Low-Volume High-Intensity Interval Versus Continuous Endurance Training: Effects on Hematological and Cardiorespiratory System Adaptations in Professional Canoe Polo Athletes

Selected Immunoendocrine and Physiological Performance Adaptations to Different Volume of Upper-Body Plyometric Training in National-Level Male Volleyball Players

PURPOSE

This study aimed to investigate the impact of a 6-week upper-body plyometric-training (PT) program with varying volumes on the immunoendocrine, physiological parameters, and physical performance adaptations in male volleyball players.

METHODS

Twenty-four trained college players were randomly allocated into 3 groups with 8 participants. Each group performed 5 exercises at maximal effort with differences in volume: low (3 sets of 7 repetitions), moderate (3 sets of 10 repetitions), and high (3 sets of 13 repetitions). The training program lasted 6 weeks with participants undertaking 3 sessions of PT per week.

RESULTS

Following the intervention, all groups exhibited significant (P = .001) improvements in physical and physiological parameters, as well as skill-based performances, with effect sizes ranging from small to very large. Comparative analysis of individual changes indicated that the high-volume group resulted in greater adaptive responses in the medicine-ball throw (P = .004), peak (P = .001) and average (P = .022) power output, push-ups (P = .001), and strength (P = .032) compared with the low-volume group. No significant between-groups difference (P > .05) was observed regarding immunoendocrine measures, reaction time, attacking, and serving skills.

CONCLUSIONS

The findings indicate that short-term upper-body PT positively influenced performance adaptations, emphasizing that the adaptive response to PT depends on the varying volumes. The study proposes that integrating higher volumes of PT results in more significant adaptive responses among volleyball players with the same immunoendocrine responses as the other training volumes.

Meta-analyses of the effects of high-intensity interval training in elite athletes-part I: mean effects on various performance measures

Introduction

Meta-analysts have found that high-intensity interval training (HIIT) improves physical performance, but limited evidence exists regarding its effects on highly trained athletes, measures beyond maximum oxygen uptake (V ˙ O2max), and the moderating effects of different types of HIIT. In this study, we present meta-analyses of the effects of HIIT focusing on these deficits.

Methods

The effects of 6 types of HIIT and other moderators were derived from 34 studies involving highly trained endurance and elite athletes in percent units via log-transformation from separate meta-regression mixed models for sprint, time-trial, aerobic/anaerobic threshold, peak speed/power, repeated-sprint ability,V ˙ O2max, and exercise economy. The level of evidence for effect magnitudes was evaluated based on the effect uncertainty and the smallest important change of 1%.

Results

Compared with control training, HIIT showed good to excellent evidence for the substantial enhancement of most measures for some athlete subgroups in practically important study settings defined by effect moderators (maximum of 12.6%, for endurance female athletes after 6 weeks of aerobic traditional long intervals). The assessment of the moderators indicated good evidence of greater effects as follows: with more aerobic types of HIIT forV ˙ O2max (+2.6%); with HIIT added to conventional training for most measures (+1.1-2.3%); during the competition phase forV ˙ O2max (+4.3%); and with tests of longer duration for sprint (+5.5%) and time trial (+4.9%). The effects of sex and type of athlete were unclear moderators. The heterogeneity of HIIT effects within a given type of setting varied from small to moderate (standard deviations of 1.1%-2.3%) and reduced the evidence of benefit in some settings.

Conclusion

Although athletes in some settings can be confident of the beneficial effects of HIIT on some measures related to competition performance, further research is needed. There is uncertainty regarding the mean effects on exercise economy and the modifying effects of sex, duration of intervention, phase of training, and type of HIIT for most measures.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=236384.

Optimizing concurrent training programs: A review on factors that enhance muscle strength

The purpose of this study is to explore the factors that should be considered when designing concurrent training programs to minimize the "interference effect." This study provides a comprehensive summary of various perspectives from existing studies on factors such as the ability level of the target group, the frequency and intensity of concurrent training, the order and interval time of resistance and endurance training, nutritional arrangements during training, and gender differences in concurrent training. The results of this study suggest that the emergence of the "interference effect" in concurrent training is influenced by several factors, with a particular emphasis on the adaptation status of muscle fitness when compared to resistance training alone. However, it is important to note that the current understanding of this theory remains somewhat ambiguous. The ability level of participants plays a crucial role in training adaptation and the specificity of post-training skeletal muscle molecular responses. Therefore, the participant's capacity level is likely a key determinant of the extent of the interference effect in concurrent training. In addition to training-related factors such as frequency, duration, intensity, volume, training sequence, recovery time, and nutritional intake, non-training-related variables, including the methodology used to assess various metrics, also significantly impact the design of concurrent training programs. These factors collectively influence the overall outcomes and provide insight into the extent of the "interference effect" in concurrent training. Understanding these aspects is essential for comprehending the phenomenon of the "interference effect" in concurrent training.

Effects of Short Sprint Interval Training Frequency on Physical and Physiological Performance Adaptations in Male Soccer Players

The study aimed to evaluate the effects of varying frequencies (1 vs. 2 vs. 3) of short sprint interval training (sSIT) on young male soccer players' physical performance and physiological parameters. Forty young male soccer players were randomly assigned to four experimental groups engaging in 36 trials sSIT for a duration of 6 weeks as follows: once weekly (1sSIT = 4 sets of 9 × 5 sec all-out runs), twice weekly (2sSIT = 2 sets of 9 × 5 sec all-out runs), and three times weekly (3sSIT = 2 sets of 6 × 5 sec all-out runs), or an active control group which continued their soccer practice routines. Before and after the 6-week training period, physical performance (countermovement vertical jump, 20-m sprint, Illinois change of direction, Yo-Yo intermittent recovery level 1 [Yo-Yo IR 1] and kicking distance) and physiological parameters (cardiorespiratory fitness, peak and average power output) were evaluated. All sSIT groups demonstrated significant (p < 0.01) and small to very large training effects (i.e., effect size) on measured parameters. More importantly, a comparison of inter-individual variability in the adaptive changes revealed that the 3sSIT group results in lower residuals in changes in cardiorespiratory fitness and anaerobic power, coupled with lower coefficient of variations in the mean group changes and perceived exertion throughout the training period. The findings indicate that incorporating one, two, or three weekly sessions of sSIT into routine soccer training can lead to similar enhancements in soccer players' physiological and performance adaptations. More importantly, higher training frequencies result in more homogenized adaptations among team members by reducing inter-individual variability in the magnitude of the adaptive responses.

