Stress and recovery perception, creatine kinase levels, and performance parameters of male volleyball athletes in a preseason for a championship

A two-year examination of the relation between internal and external load and heart rate variability in Australian Rules Football

The relationship between heart rate variability (HRV) and training load in team-sport is unknown. We therefore assessed relations between completed training-load in the previous 1-, 3- and 7-days and waking HRV in professional Australian Rules Football. Linear-mixed models analysed changes in HRV, considering training load from the previous 1-, 3- and 7-days. Total Distance (TD), distance >14.4 km ‧ h-1 (HSR) and >24.9 km ‧ h-1 (Sprint-Distance), duration >85% max heart rate and Rating of Perceived Exertion were included as independent variables. Sub-group analysis of season-phase and years of professional experience was also conducted. Increased three-day Sprint-Distance reduced HRV in the first 8-weeks of pre-season (-13.1 ms, p = 0.03) and across the data collection period (-3.75 ms, p = 0.01). In first-year players, higher previous-day (-63.3 ms, p=0.04) and seven-day TD (-38.2 ms, p = 0.02) reduced HRV, whilst higher seven-day HSR increased HRV (34.5 ms, p = 0.01). In players with five-to-seven years of professional experience, higher three-day (-14.4 ms, p = 0.02) and seven-day TD (-15.7 ms, p = 0.01) reduced HRV, while higher three-day HSR increased HRV (12.5 ms, p = 0.04). In players with greater than eight years of professional experience, higher previous-day Sprint-Distance reduced HRV (-13.1 ms, p < 0.008). Completed training load across the previous 7-days influences HRV, but the relation between variables is complex and influenced by professional experience and season-phase.

Effect of Level of Competition and Drill Typology on Internal and External Load in Male Volleyball Players During the Preseason Period

PURPOSE

This study aimed at evaluating the effect of level of competition and drill typology on loads during the preseason period in male volleyball players.

METHODS

Internal (percentage of peak heart rate [HR] and summated HR zone) and external (PlayerLoad per minute, total and high accelerations per minute [tACCmin and hACCmin], decelerations per minute [tDECmin and hDECmin], and jumps per minute [tJUMPmin and hJUMPmin]) loads were monitored across a 5-week preseason period in 12 Division 1 (age: 22.5 [3.9] y; stature: 188 [6.2] cm; body mass: 85 [11.6] kg; training experience: 9.4 [4.2] y) and 12 Division 2 (age: 20.7 [2.9] y; stature: 186 [6.2] cm; body mass: 77.8 [9.6] kg; training experience: 5.6 [2.3] y) male volleyball players. Furthermore, differences in load were assessed for each drill typology (warm-up, conditioning, technical, tactical, and integral).

RESULTS

No effects (P > .05) of level of competition on the internal (except for summated HR zone, P = .05) and external loads (except for tJUMPmin, P = .002) were found. Differently, drill typologies showed an effect (P < .001) on all the investigated internal- and external-load measures. The main post hoc results revealed higher (P < .05) percentage of peak HR, summated HR zone, PlayerLoad per minute, and tACCmin in warm-up and conditioning drills, while higher (P < .05) hDECmin and hJUMPmin were found in tactical and integral drills.

CONCLUSIONS

These results suggest that volleyball coaches use warm-up and conditioning drills when aiming at increasing the internal loads, PlayerLoad per minute, and tACCmin, while tactical and integral drills should be preferred to enhance the number of hDECmin and hJUMPmin.

A Narrative Review on Adipose Tissue and Overtraining: Shedding Light on the Interplay among Adipokines, Exercise and Overtraining

Lifestyle factors, particularly physical inactivity, are closely linked to the onset of numerous metabolic diseases. Adipose tissue (AT) has been extensively studied for various metabolic diseases such as obesity, type 2 diabetes, and immune system dysregulation due to its role in energy metabolism and regulation of inflammation. Physical activity is increasingly recognized as a powerful non-pharmacological tool for the treatment of various disorders, as it helps to improve metabolic, immune, and inflammatory functions. However, chronic excessive training has been associated with increased inflammatory markers and oxidative stress, so much so that excessive training overload, combined with inadequate recovery, can lead to the development of overtraining syndrome (OTS). OTS negatively impacts an athlete's performance capabilities and significantly affects both physical health and mental well-being. However, diagnosing OTS remains challenging as the contributing factors, signs/symptoms, and underlying maladaptive mechanisms are individualized, sport-specific, and unclear. Therefore, identifying potential biomarkers that could assist in preventing and/or diagnosing OTS is an important objective. In this review, we focus on the possibility that the endocrine functions of AT may have significant implications in the etiopathogenesis of OTS. During physical exercise, AT responds dynamically, undergoing remodeling of endocrine functions that influence the production of adipokines involved in regulating major energy and inflammatory processes. In this scenario, we will discuss exercise about its effects on AT activity and metabolism and its relevance to the prevention and/or development of OTS. Furthermore, we will highlight adipokines as potential markers for diagnosing OTS.

