High-intensity Interval Training Research Articles

An Exploratory Study on Whether the Interference Effect Occurs When High-Intensity Strength Training Is Performed Prior to High-Intensity Interval Aerobic Training

There is conflicting evidence on whether concurrent aerobic endurance and resistance training (RT) leads to synergistic enhancements in aerobic capacity and muscular strength or causes interference, limiting performance gains. We developed a concurrent training (CT) intervention, including full-body dynamic RT combined with high-intensity interval training (HIIT), on a cycle ergometer to determine whether a brief CT intervention is beneficial to both muscular strength and aerobic capacity. In an exploratory pilot study, participants (n = 10; male = 4) undertook a four-week CT intervention consisting of RT, including six compound movements (bench press, squat, deadlift, Pendley row, squat jumps, and rack pulls), plus cycle HIIT. The pre-/post-intervention improvements were assessed via bench press and leg press 3RM testing, an isometric mid-thigh pull, a countermovement jump, and the change in the relative V˙O2max. We observed significant (p < 0.1) increases in the bench press (6.4%), leg press (6.7%), IMTP (11.1%), and relative V˙O2max (7%) results. Interestingly, the participants with the highest pre-intervention relative V˙O2max demonstrated no performance improvements. These pilot test results suggest that CT is an effective strategy that enables synergistic enhancements that can be observed with very low training volumes. This suggests that CT is an effective strategy for improving muscular strength and aerobic endurance in non-elite physically active individuals.

Influence of combined high-intensity interval training and green tea extract on cardiac stress markers and insulin resistance in obese men with type 2 diabetes: a randomized double-blind placebo-controlled trial

Influence of combined high-intensity interval training and green tea extract on cardiac stress markers and insulin resistance in obese men with type 2 diabetes: a randomized double-blind placebo-controlled trial

Small-Sided Games in Handball: A Narrative Review

ABSTRACT Small-sided games (SSGs) are widely used drill-based games that mimic the dynamics of a match while allowing coaches to tailor specific objectives, such as inducing physiological/physical stimulus or developing technical/tactical behaviors. Interestingly, by designing the SSGs with different modifications, player's responses can occur with a potential impact on the physical adaptations of players. With growing evidence about using SSGs in handball, there is now an opportunity to summarize the main acute effects induced by different task constraints. Furthermore, there is also an increasing body of evidence that can help coaches decide on the effectiveness of SSGs compared with other types of high-intensity interval training for improving physical fitness. Thus, this narrative review aims to summarize the evidence regarding using SSGs in handball, particularly regarding the acute physiological and locomotor demands, and physical fitness adaptations after exposing players to SSG-based programs.

Comparative Effects of Moderate Intensity Continuous Training and High Intensity Interval Training on Serum Levels of Myonectin in Rats

Background: Myonectin (CTRP15), a recently identified myokine, plays a crucial role in regulating glucose metabolism. Objectives: This study aimed to compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on serum myonectin levels, using matched training volumes for both interventions. Methods: Twenty-four male Wistar rats, aged 18 to 20 weeks, were randomly assigned to three groups of eight: Control, MICT, and HIIT. The training groups participated in HIIT and MICT programs (three days per week) on a treadmill for eight weeks. Measurements included serum glucose, insulin, myonectin, and the homeostasis model assessment of insulin resistance (HOMA-IR). Additionally, the weight of the Flexor hallucis longus (FHL), gastrocnemius muscles, and epididymal and retroperitoneal fat pads was recorded. Results: Both HIIT and MICT significantly reduced weight gain and fat mass (epididymal and retroperitoneal) compared to the control group (P < 0.05). Eight weeks of HIIT significantly decreased serum insulin levels and HOMA-IR compared to both the control and MICT groups (P < 0.05). No significant differences in serum myonectin levels were observed between the groups. Conclusions: This study suggests that HIIT is more effective than MICT in improving metabolic status in rats, though it does not significantly affect serum myonectin levels.

Exercise as a modality to improve heart transplantation-related functional impairments: An article review.