Hematological and iron status in aerobic vs. anaerobic female athletes: an observational study

Introduction

Physical training induces iron status impairment in athletic females in the short term and over prolonged periods. Nevertheless, the existing literature lacks a comprehensive evaluation of the differential impacts of aerobic vs. anaerobic training on hematological indices and iron status among adolescent female athletes. The aim of this study was to assess the hematological factors and iron status in aerobic vs. anaerobic training in athletic females.

Methods

This observational, cross-sectional study recruited twenty-five adolescent athletic females; thirteen of them participated in an aerobic sport (long-distance running), while twelve of them participated in an anaerobic sport (broad jumping). Hematological factors were assessed by analyzing blood concentrations of hemoglobin (Hb), hematocrit (Hct), red blood cell (RBC) count, mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC), while the iron status assessment was conducted through evaluating levels of serum transferrin and serum ferritin.

Results

Athletic females who participated in the aerobic sport showed significantly lower Hb (MD -0.84; 95% CI -1.63: -0.04; p = 0.041), Hct (MD -5.49; 95% CI -7.86: -3.12; p = 0.0001), RBC count (MD -0.37; 95% CI -0.57: -0.17; p = 0.001), and MCV (MD -5.15; 95% CI -9.41: -0.89; p = 0.020), as well as significantly higher MCHC (MD 2.99; 95% CI 2.18: 3.79; p = 0.0001) and serum transferrin (MD 46.77; 95% CI 10.95: 82.59; p = 0.013) than athletic females who participated in the anaerobic sport. However, there was an insignificant difference in serum ferritin levels (MD -3.18; 95% CI -11.49: 5.13; p = 0.437) between both groups.

Conclusion

Except for the ferritin level that exhibited an insignificant difference between aerobic and anaerobic training, aerobic training was associated with a worse impact on the hematological factors and iron status than anaerobic training in adolescent athletic females.

Physiological and Performance Adaptations to Varying Rest Distributions During Short Sprint Interval Training Trials in Female Volleyball Players: A Comparative Analysis of Interindividual Variability

PURPOSE

This study aimed to examine the impact of different rest periods between short sprint interval training (SSIT) trials on the physiological and performance adaptations of female volleyball players.

METHODS

Twenty-four trained college athletes volunteered to participate in this study and were randomly assigned to 3 SSIT groups with different work-to-rest ratios (1:2 [5-s run:10-s rest], 1:4 [5-s run:20-s rest], and 1:6 [5-s work:30-s rest]). Before and after 6-week training, physiological parameters (maximum oxygen uptake, first and second ventilatory thresholds, and peak and mean power output) and physical performance measures (ie, countermovement vertical jump, 10-m sprint, and T-test change-of-direction speed) were evaluated.

RESULTS

After the training period, all groups improved (P = .001) their sport-related performance and physiological parameters, ranging from moderate to very large effect sizes. Comparative analysis of the magnitude of training effects indicated that the 1:6 SSIT group had in a significantly greater change in countermovement vertical jump (P = .007), 10-m sprint (P = .014), peak power output (P = .019), and mean power output (P = .05) compared with 1:2 SSIT group. By contrast, the 1:2 SSIT group demonstrated significantly (P = .022) greater changes in maximum oxygen uptake than the 1:6 SSIT group. However, the change-of-direction speed and changes in first and second ventilatory thresholds were the same among the groups (P > .05).

CONCLUSIONS

When performing SSIT, longer rest intervals are suitable for physical and anaerobic performance, and shorter rest periods are appropriate for enhancing the cardiorespiratory fitness of female volleyball players' performance.

The Effects of a 6-Week Plyometric and Sprint Interval Training Intervention on Soccer Player's Physical Performance

Despite the well-documented benefits of sprint interval training (SIT) and plyometric training (PT) in improving the physical fitness of soccer players, it remains unclear which of these training methods is superior for enhancing players' aerobic and anaerobic performance. Therefore, this study aimed to compare the effects of SIT and PT on physical performance measures of male soccer players. Thirty male soccer players were randomly assigned to PT (n = 10), SIT (n = 10), and an active control group (CON, n = 10). Before and after the training period, participants underwent a battery of tests consisting of vertical jump, Wingate, linear sprint with and without ball dribbling, change of direction, ball kick, and the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) tests. Both groups exhibited similar improvements in maximal kicking distance (PT, effect size [ES] = 0.68; SIT, ES = 0.92) and measures of aerobic fitness including maximum oxygen uptake (PT, ES = 1.24; SIT, ES = 1.26) and first (PT, ES = 0.85; SIT, ES = 1.08) and second (PT, ES = 0.86; SIT, ES = 0.98) ventilatory thresholds. However, PT intervention resulted in greater changes in vertical jump (ES = 1.72 vs. 0.82, p = 0.001), anaerobic power (peak power, ES = 1.62 vs. 0.97, p = 0.009; mean power, ES = 1.15 vs. 1.20, p = 0.05), linear speed (20-m, ES = -1.58 vs. -0.98, p = 0.038; 20-m with ball, ES = -0.93 vs. 0.71, p = 0.038), and change of direction ability (ES = -2.56 vs. -2.71, p = 0.046) than SIT. In conclusion, both PT and SIT demonstrated effectiveness in enhancing aerobic performance among male soccer players. However, PT yielded superior improvements in anaerobic power, vertical jump, linear speed, and change of direction performance compared to SIT. These findings suggest that PT may offer additional benefits beyond aerobic conditioning.