Training stress, neuromuscular fatigue and well-being in volleyball: a systematic review

BACKGROUND

Volleyball, with its unique calendar structure, presents distinct challenges in training and competition scheduling. Like many team sports, volleyball features an unconventional schedule with brief off-season and pre-season phases, juxtaposed against an extensive in-season phase characterized by a high density of matches and training. This compact calendar necessitates careful management of training loads and recovery periods. The effectiveness of this management is a critical factor, influencing the overall performance and success of volleyball teams. In this review, we explore the associations between training stress measures, fatigue, and well-being assessments within this context, to better inform future research and practice.

METHODS

A systematic literature search was conducted in databases including PsycINFO, MEDLINE/PubMed, SPORTDiscus, Web of Science, and Scopus. Inclusion criteria were original research papers published in peer-reviewed journals involving volleyball athletes.

RESULTS

Of the 2535 studies identified, 31 were thoroughly analysed. From these 31 articles, 22 included professional athletes, seven included collegiate-level volleyball athletes, and two included young athletes. Nine studies had female volleyball players, while the remaining 22 had male volleyball athletes.

CONCLUSIONS

Internal training load should be collected daily after training sessions and matches with the session rating of perceived exertion method. External training load should also be measured daily according to the methods based on jump height, jump count, and kinetic energy. If force platforms are available, neuromuscular fatigue can be assessed weekly using the FT:CT ratio of a countermovement jump or, in cases where force platforms are not available, the average jump height can also be used. Finally, the Hooper Index has been shown to be a measure of overall wellness, fatigue, stress, muscle soreness, mood, and sleep quality in volleyball when used daily.

Betalains Alleviate Exercise-Induced Oxidative Stress, Inflammation, and Fatigue and Improve Sports Performance: an Update on Recent Advancement

PURPOSE OF REVIEW

Beetroot juice is a popular natural food supplement commonly consumed for its health and ergogenic benefits. It contains an abundance of phytochemical compounds, which have been shown to enhance sports endurance and recovery. Among them, nitrate is well-studied and known for improving performance during exercise. On the other hand, betalains, the bioactive pigment, have shown various biological activities including antioxidant, anti-inflammatory, and anti-hypertensive, which may improve exercise performance and post-exercise recovery. Additionally, free radical scavenging activities of betalains could increase nitric oxide availability in the blood, thereby improving blood flow and oxygen supply during strenuous exercise. This review article provides a critical discussion of the non-pathological conditions induced by prolonged or strenuous exercise and betalains' potential in reducing such conditions including muscle damage, inflammation, and fatigue. Additionally, the real-time application of betalains as an ergogenic compound in competitive athletes has been discussed. Finally, future directions and conclusions on the potential of betalains as a natural ergogenic aid in sport endurance are outlined.

RECENT FINDINGS

Betalains in beetroot are the major water-soluble nitrogen-containing pigment possessing high antioxidant, anti-inflammatory, and anti-fatigue activities. Betalain supplementation could alleviate exercise-induced oxidative stress, inflammation, and fatigue in competitive athletes. Betalains have the potential to become a natural ergogenic aid or nutraceutical compound for sports people during exercise and competitive performance.

Can Prolongate Use of Social Media Immediately Before Training Worsen High Level Male Volleyball Players' Visuomotor Skills?

Our aim was to analyze the effect of mental fatigue caused by prolonged social media use on high-level volleyball players' visuomotor skills. Eighteen high-level male young volleyball players participated in this randomized, counterbalanced, crossover design. All participants underwent a 2-week experiment in which we measured their response times when performing a visuomotor task with and without mental fatigue inducement through repeated use of social media immediately before training sessions. In the control condition, participants watched TV for 30-minutes, and in the social media condition, they used a social media app (Instagram^®) on smartphones for 30-minutes. We found a significant Condition x Time interaction on visuomotor task response time (p = 0.03), but there was no significant main effect of either Time or Condition. Mental fatigue, induced by repeated app-based social media use for 30-minutes immediately before training sessions, affected elite male volleyball players' visuomotor skills.

