Sports Medicine

Intra-articular Injection Administration in UK Ex-professional Footballers During Their Playing Careers and the Association with Post-career Knee Osteoarthritis

10-01-2020 –

Abstract Background The long-term risk from knee intra-articular (KIA) injections in professional athletes such as ex-footballers remains unknown. The use of KIA injections is controversial and remains anecdotally prolific as it is perceived as being safe/beneficial. The aim of this study was to determine the number, type and frequency KIA injections administered to retired professional footballers during their playing careers and the associations with post-career knee osteoarthritis (KOA). Methods This is a cross-sectional study involving a postal questionnaire (n = 1207) and subsequent knee radiographs in a random sample of questionnaire responders (n = 470). Footballers self-reported in the questionnaire whether they had received KIA injections and the estimated total number over the course of their playing career. Participant characteristics and football career-related details were also recorded. KOA was measured as self-reported knee pain (KP), total knee replacement (TKR) and radiographic KOA (RKOA). Results 44.5% of footballers had received at least one KIA injection (mean: 7.5; SD ± 11.2) during their professional career. 71% of knee injections were cortisone/corticosteroid based. Multivariate logistic regression, adjusting for age, body mass index (BMI) and significant knee injury identified that footballers with injections were two times more likely to have KP (OR 1.81, 95% CI 1.40–2.34) and TKR (OR 2.21, 95% CI 1.43–3.42) than those without injections. However, there was no association with RKOA (OR 1.30, 95% CI 0.85–2.01). Given, the association with KP and TKR, we found a significant dose–response relationship as the more injections a player received (by dose–response groups), the greater the risk of KP and TKR outcomes after adjustment for knee injury and other confounders (p for trend < 0.01). Conclusion On average, 8 KIA injections were given to the ex-footballers during their professional career. The most commonly administered injections were cortisone based. These injections associated with KP and TKR after they retired. The associations are independent of knee injuries and are dose dependent. The study suggests that there may have been excessive use of KIA injections to expedite return to play and this contributed to detrimental long-term outcomes such as KP and TKR post-retirement from professional football.

Correction to: The Effectiveness of Two Methods of Prescribing Load on Maximal Strength Development: A Systematic Review

02-01-2020 – SW Thompson,D Rogerson,A Ruddock,A Barnes

Published Erratum

While typesetting the entries of the Table 1 were incorrectly aligned. The correct Table 1 has been copied below.

Tensor Fascia Latae Muscle Structure and Activation in Individuals With Lower Limb Musculoskeletal Conditions: A Systematic Review and Meta-Analysis

02-01-2020 – M Besomi,L Maclachlan,R Mellor,B Vicenzino,PW Hodges

Journal Article, Review

Abstract Background Dysfunction of the tensor fascia latae (TFL) muscle is often clinically implicated in many musculoskeletal disorders. Objective To systematically review the literature of the TFL muscle to determine whether there are differences in its structure and activation between individuals with and without lower limb musculoskeletal conditions. Data sources A comprehensive search in MEDLINE, EMBASE, CINHAL, and LILACS was undertaken from year of inception to 9 July 2019. Eligibility criteria for selecting studies Studies that directly investigated the structure or activity of the TFL muscle between individuals with a lower limb musculoskeletal condition and a pain-free control group. Results Seventeen studies were included (n = 556 participants), eight reporting structure and ten activation of the TFL muscle. Conditions included lateral hip pain, hip joint pathology, ACL injury, iliotibial band syndrome, and patellofemoral joint osteoarthritis. Meta-analysis identified with low confidence (p value = 0.07) a small tendency towards hypertrophy in the affected side of participants with hip joint diseases (SMD 0.37, 95% CI − 0.02, 0.77). Moderate effect sizes were found for a higher cross-sectional area of the TFL/sartorius ratio in abductor tendon tear (SMD 0.74; 95% CI 0.05, 1.43, p value = 0.04), and for a smaller body mass normalized TFL volume in patellofemoral joint osteoarthritis (SMD − 0.61; 95% CI − 1.23, 0.00, p value = 0.05). Normalised electromyography (EMG) amplitude did not differ between groups for any condition, but when EMG was analysed as linear envelopes or synergies, some differences in pattern of TFL activation were observed between individuals with lateral hip pain and controls. Timing of TFL activation did not differ between individuals with knee conditions and controls. Conclusions and implications Common clinical assumptions of the role of TFL muscle in lower limb musculoskeletal conditions are not well investigated and poorly supported by current research. There are contradictory findings on the muscle size of TFL. Differing methodology in muscle activation studies precludes a clear interpretation for comparison between groups. PROSPERO registration number CRD42017076160.

