Search

High-intensity interval training (HIIT) is an emerging exercise strategy to improve health and fitness, but previous studies have evaluated HIIT interventions across different populations and outcomes. This review aimed to comprehensively synthesize published evidence on the effects of HIIT on key cardiometabolic health parameters in children and adolescents. We searched seven databases until February 2024. Systematic reviews were eligible if they 1) compared HIIT and active/non-active control conditions with meta-analysis, 2) examined cardiorespiratory fitness, body composition and cardiometabolic risk biomarkers, and 3) examined children and adolescents. We included 18 systematic reviews with meta-analysis, including 223 original studies and 13,900 unique participants. HIIT is effective for cardiorespiratory fitness in children and adolescents with diverse health and weight status (median standardized mean difference [SMD] = 0.75). Improvements in body composition and several cardiometabolic risk biomarkers, including systolic blood pressure (median SMD = -0.40), diastolic blood pressure (median SMD = -0.22), triglyceride (median SMD = -0.30), low-density lipoprotein cholesterol (median SMD = -0.90), and high-density lipoprotein cholesterol (median SMD = 0.34), have also been observed following HIIT, with a notably more pronounced effect in youth with overweight/obesity or metabolic disorders. Our umbrella review supports the effectiveness of HIIT in enhancing cardiometabolic health, suggesting its integration into physical activity promotion programmes in schools and communities.

Purpose: Previous studies have demonstrated that physical exercise can modulate the endogenous melatonin level in children with autism spectrum disorder (ASD) and improve their sleep quality. However, it remains unclear whether physical exercise or melatonin supplement, or a combination of both, is more effective in improving sleep quality in this population. The purpose of this study is to answer this research question by comparing the effectiveness of three types of interventions (physical exercise vs. melatonin supplement or a combination of both) in improving sleep quality in children with ASD., Methods: Sixty-two (62) children diagnosed with ASD were randomly assigned to one of four groups: cycling (n = 18), melatonin supplement (n = 14), a combination of both (n = 12), and placebo control group (n = 18). Four (4) sleep parameters (sleep efficiency, sleep onset latency, sleep duration, and wake after sleep onset) were assessed., Results: The results revealed a significant improvement in sleep efficiency, sleep onset latency, and sleep duration in all of the interventions, but not in the placebo control group. However, no significant group differences were found among the interventions (ps > .05)., Conclusion: Our findings suggest similar effectiveness of physical exercise and melatonin supplementation in improving sleep quality in children with ASD., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: To assess the effectiveness of high-intensity interval training (HIIT) compared with traditional moderate-intensity continuous training (MICT) and/or non-exercise control (CON) for modification of metabolic syndrome (MetS) components and other cardiometabolic health outcomes in individuals with MetS., Design: Systematic review and meta-analysis DATA SOURCES: Five databases were searched from inception to March 2024., Study Appraisal and Synthesis: Meta-analyses of randomised controlled trials (RCTs) comparing HIIT with MICT/CON were performed for components of MetS (waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (BG)) and clinically relevant cardiometabolic health parameters. Subgroup moderator analyses were conducted based on the intervention duration and HIIT volume., Results: Out of 4819 studies, 23 RCTs involving 1374 participants were included (mean age: 46.2-67.0 years, 55% male). HIIT significantly improved WC (weighted mean difference (WMD) -4.12 cm, 95% CI -4.71 to -3.53), SBP (WMD -6.05 mm Hg, 95% CI -8.11 to -4.00), DBP (WMD -3.68 mm Hg, 95% CI -5.70 to -1.65), HDL-C (WMD 0.12 mmol/L, 95% CI 0.04 to 0.20), TG (WMD -0.34 mmol/L, 95% CI -0.41 to -0.27) and BG (WMD -0.35 mmol/L, 95% CI -0.54 to -0.16) compared with CON (all p<0.01). HIIT approaches demonstrated comparable effects to MICT across all parameters. Subgroup analyses suggested that HIIT protocols with low volume (ie, <15 min of high-intensity exercise per session) were not inferior to higher volume protocols for improving MetS components., Conclusion: This review supports HIIT as an efficacious exercise strategy for improving cardiometabolic health in individuals with MetS. Low-volume HIIT appears to be a viable alternative to traditional forms of aerobic exercise., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Context: Recent studies suggest that light-intensity physical activity may enhance cardiometabolic health and reduce mortality risk in adults. However, more information is required to understand the patterns of light-intensity physical activity and postprandial cardiometabolic health., Objective: This study examined the effects of different light-intensity walking patterns on postprandial cardiometabolic responses in young obese adults., Design: A randomized crossover trial was conducted., Setting: The study was conducted in the laboratory., Participants: The study analyzed baseline (fasting) and 6-hour postprandial concentrations of glucose, insulin, triglycerides, and blood pressure (BP) in 16 young obese adults., Interventions: Participants underwent four 7-hour experimental conditions with a 7-20-day washout period: uninterrupted sitting (SIT), 30-minute light-intensity walking (EX+SIT), 3-minute light-intensity walking every 30 minutes (BR), and 30-minute light-intensity walking with 3-minute light-intensity walking every 30 minutes (EX+BR)., Main Outcome Measures: Incremental areas under the curve (iAUC) for each outcome and average BP were compared between SIT and walking conditions., Results: Compared with SIT, all walking conditions reduced iAUCs for glucose and average diastolic BP (all p<0.05). Only EX+SIT and EX+BR reduced iAUCs for insulin (p<0.05). No significant differences were found for triglycerides iAUC and systolic BP between the four conditions (all p>0.05)., Conclusions: All patterns of light-intensity walking reduced postprandial glucose concentrations and diastolic BP in young obese adults, suggesting benefits for glycemic control. Continuous 30-minute light-intensity walking alone, or combined with brief 3-min bouts also attenuated postprandial insulin concentrations, highlighting light-intensity walking as a promising strategy for improving cardiometabolic health in young obese adults., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)

