Intermittent Training Research Articles

TREINAMENTO INTERVALADO DE ALTA INTENSIDADE APLICADO AO TREINO FÍSICO

ABSTRACT Introduction High-intensity interval training (HIIT) has been widely used in functional physical performance enhancement, with the characteristics of low time demand and fast effects. Currently, many ways and methods are adopted in sports training, but the impact of HIIT training still needs to be determined. Objective Explore the effect of HIIT on physical training. Methods The training content includes preparatory activities, intermittent training, and relaxation activities. The preparatory and relaxation activities of the experimental and control groups are completely the same, differentiating only the addition of a protocol with HIIT in the control group. HIIT of medium intensity was adopted. Results After 10 weeks of intervention, there was no significant difference in vital capacity between the experimental and control groups. Comparing the vital capacity indices of the volunteers in both groups, it was found that the vital capacity levels of the experimental and control groups showed positive differences. Still, the experimental group with HIIT had a greater gain in their vital capacity. Conclusion HIIT can effectively improve the functional physical performance of athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

EFEITOS DO TREINAMENTO INTERVALADO SOBRE A QUALIDADE DA FORÇA DOS ESTUDANTES UNIVERSITÁRIOS ESPECIALIZADOS EM AERÓBICA

ABSTRACT Introduction: Intermittent training can effectively promote better physical and psychological quality in athletes. Due to the great increase in aerobic gymnastics practice, interval training has also been gradually considered in the daily training of aerobic sports practitioners. Objective: Study the effects of the interference of high-intensity interval training interventions on strength quality and other physical indicators related to aerobic specialties. Methods: 25 subjects participated in the experimental group, and 25 participated in the control group. The participants had 12 weeks of training, with one hour of physical training on Monday, Wednesday, and Friday. The training mode of the subjects in the experimental group was interval training, while the training mode of the subjects in the control group was daily training. Results: The results of long jump, push-up, 100m run, and 30m round-trip run in the experimental group increased by 17.59%, 23.63%, 17.83%, and 23.98%, respectively. Conclusion: Aerobic gymnastic athletes' physical quality can improve through high-intensity interval training. Thus, if the teaching method of intermittent training can be combined within a given period of classroom training, it will enable an efficient and diversified training method for teaching aerobic gymnastics more innovatively and diversely. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

CARACTERÍSTICAS DO CONSUMO DE ENERGIA DOS JOGADORES DE BASQUETE COM DIFERENTES INTENSIDADES DE TREINAMENTO

ABSTRACT Introduction: In competitive basketball sports, athletes must repeatedly perform movements of maximum intensity quickly, followed by rest. A training mode called high-intensity interval training (HIIT) has the same characteristics. Objective: Explore basketball players’ energy supply characteristics and training changes under different exercise intensities. Methods: The effects of different recovery methods in the intermittent period on exercise capacity and aerobic metabolic energy supply of young male basketball players during high-intensity intermittent interval training (HIIT) were presented. Results: Increased aerobic energy production during HIIT was closely related to the acceleration of kinetics. However, although the time to exhaustion, a parameter characterizing exercise capacity, increased by 3.5% and 4.6%, respectively, in the HIITa group compared to HIITs and HIITp, there was no significant difference. After analyzing each group for the 30s, a gradual increase in strength was noticed. Conclusion: The use of HIIT as training is an important way to improve the physical performance of athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Effects of high-intensity intermittent training on some inflammatory and muscle damage indices in overweight middle-aged men

IntroductionRecently, the use of various high-intensity intermittent training (HIIT) that have quick recovery periods are of great importance. Therefore, the purpose of this research was to investigate the acute effect of HIIT training on the serum levels of inflammatory and muscle damage indices in overweight middle-aged men, as well as the kinetics of these markers at 1, 24, and 48 h after HIIT training. MethodsTwenty-two middle-aged men (40–60 years, BMI 25–30 kg/m2) were divided into two training (n=12) and control (n=10) groups. The HIIT training program consisted of running on treadmill for 30 s with an intensity of 100% maximum aerobic speed (MAV), 30 s active recovery with 50% aerobic speed (4 sets, 4 repetitions and 5 min of rest between each round). Cortisol, IL-6, CRP, ALT, AST, CPK and LDH were evaluated in pre-test, one- hour, 24 and 48 h after HIIT training. ResultsExcept for the CRP variable, Cortisol, IL-6, CPK, LDH, ALT and AST had a significant increase in one- hour after HIIT compared to the pre-test (P<0.05). Also, IL-6 and CPK variables had a significant increase in 24 h and only CPK had a significant increase in 48 h after HIIT training compared to pre-test (P<0.05). ConclusionOverall, due to long rest intervals and low activity time during HIIT, inflammatory responses and muscle damage are not severe. The recovery periods of inflammatory and muscle damage markers are faster, so this type of response can be considered an advantage for overweight middle-aged men.