Heart transplantation (HT), the treatment choice of advanced heart failure patients, is proven effective in increasing the survival and functional status of the recipients. However, compared to normal controls, functional status is lower in HT recipients. Exercise given in cardiac rehabilitation has been shown to improve exercise capacity as measured with peak oxygen uptake (VO2 peak) and muscle strength after completion of the program and cessation of exercise results in loss of exercise benefits. Several factors related to cardiac denervation and the use of immunosuppressive agents in HT recipients result in functional impairments including cardiovascular, pulmonary, exercise capacity, psychological, and quality of life (QoL) problems. High-intensity interval training (HIIT) is the most common type of exercise used in HT recipients and given as a hospital-based program. Improvement of functional impairments was found to have occurred due to primarily musculoskeletal adaptations through improvement of muscle structure and aerobic capacity and cardiovascular adaptations. In general, exercise given after transplantation improved VO2 peak significantly and improvement was better in the HIIT group compared to moderate intensity continuous training or no-exercise groups. Improvement of QoL was ascribed to improvement of exercise capacity, symptoms, pulmonary function, physical capacity improvement, anxiety, and depression.

High-intensity interval training alleviates liver inflammation by regulating the TLR4/NF-κB signaling pathway and M1/M2 macrophage balance in female rats with cisplatin hepatotoxicity

Cisplatin (CDDP) is an antineoplastic drug whose adverse effects include hepatotoxicity. The inflammatory process is crucial in the progression of liver injuries. Exercise is known for its anti-inflammatory effects, but the influence of different training modalities on hepatoprotection is still unclear. This study aims to compare the impacts between preconditioning with high-intensity interval training (HIIT) and traditional continuous training of low (LT) and moderate (MT) intensities on inflammatory markers in Wistar female rats with CDDP-induced hepatotoxicity. Thirty-five rats were divided into five groups: control and sedentary (C + Sed), treated with CDDP and sedentary (CDDP + Sed), treated with CDDP and subjected to LT (CDDP + LT), treated with CDDP and subjected to MT (CDDP + MT), and treated with CDDP and subjected to HIIT (CDDP + HIIT). The training protocols consisted of treadmill running for 8 weeks before CDDP treatment. The rats were euthanized 7 days after the treatment. Liver samples were collected to evaluate the expression of various inflammatory markers and types of macrophages. Our results indicated that HIIT was the only protocol to prevent the increase in all analyzed pro-inflammatory cytokines and reduce the number of ED-1-positive cells, attenuating the TLR4/NF-κB signaling pathway in the liver. Additionally, HIIT increased the anti-inflammatory cytokine IL-10 and regulated M1/M2 macrophage polarization. Thus, this study suggests that preconditioning with HIIT is more effective in promoting hepatoprotective effects than LT and MT, regulating inflammatory markers through modulation of the TLR4/NF-κB signaling pathway and M2 macrophage polarization in the hepatic tissue of female rats treated with CDDP.

Comparing the Impact of Continuous Endurance and High-intensity Interval Training on Cecal Butyrate and Propionate Levels in Diabetic Rats Induced by High-fat Diet

Background: Dysbiosis and metabolic disorders of the microbiota, often caused by an imbalance in the intestinal microbial composition, are significant issues linked to immobility, obesity, and diabetes. Physical exercise is recognized for its role in managing these symptoms by regulating the composition and metabolites of the intestinal microbiota, thereby improving gut health and overall metabolic function. Objectives: This study aimed to investigate and compare the effects of continuous endurance training (CET) and high-intensity interval training (HIIT) on two key cecal microbiota metabolites, butyrate and propionate, in diabetic rats. Methods: Forty-five male Wistar rats were made diabetic by a high-fat diet and were trained under CET and HIIT exercise protocols. Cecal tissue samples were taken from the rats to evaluate the effect of exercise, and the levels of two microbial metabolites, butyrate and propionate, were measured using the high-performance liquid chromatography (HPLC) method. Results: Among the exercise patterns studied, HIIT significantly improved the concentrations of butyrate and propionate, while CET showed no effect on these metabolites. Conclusions: Our findings suggest that, unlike CET, HIIT may effectively mitigate metabolic disturbances resulting from gut dysbiosis in diabetic patients. However, any definitive conclusion about the effects of CET and HIIT exercises on intestinal microbial metabolites necessitates further comprehensive tests on other metabolites and an examination of additional supporting evidence, such as changes in the composition of the intestinal microbiome.

High-Intensity Interval Training Mitigates Sarcopenia and Suppresses the Myoblast Senescence Regulator EEF1E1.

