High-intensity interval training, solutions to the programming puzzle: Part I: cardiopulmonary emphasis. Sports Med. 2013;43:313-338. [PMID: 23539308 DOI: 10.1007/s40279-013-0029-x]

Psychophysiological Responses to High-Intensity Interval Training Exercise over Menstrual Cycle Phases: An Exploratory Study

INTRODUCTION

Although there is potential for the menstrual cycle to impact psychophysiological responses to exercise, there has been a paucity of studies investigating this aspect, specifically in the context of high-intensity interval training (HIIT).

PURPOSE

This exploratory study aimed to examine the psychophysiological responses to HIIT over the menstrual cycle.

METHODS

Twenty-three healthy and physically active young women were recruited. Each woman completed a cycle ergometer HIIT session in the menstrual, follicular, and luteal phases of the menstrual cycle in a random order. Psychophysiological variables of interest were collected at baseline, and during and after exercise. Primary variables of interest were anxiety, mood, motivation, enjoyment, arousal, affect, and menstrual distress.

RESULTS

Higher pain, water retention, behavior change (related to social interactions, eating habits, and self-performance), and autonomic reactions (consisting of nausea, dizziness, hot flashes, and cold sweats) were observed before HIIT during the menstrual phase compared with the follicular phase ( P < 0.05). Participants exhibited worse psychological responses to HIIT sessions during the menstrual phase, followed by the luteal phase. Findings also noted participants arrived to the laboratory with lower motivation to initiate HIIT sessions during the luteal and menstrual phases compared with the follicular phase. This difference was observed before and during HIIT. Motivation and depressive symptoms showed a significant reduction from pre-HIIT to post-HIIT ( P < 0.05), regardless of menstrual phase.

CONCLUSIONS

The findings revealed that the menstrual cycle had a significant impact on psychophysiological responses. Moreover, HIIT could be adopted to improve motivation and depressive symptoms; however, further research is needed to explore the effects of HIIT across the menstrual cycle in women with clinical depression.

Hyperandrogenism associated with polycystic ovary syndrome may have a protective effect against fracture risk in female athletes: A pilot study

OBJECTIVES

Polycystic ovary syndrome (PCOS), characterized by polycystic ovaries, anovulation, and hyperandrogenism, is believed to be an evolutionary mismatch disease. Past research has examined PCOS as a uniform disease, despite variation in phenotypes across diagnostic categories, but establishing an evolutionary mismatch requires a focus on individual traits. We suggest PCOS hyperandrogenism may have been beneficial in ancestral environments because it reduced fracture risk and associated morbidity and mortality due to increased bone mineral density (BMD). We test this hypothesis by assessing fracture frequency, a proxy for BMD, in highly active females with and without PCOS hyperandrogenism.

METHODS

Sixty-seven reproductive-aged women were surveyed and grouped as: high intensity interval training (HIIT; a proxy for metabolic and physical stress) athletes with hyperandrogenic PCOS (31.24%), HIIT athletes without PCOS (29.85%), and nonathletes with hyperandrogenic PCOS (38.81%). Fracture occurrence was compared between the groups using independent samples Kruskal-Wallis tests for non-normally distributed data, and multiple regression analysis was used to examine anthropometrics, lifestyle and reproductive factors, PCOS status, and exercise frequency on fracture occurrence.

RESULTS

Fracture occurrence was higher in non-PCOS athletes (3.8 ± 4.3) than PCOS-athletes (1.2 ± 1.4, p = .11) and PCOS-non-athletes (1.0 ± 1.4, p < .01). PCOS-athletes and nonathletes did not differ significantly in fracture occurrence (p = .33). These results were independent of factors associated with bone health.

CONCLUSIONS

These preliminary findings suggest females with PCOS-related hyperandrogenism may be less likely to experience bone fractures and provide an initial step to explaining why PCOS has persisted despite marked negative reproductive consequences in modern populations.

Position Statement of the Italian Society of Cardiovascular Prevention (SIPREC) and Italian Heart Failure Association (ITAHFA) on Cardiac Rehabilitation and Protection Programs as a Cornerstone of Secondary Prevention after Myocardial Infarction or Revascularization

Despite the remarkable and progressive advances made in the prevention and management of cardiovascular diseases, the recurrence of cardiovascular events remains unacceptably elevated with a notable size of the residual risk. Indeed, in patients who suffered from myocardial infarction or who underwent percutaneous or surgical myocardial revascularization, life-style changes and optimized pharmacological therapy with antiplatelet drugs, lipid lowering agents, beta-blockers, renin angiotensin system inhibitors and antidiabetic drugs, when appropriate, are systematically prescribed but they might be insufficient to protect from further events. In such a context, an increasing body of evidence supports the benefits of cardiac rehabilitation (CR) in the setting of secondary cardiovascular prevention, consisting in the reduction of myocardial oxygen demands, in the inhibition of atherosclerotic plaque progression and in an improvement of exercise performance, quality of life and survival. However, prescription and implementation of CR programs is still not sufficiently considered.The aim of this position paper of the Italian Society of Cardiovascular Prevention (SIPREC) and of the Italian Heart Failure Association (ITAHFA) is to examine the reasons of the insufficient use of this strategy in clinical practice and to propose some feasible solutions to overcome this clinical gap.

MICT ameliorates hypertensive nephropathy by inhibiting TLR4/NF-κB pathway and down-regulating NLRC4 inflammasome

BACKGROUND

Hypertensive nephropathy (HN) is one of the main causes of end-stage renal disease (ESRD), leading to serious morbidity and mortality in hypertensive patients. However, existing treatment for hypertensive nephropathy are still very limited. It has been demonstrated that aerobic exercise has beneficial effects on the treatment of hypertension. However, the underlying mechanisms of exercise in HN remain unclear.

METHODS

The spontaneously hypertensive rats (SHR) were trained for 8 weeks on a treadmill with different exercise prescriptions. We detected the effects of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on inflammatory response, renal function, and renal fibrosis in SHR. We further investigated the relationship between TLR4 and the NLRC4 inflammasome in vitro HN model.

RESULTS

MICT improved renal fibrosis and renal injury, attenuating the inflammatory response by inhibiting TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. However, these changes were not observed in the HIIT group. Additionally, repression of TLR4/NF-κB pathway by TAK-242 inhibited activation of NLRC4 inflammasome and alleviated the fibrosis in Ang II-induced HK-2 cells.

CONCLUSION

MICT ameliorated renal damage, inflammatory response, and renal fibrosis via repressing TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. This study might provide new references for exercise prescriptions of hypertension.

Physiological and performance adaptations to beta alanine supplementation and short sprint interval training in volleyball players

This study aimed to elucidate the impact of combining Beta-Alanine (BA) supplementation with short sprint interval training on cardiorespiratory fitness, anaerobic power, and bio-motor abilities in volleyball players. Twenty young male athletes were randomly divided into 2 equal groups and performed 8 weeks of short sprint interval training while supplementing 4.8 g daily BA or placebo (polydextrose). The players were evaluated for volleyball-specific bio-motor abilities (vertical jump, horizontal jump, spike jump, block jump, 10-m linear sprint, and T-test change of direction speed) and physiological parameters (cardiorespiratory fitness and anaerobic power) pre- and post-intervention. Both groups demonstrated significant (p ≤ 0.05) improvements in all measured variables over time. A time-regimen interaction was observed in jumping ability enhancement from pre- to post-training, wherein BA elicited more significant changes in both vertical and horizontal jumps compared to the placebo. Analyzing residuals in changes and the coefficient of variations (CV) in mean group changes demonstrated that BA supplementation results in uniformly inducing adaptive changes among individuals. Therefore, in light of these results, it is recommended that coaches and trainers take into consideration the utilization of BA as an ergogenic aid to enhance the vertical and horizontal jumps of volleyball players and increase the homogeneity in adaptive responses over the training period.

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

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

The duration of low-intensity training (LIT) sessions ranges from 30 min to 7 h 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.

CONCLUSIONS

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.

The Relationship Between the Anaerobic Speed Reserve and Acute Responses to High-Intensity Interval Training in Female Soccer Players

ABSTRACT

Aspin, GL, Graham, M, Franklin, J, Hicks, KM, and Taylor, JM. The relationship between the anaerobic speed reserve and acute responses to high-intensity interval training in female soccer players. J Strength Cond Res XX(X): 000-000, 2024-The anaerobic speed reserve (ASR) is a popular method of profiling soccer players, often used to individualize training prescription. This study explored the reliability of ASR profiling, and the relationship between the ASR and acute physiological responses to high-intensity interval training (HIIT). Acute physiological responses to different HIIT types were also compared. Thirteen subelite female soccer players aged 20.2 ± 4.6 years completed 6 exercise sessions. In sessions 1-2, players completed a 40-m sprint to assess maximal sprint speed (MSS) and 1600-m time-trial to estimate maximal aerobic speed (MAS), which were used to calculate ASR and assess test-retest reliability. In sessions 3-6, players completed 4 HIIT sessions (repeated-sprint training, sprint interval training, long intervals, and short intervals HIIT). Intensities for long and short intervals HIIT were individualized according to MAS. Ratings of perceived exertion (RPE), heart rate (HR), and postsession blood lactates were recorded throughout. Relationships between the ASR and acute responses to HIIT, and between HIIT session comparisons in outcome measures were assessed. Anaerobic speed reserve (coefficient of variation ± 95% confidence limits; 3.1 ± 1.5%), MAS (1.8 ± 1.3%), and MSS (0.8 ± 0.6%) indicated acceptable reliability. Moderate correlations between ASR and RPE (r = 0.33), postsession blood lactate (r = 0.34), and HR (r = 0.37) were observed during long intervals HIIT. A strong correlation was observed between ASR and RPE during SIT (r = 0.50). Sprint interval training elicited higher RPE's and postsession blood lactate's than other HIIT sessions. Anaerobic speed reserve has good reliability and may influence acute physiological responses to HIIT in female soccer players.

A narrative review exploring advances in interval training for endurance athletes

Interval training is considered an essential training component in endurance athletes. Recently, there has been a focus on optimization of interval training characteristics to sustain a high fraction of maximal oxygen consumption (≥90% VO2max) to improve physiological adaptations and performance. Herein, we present a synopsis of the latest research exploring both acute and chronic studies in endurance athletes. Further, a decision flowchart was created for athletes and coaches to select the most appropriate interval training regime for specific individualized goals.

