Interval Training Sessions Research Articles

Greater improvement in aerobic capacity after a polarized training program including cycling interval training at low cadence (50–70 RPM) than freely chosen cadence (above 80 RPM)

This study compared the impact of two polarized training programs (POL) on aerobic capacity in well-trained (based on maximal oxygen uptake and training experience) female cyclists. Each 8-week POL program consisted of sprint interval training (SIT) consisting of 8–12 repetitions, each lasting 30 seconds at maximal intensity, high-intensity interval training (HIIT) consisting of 4–6 repetitions, each lasting 4 minutes at an intensity of 90–100% maximal aerobic power, and low-intensity endurance training (LIT) lasting 150–180 minutes with intensity at the first ventilatory threshold. Training sessions were organized into 4-day microcycles (1st day—SIT, 2nd day—HIIT, 3rd day—LIT, and 4th day—active rest), that were repeated throughout the experiment. In the first POL program, exercise repetitions during SIT and HIIT training were performed with freely chosen cadence above 80 RPM (POLFC group, n = 12), while in the second POL program with low cadence 50–70 RPM (POLLC group, n = 12). Immediately before and after the 8-week POL intervention, participants performed an incremental test to measure maximal aerobic power (Pmax), power achieved at the second ventilatory threshold (VT2), maximal oxygen uptake (VO2max), maximal pulmonary ventilation (VEmax), and gross efficiency (GE). Moreover, participants performed VO2max verification test. Analysis of variance showed a repeated measures effect for Pmax (F = 21.62; η2 = 0.5; p = 0.00), VO2max (F = 39.39; η2 = 0.64; p = 0.00) and VEmax (F = 5.99; η2 = 0.21; p = 0.02). A repeated measures x group mixed effect was demonstrated for Pmax (F = 4.99; η2 = 0.18; p = 0.03) and VO2max (F = 6.67; η2 = 0.23; p = 0.02). Post-hoc Scheffe analysis showed that increase in Pmax were statistically significant only in POLLC group. The Friedman test showed that VT2 differed between repeated measures only in the POLLC group (χ2 = 11; p = 0.001; W = 0.917). In conclusion, it was found that POL program where SIT and HIIT were performed at low cadence was more effective in improving aerobic capacity in well-trained female cyclists, than POL with SIT and HIIT performed at freely chosen cadence. This finding is a practical application for athletes and coaches in cycling, to consider not only the intensity and duration but also the cadence used during various interval training sessions.

The Impact of Interactive Video Games Training on the Quality of Life of Children Treated for Leukemia

Objectives: The study aimed to assess the impact of interactive video games (IVGs) as a form of physical activity (PA) on the quality of life. Methods: The study used a quality-of-life questionnaire (KIDSCREEN-10) and the HBSC questionnaire. In order to determine individual IVGs training parameters, an initial assessment of cardiorespiratory fitness level was performed, using the Cardio Pulmonary Exercise Test—Godfrey’s progressive protocol. Children in the intervention group participated in 12 interval training sessions using IVGs (Microsoft’s Xbox 360 S console with Kinect,). Results: The study included 21 patients (7–13 years old; 12 boys and 9 girls) treated for acute lymphoblastic leukemia (n = 13) and acute myeloid leukemia (n = 8). Before the IVGs, all children had insufficient PA levels (90% of children in the intervention group and 90.91% of children in the control group did not engage in any PA during the last 7 days). After the intervention, 80% of the children in the IVGs group undertook PA lasting at least 60 min a day, three times a week. They exhibited better well-being, a subjective feeling of improved physical fitness (p < 0.0001), a greater subjective sense of strength and energy (p < 0.0001), and less feeling of sadness (p = 0.0016) than the children from the control group (p = 0.0205). Conclusions: The results of our study confirmed that an attractive form of virtual game or sport is willingly undertaken by children undergoing cancer treatment, and has significant benefits in improving the quality-of-life parameters. There is a clear need to create specific recommendations and rehabilitation models for children with cancer.

