Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial

BACKGROUND

This study assessed the impact of acute caffeine intake on muscular strength, power, and endurance performance between resistance-trained male and female individuals according to load in upper- and lower-body exercises.

METHODS

Here, 76 resistance-trained individuals (38 females, 38 males) participated in a study comparing caffeine and a placebo. Each received either 3 mg/kg of caffeine or a placebo 60 min before tests measuring muscular strength and power through bench press and back squat exercises at different intensities (25%, 50%, 75%, 90% 1RM). Muscular endurance at 65% 1RM was also assessed by performing reps until reaching task failure.

RESULTS

Compared to placebo, caffeine increased mean, peak and time to reach peak velocity and power output (p < 0.01, ηp2 = 0.242-0.293) in the muscular strength/power test in males and females. This effect was particularly observed in the back squat exercise at 50%, 75% and 90% 1RM (2.5-8.5%, p < 0.05, g = 1.0-2.4). For muscular endurance, caffeine increased the number of repetitions, mean velocity and power output (p < 0.001, ηp2 = 0.177-0.255) in both sexes and exercises (3.0-8.9%, p < 0.05, g = 0.15-0.33).

CONCLUSIONS

Acute caffeine intake resulted in a similar ergogenic effect on muscular strength, power, and endurance performance in upper- and lower-body exercises for male and female resistance-trained participants.

Acute and persistence of the effects of the SuperSpeed Golf™ weighted-club warm-up on golf driving performance and kinematics

High-level golfers use various warm-up strategies to enhance clubhead and ball speed, including weighted equipment. We investigated the acute effects of the SuperSpeed Golf™ weighted-club warm-up on clubhead, ball, and swing kinematics, and the persistence of any acute effects in subsequent sets. Twelve competitive golfers (handicap < 3.0) completed five sets of five swings using their own drivers under two randomised warm-up conditions (Control and SuperSpeed). We compared swing, peak segment and club angular velocity, and centre of mass (COM) parameters collected using a 3D motion capture system (500 Hz) between conditions. The temporal persistence of any meaningful (Cohen's d ≥ small) and significant (p≤ 0.05) effect detected in the first set was investigated in subsequent sets. SuperSpeed led to small significant changes in clubhead speed (2.6 mph); downswing time; peak angular velocities of the torso, lead arm, and club; and two COM variables in the initial set. There was no significant change in ball speed, resulting in a large negative change in smash factor acutely (d - 0.82, p= 0.009). Nearly all changes observed were no longer meaningful or significant in subsequent sets. Overall, golfers can expect an increase in driving clubhead speed on the first tee using the SuperSpeed Golf™ vs Control warm-up, with trivial effects from the second tee onwards.

Decision-Making Time Analysis for Assessing Processing Speed in Athletes during Motor Reaction Tasks

Reaction time (RT) is a widely used measure for testing physical performance in motor tasks. This study focused on assessing the processing speed in athletes. Twenty-five healthy volunteers were assigned to the control (n = 16) or athletes groups (n = 9). They were evaluated during motor reaction tasks based on visual stimuli and three difficulty conditions. Physiological measures were obtained from motion capture and electromyography recordings of several muscles. Two RT phases, decision-making (DMK) and electromechanical delay (EMD), were used to analyze the processing speed. The results show significant RT differences between groups. The athletes were ~30% faster compared to the control group. Despite the fact that all participants were right-handed, RT did not show any differences between hands performances in any group. However, DMK time revealed significant differences between the hands. Controls showed a longer DMK time for the right-hand election, ~20% more than the left, while athletes showed no such disparity. These findings reveal that quantifying the decision-making component of reaction time is crucial to assessing processing speed in sport. This approach could facilitate the monitoring of adaptations in both motor-cognitive and neuromuscular processes. The theoretical implications presented in this study offer perspectives on handedness research.

