Sports Medicine

Correction to: How the 2018 US Physical Activity Guidelines are a Call to Promote and Better Understand Acute Physical Activity for Cognitive Function Gains

01-03-2020 – YK Chang,KI Erickson,E Stamatakis,TM Hung

Published Erratum

The article How the 2018 US Physical Activity Guidelines are a Call to Promote and Better Understand Acute Physical Activity for Cognitive Function Gains, written by Yu-Kai Chang, Kirk I. Erickson, Emmanuel Stamatakis and Tsung-Min Hung, was originally published Online First without Open Access. After publication in volume 49, issue 11, pages 1625–1627 #-# the author decided to opt for Open Choice and to make the article an Open Access publication.

Running to Lower Resting Blood Pressure: A Systematic Review and Meta-analysis

01-03-2020 – Y Igarashi,Y Nogami

Journal Article, Review

Abstract Background According to previous epidemiological studies, there are pros and cons for the relationship between running regularly and changes in resting blood pressure (RBP), and the changes may depend on the form of exercise. Objective The aims of the current systematic review were to summarize the effects of running regularly on RBP and to investigate the most efficacious form of running in reducing RBP for this purpose. Methods The inclusion criteria were: randomized controlled trials, involving healthy adults or adults with hypertension, the exercise group only performed regular running and the control group did not exercise, and the study reported the mean resting systolic blood pressure (RSBP) and/or diastolic blood pressure (RDBP). The mean difference (MD) in RBP in each trial was defined as follows: (mean value at post-intervention in the exercise group − mean value at baseline in the exercise group) − (mean value at post-intervention in the control group − mean value at baseline in the control group) and was calculated. The weighted MD (WMD) was defined as the synthesis of all MD. A linear meta-regression analysis, exercise intensity the percentage of maximum heart rate (%) and total exercise time throughout the intervention (hours) were selected as explanatory variables and the MD in RBP served as the objective variable. Results Twenty-two trials (736 subjects) were analyzed. When trials were limited to those involving healthy subjects, the WMD in RBP decreased significantly RSBP: − 4.2 mm
Hg (95% confidence intervals (95% CI) − 5.9 to − 2.4); RDBP: − 2.7 mm
Hg (95% CI − 4.2 to − 1.1) and did not contain significant heterogeneity (RSBP: P = 0.67, I2 = 0.0%; DBP: P = 0.38, I2 = 7.2%). When trials were limited to those involving subjects with hypertension, the WMD in RBP decreased significantly RSBP: − 5.6 mm
Hg (95% CI − 9.1 to − 2.1); RDBP: − 5.2 mm
Hg (95% CI − 9.0 to − 1.4) but contained significant heterogeneity (RSBP: P = 0.01, I2 = 62.2%; DBP: P < 0.01, I2 = 87.7) and a meta-regression analysis showed that the percentage of maximum heart rate was significantly associated with the WMD in RSBP slope: 0.56 (95% CI 0.21 to 0.92), intercept: − 48.76 (95% CI − 76.30 to − 21.22), R2 = 0.88 and RDBP slope: 0.45 (95% CI 0.01 to 0.87), intercept: − 38.06 (95% CI − 72.30 to − 4.08), R2 = 0.41. When trials were limited to those involving subjects with hypertension and a mean age ≥ 40 years, a meta-regression analysis showed that total exercise time throughout the intervention was significantly associated with the WMD in RDBP slope: 0.82 (95% CI 0.54 to 1.09), intercept: − 22.90 (95% CI − 29.04 to − 16.77), R2 = 0.99. Conclusions Running regularly decreases RBP, but the changes in subjects with hypertension may differ depending on exercise intensity or total exercise time. Therefore, running regularly at moderate intensity and at a restrained volume is recommended to lower RBP in subjects with hypertension.

Insufficient Sleep in Young Athletes? Causes, Consequences, and Potential Treatments

01-03-2020 – JL Fox,AT Scanlan,R Stanton,C Sargent

Journal Article, Review

Abstract Sleep is essential in the preparation for, and the recovery from, training and competition. Despite being important for all individuals, young athletes are considered an at-risk group for reduced sleep duration and quality. The purpose of this review is to synthesise current literature relating to sleep duration and quality in young (14–25 years) athletes. Specifically, typical sleep and wake patterns, factors affecting sleep and wake patterns, and the consequences of altered sleep and wake patterns in young athletes are discussed. Scheduling training and competition in the afternoon or evening appears to result in reduced sleep duration due to less time in bed. Evidence suggests that young athletes who obtain less than 8 h of sleep per night are at a higher risk of musculoskeletal injury. An increase in sleep duration above habitual nightly sleep may be associated with favourable performance in young athletes; however, the associations between sleep quality and performance- and health-related outcomes remain unclear.

