The relationship between aerobic fitness and recovery from high intensity intermittent exercise

Contextual factors associated with running demands in elite Australian football: a scoping review

OBJECTIVES

To identify and summarise the contextual factors associated with running demands in elite male Australian football (AF) gameplay that have been reported in the literature.

DESIGN

Scoping review.

METHODS

A contextual factor in sporting gameplay is a variable associated with the interpretation of results, yet is not the primary objective of gameplay. Systematic literature searches were performed in four databases to identify what contextual factors associated with running demands in elite male AF have been reported: Scopus, SPORTDiscus, Ovid Medline and CINAHL, for terms constructed around Australian football AND running demands AND contextual factors. The present scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and narrative synthesis was conducted.

RESULTS AND CONCLUSION

A total of 36 unique articles were identified by the systematic literature search, which included 20 unique contextual factors. The most studied contextual factors were position (n = 13), time in game (n = 9), phases of play (n = 8), rotations (n = 7) and player rank (n = 6). Multiple contextual factors, such as playing position, aerobic fitness, rotations, time within a game, stoppages, and season phase appear to correlate with running demands in elite male AF. Many identified contextual factors have very limited published evidence and thus additional studies would help draw stronger conclusions.

The influence of physical fitness qualities, individual characteristics and contextual factors on youth basketball players' perceived exertion and recovery responses to official games

BACKGROUND

This study examined the influence of physical fitness qualities, individual characteristics, and contextual factors on perceived exertion and recovery responses to official games in youth basketball players.

METHODS

Twenty-six males (age: 15.8±1.2 years; 12 guards, 9 forwards, and 5 centers) and 7 females (age: 16.1±0.9 years; 3 guards, 4 forwards) were monitored for an entire basketball season (N.=635 observations). Yo-Yo Intermittent Recovery (level 1) and countermovement jump (CMJ) tests were administered, with players categorized as high and low Yo-Yo and CMJ groups according to test results. Ratings of perceived exertion (RPE) were collected after each official game. Before the game and the day after, the Total Quality of Recovery (scores) were collected, and the difference between post- and pregame TQR was calculated (TQRΔ). Separate linear mixed models evaluated the effects of sex (M; F), fitness qualities (high Yo-Yo; low Yo-Yo) (high CMJ; low CMJ), playing position (guard; forward; center), game outcome (won; loss) and game location (home; away).

RESULTS

Male players reported higher RPE (7.0±0.3) than females (5.5±0.4) (P=0.003, effect size [ES]: moderate). Players with high Yo-Yo performance also reported higher RPE (6.7±0.4) than low Yo-Yo (5.8±0.3) (P=0.049, ES: small). TQRΔ was higher in guards (-1.3±0.2) than forwards (-0.8±0.2) (P=0.041, ES: trivial), and lower after lost games (-0.8±0.2) compared to won games (-1.2±0.2) (P=0.002, ES: small).

CONCLUSIONS

In youth basketball, postgame perceived exertion and recovery responses are influenced by players' sex, intermittent endurance capacity, and game outcome. Current findings can help youth basketball practitioners to better understand their players' performances and perceptual responses.

Metabolic recovery from submaximal exercise in hypoxia acclimated high altitude deer mice (Peromyscus maniculatus)

Animals living at high-altitude are faced with unremitting low oxygen availability. This can make it difficult to perform daily tasks that require increases in aerobic metabolism. An activity important for survival is aerobic locomotion, and the rapid recovery of muscle metabolism post exercise. Past work shows that hypoxia acclimated high-altitude mice (Peromyscus maniculatus) have a greater reliance on carbohydrates to power exercise than low altitude mice. However, it is unclear how quickly after aerobic exercise these mice can recovery and replenish muscle glycogen stores. The gastrocnemius muscle of high-altitude deer mice has a more aerobic phenotype and a greater capacity to oxidize lipids than low altitude deer mice. This suggests that high altitude mice may recover more rapidly from exercise than their lowland counterparts due to a greater capacity to support glycogen replenishment using intramuscular triglycerides (IMTG). To explore this possibility, we used low- and high-altitude native deer mice born and raised in common lab conditions and acclimated to chronic hypoxia. We determined changes in oxygen consumption following 15 min of aerobic exercise in 12% O2 and sampled skeletal muscles and liver at various time points during recovery to examine changes in key metabolites, including glycogen and IMTG. We found depletion in glycogen stores during exercise only in lowlanders, which returned to resting levels following 90 min of recovery. In contrast, IMTG's did not change significantly with exercise or during recovery in either population. These data suggest that exercise recovery is influenced by altitude ancestry in deer mice.

Influence of voluntary isocapnic hyperpnoea on recovery after high-intensity exercise in elite short-track speedskaters - randomized controlled trial

Respiratory muscle training plays a significant role in reducing blood lactate concentration (bLa) and attenuating negative physiological stress reactions. Therefore, we investigated if voluntary isocapnic hyperpnoea (VIH) performed after a maximum anaerobic effort influences bLa and perceived fatigue level in well-trained speedskaters. 39 elite short-track speedskaters participated in a trial with two parallel groups: experimental and control. All the participants performed the Wingate Anaerobic Test (WAnT). The experimental group performed a VIH-based recovery protocol 20 min after exercise, the control group used passive recovery only. Blood samples were taken 3 and 30 min after the WAnT to measure bLa. Fatigue was self-appraised on a 0-10 perceived rating-of-fatigue (ROF) scale 3 and 30 min after the WAnT. Noteworthy, but not statistically significant changes between the experimental and control groups were observed for changes in bLa (p = 0.101). However, statistically significant changes between the groups were found for ROF (p = 0.003, ηp2 = 0.211, ω2 = 0.106). Moreover, statistically significant interactions between post-exercise bLa clearance and VO2max (p = 0.028) and inspiratory muscle strength (p = 0.040) were observed. Our findings provided preliminary insight that VIH may be an efficient recovery protocol after anaerobic exercise performed by elite athletes. The association between VO2max and post-exercise bLa clearance indicates the vital role of aerobic fitness in repeated-efforts ability in short-track speedskaters. The study was registered at ClinicalTrials.gov as NCT05994092 on 15th August 2023.

Evaluating the impact of a combined aerobic and strength training intervention on the physical performance of male Chinese People's Liberation Army air force pilots

This study aimed to assess the impact of a 16-week combined training program on the physical performance of 20 male Air Force pilots, with an average age of 31.87 ± 2.75 years, body mass of 76.33 ± 0.79 kg, and height of 175.55 ± 3.65 cm. This intervention encompassed both aerobic and strength training, involving six weekly training sessions. The participants were categorized into two groups based on their initial physical performance levels to explore potential baseline influences on post-intervention adaptations. The study measured changes in estimated maximal oxygen uptake (VO2 max), maximal strength, muscular endurance, and long jump performance before and after the training program. Repeated measures ANOVA revealed significant differences over time in theV ˙ O2 max (F = 86.898; p < 0.001;η p 2  = 0.821), handgrip strength right hand (F = 160.480; p < 0.001;η p 2  = 0.894), handgrip strength left hand (F = 102.196; p < 0.001;η p 2  = 0.843), squat maximal strength (F = 525.725; p < 0.001;η p 2  = 0.965), push-ups (F = 337.197; p < 0.001;η p 2  = 0.974), sit up (F = 252.500; p < 0.001;η p 2  = 0.930) and standing long jump (F = 521.714; p < 0.001;η p 2  = 0.965). In conclusion, the 16-week combined training regimen significantly enhanced the physical performance of Air Force pilots, regardless of their initial performance levels.

Physical fitness characteristics of elite freestyle skiing aerials athletes

OBJECTIVE

To analyze the physical fitness characteristics of elite freestyle skiing aerials athletes, thereby enhancing the understanding of exercise physiologists, sports scientists, and coaches regarding the demands in this discipline.

METHODS

After health screenings, 29 athletes from the Chinese National Freestyle Skiing Aerials Team were divided into elite and general groups, including males and females. Physical fitness indexes were determined through literature reviews, expert interviews, and the Delphi method, followed by physical fitness tests assessing body morphology, physiological function, and physical quality. Data normality was verified using the Shapiro-Wilk test. Differences between the two groups were then evaluated using independent sample t-tests or Mann-Whitney U tests, after which effect sizes were calculated to assess the magnitude of the differences.

RESULTS

Significant body morphology differences were noted between elite and general groups in fat-free body weight, leg, and waist circumferences (P < 0.05). Male athletes in the elite group exhibited a significantly lower percentage of body fat (P < 0.05), whereas the reduction in body fat percentage among female elite athletes was not statistically significant. In terms of physiological function assessment, elite athletes demonstrated superior performance in both maximum anaerobic capacity and relative maximum anaerobic capacity compared to their counterparts in the general group (P < 0.05). Notably, the difference in maximum anaerobic capacity was highly significant among male athletes (P < 0.01), and the relative maximum anaerobic capacity among female athletes was also markedly significant (P < 0.01). Regarding physical quality indexes, elite athletes outperformed those in the general group in all aspects except for the quick v-up and 12-minute run tests (P < 0.05 or P<0.01).