Investigating the Alcohol Effects on the Response to Strenuous Exercise Training: Protocol for a Multidisciplinary Intervention Study in Young Healthy Adults-The BEER-HIIT Study

High-intensity interval training (HIIT) is a time-efficient strategy to improve fitness and performance. Whereas the multiple and negative effects of high intake of alcohol have been widely studied, the effect of moderate alcohol doses after exercise is not clear, and it is currently under debate. For that, a total of 80 young healthy adults are studied and allocated into 5 groups, each including 16 participants. Four groups follow a HIIT program, while the fifth group is a control non-training group. The training groups will be randomized according to the characteristics of the ingested beverage (alcohol beer, beer 0.0%, sparkling water, or ethanol). The effects of HIIT on several aspects of physical performance and mental health in young healthy adults are evaluated, also the concomitant effect of daily and moderate alcohol consumption. The novelty of this study lies in the continuous measurement of the psychological parameters associated with carrying out a highly demanding training program in conjunction with alcohol consumption in moderate quantities, reflecting real-life conditions.

The Effects of High-Intensity Interval Training on Cognitive and Physical Skills in Basketball and Soccer Players

As athletes pursue excellence, training techniques continue to advance, making structured physical activity an essential tool for enhancing performance. To optimize athletic performance in modern competitive sports, the balance of physical performance and mental clarity is required. This study seeks to examine the effects of High-Intensity Interval Training (HIIT) on cognitive and physical skills in basketball and soccer players. A 3-week HIIT protocol was incorporated based on the Wingate technique. This study included 10 soccer players and 10 basketball players with an average age of 22.79 ± 1.90 years. Participants performed pre- and post-intervention assessments. Physical proficiency was assessed using 20 m sprint, change-of-direction (COD) and dribbling tests, while cognitive skills were assessed using motion object tracking (MOT), working memory, perceptual load (PL), and attention window (AW) tests. The HIIT intervention significantly improved cognitive performance in particular; noteworthy observations were a 15% improvement in motion object tracking test scores and a 16% increase in working memory test scores for basketball players. The attention window test scores showed a 32% increase, and perceptual load test scores were 31% decreased for soccer players post-intervention. There were significant improvements in physical skills; for example, sprint times were decreased by 6%, and change-of-direction and dribbling times were reduced by 8% and 7%, respectively, indicating improved agility, speed, and ball control abilities. In conclusion, both groups performed significantly better on cognitive and physical skill tests post-HIIT intervention.

Effects of different training models and subsequent exercise cessation on adipose tissue and associated variables

BACKGROUND

The General Adaptation Syndrome and the supercompensation Model are concepts widely applied in exercise science. Considering that fat is essential for tissue and the main energy source during continuous moderate-intensity exercise (MICE), the hypothesis arises that this type of effort may pay off after a detraining period.

OBJECTIVE

This study aimed to investigate how different exercise models, followed by a period of detraining, affected adipose tissue cellularity in adult rats. Two specific models were examined: moderate-intensity continuous exercise (MICE) and high-intensity intermittent exercise (HIIT).

MATERIALS AND METHODS

This is an experimental study in which rats were allocated into three groups: i) Continuous moderate-intensity exercise (MICE); ii) High-intensity intermittent exercise (HIIT); and iii) Control group (GC). Data were collected in three moments, namely: baseline values (T1), after which the animals exercised on a treadmill for eight weeks (T2) and then were followed up for four weeks after interruption of physical exercise (T3). For statistical analysis, a two-way analysis of variance (ANOVA) was performed, with Tukey's post-hoc for the group (GC, MICE, or HIIT) and Bonferroni's for the moment (T1, T2 and T3).

RESULTS

Regarding the periepididymal mass, GC showed an increase of 45% in T3 compared to T2. The HIIT and MICE groups had lower T3 values when compared to the CG. Comparing groups relative to the delta variation between T2 and T3 showed a difference in periepididymal mass (p = 0.012), with HIIT showing lower values than CG (p = 0.009). Analysis of the number of periepididymal adipocytes showed that HIIT (p < 0.001) and GC (p = 0.003) captured smaller numbers of cells than MICE.

CONCLUSION

In conclusion, our findings demonstrated positive effects of both interventions (HIIT and MICE) in the control of periepididymal adipose tissue mass of adult rats after 4 weeks of exercise interruption, with less mass gain in HIIT. More adipocytes were observed in MICE compared to HIIT and GC. These results suggest that both exercise models helped control fat accumulation, even after detraining.

The PAD-adapted 30-20-10 during Nordic walking: A new exercise training session in patients with symptomatic peripheral artery disease

This study aimed to investigate the feasibility of a peripheral artery disease (PAD)-adapted 30-20-10 Nordic walking session in patients with symptomatic PAD and to compare the cardiovascular response of this new training session to a traditional walking (TW) and 4 × 4 minutes Nordic walking session. This is a prospective observational study. Patients with Fontaine stage II PAD were included. Patients participated in Nordic walking sessions, which were randomly assigned as TW, 4 × 4 minute intervals, and peripheral artery disease adapted 30-20-10 exercise session (PAD-adapted 30-20-10 sessions). PAD-adapted 30-20-10 and 4 × 4 minutes sessions consisted of 4 repetitions of 4 minutes of effort followed by 3 minutes of passive recovery. PAD-adapted 30-20-10 session was characterized by 4 continuous 1-min repetitions at 3 different walking speeds [high (30 seconds), moderate (20 seconds) and low (10 seconds)]. During the 4 × 4 minutes session, patients were asked to cover the maximal distance at a constant speed. During TW session, patients were asked to walk at a speed inducing moderate-to-severe claudication pain. Heart rate, rating of perceived exertion (RPE) and claudication pain intensity using a visual analog scale were assessed. The perceived enjoyment of each session was assessed using a visual analog scale ranging from 0 (not enjoyable) to 10 (very enjoyable). Eleven patients with chronic symptomatic PAD were included (62 ± 13 years; 54% women). The mean heart rate during the time of effort was significantly higher in PAD-adapted 30-20-10 group than in 4 × 4 minutes and TW groups (127 ± 12, 122 ± 12, 114 ± 11 bpm, respectively; P ≤ .001). The mean rating of perceived exertion (16 ± 1, 15 ± 1, 13 ± 1; P ≤ .001) and claudication pain intensity (8 ± 1, 7 ± 1; 7 ± 1 mm; P ≤ .019) were significantly higher during PAD-adapted 30-20-10 sessions than during 4 × 4 minutes and TW sessions. The perceived enjoyment was similar among sessions (8.7 ± 1.6 for TW, 8.6 ± 1.7 for 4 × 4 minutes, and 8.8 ± 1.8 mm for PAD-adapted 30-20-10 sessions; P = .935). The PAD-adapted 30-20-10 session is feasible and induces higher cardiovascular stimulation and claudication pain than 4 × 4 minutes and TW procedures in patients with symptomatic PAD. Despite these different responses, a similar perceived enjoyment among the sessions has been shown. Future investigations are needed to examine the effects of this new training session in these patients.

A training goal-oriented categorization model of high-intensity interval training

There are various categorization models of high-intensity interval training (HIIT) in the literature that need to be more consistent in definition, terminology, and concept completeness. In this review, we present a training goal-oriented categorization model of HIIT, aiming to find the best possible consensus among the various defined types of HIIT. This categorization concludes with six different types of HIIT derived from the literature, based on the interaction of interval duration, interval intensity and interval:recovery ratio. We discuss the science behind the defined types of HIIT and shed light on the possible effects of the various types of HIIT on aerobic, anaerobic, and neuromuscular systems and possible transfer effects into competition performance. We highlight various research gaps, discrepancies in findings and not yet proved know-how based on a lack of randomized controlled training studies, especially in well-trained to elite athlete cohorts. Our HIIT "toolbox" approach is designed to guide goal-oriented training. It is intended to lay the groundwork for future systematic reviews and serves as foundation for meta-analyses.

Effects of combining a high-intensity interval training programme with a standard programme on mobility and function in lower limb amputees

High-energy expenditure during walking is one of the most important limiting factors for lower limb amputees. Although several physical training methods have been proposed to reduce energy expenditure, little is known about the effects of high-intensity interval training in lower limb amputees. This study aimed to test the effects of a 6-week high-intensity interval training protocol in subjects with lower limb amputation on walking distance, physiological cost of walking, and functional mobility. A quasi-experimental pre and post-study included 13 subjects with lower limb amputation. They performed 12 sessions of a high-intensity interval training protocol with a frequency of 2 days/week for 6 weeks. Walking distance, physiological cost of walking, and functional mobility before and after the training protocol were assessed. Walking distance increased from 204.48 to 229.09 m (P = 0.003), physiological cost of walking decreased from 0.66 to 0.31 beats/m (P = 0.001), and functional mobility improved from 30.38 to 33.61 points (P = 0.001). High-intensity interval training improved walking distance, physiological cost of walking, and functional mobility in subjects with lower limb amputation.

A Comparative Analysis of Acute Physiological and Perceptual Responses in Whole-Body and Ergometer-Based High-Intensity Interval Training Protocols

The primary aim of the present investigation was to compare the acute physiological and perceptual responses between two modes of interval training using a randomized crossover design. More specifically, eleven young adult participants (23 ± 4 years, 77 ± 13 kg, 178 ± 7 cm) performed two protocols: one composed of whole-body calisthenics exercises and another on a cycle ergometer. Both protocols encompassed eight 20 s bouts at intensities equivalent to all-out (HIIT-WB) and 170% of the maximal power output (HIIT-C), respectively, interspersed with 10 s of passive rest. The peak and average heart rate, the rating of perceived effort, and blood lactate, creatine kinase, and lactate dehydrogenase concentrations were measured. Aside from blood lactate (HIIT-WB = 9.4 ± 1.8 mmo/L; HIIT-C = 12.5 ± 2.5 mmol/L, p < 0.05) and the rating of perceived exertion (HIIT-WB = 8.8 ± 0.9; HIIT-C = 9.6 ± 0.5, p < 0.05), physiological responses did not significantly differ between protocols (all p > 0.05), with high average heart rate values (HIIT-WB = 86 ± 6% HRmax; HIIT-C = 87 ± 4% HRmax) and a low magnitude of muscle damage, as inferred by CK and LDH concentrations (HIIT-WB = 205.9 ± 56.3 and 203.5 ± 72.4 U/L; HIIT-C = 234.5 ± 77.1 and 155.1 ± 65.3 U/L), respectively. It can be concluded that both protocols elicit vigorous heart rate responses and a low magnitude of muscle damage and, therefore, appear as viable alternatives to improve aerobic fitness. The inclusion of a whole-body HIIT protocol may be an interesting alternative for training prescription in relation to more common interval training protocols.

Impact of supra-maximal interval training vs. high-intensity interval training on cardiac auto-regulation response in physically active adults

PURPOSE

This study aimed to examine the impact of supra-maximal interval training (SMIT) and high-intensity interval training (HIIT) on cardiac auto-regulation response.

METHODS

Physically active young adults volunteered to participate in the study with a randomized cross-over counterbalanced design (N = 12). HIIT sessions consisted of 20 bouts of 10 s of exercise followed by 50 s of recovery, totaling 20 min at two different intensities; "all-out (SMIT)" vs. "115-130% Wmax (HIIT)". The cardiac auto-regulation included heart rate variability (HRV) and vascular function. HRV and vascular function were measured at baseline and five different time points after acute exercise.