APLICAÇÃO DO TREINAMENTO FUNCIONAL SOBRE A APTIDÃO FÍSICA NO BASQUETEBOL

ABSTRACT Introduction: Basketball is a predominant competitive sport among the masses. Its practice requires scoring as many points as possible within a specific time limit, manifesting a short-duration, high-intensity intermittent training session. To meet the sport's requirements, the athlete must have ample directional control, rapid changes in speed, and good jumping ability. Objective: Verify the effects of functional training on basketball players aiming to improve explosive power, stability, and agility. Methods: 18 college basketball players were randomly selected as volunteers for the investigation. They were randomly divided into experimental and control groups. Only to the experimental one was functional physical training added during routine training. The trial lasted for eight weeks. All participants were tested for agility, strength, speed, endurance, power, and cartilage repair before and after the experiment. Finally, a comprehensive statistical data analysis was performed. Results: There were significant differences between the experimental group and the control group in push-ups, 3200-meter run, physical acuity detection, 17 sidelines, and running items, and touch height (P&lt;0.05). In the experimental group, there was no significant difference in high school grades (P&gt;0.05). There was significant statistical significance in the supine project, the 3200-meter athletics project, the 17 sideline projects, and the touchdown project (P&lt;0.05). Conclusion: The physical fitness of the experimental group improved significantly after functional physical training. After routine physical training, the control group athletes had significantly positive absolute strength and endurance results. Overall, functional fitness training is superior to conventional fitness training. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

EFEITO DO TREINAMENTO INTERVALADO SOBRE A CAPACIDADE CARDIORRESPIRATÓRIA DE NADADORES

ABSTRACT Introduction: Cardiopulmonary function is directly related to the body's ability to perform metabolism under aerobic conditions. It is a key characteristic for the training of professional swimmers. It is believed that adding interval training to traditional workouts may contribute to the aerobic endurance of these athletes. Objective: Evaluate the interval training effects on the cardiorespiratory capacity of swimmers. Methods: Twenty volunteer swimmers were randomly divided into two groups for seven weeks. There were 4 hours of class per week, totaling 28 hours of training. In the formal training stage, the experimental group performed intermediate-intensity training, while the control group continued to perform traditional swim team training. The experimental indicators pertinent to the evaluated athletes were collected, tested, and analyzed before and after the experiment. Results: The VO2 of the athletes in the experimental group increased from 3.90±0.67L/min before the experiment to 4.06±0.73L/min after the experiment; VE increased from 156.08±35.76L before the experiment to 180.08±39.42L after the experiment; underwater endurance time increased from 46.80±8.43s before the experiment to 55.49±7.60s after the experiment. Conclusion: Intermittent training improves athletes' physical fitness and sports capacity, being an effective method to improve cardiopulmonary function. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Retracted: Physical Fitness Recovery of Athletes Based on High‐Intensity Sports Intermittent Training

Retracted: Physical Fitness Recovery of Athletes Based on High‐Intensity Sports Intermittent Training

EXERCÍCIO INTERMITENTE DE ALTA INTENSIDADE ASSOCIADO AOS FÁRMACOS EM PACIENTES COM DIABETES TIPO 2

ABSTRACT Introduction: Some studies point out that high-intensity intermittent training exercises combined with drugs may improve the endurance of patients with type 2 diabetes. However, the information concerning blood glucose control still needs to be better evidenced. Objective: Explore further the effect of intermittent high-intensity exercise combined with drugs on blood glucose control in patients with type 2 diabetes. Methods: Through a control experiment, 100 patients were selected from volunteers, and divided equally into two groups for this experiment. A protocol with high-intensity intermittent exercise for intervention associated with drug treatment was added to the experimental group, while the control received standard drug treatment. Results: The results of each index in the experimental group were: TC pre 4.80±1.00, post 4.56±0.78; TG pre 1.77±1.15, post 1.49±1.16; LDL pre 2.94±0.83, post 2.51±0.73. The experimental results proved that all indices in the experimental group were improved, but the changes in the control group were not evidenced. Conclusion: Intermittent high-intensity exercise combined with drugs positively affected blood glucose control in patients with type 2 diabetes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