CONCLUSION

Elite athletes exhibit superior physical fitness characteristics compared to general athletes, attributable to differences in age, years of training, and their participation in ongoing specialized physical training within structured, cyclical programs. Specifically, elite athletes demonstrated higher fat-free body weight, larger waist and leg circumferences in terms of body morphology. Particularly, male athletes showed a trend towards lower body fat percentage. Physiologically, they exhibited stronger anaerobic metabolism capabilities. In terms of physical quality, elite athletes displayed superior limb strength, lower limb explosive power, and specialized core strength, along with better speed, agility, and overall coordination.

Aerobic and Anaerobic Fitness Levels of Pre-Professional Contemporary Dancers: An Exploration of 2 Dance-Specific Field Tests

INTRODUCTION

The primary aim of this study was to present descriptive heart rate (HR), heart rate recovery (HRR) and RPE data for the DAFT and HIDT within one sample of contemporary dance students. The second aim was to explore if objective (HR) and subjective (RPE) data were correlated between tests.

METHOD

40 (11 males, 29 females) university dance students with a mean age of 18.8 ± 1.8 years performed the DAFT and HIDT on 2 separate occasions within 1 week. Measurements were HR after 4 minutes in all stages of the DAFT, the percentage of age-predicted maximal HR (%HRmax) of all stages of the DAFT and at the end of the HIDT, and peak HR (HRpeak) at the end of both tests. Subjective ratings of perceived exertion (RPE) and HR recovery after 1 minute of rest (HRR) were determined after the tests.

RESULTS

HRpeak of the DAFT and HIDT were 188.1 ± 11.0 and 185.3 ± 7.3 beats·min-1, respectively. There were high positive correlations between HRpeak of the HIDT and stages 3 to 5 of the DAFT (r = 0.716-0.740, all P-values < .01). HRR (r = .678, P < .01) and %HRmax (r = .746, P < .01) showed moderate to high correlations between the DAFT and HIDT. The anaerobic training zone was reached in stages 4 and 5 of the DAFT and at the end of the HIDT. The subjective RPE scores did not significantly correlate between DAFT and HIDT, neither with objective HR data.

CONCLUSION

Although the DAFT and HIDT differ in intensity and work-to-rest ratio, there were high correlations between HR and HRR data of both tests and both tests reached intensities above the anaerobic threshold (%HRmax > 85%).

The impact of high-intensity arm crank exercise on reaction time in wheelchair fencers: gender differences and mechanical predictors

To achieve high performance, wheelchair fencing (WF) athletes are required to exhibit good physiological and timing indicators. The main aims of this study were to assess the relationship between the results of the repeated sprint ability (RSA) test and reaction time (RT) in WF, and to evaluate changes in RT after repeated high-intensity sprints in the group of an international-level WF athletes. This experimental study involved 18 athletes (aged 34.6 ± 7.70) from the Paralympic WF team. To establish the impact of fatigue on psychomotor capacity, the participants undergo a series of tests. At the beginning of the study, first reaction time (RT1) was measured. Afterwards, the RSA test was performed using the arm crank ergometer to evaluate the participants' repeated sprint ability. Immediately after RSA, the second reaction time (RT2) was measured. Statistical analysis revealed moderate correlations between the RT2 and total work, decrease of work (DW), highest peak power, mean peak power, and highest peak power/kg, but these correlations were not statistically significant (p > 0.05). All fencers achieved a significantly shorter average RT2 (p < 0.005) after the RSA test (0.383 ± 0.035 s) than before the test (0.391 ± 0.038 s). Additionally, RT2 was significantly shorter than RT1 in the women's group (p < 0.001). Moreover, males had significantly greater values of repeated sprint ability parameters: highest work, total work, decrease of work and highest peak power (p < 0.05) than females. To conclude, repeated high-intensity arm crank exercise has a positive impact on simple postexercise cognitive tasks in WF fencers, especially in women, and leads to a decrease in RT. The RSA parameters can be predictors of changes in RT in men and women wheelchair fencers.

Examining the Effects of Altitude on Workload Demands in Professional Basketball Players during the Preseason Phase

Basketball involves frequent high-intensity movements requiring optimal aerobic power. Altitude training can enhance physiological adaptations, but research examining its effects in basketball is limited. This study aimed to characterize the internal/external workload of professional basketball players during preseason and evaluate the effects of altitude and playing position. Twelve top-tier professional male basketball players (Liga Endesa, ACB; guards: n = 3, forwards: n = 5, and centers: n = 4) participated in a crossover study design composed of two training camps with nine sessions over 6 days under two different conditions: high altitude (2320 m) and sea level (10 m). Internal loads (heart rate, %HRMAX) and external loads (total distances covered across speed thresholds, accelerations/decelerations, impacts, and jumps) were quantified via wearable tracking and heart rate telemetry. Repeated-measures MANOVA tested the altitude x playing position effects. Altitude increased the total distance (+10%), lower-speed running distances (+10-39%), accelerations/decelerations (+25-30%), average heart rate (+6%), time in higher-intensity HR zones (+23-63%), and jumps (+13%) across all positions (p < 0.05). Positional differences existed, with guards accruing more high-speed running and centers exhibiting greater cardiovascular demands (p < 0.05). In conclusion, a 6-day altitude block effectively overloads training, providing a stimulus to enhance fitness capacities when structured appropriately. Monitoring workloads and individualizing training by playing position are important when implementing altitude training, given the varied responses.

The Variability of the Components of Fitness along the Menstrual Cycle

This study aims to determine the variability of the components of fitness along the menstrual cycle (MC) of physically active eumenorrheic women. Fifteen subjects were monitored along two consecutive MCs through the calendar-based counting method in combination with a urine luteinizing hormone surge kit. Subjects were tested at the early follicular phase (EFP), pre-ovulatory or late follicular phase (LFP), and post-ovulatory or mid-luteal phase (MLP). In each session, the back squat one-repetition maximum (1-RM), maximum fat oxidation (MFO), maximum oxygen uptake (VO2max) and acute recovery capacity were determined. The results revealed a wide variability among components of fitness and a low to high variability among subjects (acute recovery: 3.6% [range 1.5 to 9.5%]; back squat 1-RM: 6.1% [range 2.2 to 11%]; VO2max: 6.6% [range 1.1 to 15%]; MFO: 23% [range 4.6 to 35%]). Despite the individual nature, considering the number and magnitude of the responses in each MC phase, VO2max and acute recovery capacity tended to be enhanced at the LFP, the MFO at the MLP, and the back squat 1-RM remained stable along the MC. Thus, practitioners are aware of which components are susceptible to change along the MC phase, but an individual monitoring is recommended.

Assessing criterion and longitudinal validity of submaximal heart rate indices as measures of cardiorespiratory fitness: A preliminary study in football

OBJECTIVES

To evaluate the criterion and longitudinal validity of field- and laboratory-derived heart rate (HR) indices of resting and submaximal fitness tests (SMFTs) as measures of cardiorespiratory fitness.

DESIGN

Observational, repeated measures.

METHODS

Twenty-nine semi-professional footballers participated. Laboratory assessments took place at the start and end of a preseason training period, whereby resting, SMFT HR-derived indices, and criterion measures of cardiorespiratory fitness (running economy [RE], maximal oxygen uptake [V̇O2 max] and aerobic speed [MAS]) were collected. Throughout this training period, two field-based SMFT protocols, prescribed at different intensities, were administered weekly. Individual slopes were calculated from the analysis of within-athlete change scores. Associations between laboratory and field measures were assessed via Pearson's correlation coefficient (r) and linear regression models.

RESULTS

Relationships between SMFT HR-derived indices from laboratory and field were very-large for exercise HR (r = 0.74 to 0.87) and moderate to very-large for HR recovery (0.43 to 0.76). Moderate to very-large inverse relationships were observed between exercise HR and HR recovery with V̇O2 max and MAS (-0.41 to -0.78), whereas resting HR showed no substantial relationships. Changes in exercise HR showed large and very-large inverse correlations with preseason changes in V̇O2 max (-0.54 to -0.60) and MAS (-0.64 to -0.83). Relationships between changes in HR recovery and maximal cardiorespiratory criterion measures were moderate to large (-0.32 to -0.63).

CONCLUSION

SMFT exercise HR is a valid proxy measure of cardiorespiratory fitness irrespective of test setting, whereas the validity of HRR remains elusive and appears to vary between exercise intensities.