RESULTS

The SMIT was higher in workload (31%), peak heart rate (28%), and rate of perceived exertion (40%) compared with HIIT (all p < 0.001). The R-R interval, NN50, and pNN50 measured until 60 min after acute exercise was higher in the HIIT compared with SMIT (all p < 0.05). The SMIT elicited a greater shift in ln LF/HF ratio immediately after acute exercise (3802%, p < 0.01) and induced a decrease in bilateral ba-PWV at the time point 5 min after acute exercise, persisting until 65 min after (p < 0.05). Yet, HIIT showed no change over time in the frequency domain of HRV and blood vascular tone after cessation of acute exercise.

CONCLUSION

Our findings confirmed that SMIT is a more potent modulator of the autonomic nervous system compared with HIIT. Further study is needed to monitor through complete recovery to baseline, to understand acute cardiac auto-regulation response after cessation of various exercise intensities identical interval training protocol.

Optimal Prescription for Superior Outcomes: A Comparative Analysis of Inter-Individual Variability in Adaptations to Small-Sided Games and Short Sprint Interval Training in Young Basketball Players

This study compared the inter-individual variability in adaptive responses to six weeks of small-sided games (SSG) and short sprint interval training (sSIT) in young basketball players. Thirty well-trained young athletes (age: 16.4 ± 0.6 years; stature: 190 ± 8.4 cm; weight: 84.1 ± 8.2 kg) voluntarily participated and were randomly assigned to SSG (3 sets of 5 min 3v3 on full length (28 m) and half-width (7.5 m) court, with 2 minutes of passive recovery in-between), sSIT (3 sets of 12 × 5 s sprinting with 20 s recovery between efforts and 2 min of rest between sets), or CON (routine basketball-specific technical and tactical drills) groups, each of ten. Before and after the training period, participants underwent a series of laboratory- and field-based measurements to evaluate their maximum oxygen uptake (V̇O2max), first and second ventilatory threshold (VT1 and VT2), oxygen pulse, peak and average power output (PPO and APO), linear speed, change of direction (COD), countermovement jump (CMJ), and vertical jump (VJ). Both SSG and sSIT sufficiently stimulated adaptive mechanisms involved in enhancement of the mentioned variables (p < 0.05). However, sSIT resulted in lower residuals in percent changes in V̇O2max (p = 0.02), O2pulse (p = 0.005), VT1 (p = 0.001), PPO (p = 0.03), and linear speed (p = 0.01) across athletes compared to the SSG. Moreover, sSIT resulted in more responders than SSG in V̇O2max (p = 0.02, φ = 0.500), O2pulse (p = 0.003, φ = 0.655), VT1 (p = 0.003, φ = 0.655), VT2 (p = 0.05, φ = 0.436), and linear speed (p = 0.05, φ = 0.420). Our results indicate that sSIT creates a more consistent level of mechanical and physiological stimulus than SSG, potentially leading to more similar adaptations across team members.

Small-Sided Soccer Games Promote Greater Adaptations on Vertical Jump and Change-of-Direction Deficit and Similar Adaptations in Aerobic Capacity than High-Intensity Interval Training in Females

The objective of this study was to compare the effectiveness of both small-sided games (SSG) and short interval running-based high-intensity interval training (HIIT) programs over an 8-week period in fostering adaptations in aerobic capacity, change-of-direction abilities, and jumping performances of youth female soccer players. The study involved 48 female youth participants under the age of 19, competing at the regional level, who took part in a randomized controlled trial. Participants were assigned to either the SSG group, the HIIT group, or a control group, which involved regular in-field sessions. Assessments were conducted at baseline and after the 8-week training intervention, measuring aerobic capacity using the 30-15 intermittent fitness test (VIFT), change of direction (COD) using the 5-0-5 test, and jumping performance using the countermovement jump test (CMJ). Time 5 group analysis revealed significant interactions in CMJ (p = 0.005; ηp2= 0.213) and VIFT (p < 0.001; ηp2 = 0.433), although no significant interaction were found in COD deficit (p = 0.246; ηp2 = 0.060). Within-group analysis revealed that SSG significantly improved CMJ (p < 0.001), COD deficit (p < 0.001), and VIFT (p < 0.001). HIIT group also significantly improved CMJ (p = 0.029), COD deficit (p = 0.001), and VIFT (p < 0.001). As conclusion, the study revealed that SSG promoted significantly improvements in VIFT, CMJ and COD deficit, being significantly better than control group, while HIIT was only significantly better than control in VIFT. SSG revealed to be effective approach for favoring key physical attributes of female soccer players, being an interesting and recommended training approach to increase the ecology of the training practice, while favoring physical positive adaptations.

Effects of Sprint Interval Training Surface on Physical Fitness Attributes of Collegiate Female Soccer Players: Identifying Individual Responses to Training on Grass, Sand, and Land Surfaces

This study aimed to identify the optimal surface for sprint interval training to maximize transfer effects on physical performance measures on the grass pitch. Using a randomized controlled trial design, 40 collegiate female soccer players were equally assigned to three experimental groups performing short sprint interval training (SSIT: 4 sets of 10 repetitions with 5 seconds all-out running, with a 50-second recovery period between each effort and a 3-minute rest interval between sets) on SAND, GRASS, LAND, and a control group. Before and after a 7-week training period, participants underwent a series of field-based tests to evaluate countermovement jump (CMJ), 20-m linear sprint, Illinois change of direction (CoD) speed, Yo-Yo IR1, 2.4 km time trial, and maximal kicking distance (MKD) performance. A two-way analysis of variance with repeated measures was conducted on the data, along with Bonferroni post hoc testing. After the intervention, the control group did not show any changes, while the SAND, GRASS and LAND training groups demonstrated improvements (p = 0.001) in their performance as follows: CMJ (effect size [ES] = 1.21, 0.97, 0.64), 20-m linear sprint (ES = -0.81, -0.55, -0.41), Illinois CoD (ES = -0.72, -0.79, -0.41), Yo-Yo IR1 (ES = 1.86, 1.19, 1.12), 2.4 km time trail (ES = -0.82, -0.62, -0.49), and MKD (ES = 0.60, 0.90, 0.72), respectively. Comparative analysis of SAND, GRASS, and LAND revealed that performing SSIT on SAND results in a significantly greater gain in CMJ than LAND (p = 0.041). Analyzing individual responses to training interventions indicated that the training surface had a favorable influence on CMJ (SAND vs. LAND, p = 0.009), but on other variables no statistically significant (p > 0.05) differences were observed. Considering these findings, it is advised that strength and conditioning coaches use the SAND surface as the initial choice for SSIT sessions regarding greater gains (i.e., ES) in performance. This recommendation aims to facilitate more favorable transfer in physical fitness adaptation on a soccer grass pitch. In case of unavailability of SAND surface, GRASS surface would be a suitable alternative to enhance the physical fitness of collegiate female soccer players.

Jumping Interval Training: An Effective Training Method for Enhancing Anaerobic, Aerobic, and Jumping Performances in Aerobic Gymnastics

The aim of this study was to compare the effects of jumping interval training (JIT) and running high-intensity interval training (HIIT) on the aerobic, anaerobic and jumping performances of youth female aerobic gymnasts. A randomized controlled study was conducted over an 8-week period, involving 73 youth female athletes (16.2 ± 1.3 years old) of aerobic gymnastics. The study comprised two experimental groups (JIT and HIIT) and a control group. Participants in the experimental groups engaged in two additional training sessions per week alongside their regular training regimen, while the control group followed their usual training routine. Before and after the intervention period, gymnasts were assessed for their performance in the countermovement jump test (CMJ), the specific aerobic gymnastics anaerobic test (SAGAT) and the 20-m multistage fitness test. Significant interactions time × group were found in SAGAT (p < 0.001; = 0.495), CMJ (p < 0.001; = 0.338) and 20-m multistage fitness test (p < 0.001; = 0.500). The time × group analysis post-intervention revealed significantly lower scores in SAGAT for the control group compared to the JIT (p = 0.003) and HIIT (p = 0.034). Additionally, significantly higher scores were observed for the JIT group in the CMJ test compared to the HIIT (p = 0.020) and control (p = 0.028) groups following the intervention. Finally, the 20 m multistage fitness test post-intervention revealed significantly lower scores for the control group compared to JIT (p < 0.001) and HIIT (p < 0.001). Both JIT and HIIT are recommended training strategies to adopt in aerobic gymnastics for significantly improving the aerobic and anaerobic performances of athletes. However, JIT may be particularly relevant to use as it offers additional benefits in improving vertical jumping performances.

Optimizing Short Sprint Interval Training for Young Soccer Players: Unveiling Optimal Rest Distributions to Maximize Physiological Adaptations

Present study aimed to compare the effects of SSIT intervention with varying rest distributions on hormonal, physiological, and performance adaptations in soccer players. Thirty-six players were randomly divided into three SSIT groups, each performing 4 sets of 6-10 repetitions of 6-second all-out running with rest intervals at ratios of 1:3, 1:6, and 1:9. Prior to and following the 7-week training period, aerobic fitness indices and anaerobic power were evaluated using a graded exercise test with a gas collection system and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring vertical jump, 20-m sprint, and T-test change of direction speed, Yo-Yo IR1 and maximal kicking distance. Hormonal status was also monitored by evaluating testosterone and cortisol levels. Following the 7-week training period, all SSIT interventions resulted in significant enhancements (p < 0.05) in soccer-related performance, physiological parameters, and hormonal adaptations, exhibiting effect sizes that ranged from small to large. Comparative analysis indicated that the 1:9 SSIT results in greater adaptive responses (p < 0.05) in the vertical jump, peak power, testosterone, and cortisol compared to the 1:3 SSIT group. By contrast, the 1:3 SSIT group induced more adaptive responses (p < 0.05) in the mean power output, maximum oxygen consumption (V̇O2max), and Yo-Yo IR1 compared to the 1:9 SSIT group. Hence, for enhancing physical performance, especially vertical jump height, anaerobic peak power, and hormonal adaptations, the 1:9 SSIT ratio is preferable. Conversely, shorter rest intervals (specifically, the 1:3 SSIT ratio) are better suited for eliciting heightened adaptive responses in mean power output, V̇O2max, and Yo-Yo IR1 over the 7-week training period among young male soccer players.