ANÁLISE E MEDIDAS PREVENTIVAS DE LESÕES SEM CONTATO NO FUTEBOL

ABSTRACT Introduction: Soccer is characterized by high intensity and great competitiveness, and several sports injuries frequently occur; one of the main categories of injuries is the non-contact ones. Objective: Study the situation of non-contact injuries in soccer and analyze its preventive measures. Methods: The experimental group adopted the intermittent training method to strengthen the proprioception and coordination ability of the athletes. In contrast, the control group adopted mainly traditional aerobic training, with a 40-day duration. Results: Among non-contact injuries in soccer sports, lower limb sprain and joint injuries represented an eminently serious proportion. After preventive exercise, the total FMS test score of the experimental group was 16.75 points, an increase of 26.03%, and that of the control group was 14.14 points, an increase of 3.49%. The performance of the experimental group was significantly improved. Conclusion: The sports training mode proposed in this study significantly reduces the probability of non-contact injuries during sports. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

The Effect of Video-Assisted Clean Intermittent Catheterization Training on Patients' Practical Skills and Self-Confidence.

This research was carried out in order to examine the effect of clean intermittent catheterization (CIC) training with a video developed by the researchers on patients' ability to practice CIC and self-confidence. The population of the study consisted of patients who had just started performing CIC in the urology polyclinic of a city hospital in Istanbul. The sample consisted of a total of 80 patients, 40 of whom were in the experimental group and 40 in the control group. The experimental group patients were given CIC training with a training video that was downloaded to the mobile phone of the patient, a family member, or caregiver. The patients' practice skills were evaluated by 2 independent observers. The DISCERN Inquiry Form and the Global Quality Score, the Patient Information Form, the CIC Skill Checklist and the Self-Confidence Scale in Clean Intermittent Self-Catheterization were used to collect data. In the experimental group, consisting of patients who received video-assisted training, the mean scores for the CIC Skill Checklist and the Self-Confidence Scale in Clean Intermittent Self-Catheterization were statistically significantly higher than in the control group (P<0.001), the experience of feeling pain during catheterization was less than in the control group, and the patients in the experimental group experienced statistically significantly fewer complications such as urinary tract infections, urgency, urinary incontinence, hematuria and urethral stricture (P<0.05). Video-assisted CIC training had a positive effect on patients' practical skills and self-confidence.

Effect of High-intensity Intermittent Swimming Training on peroxisome proliferator-activated receptors-αand Liver Enzymes in Non-alcoholic Steatohepatitis Male Rats

Introduction: Accumulation of fat in the liver tissue is known as the most important cause of non-alcoholic steatohepatitis, which is associated with a decrease in the protein of hepatic peroxisome proliferator-activated receptors (PPAR-α). This study aimed to investigate the effect of eight weeks of high-intensity interval training (HIST) on PPAR-α and liver enzymes in high-fat diet-induced non-alcoholic steatohepatitis rats.&#x0D; Methods: The current research was semi-experimental. 40 Spraguedauli male rats (age: 6 to 8 weeks and weight: 230 ± 20 grams) were selected and divided into two equal groups, healthy and high-fat diet (HFD). The HFD group was subjected to gavage for eight weeks with the aim of inducing the disease. Rats were divided into four groups: control-healthy (n=9), healthy-swimming (n=9), control- disease (n=9) and disease -swimming (n=9). The training groups performed HIST for eight weeks (three sessions per week, each session lasting 30 minutes). In the end, liver PPAR-α was measured by western blot analysis; and ALT, AST and GGT enzymes in serum level were measured by photometric method. One-way analysis of variance and Bonferroni's post hoc test were used to analyze the data. Significant level (P≥0.05) and all statistical methods were performed using SPSS16 software.&#x0D; Results: HIST controlled the weight gain caused by HFD and there was a significant decrease in serum ALT and AST in the healthy-swimming and sick-swimming groups compared to the control-patient group and a significant decrease in serum GGT in the healthy-swimming group compared to the control-patient (P≤0.001) and patient-swimming (P≤0.044) were observed. A significant increase in hepatic PPAR-α was observed in healthy-swimming patients compared to the control-patients (P≤0.002).&#x0D; Conclusion: HIST can control body weight and reduce liver enzymes. However, more research is needed to obtain definitive results.