Comprehensive training load monitoring with biomarkers, performance testing, local positioning data, and questionnaires - first results from elite youth soccer

Load management, i.e., prescribing, monitoring, and adjusting training load, is primarily aimed at preventing injury and maximizing performance. The search for objective monitoring tools to assess the external and internal load of athletes is of great interest for sports science research. In this 4-week pilot study, we assessed the feasibility and acceptance of an extensive monitoring approach using biomarkers, neuromuscular performance, and questionnaires in an elite youth soccer setting. Eight male players (mean ± SD: age: 17.0 ± 0.6 years, weight: 69.6 ± 8.2 kg, height: 177 ± 7 cm, VO_2max: 62.2 ± 3.8 ml/min/kg) were monitored with a local positioning system (e.g., distance covered, sprints), biomarkers (cell-free DNA, creatine kinase), questionnaires, neuromuscular performance testing (counter-movement jump) and further strength testing (Nordic hamstring exercise, hip abduction and adduction). Feasibility was high with no substantial impact on the training routine and no adverse events such as injuries during monitoring. Adherence to the performance tests was high, but adherence to the daily questionnaires was low, and decreased across the study period. Occasional significant correlations were observed between questionnaire scores and training load data, as well as between questionnaire scores and neuromuscular performance. However, due to the small sample size, these findings should be treated with caution. These preliminary results highlight the feasibility of the approach in elite soccer, but also indicate that modifications are needed in further large-scale studies, particularly in relation to the length of the questionnaire.

Effects of Postactivation Performance Enhancement on the Vertical Jump in High-Level Volleyball Athletes

The objective of this study was to evaluate the effects of a training session with and without an intervention of postactivation performance enhancement (PAPE) on countermovement jump (CMJ) height, perceived recovery status (PRS), and ratings of perceived exertion (RPEs), followed by a specific volleyball training session. The sample consisted of sixteen professional male volleyball players, with an average age of 26.8±6.1 years and average height of 195.9±6.7 cm, randomly divided into a group with PAPE intervention (GPAPE) (n=8), and a control group (CTRL) without PAPE intervention (n=8). The control group carried out the training session with plyometric exercises, and the GPAPE added conditioning protocols for PAPE to plyometric training, followed by a technical tactical volleyball session. At the end of the training session, there was an increase of 16.3% in the height of the CMJ in the GPAPE, while the CTRL showed a decrease of 5% in the height of the CMJ. PRS and RPE variables did not differ between the groups. It was concluded that PAPE had a positive effect on the height of the vertical jump after plyometric training, which was maintained until the end of the technical and tactical volleyball session.

Relationships between Fitness Status and Blood Biomarkers in Professional Soccer Players

Background

Physical conditions are recognized to be optimal after the pre-season (PS) phase in professional sports. Given that blood measures may also reveal variations, which in turn, may present associations with fitness changes.

Objective

The aim of this study is to test the changes of blood markers and physical fitness outcomes at the beginning and following the PS phase. Additionally, we aimed also to analyze the associations of training adaptations between blood markers and the physical fitness measures. Methodology. 25 professional male soccer players (28.1 ± 4.6 years old, 2.0 ± 7.8 kg, and 176.7 ± 4.9 cm) were assessed for hematological and biochemical parameters, and physical fitness measures in the baseline and after the phase of PS.

Results

Increases in platelets were observed after the PS phase (p = 0.001, η2 = 0.39). Regarding the biochemical parameters, significant increases between PS were found for creatinine (Cre) (p = 0.001, η2 = 0.66), alkaline phosphatase (ALP) (p = 0.001, η2 = 0.79), C-Reactive Protein (CRP) (p = 0.001, η2 = 0.74), cortisol (C) (p = 0.001, η2 = 0.63), and testosterone (T) (p = 0.001, η2 = 0.76), whereas significant decreases were found for albumin (Alb) (p = 0.004, η2 = 0.29), and calcium corrected (Ca Corr.) (p = 0.002, η2 = 0.32). Moderate correlations were found between albumin and the 5-meter linear sprint split (r = -0.44 (95%CI: -0.71; -0.05)) and CRP (r = -0.48 (95%CI: -0.74; -0.10)). Moderate correlations were found between VAMEVAL and hemoglobin (r = 0.44 (95%CI: 0.05; 0.71)).