Background: Although the efficacy of interval training for improving body composition has been summarized in an increasing number of systematic reviews in recent years, discrepancies in review findings and conclusions have been observed., Objective: This study aims to synthesize the available evidence on the efficacy of interval training compared with moderate-intensity continuous training (MICT) and nonexercise control (CON) in reducing body adiposity in apparently healthy adults., Methods: An umbrella review with meta-analysis was performed. A systematic search was conducted in seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) up to October 2023. Systematic reviews with meta-analyses of randomized controlled trials (RCTs) comparing interval training and MICT/CON were included. Literature selection, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers. Meta-analyses were performed using a random-effects model. Subgroup analyses were conducted based on the type of interval training [high-intensity interval training (HIIT) and sprint interval training (SIT)], intervention duration, body mass index, exercise modality, and volume of HIIT protocols., Results: Sixteen systematic reviews, including 79 RCTs and 2474 unique participants, met the inclusion criteria. Most systematic reviews had a critically low (n = 6) or low (n = 6) AMSTAR-2 score. Interval training demonstrated significantly greater reductions in total body fat percent (BF%) compared with MICT [weighted mean difference (WMD) of - 0.77%; 95% confidence interval (CI) - 1.12 to - 0.32%] and CON (WMD of - 1.50%; 95% CI - 2.40 to - 0.58%). Significant reductions in fat mass, visceral adipose tissue, subcutaneous abdominal fat, and android abdominal fat were also observed following interval training compared to CON. Subgroup analyses indicated that both HIIT and SIT resulted in superior BF% loss than MICT. These benefits appeared to be more prominent in individuals with overweight/obesity and longer duration interventions (≥ 12 weeks), as well as in protocols using cycling as a modality and low-volume HIIT (i.e., < 15 min of high-intensity exercise per session)., Conclusions: This novel umbrella review with large-scale meta-analysis provides an updated synthesis of evidence with implications for physical activity guideline recommendations. The findings support interval training as a viable exercise strategy for reducing adiposity in the general population., Competing Interests: Declarations Funding This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Conflict of interest All authors have no conflicts of interest to disclose. Availability of data and material The datasets analyzed in this review are available from the corresponding author on reasonable request. Code availability Not applicable. Author contributions E.P., J.L., S.W., and R.H. conceived the idea for the review. E.P., J.L., and R.H. conducted the search, study selection, data extraction, and quality assessment. E.P., J.L., and R.H. drafted the initial manuscript. E.P., J.L., and R.H. contributed to writing the manuscript. All authors reviewed and approved the final manuscript., (© 2024. The Author(s).)

Sprint interval training (SIT) is a potent exercise strategy to enhance athletes' anaerobic capacity in a time-efficient manner. This study aimed to investigate the impact of low-volume, court-based SIT on the anaerobic capacity and sport-specific performance in competitive tennis players. Twenty-four competitive collegiate tennis players were randomly assigned to either the SIT group (n = 12; three sessions per week of court-based repeated-sprint training) or the traditional endurance training (ET) group (n = 12; three sessions per week of 45-min continuous treadmill running, n = 12) for a 6-weeks intervention. Baseline and post-intervention assessments included the Wingate Anaerobic Test, elimination rate of blood lactate (BLAer), tennis-specific repeated sprint ability (RSA), and the Yo-Yo Intermittent Recovery Test Level 2 (YoYo-IR2). The results showed that SIT group demonstrated significant improvements in peak and average power during the Wingate test (p = 0.07; p < 0.001), along with a notable increase in YoYo-IR2 performance (7.8% increase, p = 0.04). Significant decreases were observed in both mean (5.1% decrease, p = 0.02) and sum RSA time (5.2% decrease, p = 0.02) in the tennis-specific RSA assessments. Additionally, the SIT group showed significantly higher effective training time and TRIMP in the 90-100% HRmax zone compared to the ET group (p < 0.01). This study underscores the potential benefits of low-volume, court-based SIT in enhancing anaerobic capacity and sport-specific performance in competitive tennis players, in comparison to traditional ET., (© 2024. The Author(s).)