The Effects of Repeated-Sprint Training on Physical Fitness and Physiological Adaptation in Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

Repeated-sprint training (RST) is a common training method for enhancing physical fitness in athletes. To advance RST prescription, it is important to understand the effects of programming variables on physical fitness and physiological adaptation.

OBJECTIVES

This study (1) quantifies the pooled effects of running RST on changes in 10 and 20 m sprint time, maximal oxygen consumption (VO2max), Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) distance, repeated-sprint ability (RSA), countermovement jump (CMJ) height and change of direction (COD) ability in athletes, and (2) examines the moderating effects of program duration, training frequency, weekly volume, sprint modality, repetition distance, number of repetitions per set and number of sets per session on changes in these outcome measures.

METHODS

Pubmed, SPORTDiscus and Scopus databases were searched for original research articles up to 04 July 2023, investigating RST in healthy, able-bodied athletes, between 14 and 35 years of age, and a performance calibre of trained or above. RST interventions were limited to repeated, maximal running (land-based) sprints of ≤ 10 s duration, with ≤ 60 s recovery, performed for 2-12 weeks. A Downs and Black checklist was used to assess the methodological quality of the included studies. Eligible data were analysed using multi-level mixed-effects meta-analysis, with standardised mean changes determined for all outcomes. Standardised effects [Hedges G (G)] were evaluated based on coverage of their confidence (compatibility) intervals (CI) using a strength and conditioning specific reference value of G = 0.25 to declare an improvement (i.e. G > 0.25) or impairment (i.e. G < - 0.25) in outcome measures. Applying the same analysis, the effects of programming variables were then evaluated against a reference RST program, consisting of three sets of 6 × 30 m straight-line sprints performed twice per week for 6 weeks (1200 m weekly volume).

RESULTS

40 publications were included in our investigation, with data from 48 RST groups (541 athletes) and 19 active control groups (213 athletes). Across all studies, the effects of RST were compatible with improvements in VO2max (G 0.56, 90% CI 0.32-0.80), YYIR1 distance (G 0.61, 90% CI 0.43-0.79), RSA decrement (G - 0.61, 90% CI - 0.85 to - 0.37), linear sprint times (10 m: G - 0.35, 90% CI - 0.48 to - 0.22; 20 m: G - 0.48, 90% CI - 0.69 to - 0.27), RSA average time (G - 0.34, 90% CI - 0.49 to - 0.18), CMJ height (G 0.26, 90% CI 0.13-0.39) and COD ability (G - 0.32, 90% CI - 0.52 to - 0.12). Compared with the reference RST program, the effects of manipulating training frequency (+ 1 session per week), program duration (+ 1 extra training week), RST volume (+ 200 m per week), number of reps (+ 2 per set), number of sets per session (+ 1 set) or rep distance (+ 10 m per rep) were either non-substantial or comparable with an impairment in at least one outcome measure per programming variable.

CONCLUSIONS

Running-based RST improves speed, intermittent running performance, VO2max, RSA, COD ability and CMJ height in trained athletes. Performing three sets of 6 × 30 m sprints, twice per week for 6 weeks is effective for enhancing physical fitness and physiological adaptation. Additionally, since our findings do not provide conclusive support for the manipulation of RST variables, further work is needed to better understand how programming factors can be manipulated to augment training-induced adaptations.

STUDY REGISTRATION

Open Science Framework registration https://doi.org/10.17605/OSF.IO/RVNDW .

Inspiratory muscles pre-activation in young swimmers submitted to a tethered swimming test: effects on mechanical, physiological, and skin temperature parameters

Inspiratory muscles pre-activation (IMPA) has been studied to improve subsequent performance in swimming. However, the effects of IMPA on various parameters in swimmers are still unknown. Therefore, this study aimed to investigate the effects of IMPA on the mechanical parameters, physiological responses, and their possible correlations with swimming performance. A total of 14 young swimmers (aged 16 ± 0 years) underwent a 30-s all-out tethered swimming test, preceded or not by IMPA, a load of 40% of the maximal inspiratory pressure (MIP), and with a volume of 2 sets of 15 repetitions. The mechanical (strength, impulse, and fatigue index) and physiological parameters (skin temperature and lactatemia) and the assessment of perceived exertion and dyspnea were monitored in both protocols. The IMPA used did not increase the swimming force, and skin temperature, decrease blood lactate concentration, or subjective perception of exertion and dyspnea after the high-intensity tethered swimming exercises. Positive correlations were found between mean force and blood lactate (without IMPA: r = 0.62, P = 0.02; with IMPA: r = 0.65, P = 0.01). The impulse was positively correlated with blood lactate (without IMPA: r = 0.71, P < 0.01; with IMPA: r = 0.56, P = 0.03). Our results suggest that new IMPA protocols, possibly with increased volume, should be developed in order to improve the performance of young swimmers.

Relationship between maximal oxygen uptake, within-set fatigue and between-set recovery during resistance exercise in resistance-trained men and women

BACKGROUND

The primary aim of this study was to examine the relationship between maximal oxygen update (V̇O2max) and within-set fatigue and between-set recovery during resistance exercise in men and women.

METHODS

We examined the relationship between V̇O2max and various indices of fatigue and recovery during parallel squats (3 sets, 90 s rest, 70% of 1RM to failure) and isokinetic knee extensions (3 × 10 maximal repetitions at 60 deg/s, 45 s rest) in 28 (age 27.0 ± 3.6 years) resistance-trained subjects (14 men and 14 women). We also examined whether there were sex differences in within-set fatigue and between-set recovery.

RESULTS

V̇O2max was weakly related to recovery and fatigue in both men and women (range of P-values for V̇O2max as a covariate; 0.312-0.998, range of R-values, 0.005-0.604). There were no differences between the sexes in fatigue within a set for the squat, but men showed less within-set fatigue than women in the first set of the isokinetic knee extension exercise (~ 8% torque loss difference, main effect of sex P = 0.034). Regarding recovery between sets, men showed greater relative peak power (P = 0.016) and peak torque (P = 0.034) loss between sets in both exercises, respectively, compared to women. Women also tended to complete more repetitions than men (main effect of sex, P = 0.057). Loss of peak torque between sets in knee extension was evident in both absolute and relative (%) values in men but not in women.

CONCLUSIONS

Our study suggests that aerobic capacity is weakly associated with within-set fatigue and between-set recovery in resistance training in both men and women. Women and men show comparable levels of within-set fatigue in the multi-joint squat, but women show more within-set fatigue during the single-joint isokinetic knee extension compared with men. In contrast, women recover better than men between sets in both exercises.

A Perspective on High-Intensity Interval Training for Performance and Health

Interval training is a simple concept that refers to repeated bouts of relatively hard work interspersed with recovery periods of easier work or rest. The method has been used by high-level athletes for over a century to improve performance in endurance-type sports and events such as middle- and long-distance running. The concept of interval training to improve health, including in a rehabilitative context or when practiced by individuals who are relatively inactive or deconditioned, has also been advanced for decades. An important issue that affects the interpretation and application of interval training is the lack of standardized terminology. This particularly relates to the classification of intensity. There is no common definition of the term "high-intensity interval training" (HIIT) despite its widespread use. We contend that in a performance context, HIIT can be characterized as intermittent exercise bouts performed above the heavy-intensity domain. This categorization of HIIT is primarily encompassed by the severe-intensity domain. It is demarcated by indicators that principally include the critical power or critical speed, or other indices, including the second lactate threshold, maximal lactate steady state, or lactate turnpoint. In a health context, we contend that HIIT can be characterized as intermittent exercise bouts performed above moderate intensity. This categorization of HIIT is primarily encompassed by the classification of vigorous intensity. It is demarcated by various indicators related to perceived exertion, oxygen uptake, or heart rate as defined in authoritative public health and exercise prescription guidelines. A particularly intense variant of HIIT commonly termed "sprint interval training" can be distinguished as repeated bouts performed with near-maximal to "all out" effort. This characterization coincides with the highest intensity classification identified in training zone models or exercise prescription guidelines, including the extreme-intensity domain, anaerobic speed reserve, or near-maximal to maximal intensity classification. HIIT is considered an essential training component for the enhancement of athletic performance, but the optimal intensity distribution and specific HIIT prescription for endurance athletes is unclear. HIIT is also a viable method to improve cardiorespiratory fitness and other health-related indices in people who are insufficiently active, including those with cardiometabolic diseases. Research is needed to clarify responses to different HIIT strategies using robust study designs that employ best practices. We offer a perspective on the topic of HIIT for performance and health, including a conceptual framework that builds on the work of others and outlines how the method can be defined and operationalized within each context.

A Systematic Review on the Physical, Physiological, Perceptual, and Technical-Tactical Demands of Official 3 × 3 Basketball Games

PURPOSE

To systematically review the physical, physiological, perceptual, and technical-tactical demands of official 3 × 3 basketball games.