Correction to: DNA Damage Following Acute Aerobic Exercise: A Systematic Review and Meta-analysis

01-01-2020 – DV Tryfidou,C McClean,MG Nikolaidis,GW Davison

Published Erratum

Page 17, Fig. 2

Corrections to: The Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Strength and Muscle Architecture Adaptations: A Systematic Review and Meta-analyses

01-01-2020 – M Cuthbert,N Ripley,JJ McMahon,M Evans,GG Haff,P Comfort

Published Erratum

between the studies assessed for

Reply to: “Comment on: The Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Strength and Muscle Architecture Adaptations: A Systematic Review and Meta-analyses”

01-01-2020 – M Cuthbert,N Ripley,JJ McMahon,M Evans,GG Haff,P Comfort

Letter

Comment On: “The Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Strength and Muscle Architecture Adaptations: A Systematic Review and Meta-Analyses”

01-01-2020 – T Alt,YT Nodler,J Severin,AJ Knicker,HK Strüder

Letter

Effects of Dietary Supplements on Adaptations to Endurance Training

01-01-2020 – JA Rothschild,DJ Bishop

Journal Article, Review

Abstract Endurance training leads to a variety of adaptations at the cellular and systemic levels that serve to minimise disruptions in whole-body homeostasis caused by exercise. These adaptations are differentially affected by training volume, training intensity, and training status, as well as by nutritional choices that can enhance or impair the response to training. A variety of supplements have been studied in the context of acute performance enhancement, but the effects of continued supplementation concurrent to endurance training programs are less well characterised. For example, supplements such as sodium bicarbonate and beta-alanine can improve endurance performance and possibly training adaptations during endurance training by affecting buffering capacity and/or allowing an increased training intensity, while antioxidants such as vitamin C and vitamin E may impair training adaptations by blunting cellular signalling but appear to have little effect on performance outcomes. Additionally, limited data suggest the potential for dietary nitrate (in the form of beetroot juice), creatine, and possibly caffeine, to further enhance endurance training adaptation. Therefore, the objective of this review is to examine the impact of dietary supplements on metabolic and physiological adaptations to endurance training.

Implementing Exercise in Healthcare Settings: The Potential of Implementation Science

01-01-2020 – L Czosnek,N Rankin,E Zopf,J Richards,S Rosenbaum,P Cormie

Journal Article

Abstract Exercise is an efficacious therapy for many chronic diseases. Integrating efficacious evidence-based interventions (EBIs), such as exercise, into daily healthcare practice is a slow and complex pursuit. Implementation science seeks to understand and address this phenomenon by conducting studies about the methods used to promote the routine uptake of EBIs. The purpose of this article is to explore implementation science and a common conceptual framework in the discipline, the Consolidated Framework for Implementation Research (CFIR), as it applies to exercise EBI. We conclude by offering recommendations for future research that leverage implementation science priorities to highlight the potential of this research field for advancing the implementation of exercise EBI.

The Effect of the Menstrual Cycle and Oral Contraceptives on Acute Responses and Chronic Adaptations to Resistance Training: A Systematic Review of the Literature