A Comparative Analysis of High-Intensity Technique-Specific Intervals and Short Sprint Interval Training in Taekwondo Athletes: Effects on Cardiorespiratory Fitness and Anaerobic Power

Technique-specific high-intensity interval training (HIITTS) has been proven to be an effective method to enhance the sport-specific bio-motor abilities of taekwondo athletes. However, studies regarding its effects on comprehensive measures of cardiorespiratory fitness are limited. Furthermore, there is a lack of clarity regarding the extent of individual adaptations to this method compared to HIIT in the form of repeated sprints (HIITRS). This study compared the individual adaptations to HIITRS and HIITTS on cardiorespiratory fitness and anaerobic power in trained taekwondo athletes (age = 19.8 ± 1.3 years; body mass = 75.4 ± 9.1 kg; height = 1.73 ± 0.0 .m). All participants completed three sessions per week of a 60-minute regular taekwondo training. Following the 60-minute training, participants completed 3 sets of 10 × 4 s all-out HIITRS or same sets of repeated kicks with both legs (HIITTS) over a 6-week training period. In both groups, rest intervals were set at 15 seconds between efforts and one minute between sets. Before and after the training period, participants underwent a series of lab- and field-based tests to evaluate cardiorespiratory fitness and bio-motor abilities. Both interventions resulted in significant improvements in maximum oxygen uptake (V̇O2max), O2 pulse (V̇O2/HR), first ventilatory threshold (VT1), second ventilatory threshold (VT2), cardiac output (Q̇max), stroke volume (SV), peak power output (PPO), average power output (APO), squat jump (SJ), and countermovement jump (CMJ). However, linear speed (20-m speed time) and taekwondo-specific agility test (TSAT) only responded to HIITRS. HIITRS resulted in greater changes in V̇O2max, V̇O2/HR, VT2, and Q̇max, and higher percentage of responders in measured parameters than HIITTS. In addition, HIITRS elicited lower inter-individual variability (CV) in percent changes from pre- to post-training in all measured variables. These results suggest that incorporating 3 sessions per week of HIITRS into regular taekwondo training results in significantly greater and more homogenized adaptations in cardiorespiratory fitness and bio-motor abilities than HIITTS among trained taekwondo athletes.

A Randomized Controlled Trial to Determine the Impact of Resistance Training versus Aerobic Training on the Management of FGF-21 and Related Physiological Variables in Obese Men with Type 2 Diabetes Mellitus

Fibroblast growth factor 21 (FGF-21) has been suggested as a potential therapeutic target for insulin resistance in health-related metabolic disorders such as type 2 diabetes. Despite the metabolic effects of resistance (RT) and aerobic training (AT) on diabetes symptoms, uncertainty exists regarding the superiority of effects manifested through these training approaches on FGF-21 and biochemical and physiological variables associated with metabolic disorders in men diagnosed with type 2 diabetes. This study aimed to investigate the impact of a 12-week RT and AT on FGF-21 levels and symptoms associated with metabolic disorders in male individuals diagnosed with type 2 diabetes. Thirty-six sedentary obese diabetic men (40 to 45 years old) were matched based on the level of FGF-1. They and were randomly divided into two training groups (RT, n = 12 and AT, n = 12) performing three days per week of moderate-intensity RT or AT for 12 weeks and an inactive control group (n = 12). Both training interventions significantly improved FGF-21, glucose metabolism, lipid profile, hormonal changes, strength, and aerobic capacity. Subgroup analysis revealed that RT had greater adaptive responses (p < 0.01) in fasting blood sugar (ES = -0.52), HOMA-IR (ES = -0.87), testosterone (ES = 0.52), cortisol (ES = -0.82), FGF-21 (ES = 0.61), and maximal strength (ES = 1.19) compared to AT. Conversely, AT showed greater changes (p < 0.01) in cholesterol (ES = -0.28), triglyceride (ES = -0.64), HDL (ES = 0.46), LDL (ES = -0.73), and aerobic capacity (ES = 1.18) compared to RT. Overall, both RT and AT interventions yielded significant moderate to large ES in FGF-21 levels and enhanced the management of biochemical variables. RT is an effective method for controlling FGF-21 levels and glucose balance, as well as for inducing hormonal changes. On the other hand, AT is more suitable for improving lipid profiles in overweight men with type 2 diabetes mellitus.

The effects of high-intensity interval training versus moderate-intensity continuous training on athletes' aerobic endurance performance parameters

OBJECTIVE

To systematically evaluate and meta-analyze the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on athletes of aerobic endurance performance parameters.

METHODS

PubMed, Web of Science, EBSCO, Embase, and Cochrane databases were searched. The assessment of quality was conducted employing The Cochrane Risk of Bias Assessment Tool, while heterogeneity examination and subgroup analysis were performed. Moreover, regression and sensitivity analyses were executed.

RESULTS

There was no significant difference between the effects of HIIT and MICT on the enhancement of athletes' running economy (RE) (P > 0.05); 1-3 weeks and 4-9 weeks of HIIT were more effective in improving athletes' maximum oxygen uptake (VO2max) (P < 0.05), and 10 weeks and above were not significant (P > 0.05); 1-3 weeks of HIIT was more effective in improving athletes' anaerobic threshold (AT) (P < 0.05), and 4-10 weeks was not significant (P > 0.05); 3 weeks of high-intensity interval training (HIIT) did not significantly enhance athletes' minute ventilation (VE) (P > 0.05), whereas a duration of 6-10 weeks yielded superior results (P < 0.05); 8 weeks of moderate-intensity continuous training (MICT) did not significantly enhance athletes' hemoglobin (Hb) level (P > 0.05), whereas a duration of 2-3 weeks yielded superior results (P < 0.05).

CONCLUSIONS

(1) HIIT and MICT have similar effects on enhancing athletes' RE. (2) 6-9 weeks' HIIT was more effective in improving athletes' VO2max and VE, and 3 weeks' HIIT was more effective in improving athletes' AT. (3) Within 3 weeks, MICT was more effective in improving the Hb level of athletes.

REGISTRATION NUMBER ON PROSPERO

CRD42024499039.

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.

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.