Sex Influences the Extent of Physical Performance Adaptations in Response to Small-Sided Games and Running-Based High-Intensity Interval Training: A Parallel Study Design Involving Men and Women Soccer Players

The aim of this study was two-fold: (i) to compare physical fitness adaptations following small-sided games (SSG) and running-based high-intensity interval training (HIIT), considering sex interactions; and (ii) to describe intra-individual variations of adaptations in both men and women developmental/trained soccer players over an 8-week randomized parallel study design involving 25 women and 27 men. Pre and post-intervention assessments included countermovement jump (CMJ), 10-meter linear sprint test, change-of-direction (COD) deficit, and final velocity at 30-15 Intermittent Fitness Test (VIFT). Significant interactions between time, groups and sex were found in 10-m sprint (F1,48 = 6.042; p = 0.018; ηp2 = 0.112). No significant interactions between time, groups and sex were found in CMJ (F F1,48 = 0.609; p = 0.439; ηp2 = 0.013), COD deficit (F F1,48 = 2.718; p = 0.106; ηp2 = 0.054) and VIFT (F F1,48 = 1.141; p = 0.291; ηp2 = 0.023). Significant interactions were found between time and sex in CMJ (F F1,48 = 29.342; p < 0.001; ηp2= 0.379), 10-m sprint (F F1,48 = 4.359; p = 0.042; ηp2 = 0.083), COD deficit (F F1,48 = 5.066; p = 0.029; ηp2= 0.095) and VIFT (F F1,48 = 11.248; p = 0.002; ηp2 = 0.190). In conclusion, this study suggests similar effects of HIIT in both sexes. However, for women, SSG may entail less efficacy and more inter-individual variability compared to men. Therefore, HIIT could potentially be a better solution for women, whereas both training approaches were equally effective in men.

The Analysis of Physical Performance During Official Competitions in Professional English Football: Do Positions, Game Locations, and Results Influence Players' Game Demands?

ABSTRACT

Beato, M, Youngs, A, and Costin, AJ. The analysis of physical performance during official competitions in professional English football: Do positions, game locations, and results influence players' game demands? J Strength Cond Res 38(5): e226-e234, 2024-This study aimed, first, to verify if physical parameters were different between players' positions during official matches in English professional football, and second, if the game location (H and A) or results (W, L, D) affected players' physical performance. Twenty-five male professional football players of the same team were included in this data analysis (age = 27 ± 9 years) during the 2022-23 season. Players were divided into positions: center backs, wide backs, center midfielders, attacking midfielders, and strikers. The external load parameters were distance covered, high-speed running (HSR), sprinting distance, accelerations, decelerations, and high metabolic load distance (HMLD, meters > 25.5 w·kg -1 ) that were monitored using global navigation satellite systems Apex (STATSports). Linear mixed models' analysis for positions reported a significant difference in total distance ( p = 0.011), HSR ( p < 0.001), sprinting distance ( p < 0.001), accelerations ( p = 0.003), decelerations ( p = 0.002), and HMLD ( p < 0.001). Centre backs showed the lowest physical performance in the metrics analyzed, whereas players in the other positions frequently displayed a similar physical performance. Regarding locations and results, differences were only found between locations for decelerations ( p = 0.041) and between results for HMLD ( p = 0.010). In conclusion, physical performance was influenced by players' positions, whereas game location or results seem to not affect physical performance during official competitions. Consequently, practitioners can physically prepare their players independently from the location of the match or of the possible game results, whereas specific positional training is requested to optimally prepare their players.

Repeated sprint training in hypoxia induces specific skeletal muscle adaptations through S100A protein signaling

Athletes increasingly engage in repeated sprint training consisting in repeated short all-out efforts interspersed by short recoveries. When performed in hypoxia (RSH), it may lead to greater training effects than in normoxia (RSN); however, the underlying molecular mechanisms remain unclear. This study aimed at elucidating the effects of RSH on skeletal muscle metabolic adaptations as compared to RSN. Sixteen healthy young men performed nine repeated sprint training sessions in either normoxia (FIO2 = 0.209, RSN, n = 7) or normobaric hypoxia (FIO2 = 0.136, RSH, n = 9). Before and after the training period, exercise performance was assessed by using repeated sprint ability (RSA) and Wingate tests. Vastus lateralis muscle biopsies were performed to investigate muscle metabolic adaptations using proteomics combined with western blot analysis. Similar improvements were observed in RSA and Wingate tests in both RSN and RSH groups. At the muscle level, RSN and RSH reduced oxidative phosphorylation protein content but triggered an increase in mitochondrial biogenesis proteins. Proteomics showed an increase in several S100A family proteins in the RSH group, among which S100A13 most strongly. We confirmed a significant increase in S100A13 protein by western blot in RSH, which was associated with increased Akt phosphorylation and its downstream targets regulating protein synthesis. Altogether our data indicate that RSH may activate an S100A/Akt pathway to trigger specific adaptations as compared to RSN.

Eight weeks of high-intensity interval vs. sprint interval training effects on overweight and obese adolescents carried out during the cool-down period of physical education classes: randomized controlled trial

Objective

The aim of this study was to evaluate the effect of sprint interval training (SIT) and [high intensive interval training (HIIT)] carried out during the cool-down period of the physical education classes on body composition, blood pressure variables (BP) and pulse rate (PR), and cardiorespiratory fitness of adolescents who are overweight and obese, and to compare the differences in enjoyment in response to SIT vs. HIIT.

Methods

For this randomized controlled trial, forty-five adolescents were recruited from a high school and were randomly placed into three groups. SIT and HIIT trained for 8 weeks, twice a week, for 12 min/session. Experimental group (EG) 3 was the control, and they maintained their regular physical education class schedule. The SIT group performed 6 sets of 60 s of work (90-95%HRmax) / 60 s of rest (50-55%HRmax), and the HIIT group performed 3 sets of 2 min of work (80-85%HRmax) / 2 min of rest (50-55%HRmax).

Results

Both experimental groups showed a significant improvement in fat mass (FM) (%) and trunk FM (kg). In addition, EG2 reported a significance improvement in lean mass (kg), blood pressure BP (mmHG), systolic blood pressure (SBP) (mmHg), diastolic blood pressure (DBP) (mmHg), PR (bpm), and VO2max (ml/kg/min).

Conclusion

The present study found that a HIIT protocol performed during the cool-down period of the physical education classes generated adaptations such as improvement in body composition, BP variables and PR, and cardiorespiratory fitness, in overweight and obese adolescents. In contrast, the group of overweight and obese adolescents who performed SIT showed limited benefits, with changes in fat mass only.

Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial

Purpose: Molecular hydrogen has been shown to possess antioxidant, anti-inflammatory, ergogenic, and recovery-enhancing effects. This study aimed to assess the effect of molecular hydrogen administration on muscle performance, damage, and perception of soreness up to 24 h of recovery after two strenuous training sessions performed on the same day in elite fin swimmers. Methods: Eight females (mean ± SD; age 21.5 ± 5.0 years, maximal oxygen consumption 45.0 ± 2.5 mL.kg-1.min-1) and four males (age 18.9 ± 1.3 years, maximal oxygen consumption 52.2 ± 1.7 mL.kg-1.min-1) performed 12 × 50 m sprints in the morning session and a 400 m competitive performance in the afternoon session. Participants consumed hydrogen-rich water (HRW) or placebo 3 days before the sessions (1,260 mL/day) and 2,520 mL on the experimental day. Muscle performance (countermovement jump), muscle damage (creatine kinase), and muscle soreness (100 mm visual analogue scale) were measured during the experimental day and at 12 and 24 h after the afternoon session. Results: HRW compared to placebo reduced blood activity of creatine kinase (156 ± 63 vs. 190 ± 64 U.L-1, p = 0.043), muscle soreness perception (34 ± 12 vs. 42 ± 12 mm, p = 0.045), and improved countermovement jump height (30.7 ± 5.5 cm vs. 29.8 ± 5.8 cm, p = 0.014) at 12 h after the afternoon session. Conclusion: Four days of HRW supplementation is a promising hydration strategy for promoting muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers. Clinical Trial Registration: clinicaltrials.gov, identifier NCT05799911.

Effect of sprint interval training load on maximal oxygen uptake in trained men

BACKGROUND

Sprint interval training (SIT) improves maximal aerobic and anaerobic performance, including oxygen uptake (VO2max), power output, and sprint performance. This study aimed to investigate the effect of SIT load on V̇O2max in trained subjects.

METHODS

SIT was performed twice a week for three weeks by twenty-four trained men (aged: 20.7±2.7, V̇O2max 43.6±6.5) and consisted of seven bouts of 10-s cycling sprints followed by a 4-min rest. Subjects were divided into two groups depending on the relative resistance of the load compared to their body mass (BM): 7.5% (S7.5) and 10% (S10). We measured the peak power, mean power, and peak cadence in SIT during the first and final sessions. V̇O2max, maximum aerobic power (MAP), heart rate, and lactate (La) concentration were measured before and after SIT using incremental tests.

RESULTS

After 3 weeks of SIT, V̇O2max, MAP, and La improved significantly in both S7.5 and S10 groups. In addition, changes in V̇O2max in S10 were higher than those in S7.5 (2.2±11.2% vs. 9.23±9.57%, P=0.029, adjusted by pre V̇O2max). MAP measurements showed the same results (2.2±11.3% vs. 8.3±10.0%, P=0.015, adjusted by pre-MAP). However, there was no significant interaction between time and group. A significant increase in peak cadence from first session to sixth sessions was observed in S7.5 (P=0.01, ES = 0.93, 95% confidence interval [CI]: 0.02-1.78) but not in S10 (P=0.132, ES = 0.22, 95% [CI]: -0.59-1.01).

CONCLUSIONS

Our results suggest that 3 weeks of SIT improves endurance performance in trained subjects. It seems that SIT at 10% load may tend to be more effective.

Individualizing Basketball-Specific Interval Training Using Anaerobic Speed Reserve: Effects on Physiological and Hormonal Adaptations

PURPOSE

We compared the adaptive responses to supramaximal high-intensity interval training (HIIT) individualized according to anaerobic speed reserve (ASR), the 30-15 Intermittent Fitness Test (VIFT), and velocity associated with maximum oxygen uptake (MAS) to determine which approach facilitates more identical adaptations across athletes with different profiles.

METHODS

Thirty national-level basketball players (age = 28.4 [5] y; body mass = 88.9 [6.3] kg; height = 190 [4.8] cm) were randomly assigned to 3 training groups performing 2 sets of 4, 6, 8, 6, 8, and 10-minute runs (from first to sixth week, respectively), consisting of 15-second running at Δ%20ASR (MAS + 0.2 × ASR), 95%VIFT, and 120%MAS, with 15 seconds recovery between efforts and a 3-minute relief between sets.