The optimal exercise regimen for alleviating sarcopenia remains uncertain. This study aimed to investigate the efficacy of high-intensity interval training (HIIT) over moderate-intensity continuous training (MICT) in ameliorating sarcopenia. We conducted a randomized crossover trial to evaluate plasma proteomic reactions to acute HIIT (four 4-min high-intensity intervals at 70% maximal capacity alternating with 4 min at 30%) versus MICT (constant 50% maximal capacity) in inactive adults. We explored the relationship between a HIIT-specific protein relative to MICT, identified via comparative proteomic analysis, eukaryotic translation elongation factor 1 epsilon 1 (EEF1E1) and sarcopenia in a paired case-control study of elderly individuals (aged over 65). Young (3 months old) and aged (20 months old) mice were randomized to sedentary, HIIT and MICT groups (five sessions/week for 4 weeks; n = 8 for each group). Measurements included skeletal muscle index, hand grip strength, expression of atrophic markers Atrogin1 and MuRF1 and differentiation markers MyoD, myogenin and MyHC-II via western blotting. We examined the impact of EEF1E1 siRNA and recombinant protein on D-galactose-induced myoblast senescence, measuring senescence-associated β-galactosidase and markers like p21 and p53. The crossover trial, including 10 sedentary adults (32 years old, IQR 31-32) demonstrated significant alterations in the abundance of 21 plasma proteins after HIIT compared with MICT. In the paired case-control study of 84 older adults (84 years old, IQR 69-81; 52% female), EEF1E1 was significantly increased in those with sarcopenia compared to those without (14.68 [95%CI, 2.02-27.34] pg/mL, p = 0.03) and was associated with skeletal muscle index (R2 = 0.51, p < 0.001) and hand grip strength (R2 = 0.54, p < 0.001). In the preclinical study, aged mice exhibited higher EEF1E1 mRNA and protein levels in skeletal muscle compared to young mice, accompanied by a lower muscle mass and strength, increased cellular senescence and protein degradation markers and reduced muscle differentiation efficiency (all p < 0.05). HIIT reduced EEF1E1 expression and mitigated age-related muscle decline and atrophy in aged mice more effectively than MICT. Notably, EEF1E1 downregulation via siRNA significantly counteracted D-galactose-induced myoblast senescence as evidenced by reduced markers of muscle protein degradation and improved muscle differentiation efficiency (all p < 0.05). Conversely, treatments that increased EEF1E1 levels accelerated the senescence process (p < 0.05). Further exploration indicated that the decrease in EEF1E1 was associated with increased SIRT1 level and enhanced autophagy. This study highlights the potential of HIIT as a promising approach to prevent and treat sarcopenia while also highlighting EEF1E1 as a potential intervention target.

The Role of High-Intensity Interval Training (HIIT) vs. Moderate-Intensity Continuous Training (MICT) in Improving Cardiovascular Fitness in Patients with Coronary Artery Disease

Background: Exercise is a crucial component of cardiac rehabilitation for patients with Coronary Artery Disease (CAD). High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) are two commonly used exercise modalities, but their comparative effectiveness in improving cardiovascular fitness in CAD patients remains uncertain.Objective: To compare the effects of HIIT and MICT on cardiovascular fitness in patients with CAD.Methods: A randomized controlled trial was conducted at Therapy Plus Clinics, Architect Society, Lahore, Pakistan, with 44 participants (22 in each group). Participants were randomly assigned to either HIIT or MICT for a 12-week intervention. Cardiovascular fitness was assessed using VO₂ max, resting heart rate, and blood pressure measurements before and after the intervention. Data analysis was performed to compare the outcomes between the two groups.Results: The HIIT group showed a significant improvement in VO₂ max (25.2 ± 3.5 to 30.4 ± 4.2 mL/kg/min) compared to the MICT group (24.8 ± 3.7 to 27.2 ± 3.9 mL/kg/min, p = 0.01). Additionally, the HIIT group experienced a greater reduction in resting heart rate (72.5 ± 8.2 to 68.1 ± 7.9 bpm) compared to the MICT group (73.2 ± 7.8 to 70.3 ± 7.5 bpm, p = 0.04). Both groups showed reductions in systolic and diastolic blood pressures, but the differences were not statistically significant.Conclusion: HIIT appears to be more effective than MICT in improving cardiovascular fitness, as evidenced by greater enhancements in VO₂ max and reductions in resting heart rate. These findings suggest that HIIT may be a superior exercise modality for CAD patients, offering a time-efficient alternative to traditional moderate-intensity exercise. Further research is needed to explore long-term effects and broader applicability.