Optimal homeostatic stress to maximize the homogeneity of adaptations to interval interventions in soccer players

This study examined the uniformity of adaptations in cardiorespiratory fitness and bio-motor abilities by analyzing individual responses to measures representing the mentioned qualities. Twenty-four male well-trained soccer players (Age = 26 ± 4 years; stature = 181 ± 3.8; Weight = 84 ± 6.1) were randomized to two groups performing short sprint interval training [sSIT (3 sets of 10 × 4 s all-out sprints with 20 s of recovery between efforts and 3 min of rest intervals between sets)] or a time-matched small-sided game [SSG (3 sets of 3 v 3 efforts in a 20 × 15 m area with 3 min of relief in-between)]. Before and after the 6-week training period, aerobic fitness indices, cardiac hemodynamics, and anaerobic power were assessed through a graded exercise test utilizing a gas collection system, noninvasive impedance cardiography, and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring linear speed, change of direction, and jumping ability. Comparing inter-individual variability in the adaptive changes by analyzing residuals in individual adaptations indicated that sSIT induces more uniform changes in the first and second ventilatory threshold (VT1 & VT2), stroke volume, and peak power output across team members than SSG. SSG also yielded lower proportions of responders in V ˙ O 2 ⁡ max , VT1, VT2, peak, and average power output compared to sSIT. Additionally, the coefficient of variation in mean group changes in measures of aerobic fitness and bio-motor abilities in response to sSIT were lower than in SSG. Short sprint interval training induces more homogenized adaptations in measures of cardiorespiratory fitness and anaerobic power than small-sided games across team members.

How Does Altering the Volume-Load of Plyometric Exercises Affect the Inflammatory Response, Oxidative Stress, and Muscle Damage in Male Soccer Players?

Incorporating plyometric exercises (PE) into soccer players' conditioning routines is vital for boosting their performance. Nevertheless, the effects of PE sessions with diverse volume loads on inflammation, oxidative stress, and muscle damage are not yet clearly understood. This study aimed to examine the effects of altering the volume-loads of PE on indicators of oxidative muscle damage and inflammation. The study involved forty young male soccer players who were randomly assigned to three different volume-loads of PE (Low volume-load [100 jumps]: LVL, n = 10; Moderate volume-load [150 jumps]: MVL, n = 10; and High volume-load [200 jumps]: HVL, n = 10) and a control group (CON = 10). The levels of various biomarkers including delayed onset muscle soreness (DOMS), serum lactate dehydrogenase (LDH), creatine kinase (CK), 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), protein carbonyl (PC), leukocytes, neutrophils, interleukin-6 (IL-6), and C-reactive protein (CRP) were measured at different time points. These measurements were taken at rest, immediately after completion of PE, and 24-, 48-, and 72-hours post-PE. The CK, LDH, DOMS, 8-OHdG, MDA, and PC levels were significantly increased (p < 0.05) after the PE protocol, reaching their peak values between 24 to 48 hours post-PE for all the volume-loaded groups. The levels of leukocytes, neutrophils, and IL-6 also increased after the PE session but returned to resting values within 24 hours post-PE. On the other hand, CRP levels increased at 24 hours post-PE for all the treatment groups (p < 0.05). The changes observed in the indicators of muscle damage and inflammation in response to different volume-loads of PE was not significant. However, the HVL and MVL indicated significant differences compared to LVL in the 8-OHdG (at 48-hour) and MDA (at 72-hour). Athletes engaging in higher volume-loads demonstrated more pronounced responses in terms of biochemical variables (specifically, LVL < MVL < HVL); however, these changes were not statistically significant (except 8-OHdG and MDA).

Physiological and Biochemical Adaptations to a Sport-Specific Sprint Interval Training in Male Basketball Athletes

The present study compared the effects of incorporating traditional sprint interval training (SIT) or basketball-specific SIT (SSIT) into typical off-season training of male basketball players. Adaptations to and effect size (EF) of interventions on aerobic fitness [evaluated using Yo-Yo intermittent recovery test level-1 (Yo-Yo IR1)], change of direction [T-test (TT) and Illinois agility test (IAT)], vertical jump (VJ), standing long jump (SLJ), linear speed, maximal strength [one repetition maximum test in leg press (1RMLP)], and hormonal status were examined. Male athletes (age = 25.7 ± 2.0 years; height = 188.1 ± 7.9 cm; body mass = 85.9 ± 8.0 kg) were randomly assigned to one of three groups of SIT (n = 10): three sets of 10 × 15 sec all-out intervals with 1:1 recovery between bouts and a 3-min recovery between sets; SSIT (n = 10): the same intervals as SIT + basketball-specific ball drills while running; and CON (n = 10): two sessions per week of regular basketball technical and tactical drills. SIT and SSIT resulted in significant changes compared with baseline in maximal oxygen uptake (4.9%, ES = 2.22 vs. 6%, ES = 2.57), TT (-1.8%, ES =-0.46 vs. -2.7%, ES = -1.14), IAT (-4.5%, ES = -2.01 vs. -5.4%, ES = -1.93), VJ (7.5%, ES = 0.58 vs. 12%, ES = 0.95), linear sprint time (-2.9%, ES = -0.32 vs. -4.3%, ES = -0.69), Yo-Yo IR1 (18.5%, ES = 2.19 vs. 23.7%, ES = 2.56), serum testosterone (28%, ES = 1.52 vs. 29.7%, ES = 1.59), and cortisol (-6.53%, ES = -0.37 vs. -12.06%, ES = -0.64). Incorporating SIT and SSIT into typical off-season basketball training triggers adaptive mechanisms that enhance aerobic and anaerobic performance in male basketball players. The effect size values indicate more significant effects of SSIT than SIT in most physiological and sport-specific adaptations. Such a superior effect could be attributed to the more basketball-specific movement pattern of the SSIT. Such interventions can be used by the coaches and athletes for designing the training load and for better training adaptations throughout the training seasons and competition periods.