METHODS

The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Three electronic databases (PubMed, Scopus, and Web of Science) were systematically searched to identify studies assessing physical, physiological, perceptual, and technical-tactical demands of 3 × 3 games. Data were also coded according to player sex and tournament phase. Quality assessment of the included studies was performed using a modified Downs and Black checklist.

RESULTS

Thirteen articles were finally included, with a mean quality of 8.6 (1.1) out of 11. Three-by-three basketball games have an intermittent profile (1:1 work-rest ratio), with a duration of ∼15 minutes, and are characterized by short (6-8 s) ball possessions and considerable physical (17-33 accelerations, 24-44 decelerations, 62-94 changes of directions, and 17-24 jumps per game) and physiological (lactate: ∼6.2 mmol·L-1) demands. Overall, the game performance profile is similar in males and females, with minor changes happening across tournament phases. Several key technical-tactical indicators were identified as discriminating winning and losing teams, such as better shooting and defensive efficiency, low number of turnovers, and implementing tactical actions involving more players, passing first, and ending possessions with shots from outside of the arch from the top of the key.

CONCLUSIONS

Three-by-three basketball is an intermittent, physically demanding sport characterized by quick plays and specific tactical constraints. This review provides information that should be considered by performance staff to improve training prescription, game tactical plans, and for player selection and talent identification.

[Diagnosis and treatment of osteoporosis in patients with chronic kidney disease : Joint guidelines of the Austrian Society for Bone and Mineral Research (ÖGKM), the Austrian Society of Physical and Rehabilitation Medicine (ÖGPMR) and the Austrian Society of Nephrology (ÖGN)]

DEFINITION AND EPIDEMIOLOGY

Chronic kidney disease (CKD): abnormalities of kidney structure or function, present for over 3 months. Staging of CKD is based on GFR and albuminuria (not graded). Osteoporosis: compromised bone strength (low bone mass, disturbance of microarchitecture) predisposing to fracture. By definition, osteoporosis is diagnosed if the bone mineral density T‑score is ≤ -2.5. Furthermore, osteoporosis is diagnosed if a low-trauma (inadequate trauma) fracture occurs, irrespective of the measured T‑score (not graded). The prevalence of osteoporosis, osteoporotic fractures and CKD is increasing worldwide (not graded). PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENT OF CHRONIC KIDNEY DISEASE-MINERAL AND BONE DISORDER (CKD-MBD): Definition of CKD-MBD: a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism; renal osteodystrophy; vascular calcification (not graded). Increased, normal or decreased bone turnover can be found in renal osteodystrophy (not graded). Depending on CKD stage, routine monitoring of calcium, phosphorus, alkaline phosphatase, PTH and 25-OH-vitamin D is recommended (2C). Recommendations for treatment of CKD-MBD: Avoid hypercalcemia (1C). In cases of hyperphosphatemia, lower phosphorus towards normal range (2C). Keep PTH within or slightly above normal range (2D). Vitamin D deficiency should be avoided and treated when diagnosed (1C).

DIAGNOSIS AND RISK STRATIFICATION OF OSTEOPOROSIS IN CKD

Densitometry (using dual X‑ray absorptiometry, DXA): low T‑score correlates with increased fracture risk across all stages of CKD (not graded). A decrease of the T‑score by 1 unit approximately doubles the risk for osteoporotic fracture (not graded). A T-score ≥ -2.5 does not exclude osteoporosis (not graded). Bone mineral density of the lumbar spine measured by DXA can be increased and therefore should not be used for the diagnosis or monitoring of osteoporosis in the presence of aortic calcification, osteophytes or vertebral fracture (not graded). FRAX can be used to aid fracture risk estimation in all stages of CKD (1C). Bone turnover markers can be measured in individual cases to monitor treatment (2D). Bone biopsy may be considered in individual cases, especially in patients with CKD G5 (eGFR < 15 ml/min/1.73 m2) or CKD 5D (dialysis).

SPECIFIC TREATMENT OF OSTEOPOROSIS IN PATIENTS WITH CKD

Hypocalcemia should be treated and serum calcium normalized before initiating osteoporosis therapy (1C). CKD G1-G2 (eGFR ≥ 60 ml/min/1.73 m2): treat osteoporosis as recommended for the general population (1A). CKD G3-G5D (eGFR < 60 ml/min/1.73 m2 to dialysis): treat CKD-MBD first before initiating osteoporosis treatment (2C). CKD G3 (eGFR 30-59 ml/min/1.73 m2) with PTH within normal limits and osteoporotic fracture and/or high fracture risk according to FRAX: treat osteoporosis as recommended for the general population (2B). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) with osteoporotic fracture (secondary prevention): Individualized treatment of osteoporosis is recommended (2C). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) and high fracture risk (e.g. FRAX score > 20% for a major osteoporotic fracture or > 5% for hip fracture) but without prevalent osteoporotic fracture (primary prevention): treatment of osteoporosis may be considered and initiated individually (2D). CKD G4-5D (eGFR < 30 ml/min/1.73 m2 to dialysis): Calcium should be measured 1-2 weeks after initiation of antiresorptive therapy (1C).

PHYSICAL MEDICINE AND REHABILITATION

Resistance training prioritizing major muscle groups thrice weekly (1B). Aerobic exercise training for 40 min four times per week (1B). Coordination and balance exercises thrice weekly (1B). Flexibility exercise 3-7 times per week (1B).

Relationships Between Internal and External Load Measures and Fitness Level Changes in Professional Soccer Players

Purpose: Understanding the dose-response relationship between internal and external training load with changes in aerobic fitness and intermittent running capacity, during different periods of the season, may help in optimizing training process. The aim of the present study was to investigate the dose-response relationships between load measures and changes in aerobic fitness and intermittent running capacity among a large cohort of professional soccer players. Methods: Training load, aerobic fitness and intermittent running capacity of 52 male adult professional players from 3 elite teams were monitored across an entire season and analyzed employing linear mixed models, with a significance level set at p≤0.05. Results: Relationships between load measures (training and match duration, sRPE-TL, total distance, high and very high-speed running distances) and changes in physical qualities were stronger during the preparation period (PREP) for both aerobic fitness (d= 0.48 to 0.76, p<0.031) and intermittent running capacity (d= 0.46 to 1.89, p<0.046). The magnitude of the relationships reduced during the first competitive period (d= 0.43 to 0.56) and the relationships became trivial in the second competitive period (d= 0.06 to 0.41, p= 0.063 to 0.846). Conclusion: The moderate to large relationships found between all measures of load and changes in physical capacities suggest that training prescription during the PREP was effective in improving players' fitness. During the competitive phase small changes in aerobic and intermittent running capacities were found, highlighting that coaching staff pursue different aims during the competitive period, such as technical and tactical training and recovery.       .

An Intense Bout of Acute Aerobic Exercise, but Not a Carbohydrate Supplement, Improves Cognitive Task Performance in a Sample of Black, Indigenous, and People of Color (BIPOC) Student Athletes

BACKGROUND

There are contradictory findings in the literature on whether an acute bout of aerobic exercise leads to a post-exercise improvement in cognitive function (CF). Moreover, participants used in the published literature are not representative of the racial make-up of sport or tactical populations.

METHODS

A randomized crossover design was incorporated, with participants randomly consuming water or a carbohydrate sports drink within the first 3 min of a graded maximal exercise test (GMET) conducted in a laboratory. Twelve self-identified African American participants, (seven males, five females, age = 21.42 ± 2.38 years, height = 174.94 ± 12.55 cm, mass = 82.45 ± 33.09 kg) completed both testing days. Participants completed the CF tests immediately pre- and post-GMET. CF was assessed with the Stroop color and word task (SCWT) and concentration task grid (CTG). Participants completed the GMET when they reported a score of 20 on the Borg ratings of perceived exertion scale.

RESULTS

Time to complete the SCWT incongruent task (p < 0.001) and CTG performance (p < 0.001) significantly improved post-GMET in both conditions. VO_2max was positively correlated with pre- and post-GMET SCWT performance.

CONCLUSIONS

The findings of our study suggest that an acute bout of maximal exercise significantly improves CF. Additionally, cardiorespiratory fitness is positively associated with CF in our sample of student athletes from a historically Black college and university.

