Background: We monitored changes in salivary creatine pre-and post-high-intensity exercise in young adults while also investigating the potential correlation between salivary and serum creatine levels.Method: Saliva a...Background: We monitored changes in salivary creatine pre-and post-high-intensity exercise in young adults while also investigating the potential correlation between salivary and serum creatine levels.Method: Saliva and serum samples were collected before and immediately after an incremental running-toexhaustion treadmill test in fifteen young adults(mean age [23.9 ± 2.9] years, eight females), with samples analyzed for guanidinoacetic acid, creatine, and creatinine using a liquid chromatography–tandem mass spectrometry method.Results: Following exercise, there was a substantial elevation in salivary creatine levels from(17.5 ± 14.2)μmol·L^(-1) to(43.6 ± 30.4) μmol·L^(-1)(p < 0.001), coupled with a significant increase in salivary creatinine from(11.3 ± 5.8) μmol·L^(-1) to(17.0 ± 9.3) μmol·L^(-1)(p = 0.04). In contrast, serum creatine levels were unaffected by exercise(p = 0.80), while creatinine levels exhibited a strong tendency to decrease post-exercise(from [81.8 ±17.5] μmol·L^(-1) to [73.1 ± 11.6] μmol·L^(-1);p = 0.06). A comparison of the slopes of the two regression lines(saliva vs. serum) revealed significant differences for both creatine(p = 0.01) and creatinine(p = 0.03).Conclusions: The above findings suggest a potential difference in the dynamics of creatine metabolites in these two bodily fluids, both pre and post-exercise.展开更多
Background: Exercise promotes numerous phenotypic adaptations in skeletal muscle that contribute to improved function and metabolic capacity. An emerging body of evidence suggests that skeletal muscle also releases a ...Background: Exercise promotes numerous phenotypic adaptations in skeletal muscle that contribute to improved function and metabolic capacity. An emerging body of evidence suggests that skeletal muscle also releases a myriad of factors during exercise, termed "myokines". The purpose of this study was to examine the effects of high-intensity interval training(HIIT) on the acute regulation of the mRNA expression of several myokines, including the prototypical myokine interleukin-6(IL-6), and recently identified myokines fibronectin type III domain-containing protein 5(FNDC5)(irisin) and meteorin-like protein(METRNL).Methods: Both before and after a 20-day period of twice-daily high-volume HIIT, 9 healthy males(20.5 ± 1.5 years performed a standardized bout of high-intensity interval exercise(HIIE; 5 × 4 min at ~80% pretraining peak power output) with skeletal muscle biopsy samples(vastus lateralis) obtained at rest, immediately following exercise, and at 3 h recovery.Results: Before training, a single bout of HIIE increased IL-6(p < 0.05) and METRNL(p < 0.05) mRNA expression measured at 3 h recovery when compared to rest. Following 20 days of HIIT, IL-6 and FNDC5 mRNA were increased at 3 h recovery from the standardized HIIE bout when compared to rest(both p < 0.05). Resting METRNL and FNDC5 mRNA expression were higher following training(p < 0.05), and there was an overall increase in FNDC5 mRNA post-training(main effect of training, p < 0.05).Conclusion: In human skeletal muscle(1) an acute bout of HIIE can induce upregulation of skeletal muscle IL-6 mRNA both before and after a period of intensified HIIT;(2) Resting and overall FNDC5 mRNA expression is increased by 20 days of HIIT; and(3) METRNL mRNA expression is responsive to both acute HIIE and short-term intense HIIT. Future studies are needed to confirm these findings at the protein and secretion level in humans.展开更多
Purpose: The purpose of this study was to investigate the effect of variable intensities on a simple memory recognition task during exercise.Methods: Twenty active participants took part in initial testing, a familiar...Purpose: The purpose of this study was to investigate the effect of variable intensities on a simple memory recognition task during exercise.Methods: Twenty active participants took part in initial testing, a familiarization trial and then four 60 min cycling interventions in a randomized order.Interventions consisted of no exercise（control）, constant exercise at 90% ventilatory threshold（constant） and 2 trials that initially mimicked the constant trial, but then included periods of high(90% VO2peak) and low intensities(50% VO2peak). Cardiorespiratory measures and capillary blood samples were taken throughout. A short tablet-based cognitive task was completed prior to and during（50 and 55 min into exercise） each intervention.Results: The exercise conditions facilitated response time（p = 0.009）, although the extent of this effect was not as strong in the variable exercise conditions（p = 0.011–0.089）. High intensity exercise periods resulted in some cognitive regression back towards control trial performance.Elevations in cardiorespiratory measures and periods of hypocapnia could not explain changes in cognitive performance.Conclusion: Changes in cognitive performance with variations in exercise intensity are likely to have implications for sport and occupational settings. The timing of cognitive tests to exercise intensity changes as well as use of short cognitive assessments will be important for future work.展开更多
Objectives:Adolescents using active transport(AT)to school have higher levels of physical activity(PA)compared with motorized transport(MT)users.This study compared school day and weekend day PA in adolescents using A...Objectives:Adolescents using active transport(AT)to school have higher levels of physical activity(PA)compared with motorized transport(MT)users.This study compared school day and weekend day PA in adolescents using AT,MT,or combined AT and MT(AT + MT)to travel to school.Methods:Adolescents(n= 314;age:14.7±1.4 years;32.8% boys)from Dunedin(New Zealand)wore an accelerometer for 7 days and completed a self-reported survey regarding mode of transport to school(73 AT,56 AT + MT,and 185 MT).Data were analyzed using t tests,analysis of variance,and χ2 tests.Results:Although the proportion of adolescents meeting PA guidelines significantly differed among transport groups(AT,47.9%;AT + MT,46.4%;MT,33.5%;p=0.048;overall,39.2%),the observed differences were due mainly to girls.Compared with MT,AT and AT+MT engaged in more moderate-to-vigorous PA(MVPA)per day(AT:61.2 ± 23.2 min;AT+MT:59.6 ± 21.7 min;MT:52.5 ± 19.6 min;p = 0.004;p<0.001,adjusted for gender),per school day and before school.Immediately after school(15:00-16:00),AT engaged in significantly more MVPA compared with AT + MT and MT.No differences in MVPA between the groups were observed in the late afternoon/early evening period during school days or on weekend days.Conclusion:Compared with MT users,adolescent girls using AT or AT + MT accumulated more MVPA during school commute time.AT + MT to school is also a plausible way to increase adolescent girls’ PA when AT only is not feasible.展开更多
Background:Deep body temperature is a critical indicator of heat strain.However,direct measures are often invasive,costly,and difficult to implement in the field.This study assessed the agreement between deep body tem...Background:Deep body temperature is a critical indicator of heat strain.However,direct measures are often invasive,costly,and difficult to implement in the field.This study assessed the agreement between deep body temperature estimated from heart rate and that measured directly during repeated work bouts while wearing explosive ordnance disposal(EOD)protective clothing and during recovery.Methods:Eight males completed three work and recovery periods across two separate days.Work consisted of treadmill walking on a 1%incline at 2.5,4.0,or 5.5 km/h,in a random order,wearing EOD protective clothing.Ambient temperature and relative humidity were maintained at 24℃and 50%[Wet bulb globe temperature(WBGT)(20.9±1.2)℃]or 32℃and 60%[WBGT(29.0±0.2)℃]on the separate days,respectively.Heart rate and gastrointestinal temperature(TGI)were monitored continuously,and deep body temperature was also estimated from heart rate(ECTemp).Results:The overall systematic bias between TGI and ECTemp was 0.01℃with 95%limits of agreement(Lo A)of±0.64℃and a root mean square error of 0.32℃.The average error statistics among participants showed no significant differences in error between the exercise and recovery periods or the environmental conditions.At TGI levels of(37.0–37.5)℃,(37.5–38.0)℃,(38.0–38.5)℃,and>38.5℃,the systematic bias and±95%Lo A were(0.08±0.58)℃,(–0.02±0.69)℃,(–0.07±0.63)℃,and(–0.32±0.56)℃,respectively.Conclusions:The findings demonstrate acceptable validity of the ECTemp up to 38.5℃.Conducting work within an ECTemp limit of 38.4℃,in conditions similar to the present study,would protect the majority of personnel from an excessive elevation in deep body temperature(>39.0℃).展开更多