Applied high-intensity interval cardio yoga improves cardiometabolic fitness, energetic contributions, and metabolic flexibility in healthy adults

Purpose: Currently, there is no interventional approach to increase the intensity of Surya Namaskar a popular hatha yoga sequence used worldwide. Therefore, this study investigated how tempo-based high-intensity interval cardio yoga (HIICY) and traditional interval hatha yoga (TIHY) affects cardiometabolic fitness in active adults. Methods: Twenty physically active male and female individuals were randomly separated into HIICY (5 males, 5 females, 1.5 s tempo) and TIHY (5 males, 5 females, 3 s tempo) groups. The intervention included twelve exercise sessions for 4 weeks in both groups. Participants conducted a ramp test to determine their maximal oxygen uptake (V ˙ O2max), maximal velocity at V ˙ O2max (vV ˙ O2max), and maximal heart rate (HRmax). Afterward, they performed a 10-min high-intensity cardio yoga test (HICYT) to determine heart rate (HRpeak and HRmean), oxygen uptake (V ˙ O2peak and V ˙ O2mean), respiratory exchange ratio (RER), blood lactate concentrations (La- peak and ∆La-), fat and carbohydrate oxidations (FATox, CHOox), and energetic contributions (oxidative; W Oxi, glycolytic; W Gly, and phosphagen; W PCr, total energy demand; W Total). Results: V ˙ O2max and vV ˙ O2max showed time and group × time interactions (p < 0.01, p < 0.0001, p < 0.001, respectively). V ˙ O2max after HIICY was significantly higher than in pre-testing and following TIHY (p < 0.001, p < 0.0001, respectively). V ˙ O2peak, V ˙ O2mean, RER, HRpeak, and HRmean during the 10-min HICYT showed significant time effects (p < 0.05). ∆La- indicated a group × time interaction (p < 0.05). Group x time interaction effects for FATox at the fourth and sixth minute were observed (p < 0.05, respectively). Absolute (kJ) and relative (%) W Oxi, W Gly, and W Total showed time and group × time interaction effects (p < 0.05, p < 0.01, respectively). Furthermore, %W Gly was reduced following HIICY (p < 0.05). Additionally, V ˙ O2max and vV ˙ O2max were highly correlated with W Oxi in kJ (r = 0.91, 0.80, respectively). Moderate to high correlations were observed among CHOox, FATox, and absolute V ˙ O2max (r = 0.76, 0.62, respectively). Conclusion: A 4-week period of HIICY improved cardiometabolic fitness, oxidative capacity, and metabolic flexibility compared with TIHY, in physically active adults. Therefore, HIICY is suitable as HY-specific HIIT and time-efficient approach for relatively healthy individuals.

Comparative analysis of cardiorespiratory fitness, bio-motor abilities, and body composition indicators among sprint kayakers of different age groups and expertise levels

This study compared cardiorespiratory fitness, bio-motor abilities, and body composition indexes of sprint kayakers categorized into three different age groups and two expertise levels of international- and club-level athletes. Seventy-three male juniors (n = 14, age = 16.2 ± 0.8), under 23 [U23 (n = 15, age = 20.2 ± 1.6)], professionals (n = 16, age = 27.1 ± 4.8), club-level (n = 15, age = 26.9 ± 6.6), and international-level (n = 13, age = 27.3 ± 3.2) sprint kayakers were studied. Cardiorespiratory fitness (assessed using incremental exercise test), 500 and 1,000-m paddling performance (assessed using kayak ergometer), upper-body power (assessed using 30 s all-out Wingate test) and strength (assessed through one repetition tests for bench press, cable row, and prone bench pull exercises), as well as body composition indexes (measured using dual-energy X-ray absorptiometry) were evaluated on four occasions separated by 48 h recovery. U23 and, especially, professionals indicated significantly (p < 0.05) greater outcomes for the majority of the cardiorespiratory fitness parameters [maximal oxygen uptake (VO2max), velocity corresponding to VO2max, Oxygen pulse, maximal ventilation, and second ventilatory threshold] and 500 and 1,000-m performance. U23 and professional sprint kayakers significantly (p < 0.05) differed in the first ventilatory threshold and 500, and 1,000-m performance but not in VO2max or the second ventilatory threshold. Professionals also showed a lower fat mass, higher muscle mass, and higher strength (bench press, prone bench pull, and seated cable row) and power than U23 and junior kayakers. Strength and power indicators had significantly greater values in U23 athletes compared to juniors. International-level athletes also showed superior VO2max, velocity corresponding to VO2max, middle (500-m), and long-distance (1,000-m) time trial performance, strength and power, lower fat, and higher muscle mass than club-level sprint kayakers. Cardiorespiratory fitness (particularly ventilatory threshold), body composition, and muscle strength/power are the best differentiating factors for sprint kayakers of different ages and expertise levels. These findings could aid coaches in prescribing training programs focusing on improving determining factors in paddling performance, as well as in predicting performance and identifying talent.

The Effects of Incorporating Dry-land Short Intervals to Long Aerobic-dominant In-Water Swimming Training on Physiological Parameters, Hormonal Factors, and Performance: A Randomized-Controlled Intervention Study

This study investigated the impact of a 4-week dry-land short sprint interval program (sSIT) on a swim ergometer, when incorporated into long aerobic-dominant in-water swimming training, on the physiological parameters, hormonal factors, and swimming performance of well-trained swimmers. Sixteen participants (age = 25 ± 6 years, height = 183 ± 6 cm, weight 78 ± 6 kg, body fat = 10.6 ± 3.1%) were randomized to either a long aerobic-dominant in-pool training plus three sessions/week of sSIT or a control group (CON) who didn't engage in SIT. sSIT consisted of 3 sets of 10 × 4 s, 10 × 6 s, and 10 × 8 s all-out sprints interspersed by 15, 60, and 40 s recovery between each sprint, respectively. Pre- and post-training assessments included peak oxygen uptake (V̇O2peak), O2pulse (V̇O2/HR), ventilation at V̇O2peak (V̇E@V̇O2peak), peak and average power output, and freestyle swim performance at 50, 100, and 200-m distances, stroke rate, as well as testosterone and cortisol. sSIT resulted in significant improvements in V̇O2peak (5.8%), O2pulse (4.7%), V̇E@V̇O2peak (7.1%), peak and average power output (6.7% and 13.8%, respectively), total testosterone (20%), testosterone to cortisol ratio (16.1%), and 50, 100, and 200-m freestyle swimming performance (-2.2%, -1.2%, and -1.1%, respectively). Furthermore, the observed alterations in the physiological, biochemical, and performance adaptations were significantly more substantial in the sSIT group than the CON group (p ≤ 0.05), demonstrating no modifications during the 4-week long aerobic-dominant in-water swimming without sSIT. The current research effectively established that supplementing standard long aerobic-dominant in-water swim training with three weekly dry-land sSIT sessions triggers adaptive mechanisms that foster enhancements in the aerobic and anaerobic capacity and swimming performance in well-trained swimmers.