01-01-2020 – B Thompson,A Almarjawi,D Sculley,X Janse de Jonge

Journal Article, Review

Abstract Background Resistance training is well known to increase strength and lean body mass, and plays a key role in many female athletic and recreational training programs. Most females train throughout their reproductive years when they are exposed to continuously changing female steroid hormone profiles due to the menstrual cycle or contraceptive use. Therefore, it is important to focus on how female hormones may affect resistance training responses. Objective The aim of this systematic review is to identify and critically appraise current studies on the effect of the menstrual cycle and oral contraceptives on responses to resistance training. Methods The electronic databases Embase, PubMed, SPORTDiscus and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the menstrual cycle phase or oral contraceptive cycle on resistance training responses were included. Studies were also included if they compared resistance training responses between the natural menstrual cycle and oral contraceptive use, or if resistance training was adapted to the menstrual cycle phase or oral contraceptive phase. Studies were critically appraised with the Mc
Masters Universities Critical Review Form for Quantitative Studies and relevant data were extracted. Results Of 2007 articles found, 17 studies met the criteria and were included in this systematic review. The 17 included studies had a total of 418 participants with an age range of 18–38 years. One of the 17 studies found no significant differences in acute responses to a resistance training session over the natural menstrual cycle, while four studies did find changes. When assessing the differences in acute responses between the oral contraceptive and menstrual cycle groups, two studies reported oral contraceptives to have a positive influence, whilst four studies reported that oral contraceptive users had a delayed recovery, higher levels of markers of muscle damage, or both. For the responses to a resistance training program, three studies reported follicular phase-based training to be superior to luteal phase-based training or regular training, while one study reported no differences. In addition, one study reported no differences in strength development between oral contraceptive and menstrual cycle groups. One further study reported a greater increase in type I muscle fibre area and a trend toward a greater increase in muscle mass within low-androgenic oral contraceptive users compared with participants not taking hormonal contraceptives. Finally, one study investigated androgenicity of oral contraceptives and showed greater strength developments with high androgenic compared with anti-androgenic oral contraceptive use. Conclusions The reviewed articles reported conflicting findings, and were often limited by small participant numbers and methodological issues, but do appear to suggest female hormones may affect resistance training responses. The findings of this review highlight the need for further experimental studies on the effects of the menstrual cycle and oral contraceptives on acute and chronic responses to resistance training.

Use of Compositional Data Analysis to Show Estimated Changes in Cardiometabolic Health by Reallocating Time to Light-Intensity Physical Activity in Older Adults

01-01-2020 – C Powell,LD Browne,BP Carson,KP Dowd,IJ Perry,PM Kearney,JM Harrington,AE Donnelly

Journal Article

Abstract Background All physical activity (PA) behaviours undertaken over the day, including sleep, sedentary time, standing time, light-intensity PA (LIPA) and moderate-to-vigorous PA (MVPA) have the potential to influence cardiometabolic health. Since these behaviours are mutually exclusive, standard statistical approaches are unable to account for the impact on time spent in other behaviours. Objective By employing a compositional data analysis (Co
DA) approach, this study examined the associations of objectively measured time spent in sleep, sedentary time, standing time, LIPA and MVPA over a 24-h day on markers of cardiometabolic health in older adults. Methods Participants (n =366; 64.6 years 5.3; 46% female) from the Mitchelstown Cohort Rescreen Study provided measures of body composition, blood lipid and markers of glucose control. An activ
PAL3 Micro was used to obtain objective measures of sleep, sedentary time, standing time, LIPA and MVPA, using a 7-day continuous wear protocol. Regression analysis, using geometric means derived from Co
DA (based on isometric log-ratio transformed data), was used to examine the relationship between the aforementioned behaviours and markers of cardiometabolic health. Results Standing time and LIPA showed diverging associations with markers of body composition. Body mass index (BMI), body mass and fat mass were negatively associated with LIPA (all p <0.05) and positively associated with standing time (all p <0.05). Sedentary time was also associated with higher BMI (p <0.05). No associations between blood markers and any PA behaviours were observed, except for triglycerides, which were negatively associated with standing time (p < 0.05). Reallocating 30 min from sleep, sedentary time or standing time, to LIPA, was associated with significant decreases in BMI, body fat and fat mass. Conclusion This is the first study to employ Co
DA in older adults that has accounted for sleep, sedentary time, standing time, LIPA and MVPA in a 24-h cycle. The findings support engagement in LIPA to improve body composition in older adults. Increased standing time was associated with higher levels of adiposity, with increased LIPA associated with reduced adiposity; therefore, these findings indicate that replacing standing time with LIPA is a strategy to lower adiposity.