Modified Isoinertial-Based Ruffier Test in Healthy Individuals: A Feasibility Study

Cardiorespiratory fitness is an essential indicator in sports science and sports medicine that can be assessed with several tests. The Ruffier test is a submaximal test valid to estimate maximum oxygen uptake; it consists of 30 squats in 45 s, which may be challenging for inexperienced individuals. This study aims to verify the feasibility of a modified inertial-based version of the Ruffier test to assess cardiorespiratory fitness with 10 squats in 15 s. Both classic and isoinertial Ruffier tests were administered to thirty-five healthy young adults (20 men and 15 women), age 22.06 ± 2.13 years, BMI 23.87 ± 2.74. The two one-sided test confirmed the comparability of the isoinertial Ruffier test with its classic version within equivalence bounds of ±3.726. Furthermore, gender, age, body weight, the difference between peak heart rate after isoinertial squatting and resting heart rate, and the isoinertial Ruffier index are the coefficients of our best VO₂max prediction model with an adjusted R² of 0.937, sensitivity of 0.89, and specificity of 0.81. The study evidenced the feasibility of the isoinertial Ruffier test to measure cardiorespiratory fitness through a quick, safe, and short squat test easy to perform in fitness centers and primary care clinics.

Notational Analysis and Physiological and Metabolic Responses of Male Junior Badminton Match Play

We examined the game characteristics of badminton and the physiological and metabolic responses in highly trained male junior players. Players from a Badminton England accredited Performance Centre (n = 10, age: 14.0 ± 1.2 y, height: 1.69 ± 0.06 m, body mass: 59.1 ± 5.0 kg) completed a 20-m shuttle run test (V˙O_2max: 64 ± 7 mL·kg^-1·min^-1) and a simulated ability-matched competitive singles badminton game consisting of two 12-min games with a 2-min break wearing the COSMED K5 metabolic system with notational analysis. In five games, 427 points were contested with a rally time of 5.7 ± 3.7 s, a rest time of 11.2 ± 5.9 s, shots per rally of 5.6 ± 3.6, work density of 0.50 ± 0.21, an effective playing time of 32.3 ± 8.4%, and shots frequency of 1.04 ± 0.29. During badminton play, heart rate was 151 ± 12 b·min^-1 (82 ± 10% of maximum heart rate), oxygen uptake was 39.2 ± 3.9 mL·kg^-1·min^-1 (62 ± 7% of V˙O_2max), and energy expenditure was 11.2 ± 1.1 kcal·min^-1 with a post-game blood lactate of 3.33 ± 0.83 mmol·L^-1. Compared to adult badminton play, the physiological responses of junior badminton are lower and may be due to the shorter rally durations. Male junior badminton players should be exposed to training methodologies which include rally durations in excess of what they encounter during match play so as to develop greater consistency. Our observations on game characteristics and physiological responses during junior badminton can be used to inform training practice.

Comparison of body composition components and anaerobic performance parameters of elite male motorcycle speedway riders between pre- and post-competitive season

The purpose of this study was to compare body composition components and anaerobic capacity indices in elite motorcycle speedway riders before and after the competitive season. This study included 12 volunteer male motorcycle speedway riders from the highest speedway league in Poland (PGE Speedway Ekstraliga) (age: 22.7 ± 6.0 years, body height: 171.3 ± 4.0 cm, body weight: 62.5 ± 3.1 kg). Before and after the competitive season, an assessment of body composition and Wingate test (WAnT) on a cycle ergometer with analysis of acute cardiorespiratory and biochemical responses was conducted. Sport level for all riders was defined by the number of heats won (WS), the total number of points scored in all heats including bonus points (PTS + B), and the percentage of heats won (%W). The motorcycle speedway riders participated in an average of 75.3 ± 15.0 total heats (HS) and obtained PTS + B equal 136.8 ± 48.2. The anaerobic performance, body composition, cardiorespiratory and biochemical responses did not changed after the competitive season. The significant statistical correlations were noted between the differences in the Fatigue Index during WAnT and total number of heats (r = -0.61) and with PTS + B (r = -0.58). Positively correlations were observed also between HS and differences: fat mass (FM) (r = 0.60) and percentage of fat mass (r = 0.61) (all p < 0.05). These findings reveal that the HS during the competitive season is related to the stabilization of anaerobic capacity in the WAnT. The HS is positively correlated with an increase in fat mass, and additional fat mass can adversely affect athletic performance in speedway.

What Parameters Influence the Effect of Cold-Water Immersion on Muscle Soreness? An Updated Systematic Review and Meta-Analysis

OBJECTIVE

Our objective was to determine the efficacy of cold-water immersion (CWI) on the management of muscle soreness to identify the impact of immersion time, water temperature, CWI protocol, and type of exercise on this outcome.

DESIGN

Intervention systematic review and meta-analysis.

SETTING

MEDLINE/PubMed, Embase, Central, and SPORTDiscus databases were searched from their earliest record to July 30, 2020. Only randomized controlled trials that assessed muscle soreness comparing CWI and control were included. Studies were pooled in different subgroups regarding the used protocol: water temperature (severe or moderate cold), immersion time (short, medium, or longer time), CWI protocol (intermittent or continuous application), and type of exercise (endurance or resistance exercise). Data were pooled in a meta-analysis and described as weighted mean difference (95% confidence interval, P < 0.05).

PARTICIPANTS

Athletes and nonathletes.

INTERVENTIONS

Cold-water immersion and control condition.

MAIN OUTCOME MEASURES

Muscle soreness.

RESULTS

Forty-four studies were included. For immediate effects, CWI was superior to control regardless of water temperature and protocol, and for short and medium immersion times and endurance exercises. For delayed effects, CWI was superior to control in all subgroups except longer immersions time.

CONCLUSIONS

This study suggests that CWI is better than control for the management of muscle soreness and water temperature and CWI protocol do not influence this result, but only short and medium immersions times presented positive effects. Aiming immediate effects, the best results suggest CWI application only after endurance exercises, while delayed effect CWI was superior both after endurance and resistance exercises.

[Diagnosis and management of patients with diabetes and co-existing osteoporosis (Update 2023) : Common guideline of the Austrian Society for Bone and Mineral Research and the Austrian Diabetes Society]

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. The identification and management of fracture risk in these patients remains challenging. This manuscript explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated areal bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (FRAX) in these patients. It further reviews the impact of diabetes drugs on bone tissue as well as the efficacy of osteoporosis treatments in this population. An algorithm for the identification and management of diabetic patients at increased fracture risk is proposed.

Protective effect of aerobic fitness on the detrimental influence of exhaustive exercise on information processing capacity

Although aerobic fitness has been thought to protect against the detrimental cognitive effects following exhaustive exercise, available evidence from studies using traditional mean behavioral measures remain somewhat equivocal.

PURPOSE

This study aimed to reconcile this discrepancy by using a novel theory-driven diagnostic tool, the Systems Factorial Technology (SFT).

METHODS

Sixty-six healthy young adults aged from 18 to 30 years old with different levels of aerobic fitness (n = 33 for the higher-fit and lower-fit groups) completed a go/nogo version of redundant-target task before and after a graded exercise test (GXT) until exhaustion. SFT was used to calculate the resilience capacity, which reflects the information processing capacity underlying inhibitory control.

RESULTS

Following the GXT, both higher-fit and lower-fit groups showed faster responses while leaving accuracy unchanged as compared to the performance at the pretest. On the other hand, the resilience capacity decreased for the lower-fit group but was maintained for the higher-fit group.

CONCLUSION

The present findings suggest that aerobic fitness may modulate the individual difference in decisional mechanism following exhaustive exercise. In sum, this study offers an alternative mechanistic explanation regarding cognitive individual differences in response to exhaustive exercise and provides novel insights into the significance of maintaining a state of high physical fitness for those who need to perform cognitively challenging tasks under physically stressful conditions (e.g., elite athletes).

External and Internal Load Variables Encountered During Training and Games in Female Basketball Players According to Playing Level and Playing Position: A Systematic Review

Background

Despite the growing global participation of females in basketball and number of studies conducted on the topic, no research has summarized the external and internal load variables encountered by female basketball players during training and games.

Objective

To collate existing literature investigating external and internal load variables during training and games in female basketball players according to playing level (club, high-school, representative, collegiate, semi-professional, and professional) and playing position (backcourt and frontcourt players).

Methods

A systematic review of the literature was performed using PubMed, SPORTDiscus, and Web of Science to identify studies published from database inception until June 11, 2021. Studies eligible for inclusion were observational and cross-sectional studies, published in English, reporting external and/or internal load variables during training sessions and/or games. Methodological quality and bias were assessed for each study prior to data extraction using a modified Downs and Black checklist. Weighted means according to playing level and playing position were calculated and compared if a load variable was reported across two or more player samples and were consistent regarding key methodological procedures including the seasonal phase monitored, minimum exposure time set for including player data (playing time during games), approach to measure session duration, and approach to measure session intensity.

Results

The search yielded 5513 studies of which 1541 studies were duplicates. A further 3929 studies were excluded based on title and abstract review, with 11 more studies excluded based on full-text review. Consequently, 32 studies were included in our review. Due to the wide array of methodological approaches utilized across studies for examined variables, comparisons could only be made according to playing level for blood lactate concentration during games, revealing backcourt players experienced higher lactate responses than frontcourt players (5.2 ± 1.9 mmol·L−1 vs. 4.4 ± 1.8 mmol·L−1).

