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1.

Objectives

To examine the neurophysiological correlates and brain network organization underlying physical and cognitive exertion in active young adults.

Design

Repeated measures.

Methods

Thirteen healthy adults completed three exertion tasks in a counterbalanced order: a graded working memory task (anti-saccade and serial addition task (ASAT)), a graded exercise task (cycling on a stationary bicycle) (EX) and a combined graded working memory and exercise task (ASAT + EX). All three tasks were performed under five levels of increasing difficulty. Continuous EEG was recorded in each session. Heart rate, perceived exertion and accuracy on the working memory task were recorded throughout. Power spectrum analysis and graph theoretical analysis was applied to the EEG data.

Results

Heart rate and perceived exertion increased with exercise load and in both the EX only and ASAT + EX tasks. Overall accuracy was equally high for the ASAT and ASAT + EX tasks. Analysis of EEG data showed there was an increase in theta power associated with the ASAT + EX task and increase in functional connectivity in the frontal regions of the brain compared with ASAT only task. Accuracy decreased in the last two blocks when the task was most difficult. This decrease in accuracy was associated with a decrease in theta power and a decrease in functional connectivity.

Conclusions

Combined physical and mental exertion results in significant changes in perceived exertion, EEG theta power and network organization in healthy adults and will be valuable in revealing residual neurocognitive deficits after sports related concussion.  相似文献   

2.

Objective

The aims of our study were to quantify levels and investigate sex-specific changes and trajectories in VPA longitudinally from age 7 to 15 years.

Design

Longitudinal observational study.

Methods

Participants were part of the Gateshead Millennium Study. Measures were taken at age 7 (n = 507), 9 (n = 510), 12 (n = 425) and 15 years (n = 310). Vigorous physical activity was quantified objectively using ActiGraph GT1 M accelerometers over 5–7 days at the four time-points. Multilevel linear spline random-effects model and trajectory analysis to identify sub-groups were performed.

Results

In boys, average VPA declined across childhood followed by an increase at adolescence, while in girls, average VPA declined across the 8-year study period. In boys, daily VPA decreased from 9-12 years (1.70 minutes/year) and increased from 12-15 years (1.99 minutes/year) (all p < 0.05). In girls daily VPA decreased from 7-9 years (1.70 minutes/year) (p < 0.05). Three VPA trajectories were identified which differed between the sexes. In boys, one group decreased from an initial relatively high level, one group, initially relatively low, increased, whereas the third one was stable over the 8-year period. In girls, all three groups declined from baseline.

Conclusions

Marked sex and age-specific trajectories in VPA change were observed. These novel findings should help sports and exercise medicine specialists, as well as policy makers, in their effort to maintain or increase VPA in childhood and adolescence.  相似文献   

3.

Objectives

To determine the relationship and predictive value of isometric shoulder strength in the development of shoulder pain in young swimmers.

Design

Prospective, cohort study.

Methods

Shoulder flexion, extension, external and internal rotation strength tests were performed in elevation on 85 swimmers (14–20 years; 48 females) without current shoulder pain using a hand-held dynamometer. Following testing, swimmers were emailed questionnaires to determine if significant shoulder pain developed within 24 months subsequent to testing. The differences between shoulders that did and did not develop pain and the predictive ability of shoulder strength and strength ratios were investigated using Mann Whitney U tests and receiver operating characteristic curves.

Results

Thirty-seven swimmers (47%) returned questionnaires and 18 reported shoulder pain. A comparison of individual shoulders (27 with pain reported and 47 without) determined that shoulder extension strength was lower and flexion:extension strength ratio was higher for male swimmers (n = 36 shoulders) who reported shoulder pain compared to those who did not (p = 0.04). The predictive value of extension strength was fair (0.72; p = 0.03) for males with a cut-off value for extension strength calculated at 13.5% body mass. There were no differences between the two groups in shoulder rotation strength, age, training hours or previous pain history.

Conclusions

Shoulder extension strength, a functional test for swimmers, was associated with and predictive of the development of shoulder pain in male swimmers. Low shoulder extension strength may be a risk factor for the development of shoulder pain in swimmers, proposing a direction for injury prevention and future investigation.  相似文献   

4.