There is now strong evidence that exercise has an acute effect on the urge to smoke and the accompanying withdrawal symptoms. However, the perceptions by heavy smokers of exercise and its relationship to the urge to s...There is now strong evidence that exercise has an acute effect on the urge to smoke and the accompanying withdrawal symptoms. However, the perceptions by heavy smokers of exercise and its relationship to the urge to smoke have not been well documented. The aim of the present study is to understand the experiences of heavy smokers with regard to exercise and its effect on their urge to smoke. Five physically inactive, heavy smokers are asked to abstain from smoking the night before exercising on a cycle ergometer under two conditions (one at medium and one at vigorous intensity done a week apart). Semi-structured, in-depth interviews are conducted after the second exercise session. Thematic analysis reveals six themes describing the participants’ experience of exercise, urge to smoke, exercise preferences, exercise and smoking relationship, exercise as an aid to quit smoking, and the effects of the experimental procedure. Overall, the participants’ experiences support the existing literature, which has posited affective, biological, and cognitive mechanisms contributing to a delay in the urge to smoke after exercise. The main findings pertain to: (1) the “feel-good” effect after exercise as a relief from the “feel-bad” effect during exercise;(2) the decreased urge to smoke after exercise, stated by all participants regardless of reported positive and negative feelings;and (3) exercise as a “clearing the mind” mechanism rather than an attention-distracting mechanism.展开更多
A large body of evidence shows that a single bout of strenuous exercise induces oxidative stress in circu- lating human lymphocytes leading to lipid peroxide- tion, DNA damage, mitochondrial perturbations, and protein...A large body of evidence shows that a single bout of strenuous exercise induces oxidative stress in circu- lating human lymphocytes leading to lipid peroxide- tion, DNA damage, mitochondrial perturbations, and protein oxidation. In a training experiment, Wistar rats were divided into control group (CG) and exer- cise group (EG). After a running level exercise until exhaustion, we observed an increase in the mRNA content and protein expression of SIRT1 and SIRT7 in the EG compared to the CG. Moreover, such train- ing exercise did not change mRNA transcripts and protein expression of FOXO3A and GADD45. We also observed an increase of pro-apoptotic protein bax and a decrease of the anti-apoptotic protein bcl-2 in the EG. Accordingly, we observed a caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage only in EG rats. Statistical analysis of the data showed a significant correlation between SIRT1 and SIRT7 expression and apoptotic proteins such as bax, bcl-2 in both tissues. We conclude that, in both muscle, such exercise activates both a damaging apoptotic mecha- nism with bax increase and bcl-2 decrease and a counterbalancing protective mechanism with SIRT1 and SIRT7 increase.展开更多
Dear editor,As government restrictions put in place to slow the acceleration of the coronavirus disease-2019(COVID-19)pandemic start to ease,many people,including elite athletes,will begin to return back to their norm...Dear editor,As government restrictions put in place to slow the acceleration of the coronavirus disease-2019(COVID-19)pandemic start to ease,many people,including elite athletes,will begin to return back to their normal daily activities.Although the majority of risk factors for severe COVID-19-hypertension,respiratory system disease.展开更多
Textiles with electronic components offer a portable and personalized approach for health monitoring and therapy.However,there is a lack of reliable strategy to integrate layered circuits and high-density chips on or ...Textiles with electronic components offer a portable and personalized approach for health monitoring and therapy.However,there is a lack of reliable strategy to integrate layered circuits and high-density chips on or inside textiles,which hinders system-level functionality and untethered user experiences.Herein,we propose monolithically integrated textile hybrid electronics(THE)on a textile platform,with multimodal functions and reliable performances.The textile system encompasses flexible electrodes,laser-induced sensors,and surface-mount devices,along with double-layer circuits interconnecting all of them.Vertical conductive paths are rendered by liquid metal composites infiltrated into textiles,which allows resistances less than 0.1?while reserving intact textile structures.The assembled THE exhibits endurance to handwashing and crumpling,as well as bendability.We customize a wireless textile patch for synchronously tracking multiple physiological indicators during exercise.Furthermore,a textile band is elaborated for monitoring and alleviating muscular fatigue,demonstrating potential in closed-loop diagnosis and treatment.展开更多
Marching band(MB)artists are often part of the general student population and not required to complete a preparticipation health screening to identify predisposing medical conditions or risks for injury/illness.Anecdo...Marching band(MB)artists are often part of the general student population and not required to complete a preparticipation health screening to identify predisposing medical conditions or risks for injury/illness.Anecdotally,exertional heat illnesses(EHI)are a concern for MB artists.As more athletic trainers provide MB healthcare,research is needed on EHI occurrence and MB associated EHI risk factors.We utilized an exploratory crosssectional study design to determine EHI risk factors,including previous EHI occurrence,among collegiate MB artists.MB artists(n=1207;age=[19.6±1.3]years)actively participating in their college/university's MB during the 2019 football season completed an online survey to characterize demographics,medical history,medication and supplement use,and nutrition behaviors.Chi-square and binomial logistical regressions assessed associations between categorical variables.Previous EHI was reported by 50.6%of MB artists,with 466(76.3%)experiencing exertional heat exhaustion and 31(5.1%)exertional heat stroke.More females reported exertional heat exhaustion overall(68.2%,p<0.001)and in the previous year(73.3%,p<0.001).Experiencing a previous EHI was significantly associated with having a mood/neurological condition(63.5%,p<0.001),diagnosed(74.3%,p=0.004)or perceived eating disorder(66.7%,p<0.001),and taking prescription medications(59.4%,p<0.001),over-the-counter medications(58.9%,p=0.002),and supplements(55.4%,p=0.037).Half of collegiate MB artists reported experiencing previous EHIs and engaged in behaviors known to increase EHI risk.MB artists should complete pre-participation examinations to identify pre-existing medical conditions and risks for adverse medical events.Healthcare providers working with MB artists should develop policies and procedures to mitigate EHI risks and occurrence.展开更多
This study retrospectively evaluated data from an athlete management system on the impact of a 6-week,12-session risk-reduction athletic development training program on maximal isometric strength in post-rehabilitativ...This study retrospectively evaluated data from an athlete management system on the impact of a 6-week,12-session risk-reduction athletic development training program on maximal isometric strength in post-rehabilitative and healthy men and women.Maximal isometric quadriceps and hamstrings strength were evaluated bilaterally before and after the training program.Out of 55 athletes that had participated in the program,a total of 37 athletes'(13-28 years old)recorded outcomes were utilized in analyses.Thirty-one athletes had undergone rehabilitation(post-rehabilitative athletes)after orthopedic knee surgeries.Six athletes with no previous surgeries performed(healthy athletes)also completed the 6-week program.Repeated measures analyses of variance(leg×time)assessed changes in quadriceps and hamstrings strength at an alpha of p≤0.05.There was a main effect for time where the post-rehabilitative athletes’quadriceps and hamstrings strength increased by(mean difference±standard error)(4.2±0.7)kg(p<0.01)and(4.5±0.9)kg(p<0.01)respectively,with legs(operative[OP])and (non-operative[NOP])combined.With time points combined,the OP limb was weaker than the NOP limb for quadriceps strength by(2.9±0.7)kg(p<0.01)with no differences in hamstrings strength.For the healthy athletes,there were no changes for quadriceps strength and hamstring strength improved across time by(5.3±1.4)kg(p=0.01)with legs combined.In conclusion,there were improvements in post-rehabilitative and healthy athletes’isometric strength after the training program.However,between-limb strength asymmetries were still apparent in the post-rehabilitation cohort.展开更多
Background:Stretching has wide appeal,but there seems to exist some mismatch between its purported applications and what the evidence shows.There is compelling evidence for some stretching applications,but for others,...Background:Stretching has wide appeal,but there seems to exist some mismatch between its purported applications and what the evidence shows.There is compelling evidence for some stretching applications,but for others,the evidence seems heterogeneous or unsupportive.The discrepancies even affect some systematic reviews,possibly due to heterogeneous eligibility criteria and search strategies.This consensus paper seeks to unify the divergent findings on stretching and its implications for both athletic performance and clinical practices by delivering evidence-based recommendations.Methods:A panel of 20 experts with a blend of practical experience and scholarly knowledge was assembled.The panel meticulously reviewed existing systematic reviews,defined key terminologies(e.g.,consensus definitions for different stretching modes),and crafted guidelines using a Delphi consensus approach(minimum required agreement:80%).The analysis focused on 8 topics,including stretching's acute and chronic(long-term)effects on range of motion,strength performance,muscle hypertrophy,stiffness,injury prevention,muscle recovery,posture correction,and cardiovascular health.Results:There was consensus that chronic and acute stretching(a)improves range of motion(although alternatives exist)and(b)reduces muscle stiffness(which may not always be desirable);the panel also agreed that chronic stretching(c)may promote vascular health,but more research is warranted.In contrast,consensus was found that stretch training does not(a)contribute substantively to muscle growth,(b)serve as an allencompassing injury prevention strategy,(c)improve posture,or(d)acutely enhance post-exercise recovery.Conclusion:These recommendations provide guidance for athletes and practitioners,highlighting research gaps that should be addressed to more comprehensively understand the full scope of stretching effects.展开更多