The subacute behavior of arterial blood pressure in street runners after a session of high-intensity continuous and interval training: Study protocol

The subacute behavior of arterial blood pressure in street runners after a session of high-intensity continuous and interval training: Study protocol

The acute effect of heart rate monitor projection on exercise effort in school students

Heart rate (HR) monitoring during exercise represents a potentially useful strategy for teachers delivering physical education lessons. This study examined how projecting HR monitor data onto a screen acutely affected school students’ exercise intensity during a high-intensity interval training (HIIT) session. Twenty students (12.3 ± 0.9 years, male = 8, female = 12) from one primary school volunteered to participate. Using a randomised crossover design within a 4-week period, participants completed four sessions of HIIT with HR projection and four sessions of HIIT with no ability to view HR. During the HR projection condition all participants viewed their HR on a class screen in real-time, with a changing colour according to HR level. Target intensity was 90% of age-predicted maximum HR. Peak HR and time above 90% HR (RED) were collected in all sessions. Student focus groups and teacher interviews were conducted to gain perceptions around the effects of the projection. Peak HR ( p = 0.005, η2 effect size = 0.049) and RED ( p = 0.000, η2 effect size = 0.083) were significantly greater during the projected condition. Qualitative data indicated that projection improved student motivation to reach the target, and ignited competition amongst peers to work harder. Projecting HR data onto a screen can increase the acute exercise intensity of school students during HIIT. HR projection therefore represents a useful strategy for the delivery of exercise sessions with an emphasis on intensity, within physical education classes.

Greater lactate accumulation does not alter peripheral concentrations of key appetite-regulating neuropeptides.

The potential mechanisms involved in lactate's role in exercise-induced appetite suppression requires further examination. We used sodium bicarbonate (NaHCO3) supplementation in a double-blind, placebo controlled, randomized crossover design to explore lactate's role on neuropeptide Y (NPY), agouti-related peptide (AgRP), and alpha-melanocyte stimulating hormone (α-MSH) concentrations. Twelve adults (7 males; 24.2±3.4 kg‧m-2; 42.18±8.56 mL‧kg-1‧min-1) completed two identical high-intensity interval training sessions following ingestion of NaHCO3 (BICARB) or sodium chloride (PLACEBO) pre-exercise. Blood lactate, acylated ghrelin, NPY, AgRP, α-MSH, and appetite perceptions were measured pre-exercise, 0-, 30-, 60-, and 90-min post-exercise. Free-living energy intake (electronic food diaries) was measured the day before, of, and after each experimental session. In BICARB, blood lactate was greater post-exercise (p<0.002, d>0.70) though acylated ghrelin was similar (p=0.075, =0.206) at all time-points post-exercise (p>0.034, d<0.22). NPY (p=0.006, >0.509) and AgRP (p<0.001, >0.488) had main effects of time increasing following exercise and returning to baseline, with no differences between sessions (NPY: p=0.0.192, =0.149; AgRP: p=0.422, =0.060). α-MSH had no main effect of time (p=0.573, =0.063) or session (p=0.269, =0.110). Appetite perceptions were similar during BICARB and PLACEBO (p=0.007, d=0.28) increasing in both sessions post-exercise (p<0.088, d>0.57). Energy intake had a main effect of day (p=0.025, =0.825), where the experimental session day was greater than the day before (p=0.010, d=0.59) with no other differences between days (p>0.260, d<0.38). The lower accumulation of lactate than our previous work did not generate exercise-induced appetite suppression as there were no differences in acylated ghrelin, appetite perceptions, or peripheral concentrations of neuropeptides.

Effects of high-intensity interval robot-assisted gait training on cardiopulmonary function and walking ability in chronic stroke survivors: A multicenter single-blind randomized controlled trial.

Chronic stroke can impair cardiopulmonary function, mobility, and daily activities. This study assessed the impact of robot-assisted gait training (RAGT) on such impairments. To investigate the effects of robot-assisted gait training on cardiopulmonary function, walking ability, lower extremity function and strength, activities of daily living (ADLs), and blood test results among individuals with chronic stroke. A multicenter, prospective, single-blinded, randomized controlled trial with 22 chronic stroke participants compared RAGT against a control exercise regimen. RAGT involved three days weekly sessions of high-intensity interval training for 8 weeks (24 sessions) with a Morning Walk® device. The control group also performed home exercises. (24 sessions) Measures included VO2max, Functional Ambulatory Category, 2-minute walk test, 10-meter walk test, Motricity Index-Lower, Korean version of the Fugl-Meyer Assessment Scale, Modified Barthel Index, Berg Balance Scale, muscle strength, InBody body composition, and blood tests (cholesterol, lipid, glucose). RAGT significantly improved VO2max, gait, balance, and lower limb strength compared with controls, with significant improvements in 2-minute walk test, 10-meter walk test, Motricity Index-Lower, and Fugl-Meyer Assessment outcomes. No changes were seen in muscle mass or blood markers. RAGT enhances cardiopulmonary function and ambulatory capacity in chronic stroke patients, underscoring its potential in stroke rehabilitation.