Effects of high-intensity interval training and resistance training on physiological parameters and performance of well-trained runners: A randomized controlled trial

This study aimed to verify the effects of 4 weeks of high-intensity interval training (HIIT), heavy (HRT) and explosive (ERT) resistance training on aerobic, anaerobic and neuromuscular parameters and performance of well-trained runners. Twenty-six male athletes were divided into HIIT (n = 10), HRT (n = 7) and ERT (n = 9) groups. Maximal oxygen uptake (V O 2 max ) and the corresponding velocity (vV O 2 max ), anaerobic threshold (AT), running economy (RE), oxygen uptake kinetics, lower-body strength (1RM) and power (CMJ), and the 1500m and 5000m time-trial (TT) were determined. Improvements were observed in vV O 2 max (mean difference (Δ): 2.6%; effect size (ES): 0.63) with HIIT, while AT was incresead in ERT (Δ: 4.3%; ES: 0.73) and HRT (Δ: 6.9%; ES: 0.72) groups. The CMJ performance was increased in ERT (Δ: 13.8%; ES: 1.03), HRT (Δ: 6.9%; ES: 0.55) and HIIT (Δ: 5.4%; ES: 0.34), whereas 1RM increase in HRT (Δ: 38.1%; ES: 1.21) and ERT (Δ: 49.2%; ES: 0.96) groups. HIIT improved the 1500m (Δ: -2.3%; ES: -0.62) and both HRT (Δ: -1.6%; ES: -0.32) and ERT (Δ: -1.7%; ES: -0.31) the 5000m TT. Despite performance adaptations were dependent on the training characteristics, both RT and HIIT model constitute an alternative for training periodization.

Analysis of Player Performance and Financial Costs Associated With Implementation of an Updated National Hockey League Concussion Protocol: A Retrospective Comparative Study

Background

An updated National Hockey League (NHL) concussion protocol (NHLCP) was established in the 2016-2017 season to mitigate the negative outcomes of sport-related concussions. However, few studies on the effects of implementing the NHLCP have been performed.

Purpose

To define concussion incidence and investigate differences in NHL player performance after a concussion during periods before and after NHLCP implementation and assess the financial impact on NHL teams associated with NHLCP implementation.

Study Design

Cohort study; Level of evidence, 3.

Methods

This was a retrospective review of NHL players who sustained a concussion before (2000-2001 to 2015-2016 seasons) and after (2016-2017 to 2020-2021 seasons) implementing the NHLCP (pre-NHLCP and post-NHLCP groups). For each group, multiple performance metrics-including 30 days, 1 season, and 3 seasons before and after concussion-were compared for both groups. Return to play, total concussion cost, and association of return to play with cost were investigated using regression analysis.

Results

A total of 452 players (423 skaters, 29 goalies) sustained concussions during the study period, including 331 players (315 skaters, 16 goalies) in the pre-NHLCP group and 121 players (108 skaters, 13 goalies) in the post-NHLCP group. For both groups, no significant differences in standard performance were observed during the 30-day and 1-season periods before and after concussion. The mean return to play was significantly higher in the pre-NHLCP group than in the post-NHLCP group (20.1 vs 15.7 days; P = .022). The mean adjusted player salary was not different between groups; nonetheless, the mean adjusted replacement player salary was significantly higher in the post-NHLCP group ($744,505 vs $896,942; P = .032). The mean cost of time missed did not differ between groups. The mean return to play time significantly decreased over the entire study period (R2 = 0.33; P = .005), and the mean return to play time was positively associated with cost R2 = 0.215; P = .030).

Conclusion

Concussion incidence did not change after implementation of the updated NHLCP; nonetheless, players had significantly less missed time from injury after protocol implementation. Changes in player performance 30 days and 1 year before and after concussion injury were not different before and after NHLCP implementation. No differences were found in the financial cost of concussions between the pre- and post-NHLCP groups, and missed time was significantly correlated with mean cost from missed time.

Integrated use of biofeedback and neurofeedback techniques in treating pathological conditions and improving performance: a narrative review

In recent years, the scientific community has begun tо explore the efficacy оf an integrated neurofeedback + biofeedback approach іn various conditions, both pathological and non-pathological. Although several studies have contributed valuable insights into its potential benefits, this review aims tо further investigate its effectiveness by synthesizing current findings and identifying areas for future research. Our goal іs tо provide a comprehensive overview that may highlight gaps іn the existing literature and propose directions for subsequent studies. The search for articles was conducted on the digital databases PubMed, Scopus, and Web of Science. Studies to have used the integrated neurofeedback + biofeedback approach published between 2014 and 2023 and reviews to have analyzed the efficacy of neurofeedback and biofeedback, separately, related to the same time interval and topics were selected. The search identified five studies compatible with the objectives of the review, related to several conditions: nicotine addiction, sports performance, Autism Spectrum Disorder (ASD), and Attention Deficit Hyperactivity Disorder (ADHD). The integrated neurofeedback + biofeedback approach has been shown to be effective in improving several aspects of these conditions, such as a reduction in the presence of psychiatric symptoms, anxiety, depression, and withdrawal symptoms and an increase in self-esteem in smokers; improvements in communication, imitation, social/cognitive awareness, and social behavior in ASD subjects; improvements in attention, alertness, and reaction time in sports champions; and improvements in attention and inhibitory control in ADHD subjects. Further research, characterized by greater methodological rigor, is therefore needed to determine the effectiveness of this method and the superiority, if any, of this type of training over the single administration of either. This review іs intended tо serve as a catalyst for future research, signaling promising directions for the advancement оf biofeedback and neurofeedback methodologies.