Due to safety concerns and side effects of many antidepressant medications, herbal psychopharmacology research has increased, and herbal remedies are becoming increasingly popular as alternatives to prescribed medicat...Due to safety concerns and side effects of many antidepressant medications, herbal psychopharmacology research has increased, and herbal remedies are becoming increasingly popular as alternatives to prescribed medications for the treatment of major depressive disorder （MDD）. Of these, accumulating trials reveal positive effects of the spice saffron （Crocus sativus L.） for the treatment of depression. A comprehensive and statistical review of the clinical trials examining the effects of saffron for treatment of MDD is warranted. OBJECTIVE： The purpose of this study was to conduct a meta-analysis of published randomized controlled trials examining the effects of saffron supplementation on symptoms of depression among participants with MDD. SEARCH STRATEGY： We conducted electronic and non-electronic searches to identify all relevant randomized, double-blind controlled trials. Reference lists of all retrieved articles were searched for relevant studies. INCLUSION CRITERIA： The criteria for study selection included the following： （1） adults （aged 18 and older） with symptoms of depression, （2） randomized controlled trial, （3） effects of saffron supplementation on depressive symptoms examined, and （4） study had either a placebo control or antidepressant comparison group. DATA EXTRACTION AND ANALYSIS： Using random effects modeling procedures, we calculated weighted mean effect sizes separately for the saffron supplementation vs placebo control groups, and for the saffron supplementation vs antidepressant groups. The methodological quality of all studies was assessed using the Jadad score. The computer software Comprehensive Meta- analysis 2 was used to analyze the data. RESULTS： Based on our pre-specified criteria, five randomized controlled trials （n = 2 placebo controlled trials, n = 3 antidepressant controlled trials） were included in our review. A large effect size was found for saffron supplementation vs placebo control in treating depressive symptoms （M ES = 1.62, P 〈 0.001）, revealing that saffron supplementation significantly reduced depression symptoms compared to the placebo control. A null effect size was evidenced between saffron supplementation and the antidepressant groups （M ES = -0.15） indicating that both treatments were similarly effective in reducing depression symptoms. The mean Jadad score was 5 indicating high quality of trials. CONCLUSION： Findings from clinical trials conducted to date indicate that saffron supplementation can improve symptoms of depression in adults with MDD. Larger clinical trials, conducted by research teams outside of Iran, with long-term follow-ups are needed before firm conclusions can be made regarding saffron＇s efficacy and safety for treating depressive symptoms.展开更多
Purpose： The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically,...Purpose： The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically, it was hypothesized that the catecholamine, lactate, and ventilatory thresholds is the point at which significant improvements in speed of cognitive function are observed. Methods： We compared mean effect sizes for threshold studies and for those studies where exercise intensity was classed as moderate （40%-- 79% VO2 or equivalent） but in which the thresholds were not measured. Results： Random effects meta-analysis showed significant, moderate, mean effect sizes for studies at the threshold （g = 0.58, Z = 2.98, p 〈 0.003） and for those during moderate intensity exercise but in which the threshold was not measured （ g = 0.54, Z = 5.0l, p 〈 0.001）. There was no significant difference between mean effect sizes, which suggests that the thresholds are unlikely to represent a trigger point. Conclusion： Moderate intensity exercise, even below the thresholds, can induce improved speed of cognition, possibly due to a combination of increased peripheral catecholamine concentrations inducing vagal/nucleus tractus solitarii pathway activation and central increases due to perceptions of stress.展开更多
Background:Cross-country skiing(XCS)racing,a popular international winter sport,is complex and challenging from physical,technical,and tactical perspectives.Despite the vast amount of research focusing on this sport,n...Background:Cross-country skiing(XCS)racing,a popular international winter sport,is complex and challenging from physical,technical,and tactical perspectives.Despite the vast amount of research focusing on this sport,no review has yet addressed the pacing strategies of elite XCS racers or the factors that influence their performance.The aim was to review the scientific literature in an attempt to determine the effects of pacing strategy on the performance of elite XCS racers.Methods:Four electronic databases were searched using relevant subject headings and keywords.Only original research articles published in peerreviewed journals and the English language and addressing performance,biomechanics,physiology,and anthropometry of XCS racers were reviewed.Results:All 27 included articles applied correlative designs to study the effectiveness of different pacing strategies.None of the articles involved the use of an experimental design.Furthermore,potential changes in external conditions(e.g.,weather,ski properties)were not taken into consideration.A comparable number of studies focused on the skating or classical technique.In most cases,positive pacing was observed,with certain indications that higher-level athletes and those with more endurance and strength utilized a more even pacing strategy.The ability to achieve and maintain a long cycle length on all types of terrain was an important determinant of performance in all of the included studies,which was not the case for cycle rate.In general,uphill performance was closely related to overall race performance,with uphill performance being most closely correlated to the success of female skiers and performance on flat terrain being more important for male skiers.Moreover,pacing was coupled to the selection and distribution of technique during a race,with faster skiers employing more double poling and kick double poling,less diagonal stride,and more V2(double dance)than V1(single dance)skating across a race.Conclusion:We propose that skiers at all levels can improve their performance with more specific training in techniques(i.e.,maintaining long cycles without compromising cycle rate and selecting appropriate techniques)in combination with training for endurance and more strength.Furthermore,we would advise less experienced skiers and/or those with lower levels of performance to apply a more even pacing strategy rather than a positive one(i.e.,starting the race too fast).2018 Published by Elsevier B.V.on behalf of Shanghai University of Sport.This is an open access article under the CC BY-NC-ND license.(http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
Background Cardiac arrhythmias are common conditions in older people.Unfortunately,there is limited literature on associations between cardiac arrhythmias and physical performance or disability.We therefore aimed to p...Background Cardiac arrhythmias are common conditions in older people.Unfortunately,there is limited literature on associations between cardiac arrhythmias and physical performance or disability.We therefore aimed to prospectively investigate associations between cardiac arrhythmias and changes in disability and physical performance during 8 years of follow-up,using data from the Italian Longitudinal Study on Aging(ILSA).Methods Cardiac arrhythmias diagnosis was posed through a screening phase,confirmed by a physician.The onset of disability in activities of daily living(ADL)and the changes in several physical performance tests during follow-up were considered as outcomes.Fully-adjusted and propensity-score Cox Proportional Hazard models and mixed models were used for exploring associations between cardiac arrhythmia and the outcomes of interest.Results The prevalence of cardiac arrhythmia at baseline was 23.3%.People reporting cardiac arrhythmia at the baseline were significantly older,more frequently male,smokers and reported a higher presence of all medical conditions investigated(hypertension,heart failure,angina,myocardial infarction,diabetes,stroke),but no difference in dementia,Parkinsonism,cognitive or mood disorder.Cardiac arrhythmia at baseline was significantly associated with the incidence of disability in ADL(HR=1.23;95%:CI:1.01–1.50;P=0.0478 in propensity score analyses;HR=1.28;95%CI:1.01–1.61;P=0.0401 in fully adjusted models).Cardiac arrhythmia at baseline was also associated with a significant worsening in balance test(P=0.0436).Conclusions The presence of cardiac arrhythmia at baseline was associated with a significant higher risk of disability and of worsening in some physical performance tests,particularly those relating to balance.Screening and frequently assessing physical performance in older people affected by cardiac arrhythmia can be important to prevent a loss of physical performance,with further,potential,complications of medical management.展开更多