A surge of public interest in NMN supplementation has been observed in recent years. However, whether NMN supplements are effective in improving metabolic health remains unclear. The objective of the review was to assess the effects of NMN supplementation on fasting glucose, triglycerides, total cholesterol, LDL-C, and HDL-C in adults. Studies were located by searching four databases (PubMed, Embase, Cochrane, and Web of Science). Two reviewers independently conducted title/abstract and full-text screening, data extraction, and risk-of-bias assessment. Of the 4049 records reviewed, 12 studies with a total of 513 participants met the criteria for analysis. Random-effects meta-analyses found an overall significant effect of NMN supplementation in elevating blood NAD levels. However, most of the clinically relevant outcomes were not significantly different between NMN supplementation and control group. Risk-of-bias assessment using RoB2 showed some concerns in seven studies and high risk of bias in the other five studies. Together, our findings suggest that an exaggeration of the benefits of NMN supplementation may exist in the field. Although the limited number of eligible studies was sufficiently powered to detect changes in the abovementioned primary outcomes, more studies are needed to conclude about the exact effects of NMN supplementation.

Background: Time-restricted eating (TRE) is increasingly popular, but its benefits in combination with exercise still need to be determined., Objectives: This systematic review and meta-analysis aimed to evaluate the efficacy of TRE combined with exercise compared with control diet with exercise in improving the body composition and metabolic health of adults., Methods: Five electronic databases were searched for relevant studies. Randomized controlled trials (RCTs) examining the effect of TRE combined with exercise on body composition and metabolic health in adults were included. All results in the meta-analysis are reported as mean difference (MD) with 95% confidence interval (CI). Study quality was assessed using the revised Cochrane Risk of Bias Tool and Grading of Recommendations Assessment, Development, and Evaluation assessment., Results: In total, 19 RCTs comprising 568 participants were included in this systematic review and meta-analysis. TRE combined with exercise likely reduced the participants' body mass (MD: -1.86 kg; 95% CI: -2.75, -0.97 kg) and fat mass (MD: -1.52 kg; 95% CI: -2.07, -0.97 kg) when compared with the control diet with exercise. In terms of metabolic health, the TRE combined with exercise group likely reduced triglycerides (MD: -13.38 mg/dL, 95% CI: -21.22, -5.54 mg/dL) and may result in a reduction in low-density lipoprotein (MD: -8.52 mg/dL; 95% CI: -11.72, -5.33 mg/dL) and a large reduction in leptin (MD: -0.67 ng/mL; 95% CI: -1.02, -0.33 ng/mL). However, TRE plus exercise exhibited no additional benefit on the glucose profile, including fasting glucose and insulin, and other lipid profiles, including total cholesterol and high-density lipoprotein concentrations, compared with the control group., Conclusions: Combining TRE with exercise may be more effective in reducing body weight and fat mass and improving lipid profile than control diet with exercise. Implementing this approach may benefit individuals aiming to achieve weight loss and enhance their metabolic well-being. This study was registered in PROSPERO as CRD42022353834., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: High-intensity interval training (HIIT) is characterized by repeated bouts of relatively intense exercise interspersed with recovery periods. Previous studies have evaluated this exercise strategy with various population subgroups, regimens, and comparator groups, limiting the generalizability of findings. We performed a novel umbrella review to generate an up-to-date synthesis of the available evidence regarding the effect of HIIT on cardiorespiratory fitness (CRF) in adults as compared to non-exercise control and traditional continuous forms of exercise such as moderate-intensity continuous training (MICT)., Methods: An umbrella review was conducted in accordance with the Preferred Reporting Items for Overviews of Reviews guideline. Seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) were searched until February 2024. Systematic reviews with meta-analyses comparing HIIT and active/non-active control conditions were included. Literature search, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers., Results: Twenty-four systematic reviews with meta-analyses, representing 429 primary studies and 12 967 unique participants, met the inclusion criteria. Most of the systematic reviews received moderate-to-critically low AMSTAR-2 scores. The data showed that HIIT, including the particularly intense variant "sprint interval training" (SIT), significantly increases CRF in adults compared to non-exercise control (standardized mean difference [SMD]: 0.28 to 4.31; weighted mean difference [WMD]: 3.25 to 5.5 mL/kg/min) and MICT (SMD: 0.18 to 0.99; WMD: 0.52 to 3.76 mL/kg/min). This effect was consistently observed across specific groups of individuals (e.g., apparently healthy adults, individuals with overweight/obesity, older adults, and high-level athletes) and HIIT modalities (e.g., low-volume HIIT, whole-body HIIT, home-based HIIT, aquatic HIIT, and short SIT)., Conclusion: Existing evidence from systematic reviews consistently supports the effect of HIIT on enhancing CRF in adults when compared to non-exercise control and MICT. Our findings offer a comprehensive basis that may potentially contribute to informing physical activity guidelines aimed at improving CRF in the general population., (© 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Background: The use of tele-exercise programs as an option for post-COVID-19 rehabilitation has been suggested, but its effectiveness in non-hospitalized individuals is not well understood., Objective: This study aimed to determine the effectiveness of an 8-week tele-exercise training program (COFIT-HK) on physical fitness, functional capacity, and health-related quality of life (HRQoL) in non-hospitalized post-COVID-19 individuals., Methods: Forty-one non-hospitalized individuals (age:47.4 ± 7.8 yrs) who had COVID-19 history were divided into two groups: the tele-exercise training group (TELE; n = 21) and the non-intervention control group (CON; n = 20). TELE engaged in online supervised multicomponent low-to-moderate intensity exercise training (including respiratory muscle, aerobic, and resistance training) three times per week, whereas CON received standardized educational leaflets based on World Health Organization (WHO) guidelines for post-COVID-19-related illness rehabilitation only. Various components of physical fitness, functional capacity, and HRQoL were assessed at baseline and after the 8-week intervention., Results: TELE showed significant improvements in handgrip strength, arm flexibility, functional lower extremity endurance, and HRQoL after the 8-week intervention (all p  < 0.05, ES = 0.50-1.10). When comparing the groups, TELE demonstrated significantly greater improvements in both the physical and mental component summary scores of HRQoL compared to CON (both p  < 0.05). Other outcomes did not reveal significant group differences., Conclusion: Our tele-exercise intervention was effective in improving physical fitness, functional capacity and HRQoL among non-hospitalized post-COVID-19 individuals. Further research is needed to explore the utility and limitations of tele-exercise programs for post-COVID-19 rehabilitation and beyond., (© 2024 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd.)