Effects of high-intensity interval training on sleep disturbances associated with posttraumatic stress disorder.

Sleep disturbances are common in individuals with posttraumatic stress disorder. Exercise interventions are a promising approach in the treatment of sleep disorders, but little is known about the efficacy of exercise interventions for sleep disturbances associated with posttraumatic stress disorder. A total of 40 individuals with posttraumatic stress disorder were randomized to six sessions of either high-intensity interval training or low-to-moderate-intensity training, administered within 12 days. Sleep quality was assessed over 24 days from baseline to post with the Pittsburgh Sleep Quality Index, a sleep log, and a waist-worn actigraphy. Analyses revealed that, regardless of group allocation, Pittsburgh Sleep Quality Index score improved significantly by 2.28 points for high-intensity interval training and 1.70 points for low-to-moderate-intensity training (d = 0.56 for high-intensity interval training; 0.49 for low-to-moderate-intensity training) over time, while there were no significant changes in any sleep log or actigraphy measure. Analysis of a subsample of those affected by clinically significant sleep disturbances (n = 24) revealed a significant time effect with no difference between exercise interventions: Pittsburgh Sleep Quality Index improved significantly by 2.65 points for high-intensity interval training and 2.89 points for low-to-moderate-intensity training (d = 0.53 for high-intensity interval training; 0.88 for low-to-moderate-intensity training), and actigraphy measure of wake after sleep onset was reduced significantly by 14.39 minutes for high-intensity interval training and 6.96 minutes for low-to-moderate-intensity training (d = 0.47 for high-intensity interval training; 0.11 for low-to-moderate-intensity training) from baseline to post. In our pilot study, we found an improvement in sleep quality from pre- to post-assessment. There were no significant differences between exercise groups. Further studies are needed to investigate whether the found time effects reflect the exercise intervention or unrelated factors.

Acute performance fatigability following continuous versus intermittent cycling protocols is not proportional to total work done.

Classical training theory postulates that performance fatigability following a training session should be proportional to the total work done (TWD); however, this notion has been questioned. This study investigated indices of performance and perceived fatigability after primary sessions of high-intensity interval training (HIIT) and constant work rate (CWR) cycling, each followed by a cycling time-to-task failure (TTF) bout. On separate days, 16 participants completed an incremental cycling test, and, in a randomized order, (i) a TTF trial at 80% of peak power output (PPO), (ii) an HIIT session, and (iii) a CWR session, both of which were immediately followed by a TTF trial at 80% PPO. Central and peripheral aspects of performance fatigability were measured using interpolated twitch technique, and perceptual measures were assessed prior to and following the HIIT and CWR trials, and again following the TTF trial. Despite TWD being less following HIIT (P=0.029), subsequent TTF trial was an average of 125s shorter following HIIT versus CWR (P<0.001), and this was accompanied by greater impairments in voluntary and electrically evoked forces (P<0.001), as well as exacerbated perceptual measures (P<0.001); however, there were no differences in any fatigue measure following the TTF trial (P≥0.149). There were strong correlations between the decline in TTF and indices of peripheral (r=0.70) and perceived fatigability (r≥0.80) measured at the end of HIIT and CWR. These results underscore the dissociation between TWD and performance fatigability and highlight the importance of peripheral components of fatigability in limiting endurance performance during high-intensity cycling exercise.

EXTOD-Immune: a randomised controlled trial to investigate whether a remotely monitored, home-based exercise intervention can reduce disease activity in people with type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease in which the adaptive immune system targets insulin-producing β-cells of pancreatic islets, leading to dependence on exogenous insulin therapy. Cytotoxic (CD8+)...

Training Session Models in Endurance Sports: A Norwegian Perspective on Best Practice Recommendations.