Background:For the past 30 years,the hamstring(H)-to-quadriceps(Q)(H:Q)torque ratio has been considered an important index of muscle strength imbalance around the knee joint.The purpose of this systematic review was t...Background:For the past 30 years,the hamstring(H)-to-quadriceps(Q)(H:Q)torque ratio has been considered an important index of muscle strength imbalance around the knee joint.The purpose of this systematic review was to examine the value of H:Q torque ratio as an independent risk factor for hamstring and anterior cruciate ligament(ACL)injuries.Methods:Database searches were performed to identify all relevant articles in PubMed,MEDLINE,Cochrane Library,and Scopus.Prospective studies evaluating the conventional(concentric H:Q),functional(eccentric H:concentric Q),and mixed(eccentric H at 300/s:concentric Q at2400/s)H:Q ratios as risk factors for occurrence of hamstring muscle strain or ACL injury were considered.Risk of bias was assessed using the Quality In Prognosis Studies tool.Results:Eighteen included studies reported 585 hamstrings injuries in 2945 participants,and 5 studies documented 128 ACL injuries in 2772participants.Best evidence synthesis analysis indicated that there is very limited evidence that H:Q strength ratio is an independent risk factor for hamstring and ACL injury,and this was not different between various ratio types.Methodological limitations and limited evidence for ACL injuries and some ratio types might have influenced these results.Conclusion:The H:Q ratio has limited value for the prediction of ACL and hamstring injuries.Monitoring strength imbalances along with other modifiable factors during the entire competitive season may provide a better understanding of the association between H:Q ratio and injury.展开更多
Purpose We compared running economy(RE)and 3-km time-trial(TT)variables of runners wearing Nike Vaporfly 4%(VP4),Saucony Endorphin lightweight racing flats(FLAT),and their habitual running(OWN)footwear.Methods Eightee...Purpose We compared running economy(RE)and 3-km time-trial(TT)variables of runners wearing Nike Vaporfly 4%(VP4),Saucony Endorphin lightweight racing flats(FLAT),and their habitual running(OWN)footwear.Methods Eighteen male recreational runners(age=33.5±11.9 year(mean±SD),peak oxygen uptake(VO_(2peak))=55.8±4.4 mL/kg·min)attended 4 sessions approximately 7 days apart.The first session consisted of a VO_(2peak) test to inform subsequent RE speeds set at 60%,70%,and 80%of the speed eliciting VO2peak.In subsequent sessions,treadmill RE and 3-km TTs were assessed in the 3 footwear conditions in a randomized,counterbalanced crossover design.Results Oxygen consumption(mL/kg·min)was less in VP4(from 4.3%to 4.4%,p≤0.002)and FLAT(from 2.7%to 3.4%,p≤0.092)vs.OWN across intensities,with a non-significant difference between VP4 and FLAT(1.0%-1.7%,p≥0.292).Findings related to energy cost(W/kg)and energetics cost of transport(J/kg·m)were comparable.VP43-km TT performance(11:07.6±0:56.6 mm:ss)was enhanced vs.OWN by 16.6 s(2.4%,p=0.005)and vs.FLAT by 13.0 s(1.8%,p=0.032).The 3-km times between OWN and FLAT(0.5%,p=0.747)were similar.Most runners(n=11,61%)ran their fastest TT in VP4.Conclusion Overall,VP4 improved laboratory-based RE measures in male recreational runners at relative speeds compared to OWN,but the RE improvements in VP4 were not significant vs.FLAT.More runners exhibited better treadmill TT performances in VP4(61%)vs.FLAT(22%)and OWN(17%).The variability in RE(-10.3%to 13.3%)and TT(-4.7%to 9.3%)improvements suggests that responses to different types of shoes are individualized and warrant further investigation.展开更多
Objective:This study aimed to examine(1)the independent effects of hypoxia on cognitive function and(2)the effects of exercise on cognition while under hypoxia.Methods:Design:Systematic review with meta-analysis.Data ...Objective:This study aimed to examine(1)the independent effects of hypoxia on cognitive function and(2)the effects of exercise on cognition while under hypoxia.Methods:Design:Systematic review with meta-analysis.Data sources:PubMed,Scopus,Web of Science,PsychInfo,and SPORTDiscus were searched.Eligibility criteria for selecting studies:randomized controlled trials and nonrandomized controlled studies that investigated the effects of chronic or acute exercise on cognition under hypoxia were considered(Aim 2),as were studies investigating the effects of hypoxia on cognition(Aim 1).Results:In total,18 studies met our inclusionary criteria for the systematic review,and 12 studies were meta-analyzed.Exposure to hypoxia impaired attentional ability(standardized mean difference(SMD)=-0.4),executive function(SMD=-0.18),and memory function(SMD=-0.26),but not information processing(SMD=0.27).Aggregated results indicated that performing exercise under a hypoxia setting had a significant effect on cognitive improvement(SMD=0.3,95%confidence interval:0.14-0.45,I^2=54%,p<0.001).Various characteristics(e.g.,age,cognitive task type,exercise type,exercise intensity,training type,and hypoxia level)moderated the effects of hypoxia and exercise on cognitive function.Conclusion:Exercise during exposure to hypoxia improves cognitive function.This association appears to be moderated by individual and exercise/hypoxia-related characteristics.展开更多
Purpose:The aim of the present study was to assess both the credibility and strength of evidence arising from systematic reviews with meta-analyses of observational studies on handgrip strength and health outcomes.Met...Purpose:The aim of the present study was to assess both the credibility and strength of evidence arising from systematic reviews with meta-analyses of observational studies on handgrip strength and health outcomes.Methods:An umbrella review of systematic reviews with meta-analyses of observational studies was conducted.We assessed meta-analyses of observational studies based on random-effect summary effect sizes and their p values,95%prediction intervals,heterogeneity,small-study effects,and excess significance.We graded the evidence from convincing(Class I)to weak(Class IV).Results:From 504 articles returned in a search of the literature,8 systematic reviews were included in our review,with a total of 11 outcomes.Overall,nine of the 11 of the outcomes reported nominally significant summary results(p<0.05),with 4 associations surviving the application of the more stringent p value(p<106).No outcome presented convincing evidence.Three associations showed Class II evidence(i.e.,highly suggestive):(1)higher handgrip values at baseline were associated with a minor reduction in mortality risk in the general population(n=34 studies;sample size=1,855,817;relative risk=0.72,95%confidence interval(95%CI):0.670.78),(2)cardiovascular death risk in mixed populations(n=15 studies;relative risk=0.84,95%CI:0.780.91),and(3)incidence of disability(n=7 studies;relative risk=0.76,95%CI:0.660.87).Conclusion:The present results show that handgrip strength is a useful indicator for general health status and specifically for early all-cause and cardiovascular mortality,as well as disability.To further inform intervention strategies,future research is now required to fully understand mechanisms linking handgrip strength scores to these health outcomes.展开更多
文摘Background: We monitored changes in salivary creatine pre-and post-high-intensity exercise in young adults while also investigating the potential correlation between salivary and serum creatine levels.Method: Saliva and serum samples were collected before and immediately after an incremental running-toexhaustion treadmill test in fifteen young adults(mean age [23.9 ± 2.9] years, eight females), with samples analyzed for guanidinoacetic acid, creatine, and creatinine using a liquid chromatography–tandem mass spectrometry method.Results: Following exercise, there was a substantial elevation in salivary creatine levels from(17.5 ± 14.2)μmol·L^(-1) to(43.6 ± 30.4) μmol·L^(-1)(p < 0.001), coupled with a significant increase in salivary creatinine from(11.3 ± 5.8) μmol·L^(-1) to(17.0 ± 9.3) μmol·L^(-1)(p = 0.04). In contrast, serum creatine levels were unaffected by exercise(p = 0.80), while creatinine levels exhibited a strong tendency to decrease post-exercise(from [81.8 ±17.5] μmol·L^(-1) to [73.1 ± 11.6] μmol·L^(-1);p = 0.06). A comparison of the slopes of the two regression lines(saliva vs. serum) revealed significant differences for both creatine(p = 0.01) and creatinine(p = 0.03).Conclusions: The above findings suggest a potential difference in the dynamics of creatine metabolites in these two bodily fluids, both pre and post-exercise.