Effect of 4 Weeks Preconditioning with High Intensity Interval Training and Moderate Intensity Continuous Training on Brain Levels of TNF-Α and TLR4 in Male Wistar Rats

Introduction: Inflammation in the brain is known as neuroinflammation and increases TNF-α (Tumor necrosis factor alpha) secretion and activates the TLR4 (Toll-like receptor 4) pathway. The aim of this study was to evaluate the effect of 4 weeks preconditioning with high intensity intermittent training (HIIT) and moderate intensity training (MICT) on TNF-α and TLR4 levels in male Wistar rats.&#x0D; Methods: The current research was an experimental study.18 male Wistar rats were divided into three groups: high intensity intermittent training (6 heads), continuous moderate intensity training (6 heads) and the control group (6 heads). HIIT program included 6 stages of 2-minute activity with intensity of 85-90% VO2max and 5 stages of active rest for 2 minutes and MICT program with intensity of 65% VO2max with the same duration as HIIT for 4 weeks and 5 days per week was implemented. 48 hours after the last training session, rats were dissected and cortical tissues and layers of mice were extracted for TNF-α and TLR-4 using western blotting. Data analysis was performed using ANOVA test at a significance level of 0.05 With the help of SPSS version 16 software.&#x0D; Results: The results of the present study showed that TNF-α and TLR4 in the cortex and stratum cerebral areas after 4 weeks of high-intensity and moderate-intensity intermittent aerobic exercise did not change significantly compared to the control group (p≥0.05).&#x0D; Conclusion: According to these findings, it can be stated that exercise with high or moderate intensity cannot be an effective factor in increasing inflammatory markers in the brain.

Mimicking Gene-Environment Interaction of Higher Altitude Dwellers by Intermittent Hypoxia Training: COVID-19 Preventive Strategies.

Cyclooxygenase 2 (COX2) inhibitors have been demonstrated to protect against hypoxia pathogenesis in several investigations. It has also been utilized as an adjuvant therapy in the treatment of COVID-19. COX inhibitors, which have previously been shown to be effective in treating previous viral and malarial infections are strong candidates for improving the COVID-19 therapeutic doctrine. However, another COX inhibitor, ibuprofen, is linked to an increase in the angiotensin-converting enzyme 2 (ACE2), which could increase virus susceptibility. Hence, inhibiting COX2 via therapeutics might not always be protective and we need to investigate the downstream molecules that may be involved in hypoxia environment adaptation. Research has discovered that people who are accustomed to reduced oxygen levels at altitude may be protected against the harmful effects of COVID-19. It is important to highlight that the study's conclusions only applied to those who regularly lived at high altitudes; they did not apply to those who occasionally moved to higher altitudes but still lived at lower altitudes. COVID-19 appears to be more dangerous to individuals residing at lower altitudes. The downstream molecules in the (COX2) pathway have been shown to adapt in high-altitude dwellers, which may partially explain why these individuals have a lower prevalence of COVID-19 infection. More research is needed, however, to directly address COX2 expression in people living at higher altitudes. It is possible to mimic the gene-environment interaction of higher altitude people by intermittent hypoxia training. COX-2 adaptation resulting from hypoxic exposure at altitude or intermittent hypoxia exercise training (IHT) seems to have an important therapeutic function. Swimming, a type of IHT, was found to lower COX-2 protein production, a pro-inflammatory milieu transcription factor, while increasing the anti-inflammatory microenvironment. Furthermore, Intermittent Hypoxia Preconditioning (IHP) has been demonstrated in numerous clinical investigations to enhance patients' cardiopulmonary function, raise cardiorespiratory fitness, and increase tissues' and organs' tolerance to ischemia. Biochemical activities of IHP have also been reported as a feasible application strategy for IHP for the rehabilitation of COVID-19 patients. In this paper, we aim to highlight some of the most relevant shared genes implicated with COVID-19 pathogenesis and hypoxia. We hypothesize that COVID-19 pathogenesis and hypoxia share a similar mechanism that affects apoptosis, proliferation, the immune system, and metabolism. We also highlight the necessity of studying individuals who live at higher altitudes to emulate their gene-environment interactions and compare the findings with IHT. Finally, we propose COX2 as an upstream target for testing the effectiveness of IHT in preventing or minimizing the effects of COVID-19 and other oxygen-related pathological conditions in the future.