DNA Damage Following Acute Aerobic Exercise: A Systematic Review and Meta-analysis

01-01-2020 – DV Tryfidou,C McClean,MG Nikolaidis,GW Davison

Journal Article, Review

Abstract Background Exercise is widely recognised for its health enhancing benefits. Despite this, an overproduction of reactive oxygen and nitrogen species (RONS), outstripping antioxidant defence mechanisms, can lead to a state of (chronic) oxidative stress. DNA is a vulnerable target of RONS attack and, if left unrepaired, DNA damage may cause genetic instability. Objective This meta-analysis aimed to systematically investigate and assess the overall effect of studies reporting DNA damage following acute aerobic exercise. Methods Web of Science, PubMed, MEDLINE, EMBASE, and Scopus were searched until April 2019. Outcomes included (1) multiple time-points (TPs) of measuring DNA damage post-exercise, (2) two different quantification methods (comet assay and 8-oxo-2′-deoxyguanosine; 8-OHd
G), and (3) protocols of high intensity (≥ 75% of maximum rate of oxygen consumption; VO2-max) and long distance (≥ 42 km). Results Literature search identified 4316 non-duplicate records of which 35 studies were included in the meta-analysis. The evidence was strong, showcasing an increase in DNA damage immediately following acute aerobic exercise with a large-effect size at TP 0 (0 h) (SMD = 0.875; 95% CI 0.5, 1.25; p < 0.05). When comparing between comet assay and 8-OHd
G at TP 0, a significant difference was observed only when using the comet assay. Finally, when isolating protocols of long-distance and high-intensity exercise, increased DNA damage was only observed in the latter. (SMD = 0.48; 95% CI − 0.16, 1.03; p = 0.15 and SMD = 1.18; 95% CI 0.71, 1.65; p < 0.05 respectively). Conclusions A substantial increase in DNA damage occurs immediately following acute aerobic exercise. This increase remains significant between 2 h and 1 day, but not within 5–28 days post-exercise. Such an increase was not observed in protocols of a long-distance. The relationship between exercise and DNA damage may be explained through the hormesis theory, which is somewhat one-dimensional, and thus limited. The hormesis theory describes how exercise modulates any advantageous or harmful effects mediated through RONS, by increasing DNA oxidation between the two end-points of the curve: physical inactivity and overtraining. We propose a more intricate approach to explain this relationship: a multi-dimensional model, to develop a better understanding of the complexity of the relationship between DNA integrity and exercise.

Change of Direction Assessment Following Anterior Cruciate Ligament Reconstruction: A Review of Current Practice and Considerations to Enhance Practical Application

01-01-2020 – JB Marques,DJ Paul,P Graham-Smith,PJ Read

Journal Article, Review

Abstract Change of direction (Co
D) has been indicated as a key mechanism in the occurrence of anterior cruciate ligament (ACL) injury during invasion sports. Despite these associations, assessments of knee function in athletic populations at the time of return to sport following ACL reconstruction (ACLr) have often focused on strength and single-leg hop tests, with a paucity of evidence to describe the Co
D characteristics. Therefore, the aim of this narrative review was to describe the movement strategies exhibited following ACLr during Co
D tasks and to critically analyze the range of tests that have been used. Specifically, we examined their ability to identify between-limb deficits and individuals who display a heightened risk of secondary injury and/or reductions in their level of pre-injury performance. MEDLINE, PubMed and SPORT Discuss databases were used and 13 articles were identified that met the inclusion criteria. Examination of the available literature indicates that current field-based practices are not representative of relevant sport demands and are unable to effectively assess knee function following ACLr. Laboratory-based studies have identified residual deficits and altered movement strategies at the time of return to sport, and this in part may be related to risk of re-injury. However, these assessments exhibit inherent limitations and are not practically viable for monitoring progress during rehabilitation. Consequently, alternative solutions that are more-aligned with the multitude of factors occurring during Co
D maneuvers in chaotic sports environments are warranted to allow practitioners to ‘bridge the gap’ between the laboratory and the sports field/court. This approach may facilitate a more informed decision-making process with the end goal being, a heightened ‘return to performance’ and a lower risk of re-injury.