Long-term high-intensity interval training reduces blood glucose in type 2 diabetes mellitus patients

This study aimed to demonstrate the long-term effects of high-intensity interval training (HIIT) on reducing blood glucose levels in patients with type 2 diabetes mellitus. The research employs a preexperimental design with a one-group pretest‒posttest design. A total of 20 patients with type 2 diabetes mellitus, aged 40–60 years, participated in the study and received the HIIT intervention three times per week for eight weeks. Data collection involved measuring fasting blood glucose levels before and after the HIIT intervention via the ONE TOUCH™ BASIC™ Plus Meter. Data analysis was conducted via paired sample t tests with a significance level of 5%, and the effect size was evaluated via Cohen's d. Paired sample t test analysis between pre-HIIT and post-HIIT blood glucose levels (181.50±17.85 mg/dL to 99.50±8.26 mg/dL, p ≤ 0.001) revealed a significant reduction, with a large effect size (Cohen's d = 5.896). This study confirms that long-term high-intensity interval training is effective in lowering fasting blood glucose levels to normal ranges in patients with type 2 diabetes mellitus. Keywords: Blood glucose, HIIT, insulin sensitivity, insulin resistance, type 2 diabetes patients

High-Intensity Interval Training and Vitamin D3 Supplementation Decrease CCL-5 and CCR5 Expression In White Adipose Tissue of Diabetic Rats Fed with A High-Fat Diet and Streptozotocin.

The purpose of this study was to investigate the effects of 8 weeks of high-intensity interval training (HIIT) and vitamin D3 supplementation on Chemokine (C-C motif) Ligand 5 (CCL-5) and C-C motif chemokine receptor 5 (CCR5) in the white adipose tissue (WAT) of male rats with type 2 diabetes (T2DM). The experimental study involved 40 male Wistar rats divided into 5 groups (n=8). These groups were healthy control (HC), diabetic control (DC), diabetic+HIIT (DHIIT), diabetic+vitamin D3 (DD3), and diabetic+HIIT+vitamin D3 (DHIITD3). The rats completed 8 weeks of HIIT, consisting of 12 sessions lasting 1 minute each at an intensity of 90-95% of their maximum running speed. Additionally, the rats were administered a weekly dose of 10,000 IU/kg of vitamin D3 for 8 weeks. The levels of CCL-5 (P<0.001) and CCR5 (P=0.003) were found to be higher in the DC group as compared to the HC group. However, when HIIT training and vitamin D3 were administered together, there was a decrease in CCL-5 (P=0.001) and CCR5 (P<0.001) in the DHIITD3 group (P=0.001). Similarly, vitamin D3 alone reduced CCR5 levels in the DD3 group (P< 0.001). Also, the decrease of CCR5 in the DD3 group was higher than in the DHIIT group (P=0.022), and the DHIITD3 group was higher than in the DHIIT group (P<0.001), but there was no difference between the DD3 and DHIITD3 groups (P≥0.05). The results indicate that combining HIIT training with vitamin D3 has a greater effect on reducing the expression of CCL-5 and CCR5 in the white adipose tissue of rats with type 2 diabetes induced by streptozotocin (STZ) and a high-fat diet (HFD), compared to the effects of each one alone. It is recommended that the study be conducted by measuring the variables involved in the mechanisms and the changes in CCL-5 and CCR5.

Assessing physical fitness adaptations in collegiate male soccer players through training load parameters: a two-arm randomized study on combined small-sided games and running-based high-intensity interval training.

To evaluate the effects of a 4-week intervention combining small-sided games (SSGs) and high-intensity interval training (HIIT) on physical fitness in collegiate male soccer players. Twenty-one soccer players were randomly assigned to either the HIIT + SSGs group (n = 11) or a control group (n = 10). Physical fitness was assessed at baseline and 1-week post-intervention, including countermovement jump (CMJ), change of direction (COD) test, sprint test, repeated sprint ability (RSA) test, and 30-15 Intermittent Fitness Test (30-15IFT). The intervention comprised eight sessions over 4weeks: four SSGs and four HIIT. The intervention group showed small to moderate improvements: mean RSA improved by 4.5% (p = 0.07), CMJ increased by 3.2% (p = 0.12), and 30-15IFT scores enhanced by 6.8% (p = 0.09). Key predictors of group membership included heart rate load per minute (OR 1.602) and various GPS variables. The 4-week intervention combining SSGs with HIIT did not produce statistically significant improvements in most physical fitness variables compared to the control group. Although there were positive trends in variables such as RSA and 30-15IFT, these changes were modest and not statistically significant. The results suggest that while the combined SSGs and HIIT approach shows potential, its impact on physical fitness over a 4-week period is limited, with some variables, like CMJ, even showing decreases.