Comparison of the Effect of 8 Weeks of Continuous, Intermittent Training on Maximum Oxygen Consumption, Muscle Endurance and General Health of Overweight Seventh Grade Male Students

Comparison of the Effect of 8 Weeks of Continuous, Intermittent Training on Maximum Oxygen Consumption, Muscle Endurance and General Health of Overweight Seventh Grade Male Students

Caffeine improves swimming speed, decreases the rate of perceived exertion and lactate concentration during a high intensity intermittent aerobic training session for male swimmers

This study aimed to investigate the acute effects of caffeine on mean speed, rate of perceived effort and lactate concentration of swimmers who underwent traditional, high-intensity intermittent aerobic training sessions. In this double-blind study, capsules containing either caffeine (6 mg kg −1 ) or placebo, were administered randomly over 2 sessions to ten male swimmers (18.2 ± 1.7 years). One hour after ingestion, the male swimmers swam ten iterations of 400 meters at heavy domain intensity, each one separated by 60 seconds of passive rest. The swimmers’ ratio perceived exertion and blood lactate levels were tested before the beginning of the test, and after the fifth and tenth iteration. The swimmers’ mean speed was higher in caffeine treatment than placebo ( P < 0.001). Additionally, exertion levels were lower after the fifth iteration in caffeine group compared to placebo ( P < 0.001). The level of lactate was lower after the fifth and tenth iteration with caffeine ingestion compared to placebo ( P < 0.001). In conclusion, the caffeine increased the speed and decreased the perceptual and lactacidemic responses during a traditional, high-intensity intermittent aerobic training session. L’objectif de cette étude a été d’enquêter sur les effets aigus de la caféine sur la vitesse moyenne, sur le taux d’effort perçu et sur la concentration en lactate de nageurs réalisant des sessions d’entraînement aérobie intermittente traditionnelle de haute intensité. Dans cette étude en double aveugle, des capsules contenant de la caféine (6 mg kg −1 ) ou un placebo ont été administrées de manière aléatoire au cours de 2 sessions à 10 nageurs de sexe masculin (18,2 ± 1,7 ans). Une heure après l’ingestion, les nageurs ont nagé 10 efforts de 400 mètres en intensité élevée, chacun séparé par 60 secondes de repos passif. Le rapport des nageurs avec l’effort perçu et les niveaux de lactate sanguin ont été testés avant le début du test et après le cinquième et le dixième effort. La vitesse moyenne des nageurs a été supérieure dans le groupe ayant ingéré de la caféine que dans le placebo ( p < 0,001). En outre, les niveaux d’effort ont été inférieurs après le cinquième effort dans le groupe de la caféine en comparaison avec le placebo ( p < 0,001). Le niveau de lactate a été inférieur après le cinquième et le dixième effort avec l’ingestion de caféine en comparaison avec le placebo ( p < 0,001). En conclusion, la caféine a augmenté la vitesse et a diminué les réponses perceptuelles et de lactacidémie durant une session d’entraînement en aérobie intermittente de haute intensité traditionnelle en natation.