Increased Risk of Musculoskeletal Injury Following Sport-Related Concussion: A Perception–Action Coupling Approach

01-01-2020 – SR Eagle,AP Kontos,GJ Pepping,CD Johnson,A Sinnott,A LaGoy,C Connaboy

Journal Article

Abstract Recent studies have concluded that athletes have increased risk of musculoskeletal injury following sport-related concussion. While an underlying explanation is still unknown, perceptual-motor control may be implicated in this increased risk. Some authors have purported that indirect perception (i.e., a “top-down” view of neuromuscular control) may be disrupted following sport-related concussion. Direct perception theory states that the athlete and environment are inextricably linked in a continuous perception–action coupling loop. That is, the athlete is able to directly perceive opportunities for action (e.g., “affordances”) in the environment. Based on these notions, the aim of the current paper was to introduce a theoretical model that argues that sport-related concussion may dysregulate the direct perception process, potentially increasing behavioral risk of musculoskeletal injury during sport. Our model is integrated with a sport-related concussion clinical treatment model, which highlights individualized profiles that characterize the heterogeneous response to sport-related concussion. These profiles have a typical constellation of symptoms (e.g., anxiety, fatigue, ocular dysfunction, etc.), which themselves have been associated with disrupted perception–action coupling, independent of sport-related concussion. Therefore, we argue that athletes who have not re-established perception–action coupling loops following sport-related concussion may be at increased risk of subsequent musculoskeletal injury.

Effects of Exercise Intervention on Health-Related Physical Fitness and Blood Pressure in Preschool Children: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

01-01-2020 – A García-Hermoso,AM Alonso-Martinez,R Ramírez-Vélez,M Izquierdo

Journal Article, Review

Abstract Background No previous systematic review has quantitatively examined the effect of physical exercise interventions on health-related physical fitness and blood pressure in children younger than 6 years old. Objective To evaluate the effects of exercise interventions on health-related physical fitness (i.e., physical fitness components and body composition) and blood pressure in preschoolers. Methods We searched four databases. Only randomized controlled trials (RCTs), evaluating the effectiveness of exercise intervention on weight-related outcomes, blood pressure, and physical fitness components in preschoolers (1–5.99 years old) were included. The effect sizes were reported as Hedges’ g using random-effects models. Results A total of 19 RCTs were included. Exercise interventions favored reductions in body mass index (g = − 0.17; 95% confidence interval CI, − 0.31 to − 0.03), waist circumference (g = − 0.25; 95% CI − 0.47 to − 0.03), and body fat percentage (g = − 0.31; 95% CI − 0.60 to − 0.23); as well as improvement in cardiorespiratory fitness (g = 0.25; 95% CI 0.08–0.42), muscular strength (g = 0.25; 95% CI 0.09–0.40), and speed–agility (g = − 0.51; 95% CI − 0.78 to − 0.24). Blood pressure was not reduced. The subgroup analysis revealed that physical exercise alone favored larger reductions in body mass index and waist circumference compared with physical exercise combined with another intervention. Also, changes in cardiorespiratory fitness, lower-body muscular strength and speed–agility were associated with larger decreases in body composition. Conclusion Physical exercise whether combined or not with additional intervention has a small effect on both body weight and physical fitness in preschoolers. Also, it seems that interventions to prevent obesity should be directed towards improving physical fitness of preschoolers.

Potential Implications of Blood Flow Restriction Exercise on Vascular Health: A Brief Review

01-01-2020 – D da Cunha Nascimento,BJ Schoenfeld,J Prestes

Journal Article, Review

Abstract Blood flow restriction (BFR) exercise (a.k.a. occlusion training) has emerged as a viable surrogate to traditional heavy-load strength rehabilitation training for a broad range of clinical populations including elderly subjects and rehabilitating athletes. A particular benefit of BFR exercise is the lower stress upon the joints as compared to traditional heavy resistance training, with similar gains in muscle strength and size. The application of an inflatable cuff to the proximal portion of the limbs increases the pressure required for venous return, leading to changes in venous compliance and wall tension. However, it is not known if long-term benefits of BFR exercise on muscle strength and size outweigh potential short and long-term complications on vascular health. BFR exercise could lead to clinical deterioration of the vasculature along with sympathetic overactivity and decreased vascular function associated with retrograde shear stress. This raises a fundamental question: Given the concern that excessive restriction could cause injury to endothelial cells and might cause detrimental effects on endothelial function, even in healthy individuals, should we critically re-evaluate the safety of this method for the general population? From this perspective, the purpose of this manuscript is to review the effects of BFR exercise on vascular function, and to provide relevant insights for training practice as well as future directions for research.