Our scientific understanding of the mechanistic and practical connections between training session prescriptions, their execution by athletes, and adaptations over time in elite endurance sports remains limited. These connections are fundamental to the art and science of coaching. By using successful Norwegian endurance coaches as key informants, the aim of this study is to describe and compare best practice session models across different exercise intensities in Olympic endurance sports. Data collection was based on a four-step pragmatic qualitative study design, involving questionnaires, training logs from successful athletes, and in-depth and semi-structured interviews, followed by negotiation among researchers and coaches to assure our interpretations. Twelve successful and experienced male Norwegian coaches from biathlon, cross-country skiing, long-distance running, road cycling, rowing, speed skating, swimming, and triathlon were chosen as key informants. They had been responsible for the training of world-class endurance athletes who altogether have won > 370 medals in international championships. The duration of low-intensity training (LIT) sessions ranges from 30min to 7h across sports, mainly due to modality-specific constraints and load tolerance considerations. Cross-training accounts for a considerable part of LIT sessions in several sports. Moderate (MIT)- and high-intensity training (HIT) sessions are mainly conducted as intervals in specific modalities, but competitions also account for a large proportion of annual HIT in most sports. Interval sessions are characterized by a high accumulated volume, a progressive increase in intensity throughout the session, and a controlled, rather than exhaustive, execution approach. A clear trend towards shorter intervals and lower work: rest ratio with increasing intensity was observed. Overall, the analyzed sports implement considerably more MIT than HIT sessions across the annual cycle. This study provides novel insights on quantitative and qualitative aspects of training session models across intensities employed by successful athletes in Olympic endurance sports. The interval training sessions revealed in this study are generally more voluminous, more controlled, and less exhaustive than most previous recommendations outlined in research literature.

Mood, Cognitive Function, and Plasma Kynurenine Metabolites Responses Following Severe Changes in Physical Activity.

To monitor changes in mood, cognitive function, brain electrical activity, and circulating kynurenine pathway metabolites in response to a 3-wk severe physical activity (PA) restriction, followed by 3 wk of resumed activity adding resistance and high-intensity interval exercise training. Twenty healthy participants (14 males, 6 females; 25.4 ± 5.2 yr) underwent 3 wk of limited PA using forearm crutches with one leg suspended (INACT) and then 3 wk of resumed activity plus supervised resistance and high-intensity interval training sessions (ACT, three to six sessions per week). At baseline, after INACT, and then after ACT, venous blood was sampled for analysis of major kynurenine pathway metabolites, a short version of the International Physical Activity Questionnaire, Hospital Anxiety and Depression Scale (HADS) and Profile of Mood States (POMS) questionnaires were completed, and cognitive tests with electroencephalography were performed. During INACT, the depression score on the HADS scale tended to increase (3.5 to 6.8; P = 0.065), whereas it was reduced with ACT compared with after INACT (2.8; P = 0.022). On the POMS scale, depression, fatigue, and confusion increased within INACT ( P < 0.05). Notably, subjects exhibited considerable variability, and those experiencing depression symptoms recorded by the HADS scale ( n = 4) displayed distinct mood disturbances on POMS. All HADS and POMS scores were fully restored to baseline with ACT. Neither INACT nor ACT induced significant changes in cognition, brain electrical activity, or kynurenine pathway metabolites ( P > 0.05). Although young healthy individuals with 3 wk of severely restricted PA do not undergo changes in circulating kynurenine pathway metabolites, cognitive performance, and brain electrical activity, their mood response is quite variable, and depression develops in some. Three weeks of resuming mobility plus exercise training reversed the mood profile.

The Clinical Outcome of Cardiac Rehabilitation in Coronary Artery Disease Patients with Regard to the Presence of Left Ventricular Systolic Dysfunction.

Background: Despite the use of advanced treatment techniques, coronary artery disease (CAD) still remains the main cause of left ventricular (LV) dysfunction and heart failure. Participation in cardiac rehabilitation (CR) programs can lead to a number of beneficial effects, but some patients do not demonstrate the expected improvement. The aim of this study is to evaluate the impact of CR on changes in exercise capacity with regard to the presence of LV dysfunction. Methods: A group of 428 patients with CAD were consecutively admitted to an outpatient comprehensive cardiac rehabilitation program comprising 24 exercise sessions of interval training on cycle ergometers, three times a week for 45 min, and a health education. The patients were compared in two subgroups, i.e., with LV systolic dysfunction (LVEF < 50%, n = 175) and LVEF ≥ 50% (n = 253). Results: In the LVEF < 50% group, the exercise capacity improved by 1 ± 0.78 MET (median 1.15 MET), and 0.86 ± 0.77 MET (median 1.08 MET) in the LVEF ≥ 50% group. Women with LVEF < 50% demonstrated a significant increase in exercise capacity by 1.2 MET, while those with LVEF ≥ 50% did not display any such increase. All men, regardless of LVEF, exhibited a similar improvement in exercise capacity greater than 1 MET. Conclusions: An outpatient eight-week cardiac rehabilitation program based on 45 min aerobic interval training sessions three times a week appears less effective for women with CAD and EF ≥ 50%. In this group, the proposed training intervention is insufficient in improving exercise capacity to an extent that could indicate a reduction in mortality risk.