Efectos del entrenamiento intermitente de alta intensidad sobre el perfil lipídico y la glucosa en sangre en estudiantes universitarios con sobrepeso/obesidad

Introduction: High-Intensity Interval Training (HIIT) involves developing exercises in short periods of time with high intensity, followed by periods of rest between the series of exercises performed, and is considered an important tool to combat obesity. Therefore, the present work aimed to identify the effects of high-intensity intermittent training on the lipid profile in overweight and obese university students. Materials and methods: quasi-experimental study, consisting of a sample of 30 students, who were randomly assigned into two groups of 15 students, thus leaving a control group (continuous training): 15 and an experimental group (intermittent exercise of high intensity: 15. Moreover, there were carried out Laboratory tests before and after training to find the lipid profile. Also, the realization of 20 training sessions, which were distributed three times a week, with an average duration of 50 minutes. Additionally, the performed of statistical tests with a level of statistical significance of p &lt;0.05. Results: there is a statistically significant relationship in the HDL value of the control and experimental group. The Glucose values show statistically significant relationships in the experimental group (p = 0.001). Conclusions: Intermittent high-intensity training and continuous moderate-intensity work generate a decrease in LDL and Triglycerides variables and an increase in HDL. However, they are not statistically significant after 20 training sessions. However, high-intensity intermittent training results in glucose-lowering in overweight and obese people.

Effects of Acute Cold Stress after Intermittent Cold Stimulation on Immune-Related Molecules, Intestinal Barrier Genes, and Heat Shock Proteins in Broiler Ileum.

Cold stress will have a negative impact on animal welfare and health. In order to explore the effect of intermittent cold stimulation training on the cold resistance of broilers. Immune-related and intestinal barrier genes were detected before and after acute cold stress (ACS), aiming to find an optimal cold stimulation training method. A total of 240 1-day-old Ross broilers (Gallus) were divided into three groups (G1, G2, and G3), each with 5 replicates (16 chickens each replicate). The broilers of G1 were raised at normal temperature, while the broilers of G2 and G3 were treated with cold stimulation at 3 °C lower than the G1 for 3 h and 6 h from 15 to 35 d, respectively, at one-day intervals. At 50 d, the ambient temperature for all groups was reduced to 10 °C for six hours. The results demonstrated that before ACS, IL6, IL17, TLR21, and HSP40 mRNA levels in G3 were apparently down-regulated (p < 0.05), while IL8 and Claudin-1 mRNA levels were significantly up-regulated compared with G1 (p < 0.05). After ACS, IL2, IL6, and IL8 expression levels in G3 were lower than those in G2 (p < 0.05). Compared to G2, Claudin-1, HSP90 mRNA levels, HSP40, and HSP70 protein levels were increased in G3 (p < 0.05). The mRNA levels of TLR5, Mucin2, and Claudin-1 in G2 and IL6, IL8, and TLR4 in G3 were down-regulated after ACS, while IL2, IL6, and IL17 mRNA levels in G2 and HSP40 protein levels in G3 were up-regulated after ACS (p < 0.05). Comprehensive investigation shows that cold stimulation at 3 °C lower than the normal feeding temperature for six hours at one day intervals can enhanced immune function and maintain the stability of intestinal barrier function to lessen the adverse effects on ACS in broilers.

Effects of Concurrent Resistance and Endurance Training Using Continuous or Intermittent Protocols on Muscle Hypertrophy: Systematic Review With Meta-Analysis.

Monserdà-Vilaró, A, Balsalobre-Fernández, C, Hoffman, JR, Alix-Fages, C, and Jiménez, SL. Effects of concurrent resistance and endurance training using continuous or intermittent protocols on muscle hypertrophy: Systematic review with meta-analysis. J Strength Cond Res 37(3): 688-709, 2023-The purpose of this systematic review with meta-analysis was to explore the effects of concurrent resistance and endurance training (CT) incorporating continuous or intermittent endurance training (ET) on whole-muscle and type I and II muscle fiber hypertrophy compared with resistance training (RT) alone. Randomized and nonrandomized studies reporting changes in cross-sectional area at muscle fiber and whole-muscle levels after RT compared with CT were included. Searches for such studies were performed in Web of Science, PubMed, Scopus, SPORTDiscus, and CINAHL electronic databases. The data reported in the included studies were pooled in a random-effects meta-analysis of standardized mean differences (SMDs). Twenty-five studies were included. At the whole-muscle level, there were no significant differences for any comparison (SMD < 0.03). By contrast, RT induced greater type I and type II muscle fiber hypertrophy than CT when high-intensity interval training (HIIT) was incorporated alone (SMD > 0.33) or combined with continuous ET (SMD > 0.27), but not compared with CT incorporating only continuous ET (SMD < 0.16). The subgroup analyses of this systematic review and meta-analysis showed that RT induces greater muscle fiber hypertrophy than CT when HIIT is included. However, no CT affected whole-muscle hypertrophy compared with RT.