Conclusions

The overall physical fitness measures improved after the PS phase. Also, significant variations (decreases/increases) were observed for the case of biomchemical and hematological outcomes. Coaches should carefully consider the adaptative changes observed in blood parameters as the changes in whole organism and metabolism after specific critical phases as the PS in professional players. Thus, optimal management of stimulus/recovery can be warranted to minimize illness and injury rate and to follow the direction and dynamics of adaptative changes.

Development of a Revised Conceptual Framework of Physical Training for Use in Research and Practice

A conceptual framework has a central role in the scientific process. Its purpose is to synthesize evidence, assist in understanding phenomena, inform future research and act as a reference operational guide in practical settings. We propose an updated conceptual framework intended to facilitate the validation and interpretation of physical training measures. This revised conceptual framework was constructed through a process of qualitative analysis involving a synthesis of the literature, analysis and integration with existing frameworks (Banister and PerPot models). We identified, expanded, and integrated four constructs that are important in the conceptualization of the process and outcomes of physical training. These are: (1) formal introduction of a new measurable component 'training effects', a higher-order construct resulting from the combined effect of four possible responses (acute and chronic, positive and negative); (2) explanation, clarification and examples of training effect measures such as performance, physiological, subjective and other measures (cognitive, biomechanical, etc.); (3) integration of the sport performance outcome continuum (from performance improvements to overtraining); (4) extension and definition of the network of linkages (uni and bidirectional) between individual and contextual factors and other constructs. Additionally, we provided constitutive and operational definitions, and examples of theoretical and practical applications of the framework. These include validation and conceptualization of constructs (e.g., performance readiness), and understanding of higher-order constructs, such as training tolerance, when monitoring training to adapt it to individual responses and effects. This proposed conceptual framework provides an overarching model that may help understand and guide the development, validation, implementation and interpretation of measures used for athlete monitoring.

Relationships of the 5-Jump Test (5JT) Performance of Youth Players With Volleyball Specific' Laboratory Tests for Explosive Power

Volleyball involves movements with and/or without horizontal approaches (i.e., spike jumps, jump setting, blocking). The 5-jump test (5JT) was suggested to assess lower limb explosive power of athletes competing in some disciplines (e.g., soccer, judo, running). It appears that no previous study has investigated the 5JT performance components in volleyball players. This study aimed to test the relationship between 5JT performance and two specific laboratory tests for explosive power (i.e., countermovement jump [CMJ] and squat jump [SJ]). Forty volleyball players (boys, mean age: 12.4 ± 0.8 years) were tested for 5JT, CMJ, and SJ tests. 5JT performance was expressed in absolute terms (m), and relative to leg length (5JT_LL) and body mass (5JT_BM). The SJ and CMJ tests were evaluated using the optojump photoelectric cells and the following data were collected: peak power (Pp) of jump (W, W.kg^-0.67), peak jumping force (F_peak, N), peak jumping velocity (V_peak, m/s), peak heights of CMJ and SJ (CMJ_H and SJ_H, respectively, cm). Only significant (p < .05) Pearson product-moment correlations (r) > 0.30 were considered. 5JT performance was significantly correlated with SJ, V_peak (r = 0.90), SJ_H (r = 0.88), Pp [W.kg^-0.67 (r = 0.86), W (r = 0.72)], F_peak (r = 0.45); and CMJ, V_peak (r = 0.82), CMJ_H (r = 0.80), Pp [W.kg^-0.67 (r = 0.89), W (r = 0.85)], F_peak (r = 0.73). 5JT_LL values were significantly related to SJ, Pp [W (r = 0.81), W.kg^-0.67 (r = 0.74)], V_peak (r = 0.82); and CMJ, Pp [W (r = 0.73), W.kg^-0.67 (r = 0.84)], V_peak (r = 0.75), F_peak (r = 0.67)]. 5JT_BM values were significantly related to SJ, Pp (W, r = −0.43). To conclude, in youth volleyball players, the 5JT may be viewed as an explosive strength diagnostic instrument under field circumstances.