Relative Body Weight and Standardised Brightness-Mode Ultrasound Measurement of Subcutaneous Fat in Athletes: An International Multicentre Reliability Study, Under the Auspices of the IOC Medical Commission

01-03-2020 – W Müller,A Fürhapter-Rieger,H Ahammer,TG Lohman,NL Meyer,LB Sardinha,AD Stewart,RJ Maughan,J Sundgot-Borgen,T Müller,M Harris,N Kirihennedige,JP Magalhaes,X Melo,W Pirstinger,A Reguant-Closa,V Risoul-Salas,TR Ackland

Journal Article

Abstract Introduction Fat is a metabolic fuel, but excess body fat is ballast mass, and therefore, many elite athletes reduce body fat to dangerously low levels. Uncompressed subcutaneous adipose tissue (SAT) thickness measured by brightness-mode ultrasound (US) provides an estimate of body fat content. Methods The accuracy for determining tissue borders is about 0.1–0.2 mm and reliability (experienced measurers) was within ± 1.4 mm (95% limit of agreement, LOA). We present here inter- and intra-measurer scores of three experienced US measurers from each of the centres C1 and C2, and of three novice measurers from each of the centres C3–C5. Each of the five centres measured 16 competitive adult athletes of national or international level, except for one centre where the number was 12. The following sports were included: artistic gymnastics, judo, pentathlon, power lifting, rowing, kayak, soccer, tennis, rugby, basketball, field hockey, water polo, volleyball, American football, triathlon, swimming, cycling, long-distance running, mid-distance running, hurdles, cross-country skiing, snowboarding, and ice hockey. SAT contour was detected semi-automatically: typically, 100 thicknesses of SAT at a given site (i.e., in a given image), with and without fibrous structures, were measured. Results At SAT thickness sums DI (of eight standardised sites) between 6.0 and 70.0 mm, the LOA of experienced measurers was 1.2 mm, and the intra-class correlation coefficient ICC was 0.998; novice measurers: 3.1 mm and 0.988. Intra-measurer differences were similar. The median DI value of all 39 female participants was 51 mm (11% fibrous structures) compared to 17 mm (18%) in the 37 male participants. Discussion DI measurement accuracy and precision enables detection of fat mass changes of approximately 0.2 kg. Such reliability has not been reached with any other method. Although females’ median body mass index and mass index were lower than those of males, females’ median DI was three times higher, and their percentage of fibrous structures was lower. The standardised US method provides a highly accurate and reliable tool for measuring SAT and thus changes in body fat, but training of measurers is important.

Comment on: “Effects of Carbohydrate Mouth Rinse on Cycling Time Trial Performance: A Systematic Review and Meta-analysis” and Subsequent Comment/Author Reply from Li et al.

01-03-2020 – FK Borszcz,RD de Lucas


Effects of Prior Cognitive Exertion on Physical Performance: A Systematic Review and Meta-analysis

01-03-2020 – DMY Brown,JD Graham,KI Innes,S Harris,A Flemington,SR Bray

Journal Article, Review

Abstract Background An emerging body of the literature in the past two decades has generally shown that prior cognitive exertion is associated with a subsequent decline in physical performance. Two parallel, but overlapping, bodies of literature (i.e., ego depletion, mental fatigue) have examined this question. However, research to date has not merged these separate lines of inquiry to assess the overall magnitude of this effect. Objective The present work reports the results of a comprehensive systematic review and meta-analysis examining carryover effects of cognitive exertion on physical performance. Methods A systematic search of MEDLINE, Psyc
INFO, and SPORTDiscus was conducted. Only randomized controlled trials involving healthy humans, a central executive task requiring cognitive exertion, an easier cognitive comparison task, and a physical performance task were included. Results A total of 73 studies provided 91 comparisons with 2581 participants. Random effects meta-analysis showed a significant small-to-medium negative effect of prior cognitive exertion on physical performance (g = − 0.38 95% CI − 0.46, − 0.31). Subgroup analyses showed that cognitive tasks lasting < 30-min (g = − 0.45) and ≥ 30-min (g = − 0.30) have similar significant negative effects on subsequent physical performance. Prior cognitive exertion significantly impairs isometric resistance (g = − 0.57), motor (g = − 0.57), dynamic resistance (g = − 0.51), and aerobic performance (g = − 0.26), but the effects on maximal anaerobic performance are trivial and non-significant (g = 0.10). Studies employing between-subject designs showed a medium negative effect (g = − 0.65), whereas within-subject designs had a small negative effect (g = − 0.28). Conclusion Findings demonstrate that cognitive exertion has a negative effect on subsequent physical performance that is not due to chance and suggest that previous meta-analysis results may have underestimated the overall effect.