Stress and sport performance: a PNEI multidisciplinary approach

Stress control is essential for avoiding a state of anxiety in sport competitions, as this state may have negative effects on other psychological variables of athletes, decreasing their self-confidence and harming their attentional control. In the present contribution a distress intervention model developed from a PNEI perspective will be sketched out. Our theoretical-methodological proposal consists of the definition of an integrated protocol of psycho-biological assessment and intervention on the allostatic load and on the levels of distress/eustress detectable in the sport environment, in relation to the person's health/well-being condition and the impact of this condition on the quality of sport performance. This paradigm has the potential to explore both the psychological dimension of stress management and the psycho-educational and psycho-physical dimension, according to a truly integrated approach to the athlete's health and psychophysical well-being. Its multidisciplinary nature requires close cooperation between different professional figures, such as the mental coach, psychologist, nutritionist, osteopath, and physiotherapist, as well as biologists, physicians and kinesiologists, both in planning and in implementation and monitoring at all stages. The potential impact of the model on sport performance will be deeply discussed.

Low Energy Intake Leads to Body Composition and Performance Decrements in a Highly-Trained, Female Athlete: The WANDER (Woman's Activity and Nutrition during an Extensive Hiking Route) Case Study

OBJECTIVE

This case study's purpose was to quantify energy intake vs energy expenditure during a thru-hiker's trek and assess its relationship to performance and health.

METHODS

A highly trained, female thru-hiker (Age (yrs): 62, Ht (cm): 157, Wt (kg): 53.5, BMI (kg/m2): 21.7, %BF: 26.0) embarked on a 4-month journey through the Pacific Crest Trail, USA. The athlete's body composition and 3-day diet record were assessed before (PRE) and after the hike (POST). During the hike, she tracked her diet and performance daily and completed a wellness survey each time she reached a town-check point. Data were analyzed for descriptive (weekly averages, means ± SD) and frequency statistics.

RESULTS

She spent 10 wk (∼70 days) on the trail and hiked 1,506.35 km (26.1 ± 3.2 km/day) with an estimated energy expenditure of ∼2334 ± 351 kcal/day. During the hike, she under consumed calories (1285.3 ± 103 kcal) and dietary carbohydrate (169.5 ± 19.5g), fat (49.7 ± 5.8g), protein (41.9 ± 4.8g; 0.8 g/kg), fiber (11.8 ± 2.1g) and sodium (1642.4 ± 298.6 mg) when compared to ultra-endurance nutrition recommendations. She was unable to complete the trail due to fatigue and anthropometric changes. By POST, she had decreased total mass (PRE: 53.5 kg vs POST: 48.4 kg), BMI (PRE 21.6 vs POST: 19.5), fat-free mass (PRE: 39.6 vs POST: 38.8), and body fat (PRE: 26% vs POST: 19.6%) when compared to PRE.

CONCLUSION

Trail-related challenges combined with high energy expenditures led to low nutrient intake which contributed to trail-ending injuries and performance decrements. Research aimed at addressing the barriers associated with thru-hike fueling is needed to identify nutritional opportunities to support hikers' performance and reduce injury risks.

Cannabis Use in Adolescent and Young Adult Athletes: A Clinical Review

CONTEXT

Cannabis use among the general population has increased over time, in part due to decriminalization of use and greater social acceptance of cannabis use. These changes have contributed to increased availability of cannabis products, thus raising the likelihood that a subset of adolescent and young adult athletes will use cannabis. Therefore, it is imperative that clinicians and other providers working with young athletes have a thorough understanding of the impact cannabis can have on the athletic performance and overall health of a young athlete.