RESULTS

All 3 interval interventions significantly (P < .05) enhanced maximum oxygen uptake (V˙O2max), oxygen pulse (V˙O2/HR), first and second ventilatory threshold (VT1 and VT2), cardiac output (Q˙max), stroke volume, peak and average power output, testosterone levels, and testosterone-to-cortisol ratio following the training period. Different values of interindividual variability (coefficient of variation) for the percentage changes of the measured variables were observed in response to HIITASR, HIITvIFT, and HIITMAS for V˙O2max (8.7%, 18.8%, 34.6%, respectively), V˙O2/HR (9.5%, 15.0%, 28.6%), VT1 (9.6%, 19.6%, 34.6%), VT2 (21.8%, 32.4%, 56.7%), Q˙max (8.2%, 16.9%, 28.8%), stroke volume (7.9%, 15.2%, 23.5%), peak power output (20%, 22%, 37.3%), average power output (21.1%, 21.3%, 32.5%), testosterone (52.9%, 61.6%, 59.9%), and testosterone-to-cortisol ratio (55.1%, 59.5%, 57.8%).

CONCLUSIONS

Supramaximal HIIT performed at Δ%20ASR resulted in more uniform physiological adaptations than HIIT interventions prescribed using VIFT or MAS. Although hormonal changes do not follow this approach, all the approaches induced an anabolic effect.

Effects of intermittent pneumatic compression on the recovery of cardiovascular parameters after repeated sprint exercise

PURPOSE

Intermittent pneumatic compression (IPC) applies gradual pressure to facilitate lymph and blood flow movement to reduce exercise-induced tissue fluid accumulation and plasma volume loss. This study aimed to evaluate the cardiovascular system response during the recovery with IPC compared with passive recovery (Sham).

METHODS

Sixteen volunteers (7 females and 9 males) executed a cycling-based exhausting sprint interval exercise (8 × 20 s all out), followed by a 30-min IPC or Sham condition. Participants performed two trials in a randomised, counterbalanced, and crossover design. Several cardiovascular parameters (blood pressure, heart function, and peripheral vascular resistance) were recorded at baseline (5'), through the recovery protocol (30'), and afterwards (5').

RESULTS

The use of IPC during the recovery phase led to a faster recovery, stated in relative values to pre-exercise, in mean blood pressure (102.5 ± 19.3% vs. 92.7 ± 12.5%; P < 0.001), and cardiac output (139.8 ± 30.0% vs. 146.2 ± 40.2%; P < 0.05) in comparison to Sham condition. Furthermore, during the IPC-based recovery, there was a slower recovery in cardiac pressure change over time (92.5 ± 25.8% vs. 100.5 ± 48.9%; P < 0.05), and a faster return to pre-exercise values in the peripheral vascular resistance (75.2 ± 25.5% vs. 64.8 ± 17.4%; P < 0.001) compared to Sham.

CONCLUSION

The application of IPC after high-intensity exercise promotes the recovery of the cardiovascular system, reducing cardiovascular strain. Future investigations should consider the effects on the sympathetic-parasympathetic balance, such as heart rate variability, to assess further bonds between the use of IPC and autonomous control.

A comparison of three different work to rest periods during intermittent sprint training on maintaining sprint effort performance

Background/objectives

Team sports are characterised by repeated maximal intensity bursts of activity, requiring significant energy contribution from the phosphagen pathways. The objective of this study was to evaluate the impact of different rest periods on repeated maximal intensity efforts.

Methods

The effect of three different recovery periods (60 s, 90 s and 120 s) during a 10 × six-seconds intermittent sprint training protocol performed on a cycle ergometer was investigated. Thirteen part-time female athletes from two sports, Rugby Sevens and Netball competing for their state participated in the study. Peak Power (PPO), Mean Power (MPO), "total work" in the form of calorie expenditure, performance decrement, repetitions over 95% PPO, blood lactate, and RPE were recorded.

Results

There was a significant effect of condition on MPO and calorie expenditure (p < 0.050). MPO was significantly lower for 60 s compared to 90 s (710.4 vs 734.4 W, ES = 0.27-0.42) and 120 s (710.4 vs 743.3 W, ES = 0.36-0.47). Calorie expenditure was significantly lower for 60 s compared to 90 s (4.41 vs 4.56 cal, ES = 0.25-0.46) and 120 s (4.41 vs 4.59 cal, ES = 0.40-0.48). There was a significant effect of time (60 s 11.7, 90 s 11.1.120 s 10.9 mmol/L, p < 0.010) but not condition (p = 0.617) for blood lactate accumulation, and a significant difference in session RPE between 60 and both 90 s and 120 s (60 s 15.5, 90 s 14.2. p = 0.034 120 s 13.9, p = 0.039).

Conclusion

Shorter recovery durations resulted in decreased mean power and calorie expenditure, but higher RPE when compared to longer recovery periods. All three recovery periods may have fallen between the fast and slow phases of PCr resynthesis of approximately 20 and 180 s resulting in partial but not complete recovery. Total training time should be a consideration when determining what protocol to implement.

The impact of sprint interval training versus moderate intensity continuous training on blood pressure and cardiorespiratory health in adults: a systematic review and meta-analysis

Background

Although aerobic exercise is the primary modality recommended for the treatment of hypertension, it remains unclear whether high-intensity all-out sprint interval training (SIT) can result in greater reductions of blood pressure (BP) and cardiorespiratory health. This systematic review aims to compare the impact of SIT versus Moderate-intensity continuous training (MICT) on improvements in resting systolic blood pressure (SBP), diastolic blood pressure (DBP) and maximal oxygen uptake (VO2 max) among adults.

Methods

We conducted a systematic search of three online databases (PubMed, Embase, and Web of Science) from January 2000 to July 2023 to identify randomized controlled trials that compared the chronic effects of SIT versus MICT on BP in participants with high or normal blood pressure. We extracted information on participant characteristics, exercise protocols, BP outcomes, and intervention settings. Furthermore, the changes in VO2 max between the two groups were analyzed using a meta-analysis. The pooled results were presented as weighted means with 95% confidence intervals (CI).

Results

Out of the 1,874 studies initially were found, eight were included in this review, totaling 169 participants. A significant decrease in SBP (MD = -2.82 mmHg, 95% CI [-4.53 to -1.10], p = 0.08, I2 =45%) was observed in the SIT group compared to before the training, but no significant decrease in DBP (MD = -0.75 mmHg, 95% CI [-1.92 to 0.42], p = 0.16, I2 = 33%) was observed. In contrast, both SBP (MD = -3.00 mmHg, 95% CI [-5.31 to -0.69], p = 0.68, I2 = 0%) and DBP (MD = -2.11 mmHg, 95% CI [-3.63 to -0.60], p = 0.72, I2 = 0%) significantly decreased in the MICT group with low heterogeneity. No significant difference was found in resting SBP and DBP between SIT and MICT after the intervention. Both SIT and MICT significantly increased VO2 peak, with SIT resulting in a mean difference (MD) of 1.75 mL/kg/min (95% CI [0.39-3.10], p = 0.02, I2 = 61%), and MICT resulting in a mean difference of 3.10 mL/kg/min (95% CI [1.03-5.18], p = 0.007, I2 = 69%). MICT was more effective in improving VO2 peak (MD = -1.36 mL/kg/min, 95% CI [-2.31 to 0.40], p = 0.56, I2 = 0%). Subgroup analysis of duration and single sprint time showed that SIT was more effective in reducing SBP when the duration was ≥8 weeks or when the sprint time was <30 s.

Conclusion

Our meta-analysis showed that SIT is an effective intervention in reducing BP and improving cardiorespiratory fitness among adults. Consequently, SIT can be used in combination with traditional MICT to increase the variety, utility, and time efficiency of exercise prescriptions for different populations.

Metabolic, cognitive and neuromuscular responses to different multidirectional agility-like sprint protocols in elite female soccer players - a randomised crossover study

PURPOSE

Resistance to fatigue is a key factor in injury prevention that needs to be considered in return-to-sport (RTS) scenarios, especially after severe knee ligament injuries. Fatigue should be induced under game-like conditions. The SpeedCourt (SC) is a movement platform for assessing multidirectional sprint performance, typical of game-sports, due to change-of-direction movements in response to a visual stimulus. Designing adequate fatigue protocols requires the suitable arrangement of several loading variables such as number of intervals, sprint distance or work/relief ratio (W:R). Therefore, this study analysed the acute fatigue effects of different SC protocols on metabolic load, cognitive function and neuromuscular performance.

METHODS

Eighteen female soccer players (mean ± SD; age: 23.1 ± 4.6 years) of the 1st German Division participated in this randomised, crossover study. Using a random allocation sequence, players completed four volume-equated protocols differing in W:R and sprint distance per interval (P1:12 × 30 m, W:R = 1:2 s; P2:12 × 30 m, W:R = 1:3 s; P3:18 × 20 m, W:R = 1:2 s; P4:18 × 20 m, W:R = 1:3 s). Pre- and post-exercise, metabolic load was measured per blood lactate concentration (BLaC), cognitive function per reaction time (RT), and neuromuscular performance including multiple rebound jumps (MRJ height, primary outcome variable; Reactive Strength Index, RSI) and 5 m sprint times (SP5).

RESULTS

Repeated-measures ANOVA revealed significant main time effects (p < .05) with improved performance post-exercise in RT (504 vs. 482 ms, d = 1.95), MRJ height (24.0 vs. 24.8 cm, d = 0.77), RSI (1.39 vs. 1.43, d = 0.52), and SP5 (1.19 vs. 1.17 s, d = 0.56). There was significant main time (p < .001) and time x protocol interaction effects in BLaC (p < .001). P1 induced higher BLaC values (4.52 ± 1.83 mmol/L) compared to P2 (3.79 ± 1.83 mmol/L; d = 0.74) and P4 (3.12 ± 1.83 mmol/L; d = 1.06), whereas P3 (4.23 ± 1.69 mmol/L) elicited higher BLaC values compared to P4 (d = 0.74).

CONCLUSION

All protocols caused an improved cognitive function and neuromuscular performance. The former may be related to enhanced noradrenergic activation or exercise specificity which induced an improved stimulus processing. The latter may be explained by a possible post-activation performance enhancement effect on jump and sprint performance. A shorter relief duration in W:R as opposed to sprint distance per interval produced higher BLaC values. The protocols may serve as reference data for improved RTS decision-making in elite female soccer players.

TRIAL REGISTRATION

Deutsches Register Klinischer Studien (DRKS), No.: DRKS00033496 , Registered 19. Februar 2024, Retrospectively Registered.