Music is well-known to elicit ergogenic effects on exercise performance; however, the moderating role of application timing remains unclear. This study examined the effects of the timing of music on fatigue perception and performance during isometric strength exercises. Using a within-subject, randomised crossover design, twelve recreationally active young adults performed two isometric strength tasks (plank-hold and wall-sit) in three separate conditions (MEE: music played during the entire exercise task; MDF: music played during fatigue alone; CON: no music). The total time to volitional exhaustion (TTE), time to the onset of fatigue perception (TFP), heart rate, and blood lactate responses were assessed during each trial. MEE resulted in a significantly longer TTE than CON in both the plank-hold (p < 0.05, d = 0.76) and wall-sit exercises (p < 0.05, d = 0.72), whereas MDF led to a significantly longer TTE than CON in wall-sit exercises alone (p < 0.05, d = 0.60). TFP was significantly longer in MEE than in CON in both the plank-hold (p < 0.05, d = 0.54) and wall-sit exercises (p < 0.05, d = 0.64). The music condition did not influence the heart rate or blood lactate changes in any of the trials. Our results suggest that listening to music during the entire exercise can delay the onset of fatigue perception in isometric strength tasks, whereas listening to music during fatigue has only a modest effect. Athletes and exercisers should consider extending music exposure throughout the entire exercise task to maximise performance benefits., (© Journal of Sports Science and Medicine.)