Effect of Strength Training on Biomechanical and Neuromuscular Variables in Distance Runners: A Systematic Review and Meta-Analysis

01-01-2020 – D Trowell,B Vicenzino,N Saunders,A Fox,J Bonacci

Journal Article, Review

Abstract Background Concurrent strength and endurance (CSE) training improves distance running performance more than endurance training alone, but the mechanisms underpinning this phenomenon are unclear. It has been hypothesised that biomechanical or neuromuscular adaptations are responsible for improvements in running performance; however, evidence on this topic has not been synthesised in a review. Objective To evaluate the effect of CSE training on biomechanical and neuromuscular variables in distance runners. Methods Seven electronic databases were searched from inception to November 2018 using key terms related to running and strength training. Studies were included if the following criteria were met: (1) population: ‘distance’ or ‘endurance’ runners of any training status; (2) intervention: CSE training; (3) comparator: running-only control group; (4) outcomes: at least one biomechanical or neuromuscular variable; and, (5) study design: randomised and non-randomised comparative training studies. Biomechanical and neuromuscular variables of interest included: (1) kinematic, kinetic or electromyography outcome measures captured during running; (2) lower body muscle force, strength or power outcome measures; and (3) lower body muscle–tendon stiffness outcome measures. Methodological quality and risk of bias for each study were assessed using the PEDro scale. The level of evidence for each variable was categorised according to the quantity and PEDro rating of the included studies. Between-group standardised mean differences (SMD) with 95% confidence intervals (95% CI) were calculated for studies and meta-analyses were performed to identify the pooled effect of CSE training on biomechanical and neuromuscular variables. Results The search resulted in 1578 potentially relevant articles, of which 25 met the inclusion criteria and were included. There was strong evidence that CSE training significantly increased knee flexion (SMD 0.89 95% CI 0.48, 1.30, p < 0.001), ankle plantarflexion (SMD 0.74 95% CI 0.21–1.26, p = 0.006) and squat (SMD 0.63 95% CI 0.13, 1.12, p = 0.010) strength, but not jump height, more than endurance training alone. Moderate evidence also showed that CSE training significantly increased knee extension strength (SMD 0.69 95% CI 0.29, 1.09, p < 0.001) more than endurance training alone. There was very limited evidence reporting changes in stride parameters and no studies examined changes in biomechanical and neuromuscular variables during running. Conclusions Concurrent strength and endurance training improves the force-generating capacity of the ankle plantarflexors, quadriceps, hamstrings and gluteal muscles. These muscles support and propel the centre of mass and accelerate the leg during running, but there is no evidence to suggest these adaptations transfer from strength exercises to running. There is a need for research that investigates changes in biomechanical and neuromuscular variables during running to elucidate the effect of CSE training on run performance in distance runners.

Exercise as Medicine for Mental and Substance Use Disorders: A Meta-review of the Benefits for Neuropsychiatric and Cognitive Outcomes

01-01-2020 – G Ashdown-Franks,J Firth,R Carney,AF Carvalho,M Hallgren,A Koyanagi,S Rosenbaum,FB Schuch,L Smith,M Solmi,D Vancampfort,B Stubbs