Objectives

Although physical fitness is considered a marker of health in youth, little is known whether physical fitness in pre-school age is related to later body composition. Thus, this study investigated (i) associations of physical fitness at 4.5 years of age with body composition 12 months later and (ii) whether improvements in physical fitness during the 12-month follow-up were associated with changes in body composition.

Design

This study included 142 children, measured at 4.5 and 5.5 years, from the control group of the MINISTOP trial.

Methods

Physical fitness (cardiorespiratory fitness, lower- and upper-body muscular strength and motor fitness) was measured using the PREFIT test battery. Body composition was assessed using air-displacement plethysmography.

Results

In adjusted regression analyses, greater cardiorespiratory fitness, lower-body muscular strength and motor fitness at 4.5 years were associated with a lower fat mass index at 5.5 years (standardized β= ?0.182 to ?0.229, p  0.028). Conversely, greater cardiorespiratory fitness, lower- and upper-body muscular strength as well as motor fitness at 4.5 years of age were associated with a higher fat-free mass index (standardized β = 0.255–0.447, p  0.001). Furthermore, improvements in cardiorespiratory fitness, lower-body muscular strength and motor fitness during the 12-month follow-up period were associated with decreases in fat mass index and/or % fat mass.

Conclusions

In conclusion, the results of this study provide evidence of the importance of physical fitness early in life. Nevertheless, further studies are needed in order to clarify the influence of physical fitness in the pre-school age with later health outcomes.  相似文献   

5.

Objectives

To evaluate the association between cardiorespiratory fitness (CRF), lung cancer incidence and cancer mortality in men.

Design

Prospective cohort study.

Methods

Maximal exercise testing was performed in 4920 men (59.2 ± 11.4 years) free from malignancy at baseline. Multivariate Cox hazard models adjusted for established cancer risk factors including smoking were analyzed for lung cancer incidence and cancer mortality among those who were diagnosed with lung cancer. Population attributable risks (PAR) of low CRF (<5 METs) were determined.

Results

During 12.7 ± 7.5 years follow-up, 105 (2.1%) participants were diagnosed with lung cancer and 83 (79%) of those died from cancer after 3.6 ± 4.6 years from diagnosis. CRF was inversely and independently associated with cancer outcomes. A 1-MET increase and categories of moderate and high CRF were associated with 10%, 47% and 65% reduction in lung cancer incidence (p = 0.002), and 13%, 58% and 76% reduction in cancer mortality (p = 0.002), respectively. Also, individuals who were diagnosed with lung cancer and were at moderate or high CRF categories at baseline exhibited longer survival time (p < 0.001). The PARs% for lung cancer incidence and cancer mortality were 8.7% and 18.5%, respectively.

Conclusions

Higher CRF is associated with lower lung cancer incidence in men. Among individuals who were diagnosed with lung cancer, higher CRF was associated with reduced cancer mortality and longer survival time. These results support the protective benefits of higher CRF in the prevention of lung cancer outcomes. Eliminating low CRF as a risk factor would potentially prevent considerable lung cancer morbidity and mortality.  相似文献   

6.

Objectives

To investigate the role of inter-individual variations in a particular glycoprotein, TNC, and its potential contribution to anterior cruciate ligament (ACL) injury susceptibility in Polish Caucasian participants. ACL rupture is one of the most prevalent and severe knee injury that predominantly occurs during sports participation, primarily via a non-contact mechanism. Several polymorphisms in genes encoding glycoproteins either independently or as allelic combinations, modulate the risk of musculoskeletal soft tissue injuries. Specifically, the TNC rs1330363 (C > T), rs2104772 (T > A) and rs13321 (G > C) variants, independently or in haplotype combinations, were analysed in this context.

Design

Case–control genetic association study.

Methods

A group of 421 physically active, unrelated participants were recruited where 229 individuals with surgically diagnosed primary ACL rupture and 192 apparently healthy participants without any history of ACL injuries. Participants were genotyped for the above variants.

Results

Genotype and allele frequencies of TNC variants did not differ between cases and controls. Haplotype analysis revealed no association between TNC and predisposition to ACL rupture.

Conclusions

Our analyses did not reveal a significant association between these TNC variants and risk of ACL rupture in Polish Caucasian participants.  相似文献   

7.

Objectives

To describe the cross-sectional association between musculoskeletal pain at multiple sites and physical work capacity (PWC) and objectively measured physical activity (PA).

Design

Observational study.