Context: Intermittent dieting incorporated with break periods (INT-B) has recently been promoted as an alternative dietary approach for optimal weight management., Objective: This study assessed the effectiveness of INT-B compared with that of conventional continuous energy restriction (CER) for improving body composition and attenuating metabolic adaptation., Data Sources: A systematic search was conducted on 6 databases using all available records until July 2023., Data Extraction: The extracted data included the lead author, year of publication, population characteristics, intervention protocols, duration, and adherence., Data Analysis: Random-effects meta-analyses were conducted for within-group and between-group comparisons of anthropometric and metabolic outcomes. Subgroup moderator analysis was performed for the types of INT-B, intervention duration, and population characteristics., Results: Of the 1469 records, 12 randomized trials (with 881 participants) were included. Within-group analyses demonstrated significant improvements in body mass, fat mass, body mass index, body fat percentage, and waist circumference following both INT-B and CER, with no significant group differences. However, resting metabolic rate (RMR) was significantly reduced following CER only. The compensatory reduction in RMR was significantly smaller following INT-B compared with CER, suggesting a lesser degree of metabolic adaptation. INT-B had a more significant effect on RMR retention in individuals with overweight/obesity compared with resistance-trained individuals., Conclusion: This review provides up-to-date evidence for INT-B as a viable dietary strategy to improve body composition and attenuate metabolic adaptation., Systematic Review Registration: PROSPERO registration no. CRD42023448959., (© The Author(s) 2024. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Low physical fitness in adolescence is linked with increased cardiometabolic risk and early all-cause mortality. This study aimed to estimate temporal trends in the physical fitness of Hong Kong adolescents aged 12-17 years between 1998 and 2015. Physical fitness (9-min run/walk, sit-ups, push-ups, and sit-and-reach) and body size data in a total of 28,059 adolescents tested across five population-representative surveys of Hong Kong secondary school pupils, were reported. Temporal trends in means were estimated at the gender-age level by best-fitting sample-weighted linear regression, with national trends estimated by a post-stratified population-weighting procedure. Overall, there were small declines in 9-min run/walk (effect size (ES)=-0.29 (95%CI: -0.32, -0.26)) and sit-ups performance (ES=-0.24 (95%CI: -0.27, -0.21)), with negligible changes in push-ups and sit-and-reach performance. There were small concurrent increases in both mean height and body mass, with a negligible increase in sum of skinfolds. Trends in mean physical fitness and body size/were not always uniform across the population distribution. The small declines in mean 9-min run/walk and sit-ups performance for Hong Kong adolescents are suggestive of corresponding declines in cardiorespiratory fitness and abdominal/core endurance, respectively. Increased national health promotion strategies are required to improve existing trends., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Low physical fitness in childhood is linked with poor health now and in later life. This study estimated temporal trends in physical fitness for Hong Kong children aged 6-12 years from 2003-04 to 2015-16. Objectively measured body size and physical fitness data for 27,513 children were obtained from four population-representative surveys of Hong Kong primary school students. Temporal trends in means were estimated by population-weighted linear regression. Trends in distributional characteristics were visually described. Overall, there was a small increase in mean height (effect size (ES) = 0.20 (95%CI: 0.13, 0.28)), with a negligible increase (ES < 0.2) in mean body mass. When adjusted for trends in age, gender, and body size, there was a small decline in sit-and-reach performance (ES = -0.43 (95%CI: -0.43, -0.42)), a small improvement in 9-min run/walk performance (9-to-12-year-olds, ES = 0.26 (95%CI: 0.26, 0.27)), with negligible declines in handgrip strength, 6-min run/walk (6-to 8-year-olds), and sit-ups performance. Temporal trends were not always uniform across the population distribution, with declines in run/walk, sit-ups, and sit-and-reach performance generally largest in children with low fitness. Increased national health promotion strategies that address culturally specific factors are encouraged to further improve the existing trends, especially for children with low fitness.

Low-volume, time-efficient high-intensity interval training (HIIT), which involves whole-body (WB) callisthenics exercises, has gained worldwide popularity in recent years. However, the physiological and perceptual impact of WB-HIIT in comparison to specialised, equipment-based training is relatively less studied. This study compared the acute physiological and perceptual responses to a single session of WB-HIIT, ergometer-based HIIT (ERG-HIIT) and conventional moderate-intensity continuous training (MICT). Fourteen physically inactive adults (age: 28.4 ± 6.5 years, VO 2peak : 31.0 ± 6.2 mL· kg -1 · min -1 ) underwent three main trials (WB-HIIT: 12 x 30-s high-intensity callisthenics workout; ERG: HIIT: 12 x 30-s high-intensity cycling bouts; MICT: 30-min cycling at 50% peak power output) in a randomized cross-over order 3-7 days apart. The mean session heart rate (HR) and perceived exertion were comparable across all three protocols ( p > 0.05). WB-HIIT attained a similar peak HR (87.4 ± 9.4 %HR max ) as that of ERG-HIIT (83.0 ± 8.6 %HR max ), and significantly greater than that of MICT (78.7 ± 5.5 %HR max , p = 0.001). However, WB-HIIT induced significantly higher blood lactate levels (7.2 ± 1.8 mmol/L) compared to both ERG-HIIT (5.1 ± 1.3 mmol/L, p < 0.05) and MICT (3.1 ± 1.5 mmol/L, p < 0.001). The participants reported higher self-efficacy and greater enjoyment with WB-HIIT compared to MICT ( p < 0.05). The mean HR and perceived exertion responses to WB-HIIT are comparable to those of equipment-based HIIT and MICT; however, WB-HIIT results in greater metabolic strain than both other modalities. Despite this, the overall perceptual responses to WB-HIIT are positive, suggesting that it could be a viable exercise alternative, especially for individuals with limited exercise time and restricted access to facilities and equipment., (© Journal of Sports Science and Medicine.)