Impact of a 12-week high-intensity interval training intervention on cardiac structure and function after COVID-19 at 12-month follow-up.

In patients previously hospitalised for COVID-19, a 12-week high-intensity interval training (HIIT) intervention has previously been shown to increase left ventricular mass (LVM) immediately after the intervention. In the present study, we examined the effects of the same HIIT scheme on LVM, pulmonary diffusing capacity, symptom severity and functional capacity at 12-month follow-up. In this investigator-blinded, randomised controlled trial, 12weeks of a supervised HIIT scheme (4×4min, three times a week) was compared to standard care (control) in patients recently discharged from hospital due to COVID-19. At inclusion and at 12-month follow-up, LVM was assessed by cardiac magnetic resonance imaging (cMRI, primary outcome), while pulmonary diffusing capacity for carbon monoxide (DLCOc, secondary outcome) was examined by the single-breath method. Symptom severity and functional status were examined by the Post-COVID-19 Functional Scale (PCFS) and King's Brief Interstitial Lung Disease (KBILD) questionnaire score. Of the 28 patients assessed at baseline, 22 completed cMRI at 12-month follow-up (12.4±0.6months after inclusion). LVM was maintained in the HIIT but not the standard care group, with a mean between-group difference of 9.68 [95% CI: 1.72, 17.64] g (P=0.0182). There was no differences in change from baseline to 12-month follow-up between groups in DLCOc % predicted (-2.45 [-11.25, 6.34]%; P=0.578). PCFS and KBILD improved similarly in the two groups. In individuals previously hospitalised for COVID-19, a 12-week supervised HIIT scheme resulted in a preserved LVM at 12-month follow-up but did not affect pulmonary diffusing capacity or symptom severity.

High-intensity interval training for cardiometabolic health in adults with metabolic syndrome: a systematic review and meta-analysis of randomised controlled trials

ObjectiveTo 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...

Transforming Sedentary Lifestyles: The impact of remote VR and flat-screen interventions on affective attitudes towards physical exertion, guided by avatar or human trainers

This study advances understanding of the impact of flat-screen and virtual reality (VR) remote exercise environments in a home setting on affective attitudes towards physical exertion, with either a human or an avatar trainer.Employing a two-by-two factorial design, we manipulated both the medium (flat screen vs. VR) and the type of trainer (human vs. avatar). A total of 108 participants engaged in the study using a custom VR application for the Oculus Quest 2 headset or training videos, both prepared specifically for this study. The participants underwent a 15-min high-intensity interval training (HIIT) regimen, completing six workouts in their homes within fourteen days. Data on their exercise experiences and their affective attitudes towards exercise were collected using the CAWI technique. These were next analysed using a model that presumes that exercise experiences can increase motivation to exercise. We also studied the roles of spatial presence and trainer relatedness.Our results show that VR physical training shifted affective attitudes towards exercise positively, in contrast to the flat-screen groups. Moreover, using a digital avatar as a trainer had no negative effect on this favourable change in attitude. The change in affective attitude was influenced primarily by baseline levels and the wellbeing experienced during training. The factors we added to the original model—relatedness to the trainer and spatial presence—also contributed significantly to wellbeing. Perception of competence was a critical determinant of wellbeing, while perceived exertion was largely irrelevant. The HIIT protocol in the study was suitable for VR exercise.

