 5, 10, 20 and 30 m) and vertical jumping abilities (r>0.8, for SJ and CMJ), and moderate correlation with COD speed (r=0.45). Although significant (except for COD), the associations between OPP outcomes and field-based measurements (speed, SJ and CMJ) were all moderate, ranging from 0.40 to 0.48. In a group composed of elite soccer players, the JS exercise is more associated with jumping and sprinting abilities than the OPP. Longitudinal studies are needed to confirm if these strong relationships imply superior training effects in favor of the JS exercise.

Longer Telomere Length in Elite Master Sprinters: Relationship to Performance and Body Composition.

Abstract: Emergent evidence suggests that the long-term healthy lifestyle of master athletes may attenuate aging. We compared telomere length (TL) of high-level master sprinters and non-athlete age-matched controls, and analyzed the relationships of TL with performance and body fat. Elite master sprinters (n=11; aged 50.1±9.2yrs) and healthy untrained controls (n=10; aged 45.4±10.9yrs) had blood samples collected for biochemical and biomolecular analyses. Master sprinters had longer TL, lower body fat and BMI, and a better lipid profile than age-matched controls (p<0.05). A large effect size was verified comparing TL between athletes vs. controls (Cohen's d=1.039), with a significant negative correlation between TL and performance decline per decade (r=-0.624, p<0.01) and a positive correlation of TL and actual performance level (r=0.641, p<0.01). In conclusion, TL of elite master sprinters was longer than their untrained peers, and seems to be not only a marker of health status, but also an indicator of sports longevity since both actual performance level and its decrease over years were related to TL. Further research might assess the TL of elite master endurance athletes for comparison with sprinters, and also investigate the underlying mechanisms by which the attenuation of telomere shortening occurs in master athletes.

Where does the One-Repetition Maximum Exist on the Force-Velocity Relationship in Squat?

Abstract: The aim was to determine the position of the one-repetition maximum (1RM) squat point on the force-velocity (F-V) relationship obtained during squat jump (SJ). Ten healthy athletes performed a 1RM squat during which ground reaction force and lower-limb extension velocity were measured, and six loaded SJs to determine individual F-V relationship. The goodness of fit of the linear F-V relationship with or without the 1RM point was tested. The vertical and horizontal coordinates were determined relative to the theoretical maximal force (F0) and the highest loaded SJ (load of 44.5±4.6% 1RM). The goodness of fit of the individual F-V relationship did not differ with or without the 1RM condition, even if the 1RM point was slightly below the curve (−5±5%, P=0.018). The 1RM point can be considered as a point of the F-V relationship. The velocity (0.22±0.05 m.s−1) of the 1RM point corresponded to ~30% of the velocity reached during the highest loaded SJ. The force developed in the 1RM condition was ~16% higher than during the highest loaded SJ and ~11% lower than F0. This finding underlines the difference between F0 and the 1RM condition.

Cardiovascular Responses to Different Resistance Exercise Protocols in Elderly.

Abstract: Increase in muscle mass and strength through resistance exercise (RE) has been highly recommended for healthy aging. On the other hand, RE could lead to acute cardiovascular risks prompted mainly by intense blood pressure elevations and cardiac autonomic imbalance. We compared the cardiovascular responses to three different RE protocols performed by 21 healthy elderly on a leg press machine. The protocols tested were high load (80% 1RM) until muscular failure (HL); low load (30% 1RM) until muscular failure (LL); low load, 30 repetitions followed by 3 sets of 15 repetitions, with 50% blood flow restriction (LL-BFR); and a control session (CON). Based on heart rate variability analysis, only LL kept parasympathetic indexes lower than CON at 30 min recovery. By finger photoplethysmography, LL-BFR prompted higher systolic and mainly diastolic blood pressure increments in many sets. The heart rate and cardiac output increase, and total peripheral resistance reduction following exercise were not different among RE protocols. There was no significant post-exercise hypotension and carotid arterial compliance changes. HL seems to be the safer protocol to be recommended for the healthy elderly, because it induces lower blood pressure increments and faster parasympathetic recovery compared to LL and LL-BFR.