基金supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (No. RGPIN 435807-13) to JPLthe ANZ-MASON foundation (to DB)supported by a Canadian Institutes of Health Research (CIHR) New Investigator Award (No. MSH-141980)
文摘Background: Exercise promotes numerous phenotypic adaptations in skeletal muscle that contribute to improved function and metabolic capacity. An emerging body of evidence suggests that skeletal muscle also releases a myriad of factors during exercise, termed "myokines". The purpose of this study was to examine the effects of high-intensity interval training(HIIT) on the acute regulation of the mRNA expression of several myokines, including the prototypical myokine interleukin-6(IL-6), and recently identified myokines fibronectin type III domain-containing protein 5(FNDC5)(irisin) and meteorin-like protein(METRNL).Methods: Both before and after a 20-day period of twice-daily high-volume HIIT, 9 healthy males(20.5 ± 1.5 years performed a standardized bout of high-intensity interval exercise(HIIE; 5 × 4 min at ~80% pretraining peak power output) with skeletal muscle biopsy samples(vastus lateralis) obtained at rest, immediately following exercise, and at 3 h recovery.Results: Before training, a single bout of HIIE increased IL-6(p < 0.05) and METRNL(p < 0.05) mRNA expression measured at 3 h recovery when compared to rest. Following 20 days of HIIT, IL-6 and FNDC5 mRNA were increased at 3 h recovery from the standardized HIIE bout when compared to rest(both p < 0.05). Resting METRNL and FNDC5 mRNA expression were higher following training(p < 0.05), and there was an overall increase in FNDC5 mRNA post-training(main effect of training, p < 0.05).Conclusion: In human skeletal muscle(1) an acute bout of HIIE can induce upregulation of skeletal muscle IL-6 mRNA both before and after a period of intensified HIIT;(2) Resting and overall FNDC5 mRNA expression is increased by 20 days of HIIT; and(3) METRNL mRNA expression is responsive to both acute HIIE and short-term intense HIIT. Future studies are needed to confirm these findings at the protein and secretion level in humans.
基金the University of Canberra Research Institute for Sport and Exercise for supporting this project
文摘Purpose: The purpose of this study was to investigate the effect of variable intensities on a simple memory recognition task during exercise.Methods: Twenty active participants took part in initial testing, a familiarization trial and then four 60 min cycling interventions in a randomized order.Interventions consisted of no exercise（control）, constant exercise at 90% ventilatory threshold（constant） and 2 trials that initially mimicked the constant trial, but then included periods of high(90% VO2peak) and low intensities(50% VO2peak). Cardiorespiratory measures and capillary blood samples were taken throughout. A short tablet-based cognitive task was completed prior to and during（50 and 55 min into exercise） each intervention.Results: The exercise conditions facilitated response time（p = 0.009）, although the extent of this effect was not as strong in the variable exercise conditions（p = 0.011–0.089）. High intensity exercise periods resulted in some cognitive regression back towards control trial performance.Elevations in cardiorespiratory measures and periods of hypocapnia could not explain changes in cognitive performance.Conclusion: Changes in cognitive performance with variations in exercise intensity are likely to have implications for sport and occupational settings. The timing of cognitive tests to exercise intensity changes as well as use of short cognitive assessments will be important for future work.
基金supported by the Health Research Council of New Zealand Emerging Researcher First Grant (14/565)National Heart Foundation of New Zealand(1602 and 1615)+2 种基金Lottery Health Research Grant (Applic 341129)University of Otago Research Grant (UORG 2014)Dunedin City Council and internal grants from the School of Physical Education,Sport and Exercise Sciences,University of Otago
文摘Objectives:Adolescents using active transport(AT)to school have higher levels of physical activity(PA)compared with motorized transport(MT)users.This study compared school day and weekend day PA in adolescents using AT,MT,or combined AT and MT(AT + MT)to travel to school.Methods:Adolescents(n= 314;age:14.7±1.4 years;32.8% boys)from Dunedin(New Zealand)wore an accelerometer for 7 days and completed a self-reported survey regarding mode of transport to school(73 AT,56 AT + MT,and 185 MT).Data were analyzed using t tests,analysis of variance,and χ2 tests.Results:Although the proportion of adolescents meeting PA guidelines significantly differed among transport groups(AT,47.9%;AT + MT,46.4%;MT,33.5%;p=0.048;overall,39.2%),the observed differences were due mainly to girls.Compared with MT,AT and AT+MT engaged in more moderate-to-vigorous PA(MVPA)per day(AT:61.2 ± 23.2 min;AT+MT:59.6 ± 21.7 min;MT:52.5 ± 19.6 min;p = 0.004;p<0.001,adjusted for gender),per school day and before school.Immediately after school(15:00-16:00),AT engaged in significantly more MVPA compared with AT + MT and MT.No differences in MVPA between the groups were observed in the late afternoon/early evening period during school days or on weekend days.Conclusion:Compared with MT users,adolescent girls using AT or AT + MT accumulated more MVPA during school commute time.AT + MT to school is also a plausible way to increase adolescent girls’ PA when AT only is not feasible.