The study aimed to investigate the post-activation performance enhancement (PAPE) of flywheel training (FT) on lower limb explosive power performance. Using a randomized crossover design, 20 trained men (age = 21.5 ± 1.4 years; training experience 5.5 ± 1.2 years) completed seven main conditions after three familiarization sessions. The first three conditions tested the PAPE of the FT on the counter movement jump (CMJ) under three different inertial loads (0.041 kg·m 2 as L; 0.057 kg·m 2 as ML; and 0.122 kg·m 2 as P), whereas the following four conditions tested the PAPE of FT on the 30 m sprint, which consisted of three inertial loads (L, ML, and P) and a control condition. Participants were required to perform the CMJ or 30 m sprint at baseline (Tb) and immediately (T0), 4 min (T4), 8 min (T8), 12 min (T12), and 16 min (T16) after exercise, respectively. The results of the CMJ conditions showed that PAPE peaked at T4 ( p < 0.01) and almost subsided at T12 ( p > 0.05) in ML and P conditions. Meanwhile, PAPE appeared earlier in the P condition, and the effect was more significant (P:ES = 1.09; ML:ES = 0.79). 30 m sprint results showed significant improvement only in the ML condition. The PAPE peaked at T4 ( p < 0.05, ES = -0.47) and almost subsided at T8 ( p > 0.05). It was mainly due to the significant enhancement of the 10-30 m segmental timing performance at T4 ( p < 0.05, ES = -0.49). This study indicates that the size of the inertial load could influence the magnitude of the PAPE produced by the explosive force of the lower limb. The PAPE of the vertical explosive force increased with increasing inertial load, but the PAPE of the horizontal explosive force did not appear at the maximum inertial load. The most effective elicitation of the PAPE was at 4-8 min after the FT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Fu, Chen, Poon, Wang, Li, Liu and Ho.)

Background: High-intensity interval training (HIIT) has been promoted as a time-efficient exercise strategy to improve health and fitness in children and adolescents. However, there remains little consensus in the literature regarding its efficacy in children and adolescents with special educational needs (SEN). This study aimed to examine HIIT as a means of improving key health and fitness parameters in children and adolescents with SEN., Methods: A systematic search was conducted on eight databases (MEDLINE, Embase, SPORTDiscus, Web of Science, Scopus, PsycINFO, CINAHL, and Cochrane Library). Studies were eligible if they 1) included an HIIT protocol, 2) examined parameters related to both physical and mental aspects of health and fitness, and 3) examined children and adolescents with SEN aged 5-17 years., Results: Of the 1727 studies yielded by the database search, 13 (453 participants) were included and reviewed. We found that HIIT generally improved body composition, physical fitness, and cardiometabolic risk biomarkers across a spectrum of SEN (e.g., attention deficit hyperactivity disorder, cerebral palsy, developmental coordination disorder, and mental illness). Improvements in mental health and cognitive performance following HIIT have also been observed., Conclusion: This review provides up-to-date evidence for HIIT as a viable exercise strategy for children and adolescents with SEN. Further research investigating the benefits of HIIT in a wider range of SEN populations is warranted., Trial Registration: This study was registered in the International Prospective Register of Systematic Review (PROSPERO; registration number CRD42022352696)., (© 2023. The Author(s).)

Background: High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) alone has been shown to improve metabolic health, but the effects of alternating the two training approaches as often practiced in real life remained unclear., Purpose: To examine the effects of HIIT or MICT alone or alternating HIIT-MICT on cardiometabolic responses in inactive obese middle-aged men., Methods: Forty-two participants (age: 42 ± 5 y; BMI: 26.3 ± 2.1 kg m -2 ) were randomly assigned to four groups: HIIT (12 x 1-min running bouts at 80-90% HR max interspersed with 1-min active recovery at 50% HR max ), MICT (40-min brisk walk at 65-70% HR max ), alternating HIIT-MICT or a non-exercise control group (CON). Exercise sessions were conducted three times per week for 16 weeks. Maximal oxygen uptake (VO 2max ), body composition (by bioelectrical impedance analysis), blood pressure, fasting blood glucose, insulin resistance (HOMA-IR) and lipid profile were assessed at baseline and after the 16-week intervention. Enjoyment and self-efficacy were also assessed at the end of intervention., Results: All exercise groups showed a similar VO 2max increase of ∼15% (HIIT: 34.3 ± 4.4 vs 39.1 ± 5.4; MICT: 34.9 ± 5.0 vs 39.4 ± 7.2; and alternating HIIT-MICT: 34.4 ± 5.0 vs 40.3 ± 4.6 mL kg -1 min -1 ) compared to baseline and CON (all p < 0.05). Weight, BMI, % fat and waist circumference also showed similar reductions in all exercise groups compared to baseline and CON (all p < 0.05). No significant group difference was observed for all blood markers. Compared to baseline, total cholesterol decreased after HIIT-MICT, while HIIT significantly decreased fasting insulin level and improved insulin resistance (p < 0.05). Enjoyment, self-efficacy and adherence were similar among all exercise groups., Conclusion: HIIT or MICT alone or alternating HIIT-MICT similarly improve cardiovascular fitness and body composition in obese middle-aged men despite differences in total training volume and time commitment., (© 2021 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd.)