Evaluating Exercise Training Effects on VO2max: A Systematic Review of Protocol Efficacy and Measurement Variability

Background: Despite extensive research on the effects of exercise training on VO2max, current literature still lacks to be more conclusive regarding the optimal protocols for maximizing these effects. Variability in study designs, participant populations, and measurement techniques has contributed to inconsistencies in findings, leaving important questions unanswered regarding the most effective exercise strategies. Purpose: This systematic review aims to integrate current research to understand better how different exercise interventions influence VO2max outcomes. Methods: Using Covidence, a web-based platform for systematic reviews, 22,617 studies were initially imported. Following rigorous inclusion and exclusion criteria, such as focusing on experimental studies with human participants aged 18 or older, VO2max measured via indirect calorimetry, and supervised aerobic training, 724 studies were selected for detailed analysis. Results: A swift analysis of imported studies reveals that most of the studies included in this review were conducted in the United States (n=158), Canada (n=75), and Australia (n=59), reflecting a predominance of research from these regions. Among the studies analyzed, 159 employed moderate-intensity continuous training (MICT), 100 utilized high-intensity interval training (HIIT), and 54 implemented sprint interval training (SIT). This distribution highlights the varied approaches to exercise training across different geographical locations and research settings, providing a broad base for understanding how these protocols impact VO2max. Conclusion: The findings from further analysis of this data will help clarify the impact of various exercise intensities and modalities on VO2max, offering guidance for optimizing training protocols, as such it serves as a crucial tool for addressing key questions in exercise physiology, including whether there are significant sex differences in VO2max responses and which exercise training protocols are most effective.

Sodium Nitrate Improves Oxidative Energy Contribution and Reduces Phosphocreatine Contribution During High-Intensity Intermittent Exercise

ABSTRACT The present study aimed to verify the effect of acute nitrate supplementation on oxidative, phosphocreatine, and glycolytic energy contribution (COXI, CPCr, and CLAC , respectively) during a high-intensity intermittent exercise (HIIE). Fifteen physically active subjects were submitted to incremental running test on a treadmill and two random HIIE (10 × 1 min at maximal aerobic speed with 1 min of passive recovery) in the following conditions: sodium nitrate (SN) or Placebo (PL). Repeated measure ANOVA was used to compare COXI, and CPCr within the 10 efforts. Student t test was used to compare total COXI, CPCr, CLAC, as well oxidative and non-oxidative contribution. Considering the 10 efforts, COXI presented the main effect for condition (F = 16.7; p = .001; SN: 1.9 ± 0.1 L; PL: 1.6 ± 0.1 L), and no interaction effect (F = 0.9; p = .415), while CPCr presented effect for condition (F = 13.4; p = .003; SN: 1.2 ± 0.1; PL: 1.4 ± 0.8 L), and no interaction (F = 1.2; p = .317). Total oxidative contribution were higher (p < .001) after SN (19.1 ± 3.4 L) than Placebo (16.7 ± 3.1 L), while total CPCr were lower (p = .002) after SN (12.4 ± 2.5 L) than PL (14.1 ± 2.6 L). Total energy contribution were not different between trials. Acute dose of SN supplementation improved oxidative contribution during HIIE, and reduced CPCr. Higher COXI is likely related to increased oxygen kinetics, while the lower CPCr might be related to the improved energetic efficiency.

Training Intensity Distribution of a 7-Day HIIT Shock Microcycle: Is Time in the “Red Zone” Crucial for Maximizing Endurance Performance? A Randomized Controlled Trial