Acute physiological responses of blood flow restriction between high-intensity interval repetitions in trained cyclists.

Blood flow restriction (BFR) is increasingly being used to enhance aerobic performance in endurance athletes. This study examined physiological responses to BFR applied in recovery phases within a high-intensity interval training (HIIT) session in trained cyclists. Eleven competitive road cyclists (mean±SD, age: 28±7years, body mass: 69±6kg, peak oxygen uptake: 65±9mL ·kg-1· min-1) completed two randomised crossover conditions: HIIT with (BFR) and without (CON) BFR applied during recovery phases. HIIT consisted of six 30-s cycling bouts at an intensity equivalent to 85% of maximal 30-s power (523±93W), interspersed with 4.5-min recovery. BFR (200mmHg, 12cm cuff width) was applied for 2-min in the early recovery phase between each interval. Pulmonary gas exchange (V̇O2, V̇CO2, and V̇E), tissue oxygen saturation index (TSI), heart rate (HR), and serum vascular endothelial growth factor concentration (VEGF) were measured. Compared to CON, BFR increased V̇CO2 and V̇E during work bouts (both p<0.05, dz<0.5), but there was no effect on V̇O2, TSI, or HR (p>0.05). In early recovery, BFR decreased TSI, V̇O2, V̇CO2, and V̇E (all p<0.05, dz>0.8) versus CON, with no change in HR (p>0.05). In late recovery, when BFR was released, V̇O2, V̇CO2, V̇E, and HR increased, but TSI decreased versus CON (all p<0.05, dz>0.8). There was a greater increase in VEGF at 3-h post-exercise in BFR compared to CON (p<0.05, dz>0.8). Incorporating BFR into HIIT recovery phases altered physiological responses compared to exercise alone.

Effects of Different Recovery Periods Following a Very Intense Interval Training Session on Strength and Explosive Performance in Elite Female Ice Hockey Players.

Petré, H, Tinmark, F, Rosdahl, H, and Psilander, N. Effects of different recovery periods following a very intense interval training session on strength and explosive performance in elite female ice hockey players. J Strength Cond Res 38(7): e383-e390, 2024-This study investigates how different recovery periods after high-intensity interval training (HIIT) affects strength and explosive performance during a power training (PT) session. Fifteen female elite ice hockey players (22.5 ± 5.2 years) performed PT, including 6 sets of 2 repetitions (reps) of isometric leg press (ILP) and 6 sets of 3 reps of countermovement jump (CMJ), following a rested state and 10 minutes, 6 hours, or 24 hours after HIIT (3 sets of 8 × 20 seconds at 115% of power output at maximal oxygen consumption on a cycle ergometer). Peak force (PF) and peak rate of force development (pRFD) were measured during the ILP. Peak jump height (PJH), concentric phase duration (ConDur), eccentric phase duration, total duration, peak power (PP), velocity at peak power (V@PP), and force at peak power were measured during CMJ. The following variables were significantly reduced when only a 10-minute recovery period was allowed between HIIT and PT: PF was reduced by 7% ( p < 0.001), pRFD by 17% ( p < 0.001), PJH by 4% ( p < 0.001), ConDur by 4% ( p = 0.018), PP by 2% ( p = 0.016), and V@PP by 2% ( p = 0.007). None of the measured variables were reduced when PT was performed 6 and 24 hours after HIIT. We conclude that strength and explosive performance of elite female ice hockey players is reduced 10 minutes after HIIT but not negatively affected if a rest period of at least 6 hours is provided between HIIT and PT.

Performance Evaluation of a New Sport Watch in Sleep Tracking: A Comparison against Overnight Polysomnography in Young Adults.