Conclusions

Inconsistencies in the methods utilized to measure common load variables across studies limited our ability to report and compare typical external and internal loads during training and games according to playing level and position in female basketball players. It is essential that standardized methodological approaches are established for including player data as well as measuring session duration (e.g., total time, live time) and intensity (e.g., consistent rating of perceived exertion scales, intensity zone cut points) in future female basketball research to permit meaningful interpretation and comparisons of load monitoring data across studies.

Effects of a small-sided games training program in youth male soccer players: variations of the locomotor profile while interacting with baseline level and with the accumulated load

Purpose

This study aimed to (1) analyze the impact of a small-sided game training program in the locomotor profile of youth male soccer players (while interacting with the baseline level – higher and lower level); and (2) test the relationships between variation in locomotor profile and the accumulated demands in 3v3, 5v5 and match over the period of observation.

Methods

The cohort lasted 3-weeks. Twenty under-17 male amateur soccer players (16.8 ± 0.41 years; experience: 6.35 ± 0.67 years) were assessed twice for their final velocity at 30−15 intermittent fitness test (VIFT), peak speed at 30-m sprint test (PSS) and anaerobic speed reserve (ASR). The PSS was estimated using a Global Positioning System, while the VIFT was estimated using the maximum level attained by the players during the test. Based on the baseline levels, the scores were standardized using the Z-score. The total score of athleticism (TSA) was calculated per player to organize the players into two groups: lower TSA and higher TSA. Over the three weeks of observation, the small-sided games of 3v3 and 5v5 and match demands were monitored using polar team pro. The heart rate responses (mean and peak), distance covered (overall and split by speed thresholds), and peak speed in these games were obtained and summed over the weeks. The repeated measures ANCOVA tested the variations (time) of the locomotor profile of players while considering the baseline as covariable and the group as a factor. The Pearson-product correlation test analyzed the relationships between variations in locomotor profile (Δ, post-baseline) and the accumulated demands in 3v3, 5v5, and match.

Results

Between-groups analysis (lower TSA vs. higher TSA) revealed no significant differences on VIFT (p = 0.915), PSS (p = 0.269), ASR (p = 0.258) and TSA score (p = 0.138). Within-group (baseline vs. post-observation) analysis revealed significant difference on VIFT (p < 0.001), PSS (p = 0.008), while no significant differences were found on ASR (p = 0.949) and TSA score (p = 0.619). Significant correlations were found between ΔPSS and match total distance (r = 0.444; p = 0.050), match Z2 (r = 0.481; p = 0.032) and match Z3 (r = 0.454; p = 0.044). Significant correlations were found between ΔTSA and match total distance (r = 0.457; p = 0.043), match Z1 (r = 0.451; p = 0.046), match Z2 (r = 0.500; p = 0.025) and match Z3 (r = 0.468; p = 0.037).

Conclusion

Significant improvements were observed after the period of observation. However, the fitness baseline level and the accumulated training load in the small-sided games seem to have no significant impact on the observed improvements.

Tracking Health, Performance and Recovery in Athletes Using Machine Learning

Training and competitive periods can temporarily impair the performance of an athlete. This disruption can be short- or long-term, lasting up to several days. We analyzed the health indicators of 3661 athletes during an in-depth medical examination. At the time of inclusion in the study, the athletes were healthy. Instrumental examinations (fluorography, ultrasound examination of the abdominal cavity and pelvic organs, echocardiography, electrocardiography, and stress testing “to failure”), laboratory examinations (general urinalysis and biochemical and general clinical blood analysis), and examinations by specialists (ophthalmologist, otolaryngologist, surgeon, cardiologist, neurologist, dentist, gynecologist (women), endocrinologist, and therapist) were performed. This study analyzed the significance of determining the indicators involved in the implementation of the “catabolism” and “anabolism” phenotypes using the random forest and multinomial logistic regression machine learning methods. The use of decision forest and multinomial regression models made it possible to identify the most significant indicators of blood and urine biochemistry for the analysis of phenotypes as a characterization of the effectiveness of recovery processes in the post-competitive period in athletes. We found that the parameters of muscle metabolism, such as aspartate aminotransferase, creatine kinase, lactate dehydrogenase, and alanine aminotransferase levels, and the parameters of the ornithine cycle, such as creatinine, urea acid, and urea levels, made the most significant contribution to the classification of two types of metabolism: catabolism and anabolism.

Critical Power, Work Capacity, and Recovery Characteristics of Team-Pursuit Cyclists

PURPOSE

Leading a 4-km team pursuit (TP) requires high-intensity efforts above critical power (CP) that deplete riders' finite work capacity (W'), whereas riders following in the aerodynamic draft may experience some recovery due to reduced power demands. This study aimed to determine how rider ability and CP and W' measures impact TP performance and the extent to which W' can reconstitute during recovery positions in a TP race.

METHODS

Three TP teams, each consisting of 4 males, completed individual performance tests to determine their CP and W'. Teams were classified based on their performance level as international (INT), national (NAT), or regional (REG). Each team performed a TP on an indoor velodrome (INT: 3:49.9; NAT: 3:56.7; and REG: 4:05.4; min:s). Ergometer-based TP simulations with an open-ended interval to exhaustion were performed to measure individual ability to reconstitute W' at 25 to 100 W below CP.

RESULTS

The INT team possessed higher CP (407 [4] W) than both NAT (381 [13] W) and REG (376 [15] W) (P < .05), whereas W' was similar between teams (INT: 27.2 [2.8] kJ; NAT: 29.3 [2.4] kJ; and REG: 28.8 [1.6] kJ; P > .05). The INT team expended 104% (5%) of their initial W' during the TP and possessed faster rates of recovery than NAT and REG at 25 and 50 W below CP (P < .05).

CONCLUSIONS

The CP and rate of W' reconstitution have a greater impact on TP performance than W' magnitude and can differentiate TP performance level.

Physiological Responses at 15 Minutes of Recovery after a Session of Functional Fitness Training in Well-Trained Athletes

Background: the aim of this study was to analyse muscle fatigue and metabolic stress at 15 min of recovery after performing two independent sessions of functional fitness training (FFT): a session of strength functional fitness training (FFTstrength) and a session of endurance functional fitness training (FFTendurance). Methods: eighteen well-trained men conducted two protocols, separated by one week of rest: FFTstrength (3 sets of 21, 15 and 9 repetitions of Thruster with bar + Pull ups) and FFTendurance (3 sets × (30 kcal rowing + 15 kcal assault air bike)). Neuromuscular fatigue and metabolic stress were measured right before, right after and at 10 and 15 min after completing the FFT workout, as well as the mean heart rate (HRmean) and the rating of perceived exertion (RPE) at the end of the FFT. Results: FFTendurance recovered the velocity loss values after 15 min of recovery. On the other hand, FFTstrength only recovered velocity in the 1 m·s⁻¹ Tests in squat (SQ), since the velocity levels were 7% lower in the 1 m·s⁻¹ Tests in military press exercise (MP) after 15 min. Conclusions: These data indicate that there are specific recovery patterns not only as a function of the exercise and the body regions involved, but also regarding the recovery of neuromuscular and metabolic factors, since both FFT workouts obtained high blood lactate concentrations.

Hydration Influence on the Autonomic Recovery of the Coronary Diseases Patient: Geometric Indices Analysis

Purpose: To evaluate the recovery period of autonomic modulation, through geometric indices of heart rate variability (HRV), on coronary artery disease (CAD) patients submitted to a cardiovascular rehabilitation session (CR), associated with hydration. Methods: Thirty male participants of a CR program, diagnosed with CAD were submitted to the control (CP) and hydration protocol (HP) characterized by a CR session. Only during HP were the participants given 8 equal portions of water. The water amount was determined through the hydric loss measured at the CP. During the protocols, the heart rate was measured beat-by-beat at rest (5-10 minutes[M1]) and at recovery (0-5 minutes [M2], 5-10 minutes [M3], 15-20 minutes [M4], 25-30 minutes [M5], 40-45 minutes [M6], 55-60 minutes [M7]) for the HRV analysis, performed by the geometric indices: TINN, RRTRI, SD1, SD2 and SD1/SD2 ratio. Results: Statistically significant differences were observed between the protocols (SD1, p_value = 0.022), moments (TINN, p_value = 0.001; SD1, p_value = 0.019; SD2, p_value = 0.001; SD1/SD2, p_value = 0.001) and moments vs. protocol interaction (SD1, p_value = 0.019). The SD1 index pointed to acceleration of parasympathetic recovery in the first minutes after exercising (HP recovery after M3 [86.07 ± 32.31%] vs. CP recovery after M5[86.43 ± 24.56]) and increase in global variability (TINN-HP remained increased in longer, until M5 (M1 83.10 ± 55.76 ms to M5 116.82 ± 67.54 ms) vs. CP that remained increased for a short time, until M2 (M1 77.93 ± 68.56 ms to M2 134.82 ± 56.08 ms). Conclusions: In CAD patients, hydration promoted a more efficient recovery on parasympathetic autonomic modulation and increased the global HRV in the recovery period.