Frontiers and hotspots of high-intensity interval exercise in children and adolescents: text mining and knowledge domain visualization

Background: During the past two decades, research on high-intensity interval exercise (HIIE) in children and adolescents has steadily accumulated, especially on the subthemes of improving cardiometabolic and cardiovascular health. However, there is still little scientific understanding of using scientometric analysis to establish knowledge maps. Exploring the relationship between known and new emerging ideas and their potential value has theoretical and practical implications in the context of a researcher's limited ability to read, analyze, and synthesize all published works. Objective: First, this study aims to provide extensive information on HIIE research in children and adolescents, including authors, institutions, countries, journals, and references. Second, the objective is to use co-occurrence, burst, and co-citation analyses based on hybrid node types to reveal hotspots and forecast frontiers for HIIE research in children and adolescents. Methods: Using the bibliographic data of the Web of Science Core Collection (WoSCC) as the data source, publications, authors, and journals were analyzed with the help of bibliometric methods and visualization tools such as CiteSpace, VOSviewer, Pajek, and Bibliometrix R package. Authorial, institutional, and national collaboration networks were plotted, along with research hotspots and research frontiers based on keyword bursts and document co-citations. Results: This study found that executive function, high-intensity interval training, heart rate variability, and insulin resistance are emerging research topics; high-intensity training, mental health, exercise intensity, and cardiometabolic risk factors are continual frontier research areas in the subthemes. Conclusion: Our study has three novel contributions. First, it explicitly and directly reflects the research history and current situation of the HIIE intervention strategy in children and adolescents. This approach makes it clear and easy to trace the origin and development of this strategy in specific groups of children and adolescents. Second, it analyzes the research hotspots of HIIE in the field and predicts the research frontiers and development trends, which will help researchers get a deeper understanding of HIIE and pediatric health research. Third, the findings will enable researchers to pinpoint the most influential scholars, institutions, journals, and references in the field, increasing the possibility of future collaborations between authors, institutions, and countries.

Telehealth Movement-to-Music With Arm-Based Sprint-Intensity Interval Training to Improve Cardiometabolic Health and Cardiorespiratory Fitness in Children With Cerebral Palsy: Protocol for a Pilot Randomized Controlled Trial

BACKGROUND

Children with mobility disabilities, including those with cerebral palsy, have limited options and limited time to exercise to manage their cardiometabolic health and cardiorespiratory fitness. Regular cardiovascular exercise during childhood is a critical health behavior for preventing health decline in adulthood. Thus, there is an urgent need for accessible, age-appropriate, convenient exercise modalities in this group. Sprint-intensity interval training (SIT), combined with telehealth procedures, may be ideal for children with disabilities. SIT includes repetitive bouts of maximal exercise effort combined with rest periods, which can be effective in eliciting comparable results to moderate-exercise training with very short training durations.

OBJECTIVE

This phase 1 pilot feasibility randomized controlled trial aims to investigate the potential effects of a 12-week SIT program on indicators of cardiorespiratory fitness and cardiometabolic health among children with cerebral palsy. An ancillary aim is to evaluate the feasibility of the program through several process feasibility metrics.

METHODS

This study uses a 2-armed parallel group design. A total of 50 physically inactive children with cerebral palsy (aged 6-17 years) will be randomly allocated into 1 of 2 groups: a 12-week SIT or a waitlist control group that continues habitual activity for 12 weeks. The SIT prescription includes 3 tele-supervised sessions per week with 30 repeated sequences of 4 seconds of maximal arm exercise, with active recovery, warm-up, and cooldown periods (for an approximately 20-minute total session). SIT includes guided videos with child-themed arm routines and music. The exercise sessions will be remotely supervised through a web-based videoconference application and include safety monitoring equipment. Outcomes are measured at pre- and postintervention (weeks 0 and 13, respectively). Health outcome measures include peak oxygen consumption (VO2 peak), measured by a graded exercise test; high-sensitivity C-reactive protein and blood insulin, hemoglobin A1c, triglycerides, and cholesterol using a finger stick dried blood spot test; blood pressure, using a sphygmomanometer; and body composition (total mass, total lean mass, tissue % lean, and tissue % fat) using dual x-ray absorptiometry. Feasibility will be evaluated by the following metrics: adverse events or problems experienced throughout the intervention related to participant safety; perceived enjoyment; and recruitment, enrollment, and attrition rates.

RESULTS

Recruitment procedures started in November 2023. All data are anticipated to be collected by February 2025. Full trial results are anticipated to be analyzed and submitted for publication by March 2025. Secondary analyses of data will be subsequently published.

CONCLUSIONS

This trial tests an accessible and low-cost exercise program that leverages principles of high-intensity exercise to provide a convenient program for children with physical disabilities. Knowledge obtained from this study will inform the development of a larger trial for improving the cardiometabolic health, cardiorespiratory fitness, and well-being of children with physical disabilities.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05619211; https://clinicaltrials.gov/study/NCT05619211.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/56499.

Effects of Passive or Active Recovery Regimes Applied During Long-Term Interval Training on Physical Fitness in Healthy Trained and Untrained Individuals: A Systematic Review

BACKGROUND

Intermittent exercise programs characterized through intensive exercise bouts alternated with passive or active recovery (i.e., interval training), have been proven to enhance measures of cardiorespiratory fitness. However, it is unresolved which recovery type (active or passive) applied during interval training results in larger performance improvements.

OBJECTIVES

This systematic review aimed to summarize recent evidence on the effects of passive or active recovery following long-term interval exercise training on measures of physical fitness and physiological adaptations in healthy trained and untrained individuals. The study protocol was registered in the Open Science Framework (OSF) platform ( https://doi.org/10.17605/OSF.IO/9BUEY ).

METHODS

We searched nine databases including the grey literature (Academic Search Elite, CINAHL, ERIC, Open Access Theses and Dissertations, Open Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, and SPORTDiscus) from inception until February 2023. Key terms as high-intensity interval training, recovery mode, passive or active recover were used. A systematic review rather than a meta-analysis was performed, as a large number of outcome parameters would have produced substantial heterogeneity.

RESULTS

After screening titles, abstracts, and full texts, 24 studies were eligible for inclusion in our final analysis. Thirteen studies examined the effects of interval training interspersed with passive recovery regimes on physical fitness and physiological responses in trained (6 studies) and untrained (7 studies) individuals. Eleven out of 13 studies reported significant improvements in physical fitness (e.g., maximal aerobic velocity (MAV), Yo-Yo running test, jump performance) and physiological parameters (e.g., maximal oxygen uptake [VO2max], lactate threshold, blood pressure) in trained (effect sizes from single studies: 0.13 < Cohen's d < 3.27, small to very large) and untrained individuals (effect sizes: 0.17 < d < 4.19, small to very large) despite the type of interval training or exercise dosage (frequency, intensity, time, type). Two studies were identified that examined the effects of passive recovery applied during interval training in young female basketball (15.1 ± 1.1 years) and male soccer players (14.2 ± 0.5 years). Both studies showed positive effects of passive recovery on VO2max, countermovement jump performance, and the Yo-Yo running test. Eleven studies examined the effects of interval training interspersed with active recovery methods on physical fitness and physiological parameters in trained (6 studies) and untrained individuals (5 studies). Despite the type of interval training or exercise dosage, nine out of eleven studies reported significant increases in measures of physical fitness (e.g., MAV) and physiological parameters (e.g., VO2max, blood pressures) in trained (effect sizes from single studies: 0.13 < d < 1.29, small to very large) and untrained individuals (effect sizes: 0.19 < d < 3.29, small to very large). There was no study available that examined the effects of active recovery on physical fitness and physiological responses in youth.

CONCLUSIONS

The results of this systematic review show that interval training interspersed with active or passive recovery regimes have the potential to improve measures of physical fitness and physiology outcomes in trained and untrained adults and trained youth. That is, the applied recovery type seems not to affect the outcomes. Nonetheless, more research is needed on the effects of recovery type on measures of physical fitness and physiological adaptations in youth.

A systematic review and cluster analysis approach of 103 studies of high-intensity interval training on cardiorespiratory fitness

AIMS

This study aims to systematically review the systematic reviews and meta-analyses examining the effect of high-intensity interval training (HIIT) protocols on improving cardiorespiratory fitness (CRF) and to characterize the main patterns of HIIT modalities using clustering statistical procedures to examine their potential differences on improving CRF. Finally, we aimed to develop a comprehensive guideline for reporting HIIT protocols.

METHODS AND RESULTS

A systematic review was conducted on PubMed and Web of Science from their inception to 31 October 2022 for systematic reviews and meta-analysis aimed at assessing the effect of HIIT on CRF in the entire study population. The Assessment of Multiple Systematic Reviews 2 tool was used to evaluate the risk of bias of each review. Additionally, a principal component analysis testing the data adequacy for the factor solution through the Kaiser-Meyer-Olkin procedure test was conducted. Once the number of factors was identified, in order to identify data patterns according to the main characteristics of the HIIT protocols, a two-step cluster analysis was conducted. Nineteen systematic reviews and/or meta-analyses comprising 103 studies were included. Clustering of systematic reviews and meta-analyses identified three HIIT modalities ('HIIT-normal mixed', 'HIIT-long running', and 'HIIT-short cycling') underlying the interventions across the included studies. Similar effectiveness in increasing CRF among the three HIIT modalities was observed. Subgroup analyses showed no significant differences in CRF by sex, weight status, study design, and baseline physical activity level (P > 0.05), but differences were observed by age group, and exercise intensity indicator was used in the HIIT programmes (P < 0.05).

CONCLUSION

All three HIIT modalities produced significant improvements of CRF, although some modalities showed greater changes for some specific age groups or intensity indicators.

Interval aerobic/resistance exercise training depresses adrenergic-induced apoptosis of lymphocytes in sedentary males

PURPOSE

Adrenergic stimulation affects lymphocyte autophagy and apoptosis by activating β1-adrenergic receptor (β1-AR) and G protein-coupled receptor kinase 2 (GRK-2) downstream signaling. This study investigated how combined aerobic and resistance exercise training on the interval or continuous pattern influences aerobic/muscular fitness and β1-AR/GRK-2 signaling, and corresponding apoptosis/autophagy of lymphocytes in sedentary males.

METHODS

Thirty-four sedentary males were randomized into interval training (IT, age = 22.5 ± 0.6 years, fitness level = 47.5 ± 0.9 mL/min/kg, body mass index (BMI) = 22.4 ± 0.4 kg/m2, n = 17) and continuous training (CT, age = 21.6 ± 0.4 years, fitness level = 45.2 ± 1.0 mL/min/kg, BMI = 22.2 ± 0.3 kg/m2, n = 17) groups. These subjects performed IT (bicycle exercise at alternating 40% and 80%VO2 reserve (VO2R) and isokinetic exercise at alternating 60°/s and 180°/s) or CT (bicycle exercise at continuously 60%VO2R and isokinetic exercise at continuously 120°/s) for 30 min/day, 5 days/week for 6 weeks. Aerobic capacity and muscular strength/endurance were determined by the graded exercise test (GXT) and isokinetic strength test, respectively. Blood lymphocyte autophagy/apoptosis and β1-AR/GRK-2 signaling were analyzed using flow cytometry.