Face masks are widely recommended as means of controlling the coronavirus disease outbreak. This study aimed to examine the physiological and perceptual responses of wearing surgical face masks while exercising at different intensities. Thirteen healthy young adults (mean age, 21.9 ± 1.4 years) conducted randomized crossover trials with or without a surgical face mask. In each trial, participants completed an incremental treadmill protocol, with three 6-min stages (light, moderate, and vigorous at 25, 50, and 75% maximal oxygen uptake, respectively). Physiological outcomes (heart rate, blood lactate, and oxygen saturation level), perceived exertion and discomfort feeling were assessed. No significant differences were observed in physiological outcomes with or without masks at different exercise intensities ( p > 0.05). However, the rating of perceived exertion (RPE) was significantly higher when exercising vigorously (mask: 15.5 ± 1.5 vs. no-mask: 14.2 ± 2.1, p < 0.05). Participants wearing masks reported marked discomfort, such as feeling hot, humid, and breathing resistance. Although face mask-wearing during exercise may not have detrimental effects on major physiological parameters, it can increase perceived exertion level and discomfort when the exercise intensity exceeds a certain threshold. Therefore, healthcare professionals should cautiously evaluate each person's ability to exercise while wearing a mask and tailor their prescription accordingly., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Poon, Zheng and Wong.)

Interval training has been promoted as a superior, time-efficient exercise strategy for enhancing cardiorespiratory fitness in the ageing population. This study assessed the effectiveness of interval training compared with that of moderate-intensity continuous training (MICT) for improving cardiorespiratory fitness in middle-aged and older adults. Six databases were systematically searched for studies with exercise interventions (minimum 2-week duration). Meta-analyses were conducted for within-group and between-group comparisons of maximal oxygen uptake (VO 2max ). Sub-group analysis was performed using the nature of interval training (high-intensity interval training [HIIT] and sprint interval training [SIT]). Of 3,257 studies, 14 were included (429 participants). Within-group analyses demonstrated significant VO 2max improvements (mL/kg/min) following interval training (mean difference: MD = 2.26; 95% confidence interval [CI] = 1.50-3.02) and MICT (MD = 1.34; 95% CI = 0.45-2.23]. When comparing the modes of training, the gain in VO 2max was significantly greater following interval training (MD = 1.10; CI = 0.55-1.64). Sub-group analysis showed that HIIT (MD = 1.04; CI = 0.21-1.88) and SIT (MD = 1.18; CI = 0.60-1.76) resulted in superior VO 2max gain than MICT. This study provides evidence synthesis for interval training as a viable exercise strategy to improve cardiorespiratory function in healthy ageing.

High-intensity interval training (HIIT) has been proposed as a time-efficient exercise protocol to improve metabolic health, but direct comparisons with higher-volume moderate-intensity continuous training (MICT) under unsupervised settings are limited. This study compared low-volume HIIT and higher-volume MICT interventions on cardiometabolic and psychological responses in overweight/obese middle-aged men. Twenty-four participants (age: 48.1±5.2yr; BMI: 25.8±2.3kg·m -2 ) were randomly assigned to undertake either HIIT (10 X 1-min bouts of running at 80-90% HR max  separated by 1-min active recovery) or MICT (50-min continuous jogging/brisk walking at 65-70% HR max ) for 3 sessions/week for 8 weeks (2-week supervised + 6-week unsupervised training). Both groups showed similar cardiovascular fitness (VO 2max ) improvement (HIIT: 32.5±5.6 to 36.0±6.2; MICT: 34.3±6.0 to 38.2±5.1mL kg -1  min -1 , p < 0.05) and %fat loss (HIIT: 24.5±3.4 to 23.2±3.5%; MICT: 23.0±4.3 to 21.5±4.1%, p< 0.05) over the 8-week intervention. Compared to baseline, MICT significantly decreased weight and waist circumference. No significant group differences were observed for blood pressure and cardiometabolic blood markers such as lipid profiles, fasting glucose and glycated haemoglobin. Both groups showed similar enjoyment levels and high unsupervised adherence rates (>90%). Our findings suggest that low-volume HIIT can elicit a similar improvement of cardiovascular fitness as traditional higher-volume MICT in overweight/obese middle-aged men.

Background/objective: High-intensity interval training (HIIT) has been recognized as an emerging trend in public health promotion, but its age-specific differences in psycho-perceptual responses have yet to be investigated. This study compared the psycho-perceptual responses after a single session of HIIT versus moderate-intensity continuous exercise (MICE) and vigorous-intensity continuous exercise (VICE) in twelve young and twelve middle-aged insufficiently active males respectively., Methods: Using a randomized cross-over design, participants undertook three main trials consisting of: HIIT (10 x 1-min run at 100% VO 2max interspersed with 1-min active recovery), MICE (40-min run at 65% VO 2max ) and VICE (20-min run at 80% VO 2max ). Affective responses, self-efficacy and exercise preference were assessed for each trial., Results: Both HIIT and VICE showed more positive in-task affective responses than MICE in young adults, while middle-aged adults reported more positive responses in both HIIT and MICE than in VICE. However, middle-aged adults displayed significantly lower exercise task self-efficacy scores towards HIIT (42.7 ± 25.3) and VICE (49.2 ± 23.9) than MICE (63.4 ± 18.3, both P  < 0.01). Additionally, only 17% of participants in the middle-aged group reported a preference to engage in HIIT as opposed to either MICE (50%) and VICE (33%)., Conclusion: Our finding revealed distinct affective and self-efficacy responses to acute HIIT versus both MICE and VICE in the two age groups which assists in our understanding of how individuals in various age populations perceive HIIT. This information will assist in the design and implementation of effective exercise programs for public health, especially for insufficiently active individuals.