Methods

Data from a subsample of the UK Biobank were utilised (n = 9856; mean age 58.5 years, mean body mass index 30.2 kg/m2, 62% female). PWC was measured by a bicycle ergometer and PA by an accelerometer. Pain experienced in hip, knee, back and neck/shoulder was collected by questionnaire. Linear regression modelling was used with adjustment for potential confounders to estimate the association between pain and PWC and PA.

Results

Increase in number of painful sites was associated with lower PWC, moderate and vigorous PA and increased low intensity PA in a dose-response relationship (all p-values for trend ≤0.001) before and after adjustment for confounders. In site specific analyses, hip pain was associated with an increased low intensity PA (β 52.8 min/week, 95% CI 2.3–103.2) and reduced moderate PA (β ?50.1 min/week, 95% CI ?98.5 to ?1.8). Knee pain was only associated with vigorous PA (β ?5.7 min/week, 95% CI ?10.0 to ?1.3). Pain at neck/shoulder pain and back were not independently associated with PWC and PA.

Conclusions

Greater number of painful sites is consistently associated with poorer PWC, increased low intensity PA and reduced moderate to vigorous PA. Clinicians should address the critical role of being physically active in managing chronic musculoskeletal pain and interventions targeting musculoskeletal pain may be needed to increase PA levels.  相似文献   

8.

Objectives

Little is known about hip function after hip arthroscopic surgery in patients with femoroacetabular impingement syndrome. Hence, the aim of the study was (1) to investigate changes in hip muscle strength from before to one year after hip arthroscopic surgery, (2) to compare patients with a reference group.

Design

Cohort study with a cross-sectional comparison.

Methods

Before and after hip arthroscopic surgery, patients underwent hip muscle strength testing of their hip flexors and extensors during concentric, isometric and eccentric contraction in an isokinetic dynamometer. Reference persons with no hip problems underwent tests at a single time point. Participants completed completed the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire and physical capacity (stair climbing loaded and unloaded, stepping loaded and unloaded and jumping) tests.

Results

After surgery, hip flexion strength improved during all tests (6–13%, p < 0.01) and concentric hip extension strength improved (4%, p = 0.002). Hip flexion and extension strength was lower for patients than for reference persons (9–13%, p < 0.05) one year after surgery. Higher hip extension strength after surgery was associated with better patient reported outcomes. Patients, who were unable to complete at minimum one test of physical capacity, demonstrated significantly weaker hip muscle strength. Compared with their healthy counterparts, female patients were more impaired than male patients.

Conclusions

One year after surgery, patients improved their maximal hip muscle strength. When compared to reference persons, maximal hip muscle strength was still impaired.  相似文献   

9.

Objectives

Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.

Design

Cross-sectional, laboratory study.

Methods

Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction.

Results

The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant.

Conclusions

There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes.  相似文献   

10.

Objectives

The Canadian Army fitness objective is FORCE COMBAT?. This consists of a 5 km march (35 kg) between 50–60 min, and the annual FORCE physical employment standard as a circuit without the usual 5 min rest intervals (FORCE circuit) in full fighting order (25 kg). The objective of this research was to determine the number of practice attempts required to establish reliability of FORCE COMBAT?. Additionally, this study aims to identify the minimal detectable change once reliability is established.

Design

The study used a within participant design.

Methods

33 Canadian Army members were divided into two groups. Group 1 performed four maximum effort attempts of FORCE COMBAT? completely. Group 2 performed only the FORCE circuit component, not the loaded march. On the fifth trial, the tasks of the groups were switched. Variability within and between trials of the FORCE circuit of FORCE COMBAT? were analysed based on six statistical factors of reliability.

Results

Four statistical factors indicated that one maximal effort practice attempt of FORCE COMBAT? is required, as reflected in the variability of performance between trials 1 and 2. The minimum detectable change, highlighting inherent measurement error of the test was 89.18 s with 95% confidence.

Conclusions

Results suggest that Canadian Army members should complete one FORCE COMBAT? in completion at maximal effort, before formal assessment. Further, members performing within 89 s of the recommended completion time, on FORCE COMBAT? should be offered a re-attempt (in its entirety).  相似文献   

11.

Objectives

The purpose of this study was to identify early life factors that were associated with childhood and adolescent organized sport participation trajectories.

Design

Participants were in the Raine Study, a pregnancy cohort in Western Australia recruited from 1989 to 1991.