Impact of Pre-exercise Hypohydration on Aerobic Exercise Performance, Peak Oxygen Consumption and Oxygen Consumption at Lactate Threshold: A Systematic Review with Meta-analysis

01-03-2020 – TA Deshayes,D Jeker,EDB Goulet

Journal Article, Review

Abstract Background Progressive exercise-induced dehydration may impair aerobic exercise performance (AEP). However, no systematic approach has yet been used to determine how pre-exercise hypohydration, which imposes physiological challenges differing from those of a well-hydrated pre-exercise state, affects AEP and related components such as peak oxygen consumption ((dot{V}{text{O}}_{{2{text{peak}}}} )) and (dot{V}{text{O}}_{2}) at lactate threshold ((dot{V}{text{O}}_{2} {text{LT}})). Objective To determine, using a systematic approach with meta-analysis, the magnitude of the effect of pre-exercise hypohydration on AEP, (dot{V}{text{O}}_{{2{text{peak}}}}) and (dot{V}{text{O}}_{2} {text{LT}}). Design This was a systematic review with meta-analysis of well-controlled studies. Data Sources MEDLINE, SPORTDiscus and CINAHL databases and cross-referencing. Inclusion Criteria for Selecting Studies (1) well-controlled human (≥ 18 years) studies; (2) pre-exercise hypohydration induced at least 1 h prior to exercise onset; (3) pre-exercise body mass loss in the hypohydrated, experimental condition was ≥ 1% and ≥ 0.5% than the well-hydrated, control condition; (4) following the dehydrating protocol body mass change in the control condition was within − 1% to + 0.5% of the well-hydrated body mass. Results A total of 15 manuscripts were included, among which 14, 6 and 6 met the inclusion criteria for AEP, (dot{V}{text{O}}_{{2{text{peak}}}}) and (dot{V}{text{O}}_{2} {text{LT}}), respectively, providing 21, 10 and 9 effect estimates, representing 186 subjects. Mean body mass decrease was 3.6 ± 1.0% (range 1.7–5.6%). Mean AEP test time among studies was 22.3 ± 13.5 min (range 4.5–54.4 min). Pre-exercise hypohydration impaired AEP by 2.4 ± 0.8% (95% CI 0.8–4.0%), relative to the control condition. Peak oxygen consumption and (dot{V}{text{O}}_{2} {text{LT}}), respectively, decreased by 2.4 ± 0.8% (95% CI 0.7–4.0%) and 4.4 ± 1.4% (95% CI 1.7–7.1%), relative to the control condition. Compared with starting an exercise hypohydrated, it is respectively likely, possible and likely that AEP, (dot{V}{text{O}}_{{2{text{peak}}}}) and (dot{V}{text{O}}_{2} {text{LT}}) benefit from a euhydrated state prior to exercise. Meta-regression analyses did not establish any significant relationship between differences in body mass loss and differences in the percent change in AEP or (dot{V}{text{O}}_{2} {text{LT}}). However, (dot{V}{text{O}}_{{2{text{peak}}}}) was found to decrease by 2.6 ± 0.8 % (95% CI 0.7–4.5%) for each percent loss in body mass above a body mass loss threshold of 2.8%. Conclusion Pre-exercise hypohydration likely impairs AEP and likely reduces (dot{V}{text{O}}_{2} {text{LT}}) (i.e., the aerobic contribution to exercise was lower) during running and cycling exercises ≤ 1 h across different environmental conditions (i.e., from 19 to 40 °C). Moreover, pre-exercise hypohydration possibly impedes (dot{V}{text{O}}_{{2{text{peak}}}}) during such exercises.

Is It Time We Better Understood the Tests We are Using for Return to Sport Decision Making Following ACL Reconstruction? A Critical Review of the Hop Tests

01-03-2020 – WT Davies,GD Myer,PJ Read

Journal Article, Review

Abstract There has been a move towards a criterion-based return to play in recent years, with 4 single-leg hop tests commonly used to assess functional performance. Despite their widespread integration, research indicates that relationships between ‘passing’ ‘hop test criteria and successful outcomes following rehabilitation are equivocal, and, therefore, require further investigation. This critical review includes key information to examine the evolution of these tests, their reliability, relationships with other constructs, and sensitivity to change over time. Recommendations for how measurement and administration of the tests can be improved are also discussed. The evidence presented in this review shows that hop tests display good reliability and are sensitive to change over time. However, the use of more than 2 hop tests does not appear to be necessary due to high collinearity and no greater sensitivity to detect abnormality. The inclusion of other hop tests in different planes may give greater information about the current function of the knee, particularly when measured over time using both relative and absolute measures of performance. It is recommended that the contralateral limb be tested prior to surgery for a more relevant benchmark for performance, and clinicians are strongly advised to measure movement quality, as hop distance alone appears to overestimate the recovery of the knee.