EVIDENCE ACQUISITION

PubMed (Medline), CINAHL, PsycINFO, and SportDiscus databases were used to perform a literature search of articles published between January 1, 2010 and December 31, 2022. Additional articles were reviewed based on references obtained from initial articles.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Survey studies suggest that up to 1 in 4 athletes have used cannabis at least once in the last year. Age, sex, race, sexual orientation, level of competition, and country of residence of an athlete all contribute to differing rates of cannabis use among athletes. The scientific literature does not support using cannabis for athletic performance, and multiple studies have demonstrated notable impairments in objective athletic performance measures. Cannabis use can also negatively impact an athlete's overall health via cardiovascular, gastrointestinal, and mental health symptoms and disorders.

CONCLUSION

Cannabis use among adolescent and young adult athletes is common, and rates of use are influenced by many different factors. Current evidence suggests that cannabis use can worsen sport performance, negatively impact an athlete's general health, and contribute to negative mental health outcomes.

Effect of the pre-taper level of fatigue on the taper-induced changes in performance in elite swimmers

Introduction

In swimming, performance gains after tapering could be influenced by the pre-taper level of fatigue. Moreover, this level of fatigue could be associated with sleep. This study aimed to assess (1) the effect of tapering on performance according to the pre-taper level of fatigue in swimmers and (2) the association between sleep and pre-taper level of fatigue.

Methods

Physiological, psychological and biomechanical profiles were evaluated in 26 elite swimmers on 2 occasions to estimate the pre-taper level of fatigue: at T0 and T1, scheduled respectively 10 and 3 weeks before the main competition. Sleep quantity and quality were also evaluated at T0 and T1. Race time was officially assessed at T0, T1 and during the main competition. The level of significance was set at p ≤ .05.

Results

Fourteen swimmers (17 ± 2 years) were allocated to acute fatigue group (AF) and 12 swimmers (18 ± 2 years) to functional overreaching group (F-OR). From T1 to the main competition, performance was improved in AF (+1.80 ± 1.36%), while it was impaired in F-OR (-0.49 ± 1.58%, p < 0.05 vs. AF). Before taper period, total sleep time was lower in F-OR, as compared to AF. Conversely, the fragmentation index was higher in F-OR (p = .06). From wakefulness to sleep, body core temperature decreased in AF but not in F-OR.

Discussion

Performance gain after tapering was higher in AF swimmers than in overreached. Moreover, pre-taper sleep was poorer in overreached swimmers, which could contribute to their different response to the same training load. This poorer sleep could be linked to a lower regulation of internal temperature.

Analysis of Sprint Ski Mountaineering Performance

Ski mountaineering sprint competitions are short individual races involving 3 uphill sections (U), 3 transitions (T), and a final descent. To date, relatively little is known about this novel Olympic discipline, and here we examined (1) the contribution of the time spent on U, T, and final descent to overall finishing time and (2) the potential relationships with final ranking. During the different rounds of 2 International Ski Mountaineering Federation World Cup sprint competitions, male and female ski mountaineers were video recorded. Correlation and multiple linear regression analyses were used to investigate the impact of U, T, and final descent on the best overall finishing time. Linear-mixed model analysis was applied to explore potential interactions between section times, rounds, and final ranking. Overall, U (r = .90-.97) and T (r = .57-.89) were closely correlated with the best overall finishing time (all P < .05). U explained approximately 80% to 90% of the variation in the best finishing time for both sexes, with U + T explaining approximately 95% to 98% of this variation. In each successive round, the ski mountaineers eliminated were all slower on U than the Top 3 (all P < .05). The fastest skiers increased their performance on U in the later rounds of the competitions, while those eliminated showed a tendency toward a decrease. Our findings reveal that world-class sprint ski mountaineers conduct transitions optimally and perform effectively uphill. Training for such competitions should aim to improve short supramaximal uphill performance (∼1.5-2.5 min), ensuring that this does not decline with multiple efforts. These insights into ski mountaineering sprint performance are of considerable value in connection with training for the 2026 Winter Olympics.