High-intensity interval training (HIIT) is considered a time-efficient exercise strategy for weight management. However, data regarding the acute appetite and energy intake responses to HIIT versus continuous training remain inconclusive. This study investigated the ad libitum energy intake and appetite responses to a single session of HIIT versus moderate-intensity continuous training (MICT) and vigorous-intensity continuous training (VICT). Using a randomized crossover design, 11 middle-aged physically inactive men (45.7 ± 7.4 years, 23.5 ± 2.1 kg m -2 ) participated in three treadmill trials at 7-day intervals. HIIT comprised 10 1-min periods at 100% VO 2max interspersed with 1-min periods of active recovery. MICT comprised a 40-min session at 65% VO 2max , while VICT comprised a 20-min session at 80% VO 2max . After each trial, the participants consumed an ad libitum buffet meal for which the energy intake was recorded. The participants' perceived appetite was assessed before and after exercise sessions using the Visual Analogue Scale (VAS). No significant differences in post-exercise ad libitum energy intake were observed between trials (HIIT: 645 ± 262.9 kcal; MICT: 614.7 ± 271.2 kcal; VICT: 623.1 ± 249.0 kcal, p > 0.05). Although the perceived appetite responses exhibited a significant main effect of time ( p < 0.01), no group differences were observed ( p > 0.05). In summary, these findings suggest that the interval or continuous nature of exercise has no significant effect on appetite responses in physically inactive middle-aged adults, at least during the short-term post-exercise period., Competing Interests: The authors declare no conflict of interest.

Weight-making practices, regularly engaged in by horse racing jockeys, have been suggested to impair both physiological and mental health. This study aimed to assess bone health markers, nutritional intake, bone-specific physical activity (PA) habits, and quality of life of professional jockeys in Hong Kong (n = 14), with gender-, age-, and body mass index-matched controls (n = 14). Anthropometric measurements, serum hormonal biomarkers, bone mineral density, bone-specific PA habits, nutritional intake, and quality of life were assessed in all participants. The jockey group displayed significantly lower bone mineral density at both calcanei than the control group (left: 0.50 ± 0.06 vs. 0.63 ± 0.07 g/cm 2 ; right: 0.51 ± 0.07 vs. 0.64 ± 0.10 g/cm 2 , both ps < .01). Thirteen of the 14 jockeys (93%) showed either osteopenia or osteoporosis in at least one of their calcanei. No significant difference in bone mineral density was detected for either forearm between the groups. The current bone-specific PA questionnaire score was lower in the jockey group than the control group (5.61 ± 1.82 vs. 8.27 ± 2.91, p < .05). Daily energy intake was lower in the jockeys than the controls (1,360 ± 515 vs. 1,985 ± 1,046 kcal/day, p < .01). No significant group difference was found for micronutrient intake assessed by the bone-specific food frequency questionnaire, blood hormonal markers, and quality of life scores. Our results revealed suboptimal bone conditions at calcanei and insufficient energy intake and bone-loading PAs among professional jockeys in Hong Kong compared with healthy age-, gender-, and body mass index-matched controls. Further research is warranted to examine the effect of improved bone-loading PAs and nutritional habits on the musculoskeletal health of professional jockeys.

Weight-making practices have been shown to impair musculoskeletal and physiological function of jockeys. This study investigated the "in-race" heart rate (HR) responses and hydration status during competitive racing, as well as selected physiological and lifestyle parameters of professional jockeys based in Hong Kong. "In-race" HR responses and early morning hydration status of 20 male jockeys were examined in hot and moderate climactic occasions. Additionally, bone mineral density (BMD), dietary intake and lifestyle choices were assessed. Osteopenia was observed in the calcanei of jockeys (left: 0.51 ± 0.06; right: 0.46 ± 0.12 g · cm -2 ). Energy and protein intake were significantly lower on a race day compared to a non-race day (P < 0.05). "In-race" HR max values were similar to those from VO 2max laboratory tests (186 ± 14 vs. 185 ± 8 bpm). Hypohydration was observed on both racing days. (USG: 1.0247 ± 0.006 and 1.0256 ± 0.0258 mg · L -1 for hot and moderate conditions, respectively). Sauna usage (25.5%) and food restriction (20.4%) were the most common weight-making practices. Current lifestyle choices of jockeys result in suboptimal bone health, hydration status and nutritional intake, which can significantly enhance the fracture risk. Further research should develop exercise and nutrition guidelines for optimising their skeletal health.