Effects of a paddling-based high-intensity interval training prescribed using anaerobic speed reserve on sprint kayak performance

The aim of this study was to investigate physiological and performance adaptations to high-intensity interval training (HIIT) prescribed as a proportion of anaerobic speed reserve (ASR) compared to HIIT prescribed using maximal aerobic speed (MAS). Twenty-four highly trained sprint kayak athletes were randomly allocated to one of three 4-weak conditions (N = 8) (ASR-HIIT) two sets of 6 × 60 s intervals at ∆%20ASR (MAS-HIIT) six 2 min paddling intervals at 100% maximal aerobic speed (MAS); or controls (CON) who performed six sessions/week of 1-h traditional endurance paddling at 70%-80% maximum HR. A graded exercise test was performed on a kayak ergometer to determine peak oxygen uptake (V̇O_2peak), MAS, V̇O₂/HR, and ventilatory threshold. Also, participants completed four consecutive upper-body wingate tests to asses peak and average power output. Significant increases in V̇O_2peak (ASR-HIIT = 6.9%, MAS-HIIT = 4.8%), MAS (ASR-HIIT = 7.2%, MAS-HIIT = 4.8%), ASR (ASR-HIIT = -25.1%, MAS-HIIT = -15.9%), upper-body Wingate peak power output and average power output (p < 0.05 for both HIIT groups) were seen compared with pre-training. Also, ASR-HIIT resulted in a significant decrease in 500-m - 1.9 % , and 1,000 - m   - 1.5 % paddling time. Lower coefficient of variation values were observed for the percent changes of the aforementioned factors in response to ASR-HIIT compared to MAS-HIIT. Overall, a short period of ASR-HIIT improves 500-m and 1,000-m paddling performances in highly trained sprint kayak athletes. Importantly, inter-subject variability (CV) of physiological adaptations to ASR-HIIT was lower than MAS-HIIT. Individualized prescription of HIIT using ASR ensures similar physiological demands across individuals and potentially facilitates similar degrees of physiological adaptation.

Lymphocyte and dendritic cell response to a period of intensified training in young healthy humans and rodents: A systematic review and meta-analysis

Background: Intensified training coupled with sufficient recovery is required to improve athletic performance. A stress-recovery imbalance can lead to negative states of overtraining. Hormonal alterations associated with intensified training, such as blunted cortisol, may impair the immune response. Cortisol promotes the maturation and migration of dendritic cells which subsequently stimulate the T cell response. However, there are currently no clear reliable biomarkers to highlight the overtraining syndrome. This systematic review and meta-analysis examined the effect of intensified training on immune cells. Outcomes from this could provide insight into whether these markers may be used as an indicator of negative states of overtraining. Methods: SPORTDiscus, PUBMED, Academic Search Complete, Scopus and Web of Science were searched until June 2022. Included articles reported on immune biomarkers relating to lymphocytes, dendritic cells, and cytokines before and after a period of intensified training, in humans and rodents, at rest and in response to exercise. Results: 164 full texts were screened for eligibility. Across 57 eligible studies, 16 immune biomarkers were assessed. 7 were assessed at rest and in response to a bout of exercise, and 9 assessed at rest only. Included lymphocyte markers were CD3⁺, CD4⁺ and CD8⁺ T cell count, NK cell count, NK Cytolytic activity, lymphocyte proliferation and CD4/CD8 ratio. Dendritic cell markers examined were CD80, CD86, and MHC II expression. Cytokines included IL-1β, IL-2, IL-10, TNF-α and IFN-γ. A period of intensified training significantly decreased resting total lymphocyte (d= -0.57, 95% CI -0.30) and CD8⁺ T cell counts (d= -0.37, 95% CI -0.04), and unstimulated plasma IL-1β levels (d= -0.63, 95% CI -0.17). Resting dendritic cell CD86 expression significantly increased (d = 2.18, 95% CI 4.07). All other biomarkers remained unchanged. Conclusion: Although some biomarkers alter after a period of intensified training, definitive immune biomarkers are limited. Specifically, due to low study numbers, further investigation into the dendritic cell response in human models is required.

Canoe polo Athletes' Anthropometric, Physical, Nutritional, and Functional Characteristics and Performance in a Rowing Task: Cross-Sectional Study

Understanding the physical, functional, mental, and nutritional attributes of canoe polo athletes is essential for training and development. Forty-three canoe polo athletes (mean age: 21.54 ± 6.03) participated in the study and were assessed for: anthropometric measurements, exercise motivation, eating habits, adherence to the Mediterranean Diet, and physical and functional abilities. Correlation and multivariate analysis were conducted. Individual performance in a rowing task showed body mass index (β = 0.41) and female gender (β = 0.34) to be the strongest anthropometric predictors, whereas body fat (β = -0.35) and triceps brachii skinfold fatty tissue (β = -0.35) were the strongest negative predictors. Pushing strength (β = 0.37) and range of motion with internal rotation (β = 0.30) were the strongest physical predictors. The physical dimension of the Exercise Motivation Index was a significant psychosocial predictor (β = 0.27). Senior participants had a higher waist-hip ratio (p = 0.04, d = 0.66), arm circumference (p = 0.03, d = 0.68), handgrip strength (p < 0.01, d = 1.27), and push strength (p < 0.01, d = 1.42) than under 21-year-olds. Understanding the highlighted sport-specific characteristics of canoe polo athletes can help trainers to design programs at all levels to optimize performance.

High-intensity interval training modulates inflammatory response in Parkinson's disease

Background

Recent discoveries show that high-intensity interval training (HIIT) can bring many positive effects such as decreases in fat tissue, lower blood sugar levels, improved learning and memory, and lower risk of cardiac disease. Parkinson’s disease (PD) is a neurodegenerative disorder characterized by loss of the dopaminergic neurons, accompanied by chronic inflammation and neuroinflammation. Previous research shows that interval training can bring a beneficial effect on the inflammation and neuroplasticity in PD.

Objectives

The objective of this study was to investigate the effect of 12 weeks of HIIT on the inflammation levels and antioxidant capacity in the serum of PD patients.