Pattern of Consumption of Sports Supplements of Spanish Handball Players: Differences According to Gender and Competitive Level

(1) Background: Given the physiological characteristics of handball, players may require the use of certain sports supplements (SS). However, very few studies have investigated the consumption of SS in handball. The aims were to determine the number of handball players who consume SS, to analyze their SS consumption pattern according to gender and competitive level, and to assess whether the SS they consume are supported by scientific evidence, and to which group they belong according to the classification of the Australian Institute of Sport (AIS). (2) Methods: A descriptive-correlational study was carried out on the habitual consumption of SS in 360 federated Spanish players by using a self-administered and validated questionnaire. (3) Results: These showed 65.8% of the sample consumed SS. According to the total number of participants, the most consumed supplements were from Group A: sports drinks (30.8%) and whey protein (30.4%). When analyzing the data by gender, the men's consumption was significantly higher for whey protein (p < 0.001), caffeine (p = 0.009), and creatine monohydrate (p < 0.001). When analyzed by competitive level, the provincial category players group showed a significantly lower consumption than the rest of the groups for protein bars (p = 0.038), whey protein (p = 0.005) and creatine monohydrate (p < 0.001), while the honor division group showed a significantly higher intake of creatine monohydrate than the remaining groups (p < 0.001). (4) Conclusions: The handball players showed a moderate consumption of SS, without using substances that were not supported by scientific evidence and opting in most cases for supplements belonging to group A from the AIS classification. Men tended to consume more SS, and SS consumption increased based on competitive level.

Reliability and Validity of the Star Excursion Balance Test for Evaluating Dynamic Balance of Upper Extremities

BACKGROUND

Upper extremity (UE) dynamic balance is a significant physical fitness ability, which includes high-level neuromuscular proprioception, joint mobility, force, and coordination. The evaluation methods of UE dynamic balance are insufficient and lack experimental support. The Star Excursion Balance Test (SEBT) is a reliable assessment of dynamic balance and injury risk of the lower extremity.

HYPOTHESIS

The UE-SEBT is a reliable and reproducible approach for evaluating dynamic balance of UEs.

STUDY DESIGN

Observational study.

LEVEL OF EVIDENCE

Level 4.

METHODS

This cross-sectional study recruited 65 healthy adults. All participants were required to complete UE-SEBT, UE Y-balance test (UE-YBT), maximal voluntary isometric contraction (MVIC) of UE, closed kinetic chain UE stability test (CKCUEST), trunk flexor endurance test (TFET), trunk extensor endurance test (TEET), and lateral trunk endurance test (LTET). Intra- and inter-rater reliability and the correlation of UE-SEBT with other outcomes were measured.

RESULTS

Among the participants, the intra- and interoperator reliability of UE-SEBT in all directions and composite score achieved a moderate-to-excellent (intraclass correlation coefficients [ICC], 0.729-0.946) reliability. For validity, the UE-SEBT had a moderate to very strong correlation with UE-YBT (r = 0.315-0.755, P < 0.01) and a strong correlation with CKCUEST (r = 0.4-0.67, P < 0.01). Furthermore, the UE-SEBT performance showed weak-to-strong correlations with MVIC (r = 0.26-0.43, P < 0.05). UE-SEBT was also correlated with LTET, TEET, and TFET to varying degrees.

CONCLUSION

UE-SEBT has good reliability and validity to assess UE dynamic balance compared with other tests.

CLINICAL RELEVANCE

UE-SEBT can be used as a clinical assessment method to evaluate UE dynamic balance and injury prevention.

Circadian Rhythms, Chrononutrition, Physical Training, and Redox Homeostasis-Molecular Mechanisms in Human Health

A multitude of physiological processes, human behavioral patterns, and social interactions are intricately governed by the complex interplay between external circumstances and endogenous circadian rhythms. This multidimensional regulatory framework is susceptible to disruptions, and in contemporary society, there is a prevalent occurrence of misalignments between the circadian system and environmental cues, a phenomenon frequently associated with adverse health consequences. The onset of most prevalent current chronic diseases is intimately connected with alterations in human lifestyle practices under various facets, including the following: reduced physical activity, the exposure to artificial light, also acknowledged as light pollution, sedentary behavior coupled with consuming energy-dense nutriments, irregular eating frameworks, disruptions in sleep patterns (inadequate quality and duration), engagement in shift work, and the phenomenon known as social jetlag. The rapid evolution of contemporary life and domestic routines has significantly outpaced the rate of genetic adaptation. Consequently, the underlying circadian rhythms are exposed to multiple shifts, thereby elevating the susceptibility to disease predisposition. This comprehensive review endeavors to synthesize existing empirical evidence that substantiates the conceptual integration of the circadian clock, biochemical molecular homeostasis, oxidative stress, and the stimuli imparted by physical exercise, sleep, and nutrition.