基金the Australian Government,managed by the National Security Science&Technology Centre within the Defence Science&Technology Organisation,and the US Government through the Technical Support Working Group within the Combating Terrorism Technical Support Office。
文摘Background:Deep body temperature is a critical indicator of heat strain.However,direct measures are often invasive,costly,and difficult to implement in the field.This study assessed the agreement between deep body temperature estimated from heart rate and that measured directly during repeated work bouts while wearing explosive ordnance disposal(EOD)protective clothing and during recovery.Methods:Eight males completed three work and recovery periods across two separate days.Work consisted of treadmill walking on a 1%incline at 2.5,4.0,or 5.5 km/h,in a random order,wearing EOD protective clothing.Ambient temperature and relative humidity were maintained at 24℃and 50%[Wet bulb globe temperature(WBGT)(20.9±1.2)℃]or 32℃and 60%[WBGT(29.0±0.2)℃]on the separate days,respectively.Heart rate and gastrointestinal temperature(TGI)were monitored continuously,and deep body temperature was also estimated from heart rate(ECTemp).Results:The overall systematic bias between TGI and ECTemp was 0.01℃with 95%limits of agreement(Lo A)of±0.64℃and a root mean square error of 0.32℃.The average error statistics among participants showed no significant differences in error between the exercise and recovery periods or the environmental conditions.At TGI levels of(37.0–37.5)℃,(37.5–38.0)℃,(38.0–38.5)℃,and>38.5℃,the systematic bias and±95%Lo A were(0.08±0.58)℃,(–0.02±0.69)℃,(–0.07±0.63)℃,and(–0.32±0.56)℃,respectively.Conclusions:The findings demonstrate acceptable validity of the ECTemp up to 38.5℃.Conducting work within an ECTemp limit of 38.4℃,in conditions similar to the present study,would protect the majority of personnel from an excessive elevation in deep body temperature(>39.0℃).
文摘There is now strong evidence that exercise has an acute effect on the urge to smoke and the accompanying withdrawal symptoms. However, the perceptions by heavy smokers of exercise and its relationship to the urge to smoke have not been well documented. The aim of the present study is to understand the experiences of heavy smokers with regard to exercise and its effect on their urge to smoke. Five physically inactive, heavy smokers are asked to abstain from smoking the night before exercising on a cycle ergometer under two conditions (one at medium and one at vigorous intensity done a week apart). Semi-structured, in-depth interviews are conducted after the second exercise session. Thematic analysis reveals six themes describing the participants’ experience of exercise, urge to smoke, exercise preferences, exercise and smoking relationship, exercise as an aid to quit smoking, and the effects of the experimental procedure. Overall, the participants’ experiences support the existing literature, which has posited affective, biological, and cognitive mechanisms contributing to a delay in the urge to smoke after exercise. The main findings pertain to: (1) the “feel-good” effect after exercise as a relief from the “feel-bad” effect during exercise;(2) the decreased urge to smoke after exercise, stated by all participants regardless of reported positive and negative feelings;and (3) exercise as a “clearing the mind” mechanism rather than an attention-distracting mechanism.
文摘A large body of evidence shows that a single bout of strenuous exercise induces oxidative stress in circu- lating human lymphocytes leading to lipid peroxide- tion, DNA damage, mitochondrial perturbations, and protein oxidation. In a training experiment, Wistar rats were divided into control group (CG) and exer- cise group (EG). After a running level exercise until exhaustion, we observed an increase in the mRNA content and protein expression of SIRT1 and SIRT7 in the EG compared to the CG. Moreover, such train- ing exercise did not change mRNA transcripts and protein expression of FOXO3A and GADD45. We also observed an increase of pro-apoptotic protein bax and a decrease of the anti-apoptotic protein bcl-2 in the EG. Accordingly, we observed a caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage only in EG rats. Statistical analysis of the data showed a significant correlation between SIRT1 and SIRT7 expression and apoptotic proteins such as bax, bcl-2 in both tissues. We conclude that, in both muscle, such exercise activates both a damaging apoptotic mecha- nism with bax increase and bcl-2 decrease and a counterbalancing protective mechanism with SIRT1 and SIRT7 increase.
文摘Dear editor,As government restrictions put in place to slow the acceleration of the coronavirus disease-2019(COVID-19)pandemic start to ease,many people,including elite athletes,will begin to return back to their normal daily activities.Although the majority of risk factors for severe COVID-19-hypertension,respiratory system disease.
基金support from the National Natural Science Foundation of China(Grant Nos.52475610 and 52105593)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LDQ24E050001)+2 种基金the‘Pioneer’and‘Leading Goose’R&D Program of Zhejiang(Grant No.2023C01051)the Leading Innovation and Entrepreneurship Team Project in Zhejiang(Grant No.2022R01001)the Fundamental Research Funds for the Central Universities(Grant No.226-2024-00085)。
文摘Textiles with electronic components offer a portable and personalized approach for health monitoring and therapy.However,there is a lack of reliable strategy to integrate layered circuits and high-density chips on or inside textiles,which hinders system-level functionality and untethered user experiences.Herein,we propose monolithically integrated textile hybrid electronics(THE)on a textile platform,with multimodal functions and reliable performances.The textile system encompasses flexible electrodes,laser-induced sensors,and surface-mount devices,along with double-layer circuits interconnecting all of them.Vertical conductive paths are rendered by liquid metal composites infiltrated into textiles,which allows resistances less than 0.1?while reserving intact textile structures.The assembled THE exhibits endurance to handwashing and crumpling,as well as bendability.We customize a wireless textile patch for synchronously tracking multiple physiological indicators during exercise.Furthermore,a textile band is elaborated for monitoring and alleviating muscular fatigue,demonstrating potential in closed-loop diagnosis and treatment.
文摘Marching band(MB)artists are often part of the general student population and not required to complete a preparticipation health screening to identify predisposing medical conditions or risks for injury/illness.Anecdotally,exertional heat illnesses(EHI)are a concern for MB artists.As more athletic trainers provide MB healthcare,research is needed on EHI occurrence and MB associated EHI risk factors.We utilized an exploratory crosssectional study design to determine EHI risk factors,including previous EHI occurrence,among collegiate MB artists.MB artists(n=1207;age=[19.6±1.3]years)actively participating in their college/university's MB during the 2019 football season completed an online survey to characterize demographics,medical history,medication and supplement use,and nutrition behaviors.Chi-square and binomial logistical regressions assessed associations between categorical variables.Previous EHI was reported by 50.6%of MB artists,with 466(76.3%)experiencing exertional heat exhaustion and 31(5.1%)exertional heat stroke.More females reported exertional heat exhaustion overall(68.2%,p<0.001)and in the previous year(73.3%,p<0.001).Experiencing a previous EHI was significantly associated with having a mood/neurological condition(63.5%,p<0.001),diagnosed(74.3%,p=0.004)or perceived eating disorder(66.7%,p<0.001),and taking prescription medications(59.4%,p<0.001),over-the-counter medications(58.9%,p=0.002),and supplements(55.4%,p=0.037).Half of collegiate MB artists reported experiencing previous EHIs and engaged in behaviors known to increase EHI risk.MB artists should complete pre-participation examinations to identify pre-existing medical conditions and risks for adverse medical events.Healthcare providers working with MB artists should develop policies and procedures to mitigate EHI risks and occurrence.
文摘This study retrospectively evaluated data from an athlete management system on the impact of a 6-week,12-session risk-reduction athletic development training program on maximal isometric strength in post-rehabilitative and healthy men and women.Maximal isometric quadriceps and hamstrings strength were evaluated bilaterally before and after the training program.Out of 55 athletes that had participated in the program,a total of 37 athletes'(13-28 years old)recorded outcomes were utilized in analyses.Thirty-one athletes had undergone rehabilitation(post-rehabilitative athletes)after orthopedic knee surgeries.Six athletes with no previous surgeries performed(healthy athletes)also completed the 6-week program.Repeated measures analyses of variance(leg×time)assessed changes in quadriceps and hamstrings strength at an alpha of p≤0.05.There was a main effect for time where the post-rehabilitative athletes’quadriceps and hamstrings strength increased by(mean difference±standard error)(4.2±0.7)kg(p<0.01)and(4.5±0.9)kg(p<0.01)respectively,with legs(operative[OP])and (non-operative[NOP])combined.With time points combined,the OP limb was weaker than the NOP limb for quadriceps strength by(2.9±0.7)kg(p<0.01)with no differences in hamstrings strength.For the healthy athletes,there were no changes for quadriceps strength and hamstring strength improved across time by(5.3±1.4)kg(p=0.01)with legs combined.In conclusion,there were improvements in post-rehabilitative and healthy athletes’isometric strength after the training program.However,between-limb strength asymmetries were still apparent in the post-rehabilitation cohort.