Introduction: This study aimed to validate the ability of a prototype sport watch (Polar Electro Oy, FI) to recognize wake and sleep states in two trials with and without an interval training session (IT) 6 h prior to bedtime. Methods: Thirty-six participants completed this study. Participants performed a maximal aerobic test and three polysomnography (PSG) assessments. The first night served as a device familiarization night and to screen for sleep apnea. The second and third in-home PSG assessments were counterbalanced with/without IT. Accuracy and agreement in detecting sleep stages were calculated between PSG and the prototype. Results: Accuracy for the different sleep stages (REM, N1 and N2, N3, and awake) as a true positive for the nights without exercise was 84 ± 5%, 64 ± 6%, 81 ± 6%, and 91 ± 6%, respectively, and for the nights with exercise was 83 ± 7%, 63 ± 8%, 80 ± 7%, and 92 ± 6%, respectively. The agreement for the sleep night without exercise was 60.1 ± 8.1%, k = 0.39 ± 0.1, and with exercise was 59.2 ± 9.8%, k = 0.36 ± 0.1. No significant differences were observed between nights or between the sexes. Conclusion: The prototype showed better or similar accuracy and agreement to wrist-worn consumer products on the market for the detection of sleep stages with healthy adults. However, further investigations will need to be conducted with other populations.

Easy interval method, an alternative approach to improve anaerobic threshold speed

This paper presents the specific training method in distance running developed by the Dutch running coach Herman Verheul and successfully applied in the 1970s, its historical background, its afterlife, and its possible applications. The Verheul method can be traced back to the Stampfl interval method used in the 1960s. It involves the use of shorter (200 and 400 meters) and longer (1000 and later 2000 meters) interval training sessions on a daily basis. The method is characterised by a low intensity of partial distances compared to traditional interval training and a relatively long active recovery period equal to the interval distance. For these reasons, the workouts remain predominantly aerobic, without significant lactic acid accumulation, allowing interval training to be used daily and avoiding over-exertion. The method allows runners to achieve high weekly volumes at high running speeds, crucial for establishing anaerobic threshold speed (vLT2) and economical running movement (RE), essential for successful distance running performance. The easy interval method offers an alternative means of improving anaerobic threshold speed. It may provide a new tool to the recently used sustained tempo runs and the anaerobic threshold intervals that are prevalent today.

The Development and Evaluation of Netball-Specific High-Intensity Interval Training Sessions: The Netball-HIIT Study.

This two-phase study involved the design, development, and evaluation of netball-specific high-intensity interval training sessions (Netball-HIIT) for use with netballers of varied ages and abilities. In Phase 1 (2020), a systematic analysis of netball GPS data from 30 netball players and gameplay video footage (10 h) was conducted, followed by the design and testing of five 8 min Netball-HIIT sessions involving 100 netball players (age 21 ± 8.44 years; Australia). In Phase 2 (2021), the feasibility and preliminary efficacy of delivering one Netball-HIIT session each week for five weeks was assessed using a two-armed, dose-matched, randomized, controlled feasibility study with netball players (born in 2010) (Netball HIIT n = 15; Netball Knee Program: NKP n = 15). Cardiorespiratory and muscular fitness was assessed at baseline and 6 weeks. Data were analyzed using linear mixed models and Cohen's d effect sizes. Netball-HIIT sessions were highly rated by players, and higher average (139 bpm) and peak heart rates (156 bpm) were detected amongst Netball-HIIT participants (KNP = 127 bpm and 152 bpm). We observed a large effect for cardiorespiratory fitness (+2.4 laps, d = 0.89), and a small to medium effect for muscular fitness (push-ups +1.2, d = 0.49; standing jump +0.8 cm, d = 0.36) in favor of Netball-HIIT, suggesting that coach-led Netball-HIIT may provide a time-efficient and effective training component for use in netball.