Effects of dominance and vision on unipedal balance tests in futsal players using a triaxial accelerometer

Optimal postural control improves performance and reduces the risk of injury in futsal. In this context, wearable accelerometers may detect velocity changes of the centre of mass during a task, enabling the analysis of postural control in different environments. This work aimed to determine the influence of vision and dominance on unipodal static postural balance in non-professional athletes. Twenty-four university male futsal players performed a unipodal balance test to assess their body sway using a triaxial accelerometer. To assess dominance, the preferred limb for kicking the ball was considered, while vision was manipulated by asking participants to close their eyes during the test. Root mean square (RMS) and sample entropy (SaEn) of centre of mass variables were analysed. For statistical analysis, a multivariate analysis of variance model was used. Our results suggest an effect of vision, but not of dominance nor the interaction between vision and limb dominance. Specifically, a higher-acceleration RMS in the mediolateral axis was observed, as well as an increased SaEn in the three axes. To conclude, unipodal postural demand in futsal players under visual input suppression was not influenced by their limb dominancy.

Analysis of the Performance and Sailing Variables of the Optimist Class in a Variety of Wind Conditions

The aim of this study was to analyse the variables that determine the performance of the Optimist class during a regatta in different wind conditions. A total of 203 elite sailors of the Optimist class (121 boys and 82 girls) participated in the study. According to their ranking in the regatta, the sample was divided into four performance groups. In a regatta with 11 races, the velocity made good (VMG), the distance and the manoeuvres were evaluated by means of GNSS equipment in three different courses. The boys performed a greater number of upwind and running manoeuvres than the girls. The very-low-level sailors obtained a lower VMG in all the courses analysed compared with the rest of the groups of sailors of higher levels. Upwind manoeuvres, broad reach and running VMG were significant variables for establishing differences in performance level when the wind speed was in a range of 5 to ≤8 knots. When the wind speed was in the >8 to ≤12 knot range, upwind distance was the key variable in determining performance differences. VMG, upwind and broad reach distance and broad reach manoeuvres were the most important variables when the wind speed was in the >12 to 15 knots range. The boys performed more manoeuvres than the girls in the upwind and running courses.

Relationship between external and internal load indicators and injury using machine learning in professional soccer: a systematic review and meta-analysis

This study verified the relationship between internal load (IL) and external load (EL) and their association on injury risk (IR) prediction considering machine learning (ML) approaches. Studies were included if: (1) participants were male professional soccer players; (2) carried out for at least 2 sessions, exercises, or competitions; (3) correlated training load (TL) with non-contact injuries; (4) applied ML approaches to predict TL and non-contact injuries. TL included: IL indicators (Rating of Perceived Exertion, RPE; Session-RPE, Heart Rate, HR) and EL indicators (Global Positioning System, GPS variables); the relationship between EL and IL through index, ratio, formula; ML indicators included performance measures, predictive performance of ML methods, measure of feature importance, relevant predictors, outcome variable, predictor variable, data pre-processing, features selection, ML methods. Twenty-five studies were included. Eleven addressed the relationship between EL and IL. Five used EL/IL indexes. Five studies predicted IL indicators. Three studies investigated the association between EL and IL with IR. One study predicted IR using ML. Significant positive correlations were found between S-RPE and total distance (TD) (r = 0.73; 95% CI (0.64 to 0.82)) as well as between S-RPE and player load (PL) (r = 0.76; 95% CI (0.68 to 0.84)). Association between IL and EL and their relationship with injuries were found. RPE, S-RPE, and HR were associated with different EL indicators. A positive relationship between EL and IL indicators and IR was also observed. Moreover, new indexes or ratios (integrating EL and IL) to improve knowledge regarding TL and fitness status were also applied. ML can predict IL indicators (HR and RPE), and IR. The present systematic review was registered in PROSPERO (CRD42021245312).

The Effect of Caffeine Supplementation on Female Volleyball Players' Performance and Wellness during a Regular Training Week

BACKGROUND

caffeine is an ergogenic aid that still needs to be investigated in women's sports performance.

METHODS

Eight semi-professional women's volleyball players (height = 1.63 ± 0.08 m; weight = 66.67 ± 4.74 kg) voluntarily participated in this study. A randomized crossover design was implemented where players underwent caffeine and placebo conditions. In the caffeine condition, participants consumed 5 mg/kg of caffeine based on their body weight before acute training. The evaluations were performed over two weeks of training. In both conditions, the countermovement jump, repeated jumps for 15 s, and handgrip tests were performed. The change of direction was assessed using the 505 test. Well-being was also assessed with a wellness questionnaire. A repeated measures ANOVA and correlation analysis were performed.