Acute Effects of Beetroot Juice Supplements on Lower-Body Strength in Female Athletes: Double-Blind Crossover Randomized Trial

BACKGROUND

Beetroot juice (BRJ) is used as an ergogenic aid, but no previous study has analyzed the effect this supplement has on the production of explosive force and muscular endurance in physically active women.

HYPOTHESIS

BRJ improves explosive force and muscular endurance in the lower limbs of physically active women.

STUDY DESIGN

Randomized double-blind crossover study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Fourteen physically active women performed a countermovement jump (CMJ) test, a back squat test for assessing velocity and power at 50% and 75% of one-repetition maximum (1RM), and the number of repetitions on a muscular endurance test consisting of 3 sets at 75% of 1RM in a resistance training protocol comprising 3 exercises (back squat, leg press, and leg extension). The participants performed the test in 2 sessions, 150 minutes after ingesting 70 mL of either BRJ (400 mg of nitrate) or a placebo (PLA).

RESULTS

A greater maximum height was achieved in the CMJ after consuming BRJ compared with a PLA (P = 0.04; effect size (ES) = 0.34). After a BRJ supplement at 50% 1RM, a higher mean velocity [+6.7%; P = 0.03; (ES) = 0.39 (-0.40 to 1.17)], peak velocity (+6%; P = 0.04; ES = 0.39 [-0.40 to 1.17]), mean power (+7.3%; P = 0.02; ES = 0.30 [-0.48 to 1.08]) and peak power (+6%; P = 0.04; ES = 0.20 [-0.59 to 0.98]) were attained in the back squat test. In the muscular endurance test, BRJ increased performance compared with the PLA (P < 0.00; η_p² = 0.651).

CONCLUSION

BRJ supplements exert an ergogenic effect on the ability to produce explosive force and muscular endurance in the lower limbs in physically active women.

CLINICAL RELEVANCE

If physically active women took a BRJ supplement 120 minutes before resistance training their performance could be enhanced.

Anaerobic performance after 3-day consecutive CO2-rich cold-water immersion in physically active males

Background Objective

We investigated the effects of a 3-day consecutive CO₂-rich cold (20 °C) water immersion (CCWI) following a high-intensity intermittent test (HIIT) on subjects' sublingual temperature (T_sub), blood lactate ([La]b), and heart rate (HR) compared to cold (20 °C) tap-water immersion (CWI) or passive recovery (PAS).

Methods

Thirty-two subjects were randomly allocated into three groups (CCWI, CWI, and PAS), each of which completed 4 consecutive days of cycling experiments. HR, T_sub, and [La]b were recorded on each day of exercise testing (immersion from Day 1 to Day 3 and Day 4). HIIT consisted of 8 sets of 20-sec maximum exercise at an intensity of 120% of VO₂max with 10-sec passive rest. The mean and peak power, and peak pedal repetitions (PPR) within HIIT were averaged and the decline in PPR (ΔPPR) from Day 1 to Day 4 was measured.

Results

In CCWI and CWI, HR declined significantly following each immersion, with CCWI showing the larger reduction (p < 0.001). At Day 2, CCWI showed a significantly lower [La]b compared to PAS (p < 0.01). The changes in mean and peak power from Day 1 to Day 4 did not differ among the groups (p = 0.302). ΔPPR of HIIT was significantly correlated with the HR and [La]b values after immersions (ΔPPR-HR: r² = 0.938, p < 0.001, ΔPPR-[La]b: r² = 0.999, p < 0.001).

Conclusions

These findings indicate that CCWI is a promising intervention for maintaining peak performance in high-intensity intermittent exercise, which is associated with a reduction in [La]b and HR.

The Effect of Acetaminophen on Running Economy and Performance in Collegiate Distance Runners

Acetaminophen (ACT) may decrease perception of pain during exercise, which could allow runners to improve running economy (RE) and performance. The aim of this study was to determine the effects of ACT on RE and 3 km time trial (TT) performance in collegiate distance runners. A randomized, double blind, crossover study was employed in which 11 track athletes (9M/2F; age: 18.8 ± 0.6 years; VO₂ max: 60.6 ± 7.7 mL/kg/min) completed three intervention sessions. Participants ingested either nothing (baseline, BSL), three gelatin capsules (placebo, PLA), or three 500 mg ACT caplets (ACT). One hour after ingestion, participants completed a graded exercise test consisting of 4 × 5 min steady-state stages at ~55–75% of VO₂ max followed by a 3 km TT. There was no influence of ACT on RE in any stage. Similarly, ACT did not favorably modify 3 km TT performance [mean ± SD: BSL = 613 ± 71 s; PLA = 617 ± 70 s; ACT = 618 ± 70 s; p = 0.076]. The results indicate that ACT does not improve RE or TT performance in collegiate runners at the 3 km distance. Those wanting to utilize ACT for performance must understand that ACT’s benefits have yet to be significant amongst well-trained runners. Future studies should examine the effects of ACT on well-trained runners over longer trial distances and under more controlled conditions with appropriate medical oversight.

Effects of Small-Sided Games Training versus High-Intensity Interval Training Approaches in Young Basketball Players

This study aimed to investigate the effects of the 6-week small-sided games training (SSGs) vs. high-intensity interval training (HIIT) on the psychophysiological and performance responses, and technical skills of young basketball players. Thirty-two male players (age: 14.5 ± 0.5 years of age) were randomly divided into SSGs group (n = 16) and HIIT group (n = 16) training methods thrice per week for 6 weeks. The players in the SSGs group performed two 5-8 min of 2 vs. 2 with 2 min rest periods, while the players in HIIT performed 12-18 min of runs at intensities (90 to 95%) related to the velocity obtained in the 30-15 intermittent fitness test (IFT). Pre-testing and post-testing sessions involved assessments of Yo-Yo Intermittent Recovery Test level 1, 30-15 intermittent fitness test, 5 and 30 m sprint times, vertical jump height, repeated sprint ability, defensive and offensive agility, and technical skills. The SSGs group demonstrated significantly higher agility-based technical responses in terms of the control dribbling and shooting skills (d = 1.71 vs. 0.20, d = 1.41 vs. 0.35, respectively) compared with the HIIT group. Conversely, the HIIT induced greater improvements in 30 m sprint times (d = 3.15 vs. 0.68). These findings provided that SSGs in youth basketball players may allow similar positive physical adaptations to HIIT, with an extra advantage of improving technical skills while improving enjoyability.

A Study on the Preliminary Validity Analysis of Korean Firefighter Job-Related Physical Fitness Test

The purpose of this study is to revise and modify the firefighter job-related performance tests from overseas to implement into the circumstances in Korea, examine its validity by analyzing the level of association between the test employed in the ongoing firefighter selection process, and propose a Korean firefighter job-related physical fitness test. Therefore, a modified version of Candidate Physical Ability Test (CPAT) from the United States firefighter selection process was conducted on 28 male firefighter officer candidates. Recorded results from VO2max, heart rate, blood lactate, anaerobic power test, and the ongoing Korean firefighter physical fitness test were analyzed to assess the validity of the modified test. IBM SPSS Statistics Ver. 27.0 was employed for the data correlation analysis in different fitness factors and the total circuit physical test time. The results revealed the proposed modified firefighter job-related physical fitness test showed significant correlation with VO2max (r = −0.450, p < 0.05), METS (r = −0.735, p < 0.01) recovery lactate over 15 min (r = −0.460, p < 0.05), peak power (r = −0.484, p < 0.05), average power (r = −0.647, p < 0.01), and in the ongoing firefighter physical fitness test, grip strength (r = −0.709, p < 0.01), lower back strength (r = −0.681, p < 0.01), standing long jump (r = −0.618, p < 0.01), sit-ups (r = −0.397, p < 0.05), and shuttle run (r = −0.523, p < 0.01). Fitness factors including VO2max, recovery lactate, anaerobic power, muscular strength, and so forth known to play a crucial role in firefighting operations were also shown to be important in the modified firefighter job-related physical fitness test. However, we suggest that studies with a larger sample size are needed in order to generalize our findings.

Impact of COVID-19 lockdown on professional soccer players' match physical activities

AIM

The COVID-19 pandemic forced the 2019-20 Italian Serie A competition to stop and players went into lockdown. During lockdown, players only trained at home, likely having a detrimental effect on players' physical fitness and capacity. This study investigated the effect of the COVID-19 lockdown on professional soccer players' match physical activities.