Associations of Pregnancy Physical Activity with Maternal Cardiometabolic Health, Neonatal Delivery Outcomes and Body Composition in a Biethnic Cohort of 7305 Mother–Child Pairs: The Born in Bradford Study

01-03-2020 – PJ Collings,D Farrar,J Gibson,J West,SE Barber,J Wright

Journal Article

Abstract Objective Physical activity is advocated for a range of benefits to the uncomplicated pregnancy. We investigated associations of mid-pregnancy physical activity with maternal and neonatal health in white British and Pakistani-origin women from a deprived urban setting. Methods The study was performed in 6921 pregnant women (53% Pakistani-origin) who contributed data for 7305 singleton births. At 26–28 weeks gestation, women were grouped into four activity levels (inactive/somewhat active/moderately active/active) based on their self-reported physical activity. Linear regression with robust standard errors was used to calculate adjusted mean differences in health markers between the four groups of physical activity (reference group: inactive). Results Three-quarters (74%) of Pakistani-origin women and 39% of white British women were inactive. Trend-tests revealed that more active white British women tended to be less adipose, had lower fasting and postload glucose levels, lower triglyceride concentrations, and their babies were less adipose (smaller triceps and subscapular skinfolds) than less active white British women. Somewhat active Pakistani-origin women exhibited lower triglyceride concentrations and systolic blood pressure, higher high-density lipoprotein cholesterol levels, and their babies were less adipose (smaller mid-upper arm and abdominal circumferences; lower cord-blood leptin concentration) compared to inactive Pakistani-origin women. No associations were observed for gestational age or birth weight. Conclusions Physical activity performed mid-pregnancy was beneficially associated with maternal cardiometabolic health and neonatal adiposity, without influencing gestational age or birth weight. Associations were dose-dependent in white British women, and even a small amount of mid-pregnancy physical activity appeared to benefit some health markers in Pakistani-origin women.

Is Physical Activity Good or Bad for the Female Pelvic Floor? A Narrative Review

01-03-2020 – K Bø,IE Nygaard

Journal Article, Review

Abstract More women participate in sports than ever before and the proportion of women athletes at the Olympic Games is nearly 50%. The pelvic floor in women may be the only area of the body where the positive effect of physical activity has been questioned. The aim of this narrative review is to present two widely held opposing hypotheses on the effect of general exercise on the pelvic floor and to discuss the evidence for each. Hypothesis 1: by strengthening the pelvic floor muscles (PFM) and decreasing the levator hiatus, exercise decreases the risk of urinary incontinence, anal incontinence and pelvic organ prolapse, but negatively affects the ease and safety of childbirth. Hypothesis 2: by overloading and stretching the PFM, exercise not only increases the risk of these disorders, but also makes labor and childbirth easier, as the PFM do not obstruct the exit of the fetus. Key findings of this review endorse aspects of both hypotheses. Exercising women generally have similar or stronger PFM strength and larger levator ani muscles than non-exercising women, but this does not seem to have a greater risk of obstructed labor or childbirth. Additionally, women that specifically train their PFM while pregnant are not more likely to have outcomes associated with obstructed labor. Mild-to-moderate physical activity, such as walking, decreases the risk of urinary incontinence but female athletes are about three times more likely to have urinary incontinence compared to controls. There is some evidence that strenuous exercise may cause and worsen pelvic organ prolapse, but data are inconsistent. Both intra-abdominal pressure associated with exercise and PFM strength vary between activities and between women; thus the threshold for optimal or negative effects on the pelvic floor almost certainly differs from person to person. Our review highlights many knowledge gaps that need to be understood to understand the full effects of strenuous and non-strenuous activities on pelvic floor health.