RESULTS

Both IT and CT groups increased isokinetic strengths at various angular velocities, whereas only IT significantly enhanced muscle endurance, indicated by lowered fatigue index from 47.0 ± 1.3% to 41.8 ± 1.6% (P < 0.05). Moreover, the IT group (143 ± 7%) revealed a higher improvement in VO2peak than CT group (132 ± 6%) (P < 0.05). Acute GXT augmented (i) GRK-2 and protein kinase A expressions, (ii) LAMP-2 upregulation and acridine orange staining, (iii) mitochondrial transmembrane potential diminishing, caspase-3 activation, and phosphatidylserine (PS) exposure caused by epinephrine in blood lymphocytes. However, the degree of epinephrine-induced lymphocyte PS exposure potentiated by GXT was suppressed from 65.2 ± 5.2% to 47.4 ± 6.5% following 6 weeks of the IT (P < 0.05).

CONCLUSION

The IT may be considered more beneficial than CT in terms of improving aerobic/muscular fitness and simultaneously ameliorating apoptosis of blood lymphocyte evoked by intense exercise or adrenergic stimulation in sedentary males.

Gender-Specific Effects of Short Sprint Interval Training on Aerobic and Anaerobic Capacities in Basketball Players: A Randomized Controlled Trial

This study compared the effects of a 6-week short sprint interval training (sSIT) on male and female basketball players' bio-motor abilities, aerobic fitness, and anaerobic power. Using a randomized controlled trial design, 40 basketball players of similar training backgrounds were randomly assigned to two training groups of females (n = 10) and males (n = 10) or two control groups of females and males (each of 10). The training groups performed 3 sets of 10 × 5-second all-out interval running, with a 1:3 work-to-recovery ratio, and a 3-minute rest between sets. The players were evaluated for bio-motor abilities, including muscular power assessed through the vertical jump, agility measured using a T-test and Illinois change of direction (COD) test, and maximal sprint speed measured by a 20-meter sprint test. Also, aerobic fitness was assessed by evaluating maximum oxygen consumption (V̇O2max) through the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR 1) test before and after the 6-week training period. After the intervention, both training groups (females and males) demonstrated significant improvements in vertical jump (effect size [ES] = 1.29, 1.06, respectively), peak power output (ES = 1.27, 1.39), T-test (ES = -0.56, -0.58), Illinois COD test (ES = -0.88, -1.1), 20-m sprint (ES = -1.09, -0.55), Yo-Yo IR1 performance (ES = 2.18, 2.20), and V̇O2max (ES = 2.28, 1.75). Gender did not exhibit any significant impact on the extent of changes observed over time. The results of this study suggest that adaptations in aerobic fitness and bio-motor abilities measured in this experiment in response to sSIT are similar across genders, and gender differences should not be a major concern when implementing sSIT in basketball players.

Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5 min high-intensity exercise within a ≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD = 1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = -1.44 [-1.68, -1.20]), diastolic blood pressure (SMD = -1.51 [-1.75, -1.27]), mean arterial pressure (SMD = -1.55 [-1.80, -1.30]), MetS z-score (SMD = -0.76 [-1.02, -0.49]), fat mass (kg) (SMD = -0.22 [-0.44, 0.00]), fat mass (%) (SMD = -0.22 [-0.41, -0.02]), and waist circumference (SMD = -0.53 [-0.75, -0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%-47% and 45%-94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose-responses were observed between the change in CRF with LV-HIIT and sprint repetitions (β = -0.52 [-0.76, -0.28]), high-intensity duration (β = -0.21 [-0.39, -0.02]), and total duration (β = -0.19 [-0.36, -0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.

Uniform Homeostatic Stress Through Individualized Interval Training Facilitates Homogeneous Adaptations Across Rowers With Different Profiles

PURPOSE

This study compared the effects of individualizing supramaximal interval rowing interventions using anaerobic power reserve (APR [high-intensity interval training (HIIT) prescribed according to individual APR (HIITAPR)]) and power associated with maximal oxygen uptake (WV˙O2max [HIIT prescribed based on the individual WV˙O2max (HIITW)]) on the homogeneity of physiological and performance adaptations.

METHODS

Twenty-four well-trained rowers (age 24.8 [4.3] y, stature 182.5 [3] cm, body mass 86.1 [4.3]) were randomized into interventions consisting of 4 × 30-second intervals at 130%APR (WV˙O2max + 0.3 × maximal sprint power) with weekly progression by increasing the number of repetitions per set (5, 6, 7, 8, 9, and 10, from first to sixth session) and the same sets and repetitions with the intensity described as 130% WV˙O2max. The work-to-recovery ratio was 1:1 for repetitions and 3 minutes between sets. Responses of aerobic fitness indices, power output, cardiac hemodynamics, locomotor abilities, and time-trial performance were examined.

RESULTS

Both HIITAPR and HIITW interventions significantly improved V˙O2max, lactate threshold, cardiac hemodynamics, and 2000-m performance, with no between-groups difference in changes over time. However, HIITAPR resulted in a lower interindividual variability in adaptations in V˙O2max and related physiological parameters, but this is not the case for athletic performance, which can depend on a multitude of factors beyond physiological parameters.

CONCLUSIONS

Results demonstrated that expressing supramaximal interval intensity as a proportion of APR facilitates imposing the same degrees of homeostatic stress and leads to more homogeneous physiological adaptations in maximal variables when compared to prescribing a supramaximal HIIT intervention using WV˙O2max. However, lower interindividual variability would be seen in submaximal variables if HIIT interventions were prescribed using WV˙O2max.

Endurance Performance Adaptations between SSG and HIIT in Soccer Players: A Meta-analysis

The objective of this systematic review with meta-analysis was to compare the endurance performance chronic adaptations induced by running-based high-intensity interval training (HIIT), small-sided games (SSGs), and combined HIIT+SSGs in male and female youth and adult soccer players. The studies included in this review followed the PICOS criteria: (i) healthy soccer players; (ii) interventions based on SSGs; (iii) comparators exposed to only HIIT or combined SSGs+HIIT; (iv) endurance performance variables. Studies were searched for in the following databases: (i) PubMed; (ii) Scopus; (iii) SPORTDiscus; (iv) Web of Science. After conducting an initial database search that retrieved a total of 5,389 records, a thorough screening process resulted in the inclusion of 20 articles that met the eligibility criteria. Sixteen studies reported outcomes related to endurance performance measured through field-based tests, while five studies provided results from direct measurements of maximal oxygen uptake (VO2max). Results showed a non-significant small-magnitude favoring effect for the HIIT groups compared to the SSG groups (ES=0.37, p=0.074) for endurance, while a non-significant small-magnitude favoring SSGs was observed (ES=-0.20, p=0.303) for VO2max. Despite the very low certainty of evidence, the findings suggest similar effects induced by both SSG and HIIT on improving endurance performance and VO2max.

Comparative Effects of Two High-Intensity Intermittent Training Programs on Sub-Elite Male Basketball Referees' Fitness Levels

This study aimed to compare the effects of an 8-week short-term training program, comprising repeated sprints or running-based high-intensity intermittent training (HIIT), on the aerobic fitness and repeated sprint ability (RSA) performance of sub-elite basketball referees. Twenty male referees participated in supervised training sessions twice a week. They were randomly assigned to either the RSA-based group (RSAG) or the running-based HIIT group (HIITG). The RSAG conducted 3-4 sets of 8 × 20-m all-out sprints, while the HIITG performed 2-3 sets of 6 × 20-s runs at 90% of their maximal velocity achieved in the 30-15 intermittent fitness test (30-15IFT). Referees underwent a graded exercise test on a treadmill, the 30-15IFT, and an RSA test before and after the training program. Both groups showed significant improvement (~3%) in the fastest (22.6 ± 1.4 vs. 23.4 ± 1.7 and 22.0 ±1.9 vs. 22.4 ± 1.7 km·h-1 in RSAG and HIITG, respectively) and mean (21.5 ± 1.2 vs. 22.4 ± 1.4 and 21.3 ± 1.8 vs. 21.7 ± 1.6 km·h-1 in RSAG and HIITG, respectively) sprint velocity of the RSA test (p < 0.05). Moreover, positive changes (p < 0.05) were observed in the 30-15IFT maximal velocity (18.6 ± 1.1 vs. 19.3 ± 1.0 and 19.4 ± 0.9 vs. 20.5 ± 0.9 km·h-1 in RSAG and HIITG, respectively). In conclusion, an 8-week training intervention using either RSA or running-based HIIT led to similar improvements in referees' RSA performance and specific aerobic fitness measures. These findings could assist in devising tailored training programs for basketball referees.

Match-Play Running Performance in Professional Male Soccer Players: The Role of Anaerobic Speed Reserve

Purpose: This study aimed to compare match-play running performance between players with a high (HASR) and low (LASR) anaerobic speed reserve (ASR) profile in professional soccer players. Method: Thirty-six male players from the same club (age: 23.3 ± 5.4 years) took part in this study. Match data were collected from 43 home matches of the first and second division of the Brazilian National Championship over two consecutive seasons. Players had their maximal sprinting (MSS) and aerobic speeds (MAS) determined during field test-based assessments. ASR was defined as MSS minus MAS. Total distance (TD), sprinting distance, number of accelerations and decelerations, absolute peak (PMS(abs)) and mean match sprint speed (MMSS(abs)) and its relative values expressed as a percentage of MSS (PMS(rel) and MMSS(rel)), distance covered > 100% MAS(abs) and > 50% MSS(abs) were compared between the groups and halves. Results: HASR presented greater sprint demand (d > 0.80), PMS(abs) (d = 1.57), and MMSS(abs) (d = 0.99) than the LASR group. The opposite was observed for PMS(rel) and MMSS(rel). The TD and amount of high-intensity accelerations and decelerations were moderately (0.77MAS(abs) and > 50% MSS(abs) decreased between halves (d = 0.72 and 0.77), while the HASR did not (d < 0.10). Conclusion: Our findings indicated that players with larger ASR had greater sprint demand, with a lower relative running intensity, and covered longer distances above MAS. The amplitude of ASR also affected the player's running ability between halves.

Acute effects of resistance-type and cycling-type high-intensity interval training on arterial stiffness, cardiac autonomic modulation and cardiac biomarkers

BACKGROUND

High-intensity interval training (HIIT) has been shown to enhance cardiovascular health. However, there is a lack of research investigating the specific cardiovascular effects of different HIIT training modes. Therefore, this study aimed to compare the acute effects of cycling-type high intensity interval training (C-HIIT) and resistance-type high intensity interval training (R-HIIT) on arterial stiffness, cardiac autonomic modulation, and cardiac biomarkers in healthy young men.

METHODS

This is a cross-over randomized trial. Eleven healthy active young men took part in both C-HIIT and R-HIIT. Cardio-ankle vascular index (CAVI), heart rate variability (HRV), and systolic blood pressure (SBP) were measured before, immediately and 30 min after the exercise in C-HIIT and R-HIIT. Meanwhile, blood samples for cardiac troponin-T (cTnT) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) were assessed using ELISA before, 5min and 35min after exercise.