METHODS

Match activities of 265 male professional soccer players were assessed in two periods prior to (PRE1 and PRE2) and one period following the lockdown (POST) using a video tracking system. Linear mixed models were used to examine differences between-periods in total (TD), very high-speed (VHS), sprint (SPR), high-acceleration (ACC) and high-deceleration (DEC) distances, considering full match data and data from six 15-min intervals.

RESULTS

TD and VHS during POST were lower than the two other competitive periods (p < 0.001, d small-moderate). SPR did not show differences between periods (p > 0.636). ACC and DEC during POST were lower than PRE2 (p < 0.015, d small). Declines in most 15-min intervals after lockdown were observed in TD and VHS.

CONCLUSIONS

There were small differences in the temporal distribution of SPR, ACC and DEC at POST. After the COVID-19 lockdown, soccer players' higher-intensity running activities were similar to those of games played before the lockdown, but TD and VHS decreased, both considering the entire match and 15-min intervals. The temporal distribution of running activities was mostly stable throughout the season.

Monitoring Performance in Show Jumping Horses: Validity of Non-specific and Discipline-specific Field Exercise Tests for a Practicable Assessment of Aerobic Performance

Show jumping is a highly specialized equestrian discipline that requires technical skill but also power and fitness. Monitoring the horses’ aerobic performance is therefore essential in order to verify whether the training has induced the desired cardiovascular and muscular adaptations. This study therefore aimed at evaluating the validity of non-specific and discipline-specific field exercise tests for objective evaluation of aerobic performance in show jumpers. For this purpose, data obtained from horses competing at Junior and Young Rider level during show jumping competitions as well as field exercise tests were retrospectively analyzed. The effect of the level of difficulty, the horses’ age, the penalty score and the horses’ previous level of performance on blood lactate concentrations after show jumping competitions (100 observations in 49 horses) was evaluated by linear mixed effects models (horse as random effect). Estimated marginal means significantly increased from 140 (4.1 mmol/L) to 150 cm (5.2 mmol/L) classes (P = 0.02). Furthermore, post-exercise lactate values significantly increased with the horses’ age (P = 0.001). Another group of 12 horses performed a standardized incremental field exercise test on a track (SET_track), a standardized show jumping course (SET_course) and a standardized grid exercise (SET_grid) each on three consecutive days. Indices of aerobic performance, derived from the SET_track [velocity at a heart rate of 140 bpm (V₁₄₀) and at a lactate concentration of 2 mmol/L (V_La2)] were highly correlated with heart rate (V₁₄₀: r = −0.75, P = 0.005; V_La2: r =−0.66, P = 0.02) and lactate (V₁₄₀: r = −0.73, P = 0.02; V_La2: r = −0.72, P = 0.02) in response to SET_course as well as heart rate during SET_grid (V₁₄₀: r = −0.73, P = 0.02; V_La2: r = −0.76, P = 0.01). Subjective rating of muscular fatigue was significantly correlated to the mean heart rate during SET_course (r = −0.64, P = 0.05) and SET_grid (r = −0.74, P = 0.02) but not to the aerobic indices calculated from SET_track. Besides non-specific incremental field tests, performance monitoring in show jumpers should therefore also include discipline-specific tests that more closely reflect the internal load induced by show jumping competitions.

Fitness improvements of young soccer players after high volume or small sided games interventions

The main goal was to determine anaerobic and aerobic improvement of young soccer players after six-week high volume (HVT) or small sided games (SSG) training intervention. One hundred and one highly trained youth soccer players (16.2 ± 1.3 years) were divided into SSG (n = 51) and HVT groups (n = 50) and according to age into an under sixteen subgroup (U16), under seventeen subgroup (U17), and under nineteen subgroup (U19). The performance was assessed by Yo-Yo intermittent test, Repeated sprint ability test (RSA), and K-test before and after both training interventions. For U16 the SSG group recorded significant improvements in the K-test (0.64 ± 0.56 s; p = .04) and RSA (0.15 ± 0.43 s; p = .01). For U19 the SSG group recorded the same improvements, in the K-test (0.43 ± 0.57 s; p = .007), RSA (0.21 ± 0.22 s; p = .048), and Yo-Yo test (127.25 ± 17.87; p = .049). HVT improved aerobic performance when the Yo-Yo test was significantly better after intervention at U17 (199.00 ± 111.83 m; p = .030), U19 (88.40 ± 66.38 m; p = .049). In total, the HVT group spent 621 min (56.45 ± 5.01 min) of aerobic training and the Small sided game group spent 291 min (26.45 ± 8.61 min) of small sided games focused on aerobic performance. This study showed that both SSG and HVT training interventions were effective for aerobic improvement for the U19 category, but not for younger players. SSG was identified to be more appropriate to fitness development of soccer players.

How Fit Are Special Operations Police Officers? A Comparison With Elite Athletes From Olympic Disciplines

The diverse tasks of special operations police (SOP) units place high physical demands on every officer. Being fit for duty requires a wide range of motor abilities which must be trained regularly and in a structured manner. But SOP operators have to plan and manage large proportions of their training alone, which makes it difficult to control. Therefore, this study aimed to highlight strengths and deficits of the SOP operators' fitness by comparing them to elite athletes, and to define future training goals. Retrospective data of 189 male SOP operators were used, who completed several isometric strength tests, a graded exercise test to determine maximal oxygen uptake, and countermovement jumps to determine leg muscle power. On the basis of a literature search, performance data were then compared to a total of 3,028 elite male athletes from 36 Summer Olympic disciplines. Pooled means and standard deviations were calculated for each discipline and effect sizes were used to analyze their similarities and differences to the SOP unit. On average, SOP operators were taller, heavier, and stronger than elite athletes. But both the ability to convert this strength into explosive movement and aerobic power was significantly less developed. From this point of view, SOP operators should consider polarized endurance training to work efficiently on improving aerobic performance. In addition, regular plyometric training seems necessary to improve leg muscle power and agility.

A Comparative Study of Two-Minute versus Three-Minute Passive Recovery on Sprint Skating Performance of Ice Hockey Forwards and Defensemen

The impact of two different passive recovery durations, two and three minutes, between sets of repeated sprint skating ability (RSSA) test on skating speed, speed decrement (S_dec), and heart rate (HR) response of ice hockey forwards (n = 12) and defensemen (n = 7) were determined. Six sets of 3 × 80 m sprint, with two-minute passive recovery between two consecutive sets, were performed in RSSA-2. A three-minute passive recovery period between two consecutive sets was allowed in RSSA-3. Skating speed, S_dec, and HR were measured in all tests. Subjects skated faster (p < 0.05) in most of the RSSA-3 sets than the corresponding set of RSSA-2. Defensemen were slower (p < 0.05) than forwards in most of the cases. The S_dec was higher in defensemen than in forwards, although the difference was significant occasionally. No difference in peak HR and minimum HR between forwards and defensemen was found. RSSA-3 is beneficial over RSSA-2 in both forwards and defensemen by increasing speed. Defensemen are slower and show early fatigability than forwards, and no difference in HR response was noted between forwards and defensemen. This study concludes that three-minute recovery is beneficial over two-minute recovery by increasing skating speed, although S_dec and HR response neither vary significantly between RSSA-2 and RSSA-3, nor between forwards and defensemen.

Influence of the MCT1-T1470A polymorphism (rs1049434) on repeated sprint ability and blood lactate accumulation in elite football players: a pilot study

PURPOSE

The aim of this study is to investigate the influence of the MCT1 T1470A polymorphism (rs1049434) on repeated sprint ability (RSA) and lactate accumulation after RSA testing.

METHODS

Twenty-six elite Italian male football players (age: 17.7 ± 0.78 years; height: 179.2 ± 7.40 cm; weight: 72.1 ± 5.38 kg) performed RSA testing (6 × 30-m sprints with an active recovery between sprints), and lactate measurements were obtained at 1, 3, 5, 7, and 10 min post-exercise. Genotyping for the MCT1 T1470A polymorphism was performed using PCR.

RESULTS

Genotype distributions were in Hardy-Weinberg equilibrium, being 42% wildtype (A/A), 46% heterozygotes (T/A), and 12% mutated homozygotes (T/T). Significant differences between genotypic groups were found in the two final sprint times of the RSA test. Under a dominant model, carriers of the major A-allele (Glu-490) in the dominant model showed a significantly lower sprint time compared to footballers with the T/T (Asp/Asp) genotype (5th Sprint time: A/A + T/A = 4.60 s vs TT = 4.97 s, 95% CI 0.07-0.67, p = 0.022; 6th Sprint: A/A + T/A = 4.56 s vs T/T = 4.87 s, 95% CI 0.05-0.57, p = 0.033).

CONCLUSIONS

The T1470A (Glu490Asp) polymorphism of MCT1 was associated with RSA. Our findings suggest that the presence of the major A-allele (Glu-490) is favourable for RSA in football players.