文摘Background:Stretching has wide appeal,but there seems to exist some mismatch between its purported applications and what the evidence shows.There is compelling evidence for some stretching applications,but for others,the evidence seems heterogeneous or unsupportive.The discrepancies even affect some systematic reviews,possibly due to heterogeneous eligibility criteria and search strategies.This consensus paper seeks to unify the divergent findings on stretching and its implications for both athletic performance and clinical practices by delivering evidence-based recommendations.Methods:A panel of 20 experts with a blend of practical experience and scholarly knowledge was assembled.The panel meticulously reviewed existing systematic reviews,defined key terminologies(e.g.,consensus definitions for different stretching modes),and crafted guidelines using a Delphi consensus approach(minimum required agreement:80%).The analysis focused on 8 topics,including stretching's acute and chronic(long-term)effects on range of motion,strength performance,muscle hypertrophy,stiffness,injury prevention,muscle recovery,posture correction,and cardiovascular health.Results:There was consensus that chronic and acute stretching(a)improves range of motion(although alternatives exist)and(b)reduces muscle stiffness(which may not always be desirable);the panel also agreed that chronic stretching(c)may promote vascular health,but more research is warranted.In contrast,consensus was found that stretch training does not(a)contribute substantively to muscle growth,(b)serve as an allencompassing injury prevention strategy,(c)improve posture,or(d)acutely enhance post-exercise recovery.Conclusion:These recommendations provide guidance for athletes and practitioners,highlighting research gaps that should be addressed to more comprehensively understand the full scope of stretching effects.
基金Support was provided by the University of Florida Claude D.Pepper Older Americans Independence Center(NIH/ NIA P30AG028740)Clinical and Translational Science Institute(NIH/NCRR UL1TR000064)+1 种基金Stephen Anton is supported by a K23 AT004251-01A2,an Early Career Investigator Award from the American Heart Association (09CRP2390173)Thomas H.Maren Foundation
文摘Due to safety concerns and side effects of many antidepressant medications, herbal psychopharmacology research has increased, and herbal remedies are becoming increasingly popular as alternatives to prescribed medications for the treatment of major depressive disorder （MDD）. Of these, accumulating trials reveal positive effects of the spice saffron （Crocus sativus L.） for the treatment of depression. A comprehensive and statistical review of the clinical trials examining the effects of saffron for treatment of MDD is warranted. OBJECTIVE： The purpose of this study was to conduct a meta-analysis of published randomized controlled trials examining the effects of saffron supplementation on symptoms of depression among participants with MDD. SEARCH STRATEGY： We conducted electronic and non-electronic searches to identify all relevant randomized, double-blind controlled trials. Reference lists of all retrieved articles were searched for relevant studies. INCLUSION CRITERIA： The criteria for study selection included the following： （1） adults （aged 18 and older） with symptoms of depression, （2） randomized controlled trial, （3） effects of saffron supplementation on depressive symptoms examined, and （4） study had either a placebo control or antidepressant comparison group. DATA EXTRACTION AND ANALYSIS： Using random effects modeling procedures, we calculated weighted mean effect sizes separately for the saffron supplementation vs placebo control groups, and for the saffron supplementation vs antidepressant groups. The methodological quality of all studies was assessed using the Jadad score. The computer software Comprehensive Meta- analysis 2 was used to analyze the data. RESULTS： Based on our pre-specified criteria, five randomized controlled trials （n = 2 placebo controlled trials, n = 3 antidepressant controlled trials） were included in our review. A large effect size was found for saffron supplementation vs placebo control in treating depressive symptoms （M ES = 1.62, P 〈 0.001）, revealing that saffron supplementation significantly reduced depression symptoms compared to the placebo control. A null effect size was evidenced between saffron supplementation and the antidepressant groups （M ES = -0.15） indicating that both treatments were similarly effective in reducing depression symptoms. The mean Jadad score was 5 indicating high quality of trials. CONCLUSION： Findings from clinical trials conducted to date indicate that saffron supplementation can improve symptoms of depression in adults with MDD. Larger clinical trials, conducted by research teams outside of Iran, with long-term follow-ups are needed before firm conclusions can be made regarding saffron＇s efficacy and safety for treating depressive symptoms.
文摘Purpose： The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically, it was hypothesized that the catecholamine, lactate, and ventilatory thresholds is the point at which significant improvements in speed of cognitive function are observed. Methods： We compared mean effect sizes for threshold studies and for those studies where exercise intensity was classed as moderate （40%-- 79% VO2 or equivalent） but in which the thresholds were not measured. Results： Random effects meta-analysis showed significant, moderate, mean effect sizes for studies at the threshold （g = 0.58, Z = 2.98, p 〈 0.003） and for those during moderate intensity exercise but in which the threshold was not measured （ g = 0.54, Z = 5.0l, p 〈 0.001）. There was no significant difference between mean effect sizes, which suggests that the thresholds are unlikely to represent a trigger point. Conclusion： Moderate intensity exercise, even below the thresholds, can induce improved speed of cognition, possibly due to a combination of increased peripheral catecholamine concentrations inducing vagal/nucleus tractus solitarii pathway activation and central increases due to perceptions of stress.
文摘Background:Cross-country skiing(XCS)racing,a popular international winter sport,is complex and challenging from physical,technical,and tactical perspectives.Despite the vast amount of research focusing on this sport,no review has yet addressed the pacing strategies of elite XCS racers or the factors that influence their performance.The aim was to review the scientific literature in an attempt to determine the effects of pacing strategy on the performance of elite XCS racers.Methods:Four electronic databases were searched using relevant subject headings and keywords.Only original research articles published in peerreviewed journals and the English language and addressing performance,biomechanics,physiology,and anthropometry of XCS racers were reviewed.Results:All 27 included articles applied correlative designs to study the effectiveness of different pacing strategies.None of the articles involved the use of an experimental design.Furthermore,potential changes in external conditions(e.g.,weather,ski properties)were not taken into consideration.A comparable number of studies focused on the skating or classical technique.In most cases,positive pacing was observed,with certain indications that higher-level athletes and those with more endurance and strength utilized a more even pacing strategy.The ability to achieve and maintain a long cycle length on all types of terrain was an important determinant of performance in all of the included studies,which was not the case for cycle rate.In general,uphill performance was closely related to overall race performance,with uphill performance being most closely correlated to the success of female skiers and performance on flat terrain being more important for male skiers.Moreover,pacing was coupled to the selection and distribution of technique during a race,with faster skiers employing more double poling and kick double poling,less diagonal stride,and more V2(double dance)than V1(single dance)skating across a race.Conclusion:We propose that skiers at all levels can improve their performance with more specific training in techniques(i.e.,maintaining long cycles without compromising cycle rate and selecting appropriate techniques)in combination with training for endurance and more strength.Furthermore,we would advise less experienced skiers and/or those with lower levels of performance to apply a more even pacing strategy rather than a positive one(i.e.,starting the race too fast).2018 Published by Elsevier B.V.on behalf of Shanghai University of Sport.This is an open access article under the CC BY-NC-ND license.(http://creativecommons.org/licenses/by-nc-nd/4.0/).
基金The Italian National Research Council(CNR)supported the ILSA project from 1991 to 1998 as part of the“Progetto Finalizzato Invecchiamento”Since 1999,the Italian CNR,the“Biology of Aging”Strategic Project and the Ministero della Sanità,through the program“Epidemiology of the Elderly”of the Istituto Superiore di Sanitàand the“Estimates of Health Needs of the Elderly”Special Programme of the Tuscany Region have been supporting the ILSA project.