Effectiveness, implementation, and monitoring variables of intermittent hypoxic bicycle training in patients recovered from COVID-19: The AEROBICOVID study.

Hypoxic exposure is safely associated with exercise for many pathological conditions, providing additional effects on health outcomes. COVID-19 is a new disease, so the physiological repercussions caused by exercise in affected patients and the safety of exposure to hypoxia in these conditions are still unknown. Due to the effects of the disease on the respiratory system and following the sequence of AEROBICOVID research work, this study aimed to evaluate the effectiveness, tolerance and acute safety of 24 bicycle training sessions performed under intermittent hypoxic conditions through analysis of peripheral oxyhemoglobin saturation (SpO2), heart rate (HR), rate of perceived exertion (RPE), blood lactate concentration ([La-]) and symptoms of acute mountain sickness in patients recovered from COVID-19. Participants were allocated to three training groups: the normoxia group (GN) remained in normoxia (inspired fraction of O2 (FiO2) of ∼20.9%, a city with 526m altitude) for the entire session; the recovery hypoxia group (GHR) was exposed to hypoxia (FiO2 ∼13.5%, corresponding to 3,000m altitude) all the time except during the effort; the hypoxia group (GH) trained in hypoxia (FiO2 ∼13.5%) throughout the session. The altitude simulation effectively reduced SpO2 mean with significant differences between groups GN, GHR, and GH, being 96.9(1.6), 95.1(3.1), and 87.7(6.5), respectively. Additionally, the proposed exercise and hypoxic stimulus was well-tolerated, since 93% of participants showed no or moderate acute mountain sickness symptoms; maintained nearly 80% of sets at target heart rate; and most frequently reporting session intensity as an RPE of "3" (moderate). The internal load calculation, analyzed through training impulse (TRIMP), calculated using HR [TRIMPHR = HR * training volume (min)] and RPE [TRIMPRPE = RPE * training volume (min)], showed no significant difference between groups. The current strategy effectively promoted the altitude simulation and monitoring variables, being well-tolerated and safely acute exposure, as the low Lake Louise scores and the stable HR, SpO2, and RPE values showed during the sessions.

Iron metabolism regulation in females and males exposed to simulated microgravity: results from the randomized trial Artificial Gravity Bed Rest—European Space Agency (AGBRESA)

Iron metabolism imbalance could contribute to physical deconditioning experienced by astronauts due to its essential role in energy metabolism, cellular respiration, and oxygen transport. In this clinical exploratory study, we wanted to determine whether artificial gravity (AG) training modulated iron metabolism, RBC indices, and body lean mass in healthy male and female participants exposed to head-down tilt (HDT) bed rest, the reference ground-based model of microgravity. We recruited 8 healthy female and 16 healthy male participants who were all exposed to HDT bed rest for 60 d. In addition, they were assigned to 3 experimental groups (n = 8/each): controls, continuous AG training in a short-arm centrifuge (1 × 30 min/d), and intermittent AG training (6 × 5 min/d). The iron metabolism responses to simulated microgravity of the AG training groups did not differ significantly from the responses of controls. Independently from AG, we found that both serum iron concentrations (+31.3%, P = 0.027) and transferrin saturation levels (+28.4%, P = 0.009) increased in males after 6 d of HDT bed rest, as well as serum hepcidin concentrations (+36.9%, P = 0.005). The increase of transferrin saturation levels persisted after 57 d of HDT bed rest (+13.5%, P = 0.026), suggesting that long-term exposure to microgravity sustainably increases serum iron availability in males, and consequently the risk of iron excess or misdistribution. In females, 6 and 57 d of HDT bed rest did not significantly change serum iron, transferrin saturation, or hepcidin levels. The data from this exploratory study suggest that 1) AG training does not influence the iron metabolism responses to microgravity; and 2) iron metabolism parameters, especially iron availability for cells, are significantly increased in males, but not in females, exposed to long-term simulated microgravity. Because of the small sample size of females, we nevertheless must be cautious before concluding that iron metabolism could differently respond to microgravity in females. This trial was registered at https://www.drks.de as DRKS00015677.