BackgroundVarious studies have shown that the type of intensity measure affects training intensity distribution (TID) computation. These conclusions arise from studies presenting data from meso- and macrocycles, while microcycles, e.g., high-intensity interval training shock microcycles (HIIT-SM) have been neglected so far. Previous literature has suggested that the time spent in the high-intensity zone, i.e., zone 3 (Z3) or the “red zone”, during HIIT may be important to achieve improvements in endurance performance parameters. Therefore, this randomized controlled trial aimed to compare the TID based on running velocity (TIDV), running power (TIDP) and heart rate (TIDHR) during a 7-day HIIT-SM. Twenty-nine endurance-trained participant were allocated to a HIIT-SM consisting of 10 HIIT sessions without (HSM, n = 9) or with (HSM + LIT, n = 9) additional low-intensity training or a control group (n = 11). Moreover, we explored relationships between time spent in Z3 determined by running velocity (Z3V), running power (Z3P), heart rate (Z3HR), oxygen uptake (Z3V˙O2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Z}}{3_{\\dot{\ ext{V}}\ ext{O}_2}}$$\\end{document}) and changes in endurance performance.ResultsBoth intervention groups revealed a polarized pattern for TIDV (HSM: Z1: 38 ± 17, Z2: 16 ± 17, Z3: 46 ± 2%; HSM + LIT: Z1: 59 ± 18, Z2: 14 ± 18, Z3: 27 ± 2%) and TIDP (Z1: 50 ± 8, Z2: 14 ± 11, Z3: 36 ± 7%; Z1: 62 ± 15, Z2: 12 ± 16, Z3: 26 ± 2%), while TIDHR (Z1: 48 ± 13, Z2: 26 ± 11, Z3: 26 ± 7%; Z1: 65 ± 17, Z2: 22 ± 18, Z3: 13 ± 4%) showed a pyramidal pattern. Time in Z3HR was significantly less compared to Z3V and Z3P in both intervention groups (all p < 0.01). There was a time x intensity measure interaction for time in Z3 across the 10 HIIT sessions for HSM + LIT (p < 0.001, pη2 = 0.30). Time in Z3V and Z3P within each single HIIT session remained stable over the training period for both intervention groups. Time in Z3HR declined in HSM from the first (47%) to the last (28%) session, which was more pronounced in HSM + LIT (45% to 16%). A moderate dose–response relationship was found for time in Z3V and changes in peak power output (rs = 0.52, p = 0.028) as well as time trial performance (rs = − 0.47, p = 0.049) with no such associations regarding time in Z3P, Z3HR, and Z3V˙O2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Z}}{3_{\\dot{\ ext{V}}\ ext{O}_2}}$$\\end{document}.ConclusionThe present study reveals that the type of intensity measure strongly affects TID computation during a HIIT-SM. As heart rate tends to underestimate the intensity during HIIT-SM, heart rate-based training decisions should be made cautiously. In addition, time in Z3V was most closely associated with changes in endurance performance. Thus, for evaluating a HIIT-SM, we suggest integrating a comprehensive set of intensity measures.Trial Registration Trial register: Clinicaltrials.gov, registration number: NCT05067426.

Effectiveness of a game-based high-intensity interval training on executive function and other health indicators of children with ADHD: A three-arm partially-blinded randomized controlled trial

BackgroundChildren with ADHD demand for effective intervention with minimum side effect to improve executive function (EF) and health well-being. MethodThis study used a three-arm partially-blinded randomized controlled trial to test the effects of two different kinds of 8-week game-based training programs (game-based HIIT program, GameHIIT; and game-based structured aerobic exercise program, GameSAE) on EF and other health indicators of children with ADHD, which was compared with a non-treatment control group. ResultsA total of 49 children with ADHD completed the program. Analyses of EF tests and parental survey indicated that (i) there is no significant intragroup difference among all measures between pre-/post-intervention tests for two game-based intervention groups. The only significant intergroup difference was observed in self-monitor score of parent-reported child's EF between GameSAE group and the control (large effect). Similarly, cerebral hemodynamic responses also found no significant group effect for all EF tests. However, the time effects were observed in several channels in the GameHIIT group in two EF tests (Color Words Stroop Test and Tower of London Test). No significant change of participants' overall ADHD symptoms was found in the pre-/post-tests for three groups. Nonetheless, further analyses revealed that both of two game-based training programs exhibited the significant positive effects on child's PA levels and the large effects on levels of physical fitness, when they were compared to the control. ConclusionBy this study, a significant enhancement in physical fitness and PA levels were found in both game-based PA interventions when they were compared with control group. However, the effectiveness of game-based PA interventions on improving EF or reducing ADHD symptoms remains unclear. This implies that a larger intervention dosage or a tailored intervention design may be warranted to improve the EF of children with ADHD.

Effect of high-intensity interval training and moderate-intensity continuous training on blood lactate clearance after high-intensity test in adult men.

This study compared the effects of High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on blood lactate clearance. 21 adult males were equally and randomly assigned to the HIIT and MICT groups, and completed 8weeks of training. Before the training intervention, after 4weeks and 8weeks of training, all subjects were tested for blood lactate levels between 0 and 55min after the same high-intensity test. The results show that after 8weeks, blood lactate levels were significantly lower than pre-tests in both the HIIT and MICT groups at "0-55min" after high-intensity test (p < 0.05), and the blood lactate clearance percentage at15-min and 30-min in both groups were significantly higher than the pre-tests (P < 0.01). The blood lactate levels in the HIIT group were significantly lower than those in the MICT group at 15min and 30min after test (P < 0.05), and the blood lactate clearance percentage at 30min in the HIIT group was significantly higher than those in the MICT group (P < 0.05). In conclusion, both HIIT and MICT enhance blood lactate clearance in adult males post high-intensity test, with HIIT demonstrating superior effectiveness, making it a viable alternative to MICT.