Methods

Three organized sport trajectories over ages 5–17 years were previously identified for girls (n = 824: consistent participators, dropouts, and non-participators in sport) and boys (n = 855: consistent participators, dropouts, joiners — those who joined sport in adolescence). Physical, psychological and social factors were measured from birth to age 5.

Results

For girls and boys, children who were breastfed, were taller, did not have behavior problems, and attended childcare were more likely to consistently participate. Girls who had a previous injury (Relative risk ratio 1.55: 95% confidence interval 1.05, 2.29 vs never been injured) or who had parents who had worries about their child’s health (1.56: 1.00, 2.42 vs no worries) were more likely to be in the dropout trajectory. Boys born preterm (2.00, 2.06, 3.76 vs full-term), did not have a previous injury (0.72, 0.53, 0.97 those with injury vs never been injured), had more difficult temperament (1.63, 1.02, 2.60 vs easy temperament), and higher family dysfunction (1.49, 1.06, 2.08) were more likely to be in the dropout trajectory.

Conclusions

Early life factors were associated with membership in sport trajectories. Physical, psychological, and social factors may serve as early warning signs for parents and practitioners that children may be at higher risk of dropping out of sports.  相似文献   

12.

Objectives

To provide epidemiological data and related costs for moderate-to-serious and serious injury claims for women’s rugby union in New Zealand.

Design

A retrospective analytical review of injury entitlement claims for women’s rugby from 2013 to 2017.

Methods

Data were analysed by year of competition, age, body site and injury type for total and moderate-to-severe (MSC) Accident Compensation Corporation (ACC) claims and costs.

Results

Over 2013 to 2017 there were 26,070 total claims for female rugby union costing $18,440,812 [AD$16,956,998]. The 15–19-year age group recorded 40% (n = 1,009) of the total female rugby union Moderate-to-serious and serious (MSC) claims and 41% ($5,419,157 [AD$4,983,112]) of the total female rugby union MSC costs. The knee was the most commonly recorded injury site accounting for 40.3% (n = 1,007) of MSC claims and 46.9% ($6,229,714 [AD$5,728732]) of MSC costs with an average cost of $1,245,943 ±$217,796 [AD$595,351 ±AD$104,070] per-year for female rugby union.

Conclusions

This is the first study to report the nature and related costs for moderate-to-serious and serious injury claims for women’s rugby union in New Zealand. A total of 26,070 injury claims were lodged over the duration of the study but only 9.6% (n = 2,501) of these were classified as MSC injury entitlement claims. Participants 25 years and older accounted for 31% of the female rugby union player claims. Females in the over 35-year age groups compete against younger participants which may account for the higher mean cost per-claim seen as the age groups increase in years until they retire from the game.  相似文献   

13.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  相似文献   

14.
Optimizing tactical fitness is important for combat readiness and injury prevention, especially as women have entered ground combat military occupational specialties.

Objectives

To assess characteristics of male and female Marines by Combat Fitness Test (CFT) performance clusters.

Design

Cross-sectional study.

Methods

Anthropometric, body composition (BF%, fat and fat-free mass [FM and FFM], and Fight load index [FLI], physiological (maximal oxygen uptake, lactate threshold and anaerobic power/capacity), and musculoskeletal (isokinetic strength of the knee, shoulder, torso, and isometric strength of the ankle) assessments were obtained from 294 male (M) and female (F) Marines. Hierarchical cluster analysis classified Marines based on performance of two CFT events (sec): Maneuver Under Fire (MANUF) and Movement to Contact (MTC). Following tests for normality, one-way ANOVA or Kruskal Wallis tests, followed by Bonferroni post-hoc tests, assessed characteristics across clusters and sex (alpha = 0.05).

Results

Two clusters (C) were determined: C1: N = 66F, 16M and C2: N = 18F, 194M, with C2 demonstrating better performance on the MANUF and MTC. C1F demonstrated significantly greater BF% and FLI than C1M, C2F, and C2M. C2M demonstrated significantly greater knee flexion strength than C1F and C2F, but C1M was only significantly greater than C1F. C2M demonstrated significantly greater ankle eversion and inversion strength than C1F.

Conclusions

Women with increased BF%, increased FM and reduced FFM relative to a fighting load may have decreased performance in combat-related tasks. Training programs based on an individual Marine’s baseline body composition and fitness characteristics can enhance combat fitness and force readiness.  相似文献   

15.