Methods

Twenty-eight people diagnosed with PD were enrolled in this study. Fifteen PD patients performed 12 weeks of HIIT on a cycloergometer. Thirteen non-exercised PD patients constitute the control group. Concentrations of inflammation markers and antioxidants’ capacity in the serum were measured at 3 sampling points (a week before, a week after, and 3 months after the HIIT).

Results

Twelve weeks of HIIT decreases the level of TNF-α (p = 0.034) and increases the level of IL-10 (p = 0.024). Those changes were accompanied by a decreased level of neutrophils (p = 0.03), neutrophil/lymphocyte ratio (p = 0.048) and neutrophil/monocyte ratio (p = 0.0049) with increases in superoxide dismutase levels (p = 0.04).

Conclusions

Twelve weeks of HIIT can decrease systemic inflammation in PD patients and improve the antioxidant capacity in their serum, which can slow down the progression of the disease.

Effects of a New Form of Resistance-Type High-Intensity Interval Training on Cardiac Structure, Hemodynamics, and Physiological and Performance Adaptations in Well-Trained Kayak Sprint Athletes

This study examined the effects of a resistance-type high-intensity interval training (RHIIT) matched with the lowest velocity that elicited V.O_2peak (100% vV.O_2peak) in well-trained kayak sprint athletes. Responses in cardiac structure and function, cardiorespiratory fitness, anaerobic power, exercise performance, muscular strength, and hormonal adaptations were examined. Male kayakers (n = 24, age: 27 ± 4 years) were randomly assigned to one of three 8-wk conditions (N = 8): (RHIIT) resistance training using one-armed cable row at 100% vV.O_2peak; paddling-based HIIT (PHIIT) six sets of paddling at 100% vV.O_2peak; or controls (CON) who performed six sessions including 1-h on-water paddling/sessions at 70–80% maximum HR per week. Significant increases (p < 0.05) in V.O_2peak, vV.O_2peak, maximal cardiac output, resting stroke volume, left ventricular end-systolic dimension, 500-m paddling performance were seen pre- to post-training in all groups. Change in V.O_2peak in response to PHIIT was significantly greater (p = 0.03) compared to CON. Also, 500-m paddling performance changes in response to PHIIT and RHIIT were greater (p = 0.02, 0.05, respectively) than that of CON. Compared with pre-training, PHIIT and RHIIT resulted in significant increases in peak and average power output, maximal stroke volume, end-diastolic volume, ejection fraction, total testosterone, testosterone/cortisol ratio, and 1,000-m paddling performance. Also, the change in 1,000-m paddling performance in response to PHIIT was significantly greater (p = 0.02) compared to that of CON. Moreover, maximum strength was significantly enhanced in response to RHIIT pre- to post-training (p < 0.05). Overall, RHIIT and PHIIT similarly improve cardiac structure and hemodynamics, physiological adaptations, and performance of well-trained kayak sprint athletes. Also, RHIIT enhances cardiorespiratory fitness and muscular strength simultaneously.

Beyond the Finish Line: The Impact and Dynamics of Biomarkers in Physical Exercise-A Narrative Review

The research of biomarkers continues to emerge as a developing academic field which is attracting substantial interest. The study of biomarkers proves to be useful in developing and implementing new screening methods for a wide variety of diseases including in the sports area, whether for leisure activities or professional sports. Novel research has brought into question the immune system and the limitations it may impose on sports practicing. As the well-being of athletes is a priority, the state of their immune function offers valuable information regarding their health status and their ability to continue training. The assessment of various biomarkers may contribute to a more accurate risk stratification and subsequent prevention of some invalidating or even fatal pathologies such as the sudden cardiac death. Therefore, we have reviewed several studies that included sports-related pathology or specific morphofunctional alterations for which some immune biomarkers may represent an expression of the underlying mechanism. These include the defensins, immunoglobulin A (IgA), interleukin-6 (IL-6), the tumoral necrosis factor α (TNF-α), and the white blood cells (WBC) count. Similarly, also of significant interest are various endocrine biomarkers, such as cortisol and testosterone, as well as anabolic or catabolic markers, respectively. Literature data highlight that these values are greatly influenced not only by the duration, but also by the intensity of the physical exercise; moderate training sessions actually enhance the immune function of the body, while a significant increase in both duration and intensity of sports activity acts as a deleterious factor. Therefore, in this paper we aim to highlight the importance of biomarkers’ evaluation in connection with sports activities and a subsequent more adequate approach towards personalized training regimens.

Caffeine co-ingested with carbohydrate on performance recovery in national-level paddlers: a randomized, double-blind, crossover, placebo-controlled trial

BACKGROUND

Caffeine enhances muscle glycogen re-synthesis post exercise; however, the next-day effects on recovery are unknown. The present study aimed to examine the effects of carbohydrate (CHO) supplementation with or without caffeine (CAF) 24-h following exhaustive exercise on time trial performance in elite paddling athletes.

METHODS

Nine highly trained male paddlers (21 ± 2 y) completed three experimental trials in a randomized, double-blind, crossover manner. Following an exhaustive exercise session (20-km timed paddle) participants ingested: (i) 0.6 g/kg of carbohydrate (CHO), (ii) 0.6 g/kg of carbohydrate with 6 mg/kg of caffeine (CAF+CHO), (iii) or placebo (PLA), at four time-points (immediately after, and 2, 6, and 12-h post-exercise) in addition to their typical dietary intake. After 24 h, 5 attempts of on-water 500-m paddling time-trial was performed, and the average time was recorded. Blood samples were taken at rest and following both the 20-km and the 5×500 m exercise to determine changes in plasma cortisol, insulin, and glucose.

RESULTS

There was a significant main effect of condition (P<0.001), with post hoc analysis revealing that both CHO conditions (CHO: 98.7 ± 2.8 s, P = 0.0003; CAF+CHO: 97.9 ± 2.3 s, P = 0.0002) were significantly faster compared to PLA (101.0 ± 3.1 s), however CAF did not augment time trial performance compared to CHO (P = 0.16). There was no significant condition by time interactions for glucose, cortisol, or insulin before and after the 20-km depleting exercise and 500-m time trial.