RESULTS

The repeated measures ANOVA revealed a main effect of supplementation (F (1.7) = 8.41, p = 0.02, η2 = 0.54) across the training week on physical performance. Additionally, there was a positive effect on perceived fatigue (F (1.7) = 7.29, p = 0.03, η2 = 0.51).

CONCLUSIONS

Caffeine improved performance and fatigue parameters over one week of training. Further research is needed on women, focusing on physical performance and wellbeing, especially during intense periods.

International selection and competition in youth sport: pin the tail on the donkey or targeted intervention?

Across sporting contexts, there is growing debate surrounding the utility of junior international age group selection in sport. In this regard, there has been considerable focus on the age of selection, with the low conversion of athletes from junior to senior international level often used to critique the efficiency of such programmes. In this perspective article, we argue that there is a need for a more nuanced consideration of the effectiveness of international age groups in talent systems. We begin this perspective article with a synthesis of the literature pertaining to junior to senior transitions in sport, followed by the implications and opportunity cost presented by international age groups. We argue for a more contextual evaluation of international age groups relative to the performance aims of a talent system, the need for manipulation of challenge dynamics, and the resource costs of doing so (e.g., providing developmental challenges for those who have early advantage, or spreading resource amongst greater numbers for broader impact). We suggest that talent systems evaluate the opportunity cost presented by international age groups, with decisions based upon individual strategic context.

The influence of the five-factor model of personality on performance in competitive sports: a review

Personality is considered to be a factor affecting athletic performance. However, inconsistency in the research results regarding size and even direction of the relationship. An evaluation of the evidence of the relationship between personality and athletic performance was conducted in order to summarize the evidence available. A systematic literature search was conducted in March 2023. Sport performance and the Big Five personality model were identified in our research. We used PubMed, Web of Science, Embase, Cochrane Library, Wang Fang (Chinese), Wei Pu (Chinese), and CNKI (Chinese) databases for the systematic literature search (Prospero registration number: CRD42022364000), screened 4,300 studies, and found 23 cross-sectional studies eligible for inclusion in this review. The results of this systematic analysis show that, besides neuroticism, openness, conscientiousness, extraversion, and agreeableness are all positively correlated with sports performance. Conscientiousness and extraversion are the two main personalities in team sports. Openness and agreeableness show different results in different sports, and it is not clear to which project they are beneficial. The value of personality as a possible predictor of athletic performance is generally positive. Therefore, professionals such as applied sports psychologists, coaching personnel, athletes, and sports administrators must comprehensively grasp the significance of personality's role in achieving success in major competitions. Considering these facts, sports practitioners should promote personality screening and personality development programs.

The Efficacy of a Mental Skills Training Course for Collegiate Athletes

CONTEXT

Psychological skills training improves performance in athletes. However, few studies have looked at the efficacy and satisfaction of mental skills training programs for collegiate athletes.

OBJECTIVE

We aimed to evaluate satisfaction of collegiate athletes with a 6-session mental skills course, and to assess changes in mental toughness and coping skills before and after the course.

DESIGN

Prospective cohort study following collegiate female athletes through a 6-session mental skills course.

SETTING

Division 1 collegiate athletic teams.

PATIENTS/PARTICIPANTS

54 Division I female athletes (mean age =19.8) participated in the program and 42 (77.7 %) completed pre-course assessments, which subsequent evaluations were matched to.

MAIN OUTCOME MEASURES

The Athletic Coping Skills Inventory (ACSI, range=0-84) and Mental Toughness Index (MTI, range=8-56) assessed coping skills and mental toughness pre-course, immediate post-course and 4-month post course. Satisfaction was assessed on a 10-point scale.

RESULTS

For participants with paired pre- and immediate post-course data (n=37, 68.5%), MTI scores improved by a mean 2.6 points (95% CI=1.1-4.1; p=0.001) and ACSI scores improved by a mean 4.0 points (95% CI=0.6-7.4; p=0.02). At four-month follow-up (n=25, 46.2%), no change was detected from pre-course in mean MTI score (p=0.72), but there was a significant increase of 3.4 points in mean ACSI (95% CI=0.4-6.4; p=0.03). Overall satisfaction had a median score of 9/10 (IQR, 8-10) at post-course, and eighteen participants (48.6%) shared positive free-text comments regarding course delivery, content, and impact. No negative feedback was reported.