文摘Background Cardiac arrhythmias are common conditions in older people.Unfortunately,there is limited literature on associations between cardiac arrhythmias and physical performance or disability.We therefore aimed to prospectively investigate associations between cardiac arrhythmias and changes in disability and physical performance during 8 years of follow-up,using data from the Italian Longitudinal Study on Aging(ILSA).Methods Cardiac arrhythmias diagnosis was posed through a screening phase,confirmed by a physician.The onset of disability in activities of daily living(ADL)and the changes in several physical performance tests during follow-up were considered as outcomes.Fully-adjusted and propensity-score Cox Proportional Hazard models and mixed models were used for exploring associations between cardiac arrhythmia and the outcomes of interest.Results The prevalence of cardiac arrhythmia at baseline was 23.3%.People reporting cardiac arrhythmia at the baseline were significantly older,more frequently male,smokers and reported a higher presence of all medical conditions investigated(hypertension,heart failure,angina,myocardial infarction,diabetes,stroke),but no difference in dementia,Parkinsonism,cognitive or mood disorder.Cardiac arrhythmia at baseline was significantly associated with the incidence of disability in ADL(HR=1.23;95%:CI:1.01–1.50;P=0.0478 in propensity score analyses;HR=1.28;95%CI:1.01–1.61;P=0.0401 in fully adjusted models).Cardiac arrhythmia at baseline was also associated with a significant worsening in balance test(P=0.0436).Conclusions The presence of cardiac arrhythmia at baseline was associated with a significant higher risk of disability and of worsening in some physical performance tests,particularly those relating to balance.Screening and frequently assessing physical performance in older people affected by cardiac arrhythmia can be important to prevent a loss of physical performance,with further,potential,complications of medical management.
文摘Background:For the past 30 years,the hamstring(H)-to-quadriceps(Q)(H:Q)torque ratio has been considered an important index of muscle strength imbalance around the knee joint.The purpose of this systematic review was to examine the value of H:Q torque ratio as an independent risk factor for hamstring and anterior cruciate ligament(ACL)injuries.Methods:Database searches were performed to identify all relevant articles in PubMed,MEDLINE,Cochrane Library,and Scopus.Prospective studies evaluating the conventional(concentric H:Q),functional(eccentric H:concentric Q),and mixed(eccentric H at 300/s:concentric Q at2400/s)H:Q ratios as risk factors for occurrence of hamstring muscle strain or ACL injury were considered.Risk of bias was assessed using the Quality In Prognosis Studies tool.Results:Eighteen included studies reported 585 hamstrings injuries in 2945 participants,and 5 studies documented 128 ACL injuries in 2772participants.Best evidence synthesis analysis indicated that there is very limited evidence that H:Q strength ratio is an independent risk factor for hamstring and ACL injury,and this was not different between various ratio types.Methodological limitations and limited evidence for ACL injuries and some ratio types might have influenced these results.Conclusion:The H:Q ratio has limited value for the prediction of ACL and hamstring injuries.Monitoring strength imbalances along with other modifiable factors during the entire competitive season may provide a better understanding of the association between H:Q ratio and injury.
基金internally funded by Te Huataki Waiora School of Health,University of Waikato,New Zealandthe Running Clinic,Canada
文摘Purpose We compared running economy(RE)and 3-km time-trial(TT)variables of runners wearing Nike Vaporfly 4%(VP4),Saucony Endorphin lightweight racing flats(FLAT),and their habitual running(OWN)footwear.Methods Eighteen male recreational runners(age=33.5±11.9 year(mean±SD),peak oxygen uptake(VO_(2peak))=55.8±4.4 mL/kg·min)attended 4 sessions approximately 7 days apart.The first session consisted of a VO_(2peak) test to inform subsequent RE speeds set at 60%,70%,and 80%of the speed eliciting VO2peak.In subsequent sessions,treadmill RE and 3-km TTs were assessed in the 3 footwear conditions in a randomized,counterbalanced crossover design.Results Oxygen consumption(mL/kg·min)was less in VP4(from 4.3%to 4.4%,p≤0.002)and FLAT(from 2.7%to 3.4%,p≤0.092)vs.OWN across intensities,with a non-significant difference between VP4 and FLAT(1.0%-1.7%,p≥0.292).Findings related to energy cost(W/kg)and energetics cost of transport(J/kg·m)were comparable.VP43-km TT performance(11:07.6±0:56.6 mm:ss)was enhanced vs.OWN by 16.6 s(2.4%,p=0.005)and vs.FLAT by 13.0 s(1.8%,p=0.032).The 3-km times between OWN and FLAT(0.5%,p=0.747)were similar.Most runners(n=11,61%)ran their fastest TT in VP4.Conclusion Overall,VP4 improved laboratory-based RE measures in male recreational runners at relative speeds compared to OWN,but the RE improvements in VP4 were not significant vs.FLAT.More runners exhibited better treadmill TT performances in VP4(61%)vs.FLAT(22%)and OWN(17%).The variability in RE(-10.3%to 13.3%)and TT(-4.7%to 9.3%)improvements suggests that responses to different types of shoes are individualized and warrant further investigation.
基金supported by grants from the National Natural Science Foundation of China(Grant#31671150)Guangdong Province Key Project(Grant#2018B030335001).
文摘Objective:This study aimed to examine(1)the independent effects of hypoxia on cognitive function and(2)the effects of exercise on cognition while under hypoxia.Methods:Design:Systematic review with meta-analysis.Data sources:PubMed,Scopus,Web of Science,PsychInfo,and SPORTDiscus were searched.Eligibility criteria for selecting studies:randomized controlled trials and nonrandomized controlled studies that investigated the effects of chronic or acute exercise on cognition under hypoxia were considered(Aim 2),as were studies investigating the effects of hypoxia on cognition(Aim 1).Results:In total,18 studies met our inclusionary criteria for the systematic review,and 12 studies were meta-analyzed.Exposure to hypoxia impaired attentional ability(standardized mean difference(SMD)=-0.4),executive function(SMD=-0.18),and memory function(SMD=-0.26),but not information processing(SMD=0.27).Aggregated results indicated that performing exercise under a hypoxia setting had a significant effect on cognitive improvement(SMD=0.3,95%confidence interval:0.14-0.45,I^2=54%,p<0.001).Various characteristics(e.g.,age,cognitive task type,exercise type,exercise intensity,training type,and hypoxia level)moderated the effects of hypoxia and exercise on cognitive function.Conclusion:Exercise during exposure to hypoxia improves cognitive function.This association appears to be moderated by individual and exercise/hypoxia-related characteristics.
文摘Purpose:The aim of the present study was to assess both the credibility and strength of evidence arising from systematic reviews with meta-analyses of observational studies on handgrip strength and health outcomes.Methods:An umbrella review of systematic reviews with meta-analyses of observational studies was conducted.We assessed meta-analyses of observational studies based on random-effect summary effect sizes and their p values,95%prediction intervals,heterogeneity,small-study effects,and excess significance.We graded the evidence from convincing(Class I)to weak(Class IV).Results:From 504 articles returned in a search of the literature,8 systematic reviews were included in our review,with a total of 11 outcomes.Overall,nine of the 11 of the outcomes reported nominally significant summary results(p<0.05),with 4 associations surviving the application of the more stringent p value(p<106).No outcome presented convincing evidence.Three associations showed Class II evidence(i.e.,highly suggestive):(1)higher handgrip values at baseline were associated with a minor reduction in mortality risk in the general population(n=34 studies;sample size=1,855,817;relative risk=0.72,95%confidence interval(95%CI):0.670.78),(2)cardiovascular death risk in mixed populations(n=15 studies;relative risk=0.84,95%CI:0.780.91),and(3)incidence of disability(n=7 studies;relative risk=0.76,95%CI:0.660.87).Conclusion:The present results show that handgrip strength is a useful indicator for general health status and specifically for early all-cause and cardiovascular mortality,as well as disability.To further inform intervention strategies,future research is now required to fully understand mechanisms linking handgrip strength scores to these health outcomes.