CONCLUSIONS

In elite male paddlers, CHO, independent of caffeine, enhanced time trial performance 24 hours following exhaustive exercise.

Acute and Chronic Effects of Interval Training on the Immune System: A Systematic Review with Meta-Analysis

Simple Summary

Interval training (IT) is a popular training strategy recognized by its positive effects on metabolic and cardiovascular system. However, there seems no consensus regarding the effects of IT on immune system parameters. Therefore, we aimed to summarize the evidence regarding the effects of IT on the immune system. As our many findings, an IT acutely promote a transitory change on immune cell count followed by reduced function. The magnitude of these changes seems to vary in accordance with IT type. On the other hand, the regular practice of IT might contribute to improve immune function without apparent change on immune cell count.

Abstract

Purpose: To summarize the evidence regarding the acute and chronic effects of interval training (IT) in the immune system through a systematic review with meta-analysis. Design: Systematic review with meta-analysis. Data source: English, Portuguese and Spanish languages search of the electronic databases Pubmed/Medline, Scopus, and SciELO. Eligibility criteria: Studies such as clinical trials, randomized cross-over trials and randomized clinical trials, investigating the acute and chronic effects of IT on the immune outcomes in humans. Results: Of the 175 studies retrieved, 35 were included in the qualitative analysis and 18 in a meta-analysis. Within-group analysis detected significant acute decrease after IT on immunoglobulin A (IgA) secretory rate (n = 115; MD = −15.46 µg·min⁻¹; 95%CI, −28.3 to 2.66; p = 0.02), total leucocyte count increase (n = 137; MD = 2.58 × 10³ µL⁻¹; 95%CI, 1.79 to 3.38; p < 0.001), increase in lymphocyte count immediately after exercise (n = 125; MD = 1.3 × 10³ µL⁻¹; 95%CI, 0.86 to 1.75; p < 0.001), and decrease during recovery (30 to 180 min post-exercise) (n = 125; MD = −0.36 × 10³ µL⁻¹;−0.57 to −0.15; p < 0.001). No effect was detected on absolute IgA (n = 127; MD = 47.5 µg·mL⁻¹; 95%CI, −10.6 to 105.6; p = 0.11). Overall, IT might acutely reduce leucocyte function. Regarding chronic effects IT improved immune function without change leucocyte count. Conclusion: IT might provide a transient disturbance on the immune system, followed by reduced immune function. However, regular IT performance induces favorable adaptations on immune function.

Mood States and Performance in Elite Canoe Polo Players: The Mediating Role of Stress

Sport performance is characterized by competitive stressful conditions that elicit emotional states. The purpose of the study was to examine whether stress mediated the relationship between mood states and performance. Thirty-two elite canoe polo players from four different Italian teams (16 senior males and 16 senior females), aged between 29 and 38 years old (M = 32.3, SD = 2.71), participated in the study. Measures included level of psychological stress, six mood dimensions, and performance outcome. We also detected the digit ratio-the lower second-to-fourth digit length (2D:4D) ratio-as it was demonstrated to be correlated to high sports performance. The assessment took place one day before the first game of the national competition "ITALY CUP". Male athletes reported lower scores on dysfunctional emotion-related states and on 2D:4D ratio than female athletes. The results of the mediation analysis showed that psychological stress plays a mediating role between moods and performance. Overall, given the limited literature, the findings supported an integrative approach to the study of the linkage between emotion and action in canoe polo.

Power profile, physiological characteristics and their correlation in elite canoe polo players

BACKGROUND

This study aimed to examine the physical capabilities of elite canoe polo players and to identify interrelationships between anthropometric or physiological characteristics and performance on a kayak ergometer.

METHODS

Eight male participants (age 24.6±4.8 years, weight 84.1±5.3 kg, height 180.0±5.9 cm) completed four all-out time trials (15 s, 180 s, 420 s, 900 s) to determine peak power output (PPO), mean power output (MPO), maximal oxygen uptake (VO<inf>2max</inf>), maximal rate of lactate accumulation (VLa<inf>max</inf>), and maximal lactate steady-state (cMLSS). Critical power (CP) and work that can be performed above CP (W') were assessed using a linear power model. Further, the 30-second end-test power (EP) and work done above EP (WEP) were derived from the 180 s time trial. Finally, indices were calculated from the metabolic and power data. The level of significance was set at P≤0.05.

RESULTS

Weak to moderate correlations were found for body weight and height compared to PPO and MPOs. VO<inf>2max</inf> correlated strongly with MPO180 and MPO420. VLa<inf>max</inf> correlated moderately with PPO and MPO15. While the calculations of CP, EP, and cMLSS correlated moderately to strongly, their means differed significantly. W' and WEP also differed significantly with a mean difference of 10.2±2.5 kJ.

CONCLUSIONS

Canoe polo players are similar to sprint paddlers in their constitution, although VO<inf>2max</inf> and PPO are lower. The high correlation between physiological and power parameters also shows that simple tests that do not require blood or gas sampling can be established quickly in daily training practice.

Can high-intensity interval training change cardiac autonomic control? A systematic review

BACKGROUND

High intensity interval training (HIIT) has been used as a cardiovascular exercise strategy to promote greater adherence in cardiovascular rehabilitation. However, little is known about the effect of this training modality on cardiac autonomic control.

OBJECTIVE

To perform a systematic review to evaluate the effects of HIIT on cardiac autonomic responses in humans.

METHODS

PEDro, SCOPUS and PubMed were searched from the inception to March 29th, 2018. Moreover, the methodological quality and statistical reporting from all eligible clinical trials were assessed by the PEDro scale. The articles were eligible if: The primary objective was related to the effects of HIIT on the cardiac autonomic nervous system. Outcomes evaluated were indirect measures of cardiac autonomic control, represented by HRV indexes.

RESULTS

The search strategies resulted in 339 citations and 2 additional citations were identified through other sources. After deleting the duplicate articles and revising the full text, 6 articles were included. Overall, the results showed an improvement in parasympathetic and/or sympathetic modulation after HIIT, when evaluated by linear and non-linear indexes of HRV.

CONCLUSIONS

HIIT is a promising tool to improve the cardiac autonomic control, with more recommendation in healthy individuals and patients with metabolic syndrome.