RESULTS

There was a significant time × group interaction effect (P = 0.019, ηp2 = 0.182) and time main effect for ⊿CAVI (P < 0.001, ηp2 = 0.729), and R-HIIT resulted in a more significant reduction in ⊿CAVI compared to C-HIIT (- 0.60 ± 0.30, P = 0.043, d = 0.924) immediately after exercise. There was a significant time main effect was observed for SBP (P = 0.001, ηp2 = 0.304). A significant time main effect for lnHF (P < 0.001, ηp2 = 0.782), lnRMSSD (P < 0.001, ηp2 = 0.693), and LF/HF (P = 0.001, ηp2 = 0.302) of HRV was observed. A significant time main effect was observed for cTnT (P = 0.023, ηp2 = 0.193) and NT-proBNP (P = 0.001, ηp2 = 0.334) of cardiac biomarkers.

CONCLUSION

R-HIIT and C-HIIT elicited similar acute responses in cardiac autonomic modulation and cardiac biomarkers. However, R-HIIT was more effective in reducing arterial stiffness in healthy young men. Furthermore, the increase in cardiac biomarkers induced by both C-HIIT and R-HIIT was reversible.

TRIAL REGISTRATION

The study was prospectively registered on 22 February 2022 at www.chictr.org.cn with identification number ChiCTR2200056897.

Validation and Calibration for Embedding Rating of Perceived Exertion Into High-Intensity Interval Exercise in Adolescents: A Lab-Based Study

PURPOSE

Rating of perceived exertion (RPE) is a convenient and cost-effective tool that can be used to monitor high-intensity interval exercise (HIIE). However, no methodological study has demonstrated the validity of RPE in this context. Therefore, the aim of this study was to validate and calibrate RPE for monitoring HIIE in adolescents.

METHODS

RPE, heart rate (HR), and oxygen uptake (V˙O2) data were retrospectively extracted from 3 lab-based crossover studies, with a pooled sample size of 45 adolescents, performing either cycling-based or running-based HIIE sessions. Within-participant correlations were calculated for RPE-HR and RPE-V˙O2, and receiver operator characteristic curve analysis was used to establish RPE cut points.

RESULTS

The results showed that RPE-HR demonstrated acceptable criterion validity (r = .53-.74, P < .01), while RPE-V˙O2 had poor validity (r = .40-.48, P < .01), except for HIIE at 100% peak power (r = .59, P < .01). RPE cut points of 4 and 5 were established in corresponding to HR/V˙O2 based thresholds.

CONCLUSION

RPE has some utility in evaluating intensity during lab-based running or cycling HIIE in adolescents. Future studies should expand the validation and calibration of RPE for prescribing and monitoring HIIE in children and adolescents in field-based contexts.

Clinical value and mechanistic analysis of HIIT on modulating risk and symptoms of depression: A systematic review

Background

The exact causal mechanisms of depression remain unclear due to the complexity of the triggers, which has led to limitations in treating depression using modern drugs. High-intensity interval training (HIIT) is as effective as medication in treating depression without toxic side effects. Typically, HIIT requires less time commitment (i.e., shorter exercise duration) and exhibits pronounced benefits on depressive symptoms than other forms of physical exercise. This review summarizes the risk reduction and clinical effects of HIIT for depression and discusses the underlying mechanisms, providing a theoretical basis for utilizing HIIT in treating depression.

Methods

A database search was conducted in PubMed, Embase, Web of Science, and Scopus from inception up to October 2022. The methodological quality of the included literature was evaluated by the physiotherapy evidence database (PEDro) scale criteria. The review focused on evaluating the changes in depression risk or symptoms of HIIT interventions in healthy individuals, patients with depression, and patients with other disorders co-morbid with depression. Consequently, the mechanisms associated with depression related HIIT were summarized.

Results

A total of 586 participants (52 % female; mean age: 43.58±8.93 years) from 22 studies were included. Implementing HIIT using different exercise types alleviates depressive symptoms in individuals with depression and in individuals with depression who have exhibited comorbidities and reduced depression scale scores in subjects immediately after acute exercise. In addition, the long-interval HIIT and short-interval HIIT in the treatment of patients with cardiovascular or psychiatric disorders may reduce depressive symptoms via complex exercise-related changes on several levels, including by effecting the following measures: releasing monoamines, reducing neuronal death, inducing neurogenesis, modulating the functional homeostasis of the HPA axis, and enhancing the level of inflammation in the body.

Conclusion

HIIT is a relatively safe and effective antidepressant, which may involve multiple neurobiological mechanisms (release of monoamines, reducing neuronal death, inducing neurogenesis, modulating the functional homeostasis of the HPA axis, and enhancing the level of inflammation in the body), thereby reducing the risk or symptoms of depression in participants.

Comparative analysis of high-intensity interval training and traditional rehabilitation programs for accelerated recovery from musculoskeletal injuries

BACKGROUND

Musculoskeletal injuries, such as strains, are prevalent across all age groups and have a substantial impact on daily functioning and quality of life.

OBJECTIVE

To examine the effectiveness of high-intensity interval training (HIIT) with traditional rehabilitation programs on pain, range of motion (ROM), muscular strength, and functional changes in promoting accelerated recovery from musculoskeletal injuries.

METHODS

A total of 80 participants (54 males, 26 females; mean age 35.6 years) with various musculoskeletal injuries were randomly assigned to either the HIIT group (n= 40) or the traditional rehabilitation group (n= 40). The HIIT group underwent a six-week supervised program, with three sessions per week. The traditional rehabilitation group followed a similar six-week program emphasizing low to moderate intensity exercises and traditional rehabilitation techniques. Outcome measures, including pain levels, ROM, muscular strength, and functional outcomes, were assessed pre- and post-intervention.

RESULTS

Significant improvements were observed in both the HIIT and traditional rehabilitation groups. However, the HIIT group demonstrated superior outcomes. Participants in the HIIT group experienced a greater reduction in pain levels compared to the traditional rehabilitation group (mean visual analog scale (VAS) score decrease of 5.2 vs. 3.8, respectively, p< 0.05). Functional outcomes significantly favored the HIIT group, with participants achieving faster completion times in the Timed Up and Go test (mean reduction of 2.1 seconds vs. 1.5 seconds, respectively, p< 0.01) and longer distances in the Single Leg Hop test (mean increase of 32 cm vs. 25 cm, respectively, p< 0.05).

CONCLUSION

HIIT showed superior effectiveness over traditional rehabilitation in accelerating recovery from musculoskeletal injuries, with greater pain reduction and improved functional outcomes. Incorporating HIIT into rehabilitation protocols may offer an efficient approach for expedited recovery and enhanced functional capacity.

Effects of small-sided games training programs on physiological and physical adaptations of youth basketball players: A systematic review

The primary objective of this study was to systematically investigate the physiological and physical fitness adaptations resulting from small-sided games (SSGs) training programs in basketball players competing at youth competitive levels, as compared to other training approaches and/or control groups. To achieve this, we conducted a literature search on PubMed, Scopus, SPORTDiscus, and Web of Science, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. From the initial 626 studies retrieved, five were considered eligible for the current study. Among the five included articles, four conducted comparisons between the effects of SSGs and running-based high-intensity interval training. Regarding this, the four studies revealed a significant improvement in the final velocity during the 30-15 Intermittent Fitness Test, ranging from 4.07% to 7.29% following SSG-based interventions. This improvement was not significantly different from the comparator group. Additionally, two studies indicated that the SSGs group showed a significant advantage in change-of-direction time, with improvements ranging from -2.11% to 6.69% after interventions, and these results were not significantly different from the comparator group. However, the effects on repeated sprint ability yielded contradictory findings; two studies reported significant improvements ranging from -5.00% to -2.16%, while two others did not show significant effects following SSGs-based interventions. Similarly, in the linear sprint, the results of SSGs-based interventions were inconsistent. In summary, based on the available research, it can be concluded that SSG-based training is effective in significantly enhancing aerobic performance and change of direction, comparable to alternative approaches. However, the effects on repeated sprint ability and sprint performance are not consistently demonstrated.

The Effects of a Supramaximal Intermittent Training Program on Aerobic and Anaerobic Running Measures in Junior Male Soccer Players

This study investigated the effectiveness of supplementing regular preseason soccer training with a supramaximal intermittent shuttle-run training (ISRT) model prescribed from Carminatti's Test peak speed (PST-CAR) in aerobic performance-related indices and sprinting speed in male junior soccer players. Twenty-three national-level soccer players (mean ± SD; age 18.07 ± 0.9 y, body height 1.76 ± 0.65 m, body mass 71.9 ± 8.7 kg) were assigned to either an experimental group (EG; n = 13) performing ISRT + soccer training or a control group (CG; n = 10) that followed regular preseason soccer training alone. The following tests were applied before and after the eight-week training intervention: (i) incremental treadmill tests (VO2max and lactate minimum speed - LMS); (ii) linear 30-m sprint test and Carminatti's Test (PST-CAR). Results indicated larger gains for the EG in LMS (Δ = 9.53% vs. 2.82%) and PST-CAR (Δ = 5.50% vs. 2.10%) than in the CG. Furthermore, changes in VO2max produced higher effect size (d) values for the EG (Δ = 6.67%; d = 0.59) than the CG (Δ = 1.88%; d = 0.18). Both groups improved (p = 0.002) their flying 20-m sprint speed (EG: Δ = 1.01%; CG: Δ = 1.56%). However, small decreases were observed for 10-m sprint speed in the CG (Δ = -2.19%; d = -0.44), while only trivial changes were noticed for the EG (Δ = -0.50%; d = -0.16). Our data support that additional supramaximal ISRT is an effective training stimulus to enhance aerobic performance-related indices and promote small improvements in maximal running speed without impairing the soccer players' acceleration capacity. This study also shows that PST-CAR can be useful for individualizing running intensity in supramaximal ISRT modes.

Effects of Different Recovery Duration on External and Internal Load Measures during Bouts of Small-Sided Games

The aim of this study was to analyse the effects of different recovery times between bouts of small-sided games (SSG) on external and internal load variables in semi-professional soccer players. Sixteen male semi-professional soccer players performed three 4 vs. 4 + goalkeeper SSG training sessions, each with different recovery bout duration: short (1 min) (SSG1), medium (2 min) (SSG2), and long (4 min) (SSG4). Time motion and neuromuscular measures were collected during all SSGs, in addition, the rating of perceived exertion (RPE) was determined at the end of the last bout of each SSG. Results showed a significant increase in the total number of accelerations (p = 0.016, ES = 0.97, large) and decelerations (p = 0.022, ES = 0.81, large) in SSG4 compared to SSG1. In terms of the internal load, SSG2 showed significantly higher RPE values (p = 0.011, ES = 1.00, large) in comparison with SSG1. If the sessions' focus is on neuromuscular training, longer recovery times between SSG bouts should be used. Conversely, if the aim is to reach a higher total and running distance at different intensities, a 2-min recovery period between bouts may be more appropriate.