Reply to Borszcz & de Lucas: Comment on: “Effects of Carbohydrate Mouth Rinse on Cycling Time Trial Performance: A Systematic Review and Meta-Analysis”

01-03-2020 – C Brietzke,PE Franco-Alvarenga,MF Goethel,TM Santos,FO Pires


Moving Sport and Exercise Science Forward: A Call for the Adoption of More Transparent Research Practices

01-03-2020 – Geen auteurs bekend

Journal Article

Abstract The primary means of disseminating sport and exercise science research is currently through journal articles. However, not all studies, especially those with null findings, make it to formal publication. This publication bias towards positive findings may contribute to questionable research practices. Preregistration is a solution to prevent the publication of distorted evidence resulting from this system. This process asks authors to register their hypotheses and methods before data collection on a publicly available repository or by submitting a Registered Report. In the Registered Report format, authors submit a stage 1 manuscript to a participating journal that includes an introduction, methods, and any pilot data indicating the exploratory or confirmatory nature of the study. After a stage 1 peer review, the manuscript can then be offered in-principle acceptance, rejected, or sent back for revisions to improve the quality of the study. If accepted, the project is guaranteed publication, assuming the authors follow the data collection and analysis protocol. After data collection, authors re-submit a stage 2 manuscript that includes the results and discussion, and the study is evaluated on clarity and conformity with the planned analysis. In its final form, Registered Reports appear almost identical to a typical publication, but give readers confidence that the hypotheses and main analyses are less susceptible to bias from questionable research practices. From this perspective, we argue that inclusion of Registered Reports by researchers and journals will improve the transparency, replicability, and trust in sport and exercise science research. The preprint version of this work is available on Sport
R(chi )iv:

Efficacy of School-Based Interventions for Improving Muscular Fitness Outcomes in Adolescent Boys: A Systematic Review and Meta-analysis

01-03-2020 – A Cox,SJ Fairclough,MC Kosteli,RJ Noonan

Journal Article, Review

Abstract Background It has been reported that boys’ and girls’ physical activity (PA) levels decline throughout adolescence. Boys are at risk of physical inactivity during adolescence; however, in intervention research, they are an under-represented group relative to girls. It is suggested that the school environment may be central to developing interventions that support adolescents in meeting the current PA guidelines. The aim of this systematic review and meta-analysis was to investigate the efficacy of school-based physical activity interventions for improving muscular fitness (MF) in adolescent males. Methods This systematic review and meta-analysis followed the preferred reporting systems for meta-analyses guidelines and was registered on PROSPERO (Registration number: CRD42018091023). Eligible studies were published in English within peer-reviewed articles. Searches were conducted in three databases, with an additional grey literature search in Google Scholar. Studies investigating MF outcomes were included. Results There were 43 data sets identified across 11 studies, from seven countries. Overall methodological quality of the studies was moderate-to-strong. Interventions targeting MF evidenced a small-to-medium effect (g = 0.32, CI 0.17, 0.48, p < 0.00). Subgroup analyses of MF delivery method resulted in small-to-medium effects: upper limb MF measures (g = 0.28, 95% CI − 0.02, 0.58, p = 0.07), lower limb MF measures (g = 0.28, 95% CI 0.09, 0.68, p = 0.03), combined MF activities (g = 0.24, 95% CI − 0.04 to 0.49, p = 0.05), plyometric activities (g = 0.39, 95% CI 0.09, 0.68, p = 0.01), body weight (g = 0.27, 95% CI − 0.10, 0.65, p = 0.15), and traditional MF methods (g = 0.43, 95% CI 0.09, 0.78, p = 0.01). Conclusions School-based interventions which aimed to increase MF outcomes in adolescent boys demonstrated small-to-moderate effects. Traditional and plyometric methods of resistance training appear to be the most effective form of PA delivery in adolescent males. More quality research is required to assess the impact of MF delivered in the school environment to inform future intervention design.

Quantification of Neuromuscular Fatigue: What Do We Do Wrong and Why?

01-03-2020 – N Place,GY Millet

Journal Article

Abstract Neuromuscular fatigue (NMF) is usually assessed non-invasively in healthy, athletic or clinical populations with the combination of voluntary and evoked contractions. Although it might appear relatively straightforward to magnetically or electrically stimulate at different levels (cortical/spinal/muscle) and to measure mechanical and electromyographic responses to quantify neuromuscular adjustments due to sustained/repeated muscle contractions, there are drawbacks that researchers and clinicians need to bear in mind. The aim of this opinion paper is to highlight the pitfalls inevitably faced when NMF is quantified. The first problem might arise from the definition of fatigue itself and the parameter(s) used to measure it; for instance, measuring power vs. isometric torque may lead to different conclusions. Another potential limitation is the delay between exercise termination and the evaluation of neuromuscular function; the possible underestimation of exercise-induced neural and contractile impairment and misinterpretation of fatigue etiology will be discussed, as well as solutions recently proposed to overcome this problem. Quantification of NMF can also be biased (or not feasible) because of the techniques themselves (e.g. results may depend on stimulation intensity for transcranial magnetic stimulation) or the way data are analyzed (e.g. M wave peak-to-peak vs first phase amplitude). When available, alternatives recently suggested in the literature to overcome these pitfalls are considered and recommendations about the best practices to assess NMF (e.g. paying attention to the delay between exercise and testing, adapting the method to the characteristics of the population to be tested and considering the limitations associated with the techniques) are proposed.