Objectives

Higher physical activity (PA) levels in adults are associated with lower cardiovascular disease risk, however it is unclear whether this association is evident in children younger than five years. Given that cardiovascular disease has early life origins, this study systematically reviews evidence of associations between PA and cardiovascular disease risk factors among children aged 3–5.5 years.

Design

Systematic review.

Method

A systematic search of multiple data bases was conducted to identify published papers reporting associations between any measure of PA and cardiovascular disease risk factors. Inclusion criteria: English language; peer-reviewed; original quantitative research; mean age or majority of sample to be between 3.0–5.5 years. Studies where the sample was characterised by a health condition (e.g. obese, hypertensive) were not eligible for inclusion.

Results

Twelve papers met the inclusion criteria. At least one study for each cardiovascular disease risk factor except inflammation was included. PA was not associated with insulin resistance, and inconsistently associated with the remaining cardiovascular disease risk factors. Studies were mostly cross-sectional and methodologically heterogeneous. Longitudinal and experimental study designs and objective measurement of PA may help provide a clearer indication of the interplay between PA and cardiovascular disease risk in the preschool population.  相似文献   

16.

Objectives

To assess the feasibility and efficacy of a 6-week pilot active break program (ACTI-BREAK) on academic achievement, classroom behaviour and physical activity.

Design

Pilot cluster randomised controlled trial.

Methods

374 children in Year 3 and 4 (74% response) were recruited from six schools across Melbourne, Australia. Schools were randomised to the ACTI-BREAK intervention or usual teaching practice. The intervention involved teachers incorporating 3 × 5 min active breaks into their classroom routine daily. Academic achievement was assessed using 1-min tests in reading and mathematics; classroom behaviour at the individual and whole class level was observed by teachers; and physical activity levels were assessed using accelerometers. Multilevel mixed effects linear regression models were conducted using intention to treat (ITT) and per protocol (PP) analyses.

Results

Significant intervention effects were found for classroom behaviour at the individual level (ITT B = 16.17; 95% CI: 6.58, 25.76); effects were stronger for boys (B = 21.42; 95% CI: 10.34, 32.49) than girls (B = 12.23; 95% CI: 1.52, 22.92). No effect was found for classroom behaviour at the whole class level, reading, math or physical activity. PP findings were similar.

Conclusions

Implementing active breaks during class time may improve classroom behaviour, particularly for boys. There was no evidence to suggest that implementing active breaks had any adverse effect on academic achievement or classroom behaviour, which may encourage classroom teachers to incorporate active breaks into their routine.  相似文献   

17.

Objectives

Among symptomatic dancers, sonographic abnormalities are common. Whether asymptomatic dancers have any abnormalities remains unknown. Some dancers became cyanosis over distal feet after ballet training. The hemodynamic changes at the feet in ballet are not clearly understood.

Design

Cross-sectional study.

Methods

In 25 dancers and 14 non-dancers, B-mode ultrasonography was used to measure cross-sectional areas (CSA) of tendons of deep posterior compartment muscles. Doppler ultrasonography was used to measure peak velocity (Vpeak) of posterior tibial artery in three ankle postures: the neutral position, passively and forced actively plantar flexion (en pointe). The big toe oxygen saturation was recorded in neutral position and during 1-min en pointe. Single-leg standing heel rise test was performed to represent the muscle function.

Results

The CSA of FHL was larger in dancers (0.26 cm2 [0.20, 0.30] vs 0.21 cm2 [0.17, 0.24], p < 0.01), while other tendons were not different (all p > 0.05). Higher Vpeak was recorded in passively plantar flexion than in neutral position (p < 0.01, in both groups). The blood flow was undetectable during en pointe, more frequently in dancers (54.9% vs 14.3%, p < 0.01). Oxygen saturation decreased during en pointe more prominently in dancers (85% [80, 90] vs 94% [84, 97], p < 0.01). There was no significant difference in muscle function.

Conclusions

US showed the FHL tendon thickening and en pointe-related vascular compromise in pre-professional dancers, even when they are asymptomatic.  相似文献   

18.