RESPOSTAS FISIOLÓGICAS AGUDAS À “HIPÓXIA INTERMITENTE DE RECUPERAÇÃO” NO HIIT

ABSTRACT Introduction: Traditional intermittent hypoxia training improves sport performance after short periods of exposure, but acute exposure to intermittent hypoxia leads to decreased training intensity and technical quality. The solution to overcome these negative effects may be to perform efforts in normoxia and the intervals between efforts in hypoxia, maintaining the quality of training and the benefits of hypoxia. Objective: This study aimed to evaluate the acute physiological responses to hypoxia exposure during recovery between high intensity efforts. Materials and methods: Randomized, one-blind, placebo-controlled study. Sixteen men performed a graded exercise test to determine their maximal intensity and two sessions of high-intensity interval training. The training intervals could be in hypoxia (HRT), FIO2: 0.136 or normoxia (NRT), FIO2: 0.209. During the two-minute interval between the ten one-minute efforts, peripheral oxygen saturation (SpO2), heart rate (HR), blood lactate ([La]), blood glucose ([Glu]) were constantly measured. Results: There were differences in HR (TRN = 120 ± 14 bpm; TRH = 129 ± 13 bpm, p &lt; 0.01) and SpO2 (TRN = 96.9 ± 1.0%; TRH = 86.2 ± 3.5%, p &lt; 0.01). No differences in [La] and [Glu] TRN (4.4 ± 1.7 mmol.l-1; 3.9 ± 0.5 mmol.l-1) and TRH (5.2 ± 2.0 mmol.l-1; 4.0 ± 0.8 mmol.l-1, p = 0.17). Conclusion: The possibility of including hypoxia only in the recovery intervals as an additional stimulus to the training, without decreasing the quality of the training, was evidenced. Level of Evidence II; Randomized Clinical Trial of Minor Quality.

Functional Impact of Interval Training on Muscle Mass and Strength in Obese Adults: An Interventional Trial

Background: Obesity is a burgeoning global health issue, with its prevalence contributing to a spectrum of comorbid conditions, including cardiovascular disease, diabetes, and decreased life expectancy. Traditional exercise regimens have been challenged by the reduced exercise tolerance observed in obese individuals. Interval training has emerged as a promising alternative that may address these concerns by effectively improving body composition and aerobic capacity. Objective: This study aimed to evaluate the effects of interval training on body composition and aerobic capacity in obese adults. The objective was to determine whether a structured interval training program could lead to significant improvements in these parameters, which are critical indicators of overall health status. Methods: In a 12-week interventional trial, 30 sedentary obese adults (BMI ≥ 30) underwent interval training sessions three times per week. Body composition was assessed using skinfold thickness and bio-impedance methods, while aerobic capacity was evaluated using lactate threshold testing and the Astrand sub-maximal test. Statistical analysis was performed using SPSS version 25, with significant changes in pre- and post-study values being highlighted. Results: Post-intervention, participants exhibited a decrease in weight from 79.3 kg to 67.5 kg and a reduction in BMI from 27.6 kg/m² to 24.01 kg/m². Fat percentage also declined from 25.2% to 22.5%. Aerobic capacity improved, with a significant increase in relative oxygen uptake from 38 ml/kg/min to 57 ml/kg/min. Additionally, the mean heart rate during submaximal testing decreased across all exercise intensities, suggesting enhanced cardiovascular efficiency. Conclusion: Interval training is an effective intervention for improving both body composition and aerobic capacity in obese adults. The study demonstrated significant reductions in body mass and fat percentage, along with improved aerobic efficiency, as evidenced by increased oxygen uptake and reduced heart rates during exercise.

A Cardiopulmonary Exercise Testing for Prescribing High-Intensity Interval Training Sessions with Elastic Resistance

This study aims to analyze the agreement of cardiopulmonary variables between a cardiopulmonary exercise test with elastic resistance (CPxEL) and high-intensity interval exercise with elastic resistance (EL-HIIE). Methods: Twenty-two physically independent participants were recruited. Visit one consisted of conducting a health survey and anthropometric assessment. On visit two, the participants performed CPxEL. After seven days, on visit three, the participants performed EL-HIIE. The CPxEL was carried out on a rubber mat demarcated by lines representing eight stages. The test consisted of alternating back and forth steps against elastic resistance. The increments were performed at a rate of one stage per minute, following a cadence controlled by a metronome calibrated by beats per minute (bpm). The EL-HIIE was performed at the stage corresponding to an intensity of ~85% VO2max, as determined by CPxEL. The EL-HIIE consisted of 10 × 1 min (work):1 min (passive rest), with a cadence of 200 bpm. Cardiopulmonary parameters, heart rate (HR), and oxygen consumption (VO2) were measured during exercise. Bland–Altman was applied to analyze the agreement between the HR and VO2 found in EL-HIIE and the values prescribed by CPxEL (~85–90% VO2max). Results: The HRpeak and VO2peak in the EL-HIIE showed good agreement with the VO2CPxEL and HRCPxEL values, showing an average difference of (−1.7 mL·kg−1·min−1) and (0.3 bpm). Conclusions: The results of the present study demonstrate the agreement of cardiopulmonary variables between the CPxEL and the EL-HIIE. Therefore, for a more specific prescription of EL-HIIE intensity, CPxEL can be used.