The Association Between the Acute:Chronic Workload Ratio and Injury and its Application in Team Sports: A Systematic Review

01-03-2020 – A Griffin,IC Kenny,TM Comyns,M Lyons

Journal Article, Review

Abstract Background There has been a recent increase in research examining training load as a method of mitigating injury risk due to its known detrimental effects on player welfare and team performance. The acute:chronic workload ratio (ACWR) takes into account the current training load (acute) and the training load that an athlete has been prepared for (chronic). The ACWR can be calculated using; (1) the rolling average model (RA) and (2) the exponentially weighted moving average model (EWMA). Objective The primary aim of this systematic review was to investigate the literature examining the association between the occurrence of injury and the ACWR and to investigate if sufficient evidence exists to determine the best method of application of the ACWR in team sports. Methods Studies were identified through a comprehensive search of the following databases: EMBASE, Medline, SPORTDiscus, SCOPUS, AMED and CINAHL. Extensive data extraction was performed. The methodological quality of the included studies was assessed according to the Newcastle–Ottawa Scale (NOS) for Cohort Studies. Results A total of 22 articles met the inclusion criteria. The assessment of article quality had an overall median NOS score of 8 (range 5–9). The findings of this review support the association between the ACWR and non-contact injuries and its use as a valuable tool for monitoring training load as part of a larger scale multifaceted monitoring system that includes other proven methods. There is support for both models, but the EWMA is the more suitable measure, in part due to its greater sensitivity. The most appropriate acute and chronic time periods, and training load variables, may be dependent on the specific sport and its structure. Conclusions For practitioners, it is the important to understand the intricacies of the ACWR before deciding the best method of calculation. Future research needs to focus on the more sensitive EWMA model, for both sexes, across a larger range of sports and time frames and also combinations with other injury risk factors.

Association Between Muscular Strength and Bone Health from Children to Young Adults: A Systematic Review and Meta-analysis

14-02-2020 –

Abstract Background Osteoporosis is a major worldwide health concern. The acquisition of bone mass during growth decreases the risk of osteoporosis later in life. Muscular strength is an important and modifiable factor to improve bone development in this period. Objective The aim of this review was to summarize the relationship between muscular strength and bone health. Methods Cross-sectional data from studies addressing this association from childhood to young adulthood were systematically searched. The Der
Simonian and Laird method was used to compute pooled estimates of effect size and respective 95% CI. The meta-analyses were conducted separately for upper limbs or lower limbs muscular strength and for bone regions. Additionally, a regression model was used to estimate the influence of determinants such as age, lean mass, fat mass, height, weight and cardiorespiratory fitness in this association. Results Thirty-nine published studies were included in the systematic review. The pooled effect size for the association of upper limbs muscular strength with upper limbs, spine and total body BMD ranged from 0.70 to 1.07 and with upper limbs, spine and total body BMC ranged from 1.84 to 1.30. The pooled effect size for the association of lower limbs muscular strength with lower limbs, spine and total body BMD ranged from 0.54 to 0.88 and with lower limbs, spine and total body BMC ranged between 0.81 and 0.71. All reported pooled effect size estimates were statistically significant. Conclusion This systematic review and meta-analysis supports that muscular strength should be considered as a useful skeletal health marker during development and a target outcome for interventions aimed at improving bone health.

Effects of Resistance Training Movement Pattern and Velocity on Isometric Muscular Rate of Force Development: A Systematic Review with Meta-analysis and Meta-regression