CONCLUSIONS

Mental toughness and coping skills scores significantly improved at post-course assessment, with coping skills scores maintaining their effect at four months. The improvements identified spark the question of the potential impact of mental skills training programs when studied in larger athlete populations or over more sustained periods of time. Athletes reported being highly satisfied with course content and reported overall positive experiences.

Fundamentals or Icing on Top of the Cake? A Narrative Review of Recovery Strategies and Devices for Athletes

The sport and athletic performance industry has seen a plethora of new recovery devices and technologies over recent years, and it has become somewhat difficult for athletes, coaches, and practitioners to navigate the efficacy of such devices or whether they are even required at all. With the increase in recovery devices and tools, it has also become commonplace for athletes to overlook more traditional, well-established recovery strategies. In this narrative review, we discuss recovery strategies in relation to the hierarchy of scientific evidence, classifying them based on the strength of the evidence, ranging from meta-analyses through to case studies and reports. We report that foam rolling, compression garments, cryotherapy, photobiomodulation, hydrotherapy, and active recovery have a high level of positive evidence for improved recovery outcomes, while sauna, recovery boots/sleeves, occlusion cuffs, and massage guns currently have a lower level of evidence and mixed results for their efficacy. Finally, we provide guidance for practitioners when deciding on recovery strategies to use with athletes during different phases of the season.

Monitoring lower limb biomechanical asymmetry and psychological measures in athletic populations-A scoping review

BACKGROUND

Lower limb biomechanics, including asymmetry, are frequently monitored to determine sport performance level and injury risk. However, contributing factors extend beyond biomechanical and asymmetry measures to include psychological, sociological, and environmental factors. Unfortunately, inadequate research has been conducted using holistic biopsychosocial models to characterize sport performance and injury risk. Therefore, this scoping review summarized the research landscape of studies concurrently assessing measures of lower limb biomechanics, asymmetry, and introspective psychological state (e.g., pain, fatigue, perceived exertion, stress, etc.) in healthy, competitive athletes.

METHODS

A systematic search of MEDLINE, Embase, CINAHL, SPORTDiscus, and Web of Science Core Collections was designed and conducted in accordance with PRISMA guidelines. Fifty-one articles were included in this review.

RESULTS

Significant relationships between biomechanics (k = 22 studies) or asymmetry (k = 20 studies) and introspective state were found. Increased self-reported pain was associated with decreased range of motion, strength, and increased lower limb asymmetry. Higher ratings of perceived exertion were related to increased lower limb asymmetry, self-reported muscle soreness, and worse jump performance. Few studies (k = 4) monitored athletes longitudinally throughout one or more competitive season(s).

CONCLUSION

This review highlights the need for concurrent analysis of introspective, psychological state, and biomechanical asymmetry measures along with longitudinal research to understand the contributing factors to sport performance and injury risk from biopsychosocial modeling. In doing so, this framework of biopsychosocial preventive and prognostic patient-centered practices may provide an actionable means of optimizing health, well-being, and sport performance in competitive athletes.

Iron Status and Physical Performance in Athletes

Iron is an important mineral in the body, essential for muscle function and oxygen transport. Adequate levels of iron in the blood are necessary for athletes, as iron-deficiency anemia can reduce physical performance. Several studies have investigated iron status and supplementation in iron-deficient athletes, and determined how physical strain can change iron balance and markers related to iron status. The question of how to influence and optimize iron status, as well as other markers that can affect iron metabolism, has been less thoroughly investigated. Therefore, the aim of this review is to take a closer look at the importance of iron values, iron markers, and factors that can change iron metabolism for physical performance and the extent to which physical performance can be influenced in a positive or negative way. A systematic search of the PubMed database was performed, with the use of « iron» or «iron deficiency» or «hemoglobin» AND «athletes» AND «athletic performance» as a strategy of the search. After the search, 11 articles were included in the review after the application of inclusion and exclusion criteria. Major findings include that iron supplementation had the best effect in athletes with the lowest iron status, and effects on physical performance were mostly achieved in those who were originally in a deficit. Iron supplementation could be beneficial for optimal erythropoietic response during altitude training, even in athletes with normal iron stores at baseline, but should be performed with caution. Alteration of the hepcidin response can affect the use of existing iron stores for erythropoiesis. Energy intake, and the amount of carbohydrates available, may have an impact on the post-exercise hepcidin response. Optimal vitamin D and B12 levels can possibly contribute to improved iron status and, hence, the avoidance of anemia.