Objectives

Greater arterial stiffness and poor 24 h blood pressure (BP) are recognized as indicators of poor cardiovascular health. Evidence has shown that high intensity interval training (HIIT) may be a superior alternative to moderate intensity continuous training (MICT) for improving cardiovascular disease risk factors such as cardiorespiratory fitness and vascular function. However, there are limited data comparing the effect of HIIT to MICT on central arterial stiffness and/or 24 h BP response. The purpose of this study was to compare HIIT versus MICT on central arterial stiffness and 24 h BP outcomes by systematic review and meta-analysis.

Design

A systematic review and meta-analysis was conducted.

Methods

Eligible studies were exercise training interventions (≥4 weeks) that included both HIIT and MICT and reported central arterial stiffness, as measured by pulse wave velocity and augmentation index and/or 24 h BP outcome measures.

Results

HIIT was found to be superior to MICT for reducing night-time diastolic BP (ES: ?0.456, 95% CI: ?0.826 to ?0.086 mmHg; P = 0.016). A near-significant greater reduction in daytime systolic (ES: ?0.349, 95% CI: ?0.740 to 0.041 mmHg; p = 0.079) and diastolic BP was observed with HIIT compared to MICT (ES: ?0.349, 95% CI: ?0.717 to 0.020 mmHg; p = 0.063). No significant difference was found for other BP responses or arterial stiffness outcomes.

Conclusions

HIIT leads to a superior reduction in night-time diastolic BP compared to MICT. Furthermore, a near-significant greater reduction in daytime BP was found with HIIT compared to MICT. No significant difference was observed for changes to central arterial stiffness between HIIT and MICT.  相似文献   

19.

Objectives

It is suggested that individuals will not reach their heart rate maximum (HRmax) at an incremental cardiorespiratory fitness (CRF) test and commonly five beats per minute (bpm) are added to the highest heart rate (HR) reached. To our knowledge, there is not sufficient data justifying such estimation. Our aim was to assess whether individuals reached HRmax in an incremental CRF test to exhaustion.

Design and methods

Fifty-one males and 57 females (aged 22–70 years) completed both an incremental CRF test (gradual increase in speed and/or inclination until volitional exhaustion) and a test designed to reach HRmax (with repeated work bouts at high intensity before maximal exertion) ≥48 h apart. We investigated the relationship between the highest HR in the two tests using hierarchical linear regression analysis, with HRmax from the HRmax test as a dependent variable, and the highest HR reached at the CRF test (HRcrf), whether maximum oxygen uptake was reached on the CRF test, CRF, sex and age as independent variables.

Results

HRmax was 2.2 (95% confidence interval, 1.5–2.9) bpm higher in the test designed to reach HRmax than in the CRF test (p < 0.001). Only HRcrf significantly predicted HRmax, with no contribution of the other variables in the model. HRmax was predicted from the highest HR reached in an incremental CRF test by multiplying HRcrf with 0.967, and adding 8.197 (HRmax = 8.197 + [0.967 × HRcrf]) beats/min.

Conclusion

Non-athletes reached close to HRmax in a standard CRF test.  相似文献   

20.

Objectives

Appropriate statistical analysis of clustered data necessitates accounting for within-participant effects to ensure results are repeatable and translatable to real-world applications. This study aimed to compare statistical output and injury risk interpretation differences from two statistical regression models built from a clinical movement sidestepping database. A “naïve” regression model, which does not account for within-participant effects, was compared with an appropriately applied mixed effects model.

Design

Comparative study.

Methods

Three-dimensional unplanned sidestepping joint angle data (trunk, hip, and knee) from 35 males (112 observations) were used to model peak knee valgus moments and anterior cruciate ligament injury risk during the impact phase of stance. Both statistical models were cross-validated using a k-fold analysis.

Results

The naïve regression returned inflated goodness of fit statistics (R2 = 0.50), which was evident following cross-validation (predicted R2 = 0.43). Following cross-validation, the mixed effects model (predicted R2 = 0.40) explained a similar amount of variance, despite containing three less predictors. The naïve model produced inaccurate parameter estimates, overestimating the effects of certain kinematic parameters by as much as 79 %.

Conclusions

A regression model naïvely applied to clustered observations of sidestepping data resulted in erroneous parameter estimates and goodness of fit statistics which have the potential to mislead future research and real-world applications. It is important for sport and clinical scientists to use statistically appropriate mixed effects models when modelling clustered motion capture data for injury biomechanics research to protect the translatability of the findings.  相似文献   

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