08-02-2020 – AJ Blazevich,CJ Wilson,PE Alcaraz,JA Rubio-Arias

Journal Article, Review

Abstract Background Muscular rate of force development (RFD) is positively influenced by resistance training. However, the effects of movement patterns and velocities of training exercises are unknown. Objectives To determine the effects of velocity, the intent for fast force production, and movement pattern of training exercises on the improvement in isometric RFD from chronic resistance training. Methods A systematic search of electronic databases was conducted to 18 September, 2018. Meta-regression and meta-analytic methods were used to compute standardized mean differences (SMD ± 95% confidence intervals) to examine effects of movement pattern similarity (between training and test exercises; specific vs. non-specific) and movement speed (fast vs. slow vs. slow with intent for fast force production) for RFD calculated within different time intervals. Results The search yielded 1443 articles, of which 54 met the inclusion criteria (59 intervention groups). Resistance training increased RFD measured to both early (e.g., 50 ms; standardized mean difference 95% CI 0.58 0.40, 0.75) and later (e.g., 200 ms; 0.39 0.25, 0.52) times from contraction onset, as well as maximum RFD (RFDmax; 0.35 0.21, 0.48). However, sufficient data for sub-analyses were only available for RFDmax. Significant increases relative to control groups were observed after training with high-speed (0.54 0.05, 1.03), slow-speed with intent for fast force production (0.41 0.20, 0.63), and movement pattern-specific (0.38 0.17, 0.59) exercises only. No clear effect was observed for slow-speed without intent for fast force production (0.21 0.00, 0.42, p = 0.05) or non-movement-specific (0.27 − 0.32, 0.85, p = 0.37) exercises. Meta-regression did not reveal a significant difference between sexes (p = 0.09); however, a negative trend was found in women (− 0.57 − 1.51, 0.37, p = 0.23), while a favorable effect was found in men (0.40 0.22, 0.58, p < 0.001). Study duration did not statistically influence the meta-analytic results, although the greatest RFD increases tended to occur within the first weeks of the commencement of training. Conclusions Resistance training can evoke significant increases in RFD. For maximum (peak) RFD, the use of faster movement speeds, the intention to produce rapid force irrespective of actual movement speed, and similarity between training and testing movement patterns evoke the greatest improvements. In contrast to expectation, current evidence indicates a between-sex difference in response to training; however, a lack of data in women prevents robust analysis, and this should be a target of future research. Of interest from a training program design perspective was that RFD improvements were greatest within the first weeks of training, with less ongoing improvement (or a reduction in RFD) with longer training, particularly when training velocity was slow or there was a lack of intent for fast force production.

A Normative Reference vs. Baseline Testing Compromise for ImPACT: The CARE Consortium Multiple Variable Prediction (CARE-MVP) Norms

07-02-2020 – Geen auteurs bekend

Journal Article

Abstract Background Sports medicine clinicians routinely use computerized neurocognitive testing in sport-related concussion management programs. Debates continue regarding the appropriateness of normative reference comparisons versus obtaining individual baseline assessments, particularly for populations with greater likelihood of having below- or above-average cognitive abilities. Improving normative reference methods could offer alternatives to perceived logistical and financial burdens imposed by universal baseline testing. Objectives To develop and validate the Concussion Assessment, Research, and Education (CARE) Consortium Multiple Variable Prediction (MVP) norms for the Immediate Postconcussion Assessment and Cognitive Testing (Im
PACT). Methods We developed the CARE-MVP norms for Im
PACT composite scores using regression-based equations. Predictor variables included sex, race (white/Caucasian, black/African American, Asian, or Multiple Races), medical history attention-deficit/hyperactivity disorder (ADHD), learning disorder (LD), prior concussion(s), prior psychiatric diagnosis, and an estimate of premorbid intellect (Wechsler Test of Adult Reading). CARE-MVP norms were first validated in an independent sample of healthy collegiate athletes by comparing predicted and actual baseline test scores using independent-samples t-tests and Cohen’s d effect sizes. We then evaluated base rates of low scores in athletes self-reporting ADHD/LD (vs. non-ADHD/LD) and black/African American race (vs. white/Caucasian) across multiple normative reference methods (Chi square, Cramer’s V effect size). Lastly, we validated the CARE-MVP norms in a concussed sample (dependent samples t test, Cohen’s d effect size). Results A total of 5233 collegiate athletes (18.8 ± 1.2 years, 70.5% white/Caucasian, 39.1% female) contributed to the CARE-MVP norms (development N = 2616; internal validation N = 2617). Race and WTAR score were the strongest and most consistent Im
PACT score predictors. There were negligible mean differences between observed and predicted (CARE-MVP) baseline scores (Cohen’s d < 0.1) for all Im
PACT composite scores except Reaction Time (predicted ~ 20 ms faster than observed, d = − 0.28). Low score base rates were similar for athletes across subpopulations when using CARE-MVP norms (ADHD/LD, V = 0.017–0.028; black/African American, V = 0.043–0.053); while, other normative reference methods resulted in disproportionately higher rates of low scores (ADHD/LD, V = 0.062–0.101; black/African American race, V = 0.163–0.221). Acute (24–48 h) postconcussion Im
PACT scores were significantly worse than CARE-MVP norms but notably varied as a function of concussion symptom severity. Conclusions Results support CARE-MVP norm use in populations typically underrepresented or not adjusted for in traditional normative reference samples, such as those self-reporting ADHD/LD or black/African American race. CARE-MVP norms improve upon prior normative methods and may offer a practical, simple alternative for collegiate institutions concerned about logistical and financial burden associated with baseline testing. An automated scoring program is provided.