Journal Article, Review

Abstract Background Exercise may improve neuropsychiatric and cognitive symptoms in people with mental disorders, but the totality of the evidence is unclear. We conducted a meta-review of exercise in (1) serious mental illness (schizophrenia spectrum, bipolar disorder and major depression (MDD)); (2) anxiety and stress disorders; (3) alcohol and substance use disorders; (4) eating disorders (anorexia nervosa bulimia nervosa, binge eating disorders, and (5) other mental disorders (including ADHD, pre/post-natal depression). Methods Systematic searches of major databases from inception until 1/10/2018 were undertaken to identify meta-analyses of randomised controlled trials (RCTs) of exercise in people with clinically diagnosed mental disorders. In the absence of available meta-analyses for a mental disorder, we identified systematic reviews of exercise interventions in people with elevated mental health symptoms that included non-RCTs. Meta-analysis quality was assessed with the AMSTAR/+. Results Overall, we identified 27 systematic reviews (including 16 meta-analyses representing 152 RCTs). Among those with MDD, we found consistent evidence (meta-analyses = 8) that exercise reduced depression in children, adults and older adults. Evidence also indicates that exercise was more effective than control conditions in reducing anxiety symptoms (meta-analyses = 3), and as an adjunctive treatment for reducing positive and negative symptoms of schizophrenia (meta-analyses = 2). Regarding neurocognitive effects, exercise improved global cognition in schizophrenia (meta-analyses = 1), children with ADHD (meta-analyses = 1), but not in MDD (meta-analyses = 1). Among those with elevated symptoms, positive mental health benefits were observed for exercise in people with pre/post-natal depression, anorexia nervosa/bulimia nervosa, binge eating disorder, post-traumatic stress disorder and alcohol use disorders/substance use disorders. Adverse events were sparsely reported. Conclusion Our panoramic meta-overview suggests that exercise can be an effective adjunctive treatment for improving symptoms across a broad range of mental disorders.

The Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Strength and Muscle Architecture Adaptations: A Systematic Review and Meta-analyses

01-01-2020 – M Cuthbert,N Ripley,JJ McMahon,M Evans,GG Haff,P Comfort

Journal Article, Review

Abstract Background Although performance of the Nordic hamstring exercise (NHE) has been shown to elicit adaptations that may reduce hamstring strain injury (HSI) risk and occurrence, compliance in NHE interventions in professional soccer teams is low despite a high occurrence of HSI in soccer. A possible reason for low compliance is the high dosages prescribed within the recommended interventions. The aim of this review was to investigate the effect of NHE-training volume on eccentric hamstring strength and biceps femoris fascicle length adaptations. Methods A literature search was conducted using the SPORTDiscus, Ovid, and PubMed databases. A total of 293 studies were identified prior to application of the following inclusion criteria: (1) a minimum of 4 weeks of NHE training was completed; (2) mean ± standard deviation (SD) pre- and post-intervention were provided for the measured variables to allow for secondary analysis; and (3) biceps femoris muscle architecture was measured, which resulted in 13 studies identified for further analysis. The TESTEX criteria were used to assess the quality of studies with risk of bias assessment assessed using a fail-safe N (Rosenthal method). Consistency of studies was analysed using I2 as a test of heterogeneity and secondary analysis of studies included Hedges’ g effect sizes for strength and muscle architecture variables to provide comparison within studies, between-study differences were estimated using a random-effects model. Results A range of scores (3–11 out of 15) from the TESTEX criteria were reported, showing variation in study quality. A ‘low risk of bias’ was observed in the randomized controlled trials included, with no study bias shown for both strength or architecture (N = 250 and 663, respectively; p < 0.001). Study consistency was moderate to high for strength (I2 = 62.49%) and muscle architecture (I2 = 88.03%). Within-study differences showed that following interventions of ≥ 6 weeks, very large positive effect sizes were seen in eccentric strength following both high volume (g = 2.12) and low volume (g = 2.28) NHE interventions. Similar results were reported for changes in fascicle length (g ≥ 2.58) and a large-to-very large positive reduction in pennation angle (g ≥ 1.31). Between-study differences were estimated to be at a magnitude of 0.374 (p = 0.009) for strength and 0.793 (p < 0.001) for architecture. Conclusions Reducing NHE volume prescription does not negatively affect adaptations in eccentric strength and muscle architecture when compared with high dose interventions. These findings suggest that lower volumes of NHE may be more appropriate for athletes, with an aim to increase intervention compliance, potentially reducing the risk of HSI.

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

24-12-2019 – 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.