Effect of High-Intensity Interval Training Versus Sprint Interval Training on Time-Trial Performance: A Systematic Review and Meta-analysis

07-02-2020 – MA Rosenblat,AS Perrotta,SG Thomas

Journal Article, Review

Abstract Background Two forms of interval training commonly discussed in the literature are high-intensity interval training (HIIT) and sprint interval training (SIT). HIIT consists of repeated bouts of exercise that occur at a power output or velocity between the second ventilatory threshold and maximal oxygen consumption (VO2max). SIT is performed at a power output or velocity above those associated with VO2max. Objective The primary objective of this study is to systematically review published randomized and pair-matched trials to determine which mode of interval training, HIIT versus SIT, leads to a greater improvement in TT performance in active and trained individuals. The second objective of this review is to perform a subgroup analysis to determine if there is a distinction between HIIT programs that differ in work-bout duration. Data Sources SPORTDiscus (1800–present) and Medline with Full Text (1946–present) were used to conduct a systematic literature search. Study Selection Studies were selected for the review if they met the following criteria: (1) individuals (males and females) who were considered at least moderately trained (~ 3-h per week of activity) as specified by the authors of the included studies; (2) between the ages of 18 and 45 years; (3) randomized or pair-matched trials that included a HIIT and a SIT group; (4) provided detailed information about the interval training program; (5) were at least 2 weeks in duration; (6) included a TT test that required participants to complete a set distance. Results A total of 6 articles met the inclusion criteria for the subjective and objective analysis. The pooled analysis was based on a random-effects model. There was no difference in the change in TT performance when comparing all HIIT versus SIT (0.9%; 90% CI − 1.2–1.9%, p = 0.18). However, subgroup analysis based on duration of work interval indicated a 2% greater improvement in TT performance following long-HIIT (≥ 4 min) when compared to SIT. There was no difference in change in VO2max/peak oxygen consumption (VO2peak) between groups. There was a moderate effect (ES = 0.70) in favor of HIIT over SIT in maximal aerobic power (MAP) or maximal aerobic velocity (MAV). Conclusion The results of the meta-analysis indicate that long-HIIT may be the optimal form of interval training to augment TT performance. Additional research that directly compares HIIT exercise differing in work-bout duration would strengthen these results and provide further insight into the mechanisms behind the observed benefits of long-HIIT.

Rates and Correlates of Mental Health Symptoms in Currently Competing Elite Athletes from the Australian National High-Performance Sports System

06-02-2020 – R Purcell,S Rice,M Butterworth,M Clements

Journal Article

Abstract Aims Elite athletes are at risk of mental ill-health via exposure to sports-related stressors and the overlap in competitive playing years with the peak age of onset of mental ill-health. Despite this risk, there is a paucity of robust empirical data on mental health symptoms in currently competing athletes. The purpose of this study was to assess the prevalence and correlates of mental health symptoms in a representative, national sample of elite athletes and to compare rates against published community norms. Methods A cross-sectional, anonymous, online survey was administered to all categorised (e.g. highest level) athletes, aged 17 years and older, registered with the Australian Institute of Sport (n = 1566). Main outcomes were self-reported scores on validated measures of psychological distress, probable ‘caseness’ (i.e. the experience of mental health symptoms that would usually warrant a need for care by a health professional), risky alcohol consumption, body weight and shape dissatisfaction, self-esteem, life satisfaction and problem gambling. Correlates of outcomes included demographic, individual vulnerability (e.g. social support, coping style) and sport-related variables. Results The participation rate was 51.7% (n = 810), of whom 749 athletes completed most or all outcomes measures. Compared to published community norms, athletes were significantly more likely to report ‘high to very high’ psychological distress (9.5% vs 17.7%, respectively) and to meet the threshold for ‘probable caseness’ (19% vs 35%). In contrast, athletes reported significantly lower rates of risky alcohol consumption, problem gambling and body dissatisfaction compared to community norms, and conversely higher self-esteem and life satisfaction. The adjusted odds of psychological distress and caseness were increased in athletes who reported prior treatment for a mental health problem (OR = 1.28–2.84), inadequate social support (OR = − 2.59 to 0.37) and more recent adverse life events (OR = 0.61–1.32); while, the odds of risky alcohol consumption were lower in female athletes (OR = − 1.36) and para-athletes (OR = − 1.20). Conclusions In a representative and national sample of currently competing elite athletes, inclusive of gender and para-status, psychological distress and probable caseness were elevated relative to community norms, although other aspects of functioning were as good as, if not better than, community peers. Sports medicine and mental health professionals working with elite athletes should screen for psychological distress in athletes who may otherwise appear to be well-functioning, to provide timely, optimal treatment.