Is Coffee a Useful Source of Caffeine Preexercise?

Caffeine is a well-established ergogenic aid, with its performance-enhancing effects demonstrated across a wide variety of exercise modalities. Athletes tend to frequently consume caffeine as a performance enhancement method in training and competition. There are a number of methods available as a means of consuming caffeine around exercise, including caffeine anhydrous, sports drinks, caffeine carbohydrate gels, and gum. One popular method of caffeine ingestion in nonathletes is coffee, with some evidence suggesting it is also utilized by athletes. In this article, we discuss the research pertaining to the use of coffee as an ergogenic aid, exploring (a) whether caffeinated coffee is ergogenic, (b) whether dose-matched caffeinated coffee provides a performance benefit similar in magnitude to caffeine anhydrous, and (c) whether decaffeinated coffee consumption affects the ergogenic effects of a subsequent isolated caffeine dose. There is limited evidence that caffeinated coffee has the potential to offer ergogenic effects similar in magnitude to caffeine anhydrous; however, this requires further investigation. Coingestion of caffeine with decaffeinated coffee does not seem to limit the ergogenic effects of caffeine. Although caffeinated coffee is potentially ergogenic, its use as a preexercise caffeine ingestion method represents some practical hurdles to athletes, including the consumption of large volumes of liquid and difficulties in quantifying the exact caffeine dose, as differences in coffee type and brewing method may alter caffeine content. The use of caffeinated coffee around exercise has the potential to enhance performance, but athletes and coaches should be mindful of the practical limitations.

Using Principal Component Analysis to Compare the Physical Qualities Between Academy and International Youth Rugby League Players

PURPOSE

To compare the physical qualities between academy and international youth rugby league (RL) players using principal component analysis.

METHODS

Six hundred fifty-four males (age = 16.7 [1.4] y; height = 178.4 [13.3] cm; body mass = 82.2 [14.5] kg) from 11 English RL academies participated in this study. Participants completed anthropometric, power (countermovement jump), strength (isometric midthigh pull; IMTP), speed (10 and 40 m speed), and aerobic endurance (prone Yo-Yo IR1) assessments. Principal component analysis was conducted on all physical quality measures. A 1-way analysis of variance with effect sizes was performed on 2 principal components (PCs) to identify differences between academy and international backs, forwards, and pivots at under 16 and 18 age groups.

RESULTS

Physical quality measures were reduced to 2 PCs explaining 69.4% of variance. The first PC (35.3%) was influenced by maximum and 10-m momentum, absolute IMTP, and body mass. Ten and forty-meter speed, body mass and fat, prone Yo-Yo, IMTP relative, maximum speed, and countermovement jump contributed to PC2 (34.1%). Significant differences (P < .05, effect size = -1.83) were identified between U18 academy and international backs within PC1.

CONCLUSION

Running momentum, absolute IMTP, and body mass contributed to PC1, while numerous qualities influenced PC2. The physical qualities of academy and international youth RL players are similar, excluding U18 backs. Principal component analysis can reduce the dimensionality of a data set and help identify overall differences between playing levels. Findings suggest that RL practitioners should measure multiple physical qualities when assessing physical performance.

Let's Talk About Mental Health and Mental Disorders in Elite Sports: A Narrative Review of Theoretical Perspectives

The objective of this article is to discuss: (a) the various theoretical perspectives on mental health and mental health disorders adopted in sport psychology, and (b) how the adoption of these various theoretical perspectives in studies might impact upon the interpretations and conclusions in research about the mental health of participants in elite sports. Well-being as a target construct, holistic models, the single continuum or stage models, and Keyes' dual-continuum model of mental health are described, together with a sports psychiatric view of mental health. The strengths and limitations of various mental health perspectives are discussed. We conclude that mental health is a complex construct and that the sport psychology literature, much like the clinical psychology literature, has struggled to reach a consensus regarding a definition or a feasible approach to investigating mental health. For the researcher, it becomes important to make explicit the underlying theoretical perspective adopted and the operationalization upon which conclusions about elite athletes' mental health are based so that an increased knowledge base with high scientific credibility can be established and consolidated over time.

Nocebo effects on motor performance: A systematic literature review

Directionally opposite to placebo effects are the nocebo effects that negatively impact people's thoughts, feelings, and actions. An important but scarcely studied aspect of everyday functioning is motor performance, in which nocebo effects might impair athletic skills and the much-needed purposeful daily movements and motor actions. The aim of this literature review is to unveil the nocebo effects on motor performance. Searched databases were PubMed, PsycINFO, and SPORTDiscus. Twenty-one articles, reporting 23 studies, met the eligibility criteria for inclusion in the current review. All reports exhibited "some" risk of bias. Of the 23 studies, 14 found a nocebo effect on motor performance, equivocal results emerged from two studies, and negative findings were reported in seven studies. Most (10/12) studies using a between-subjects design have reported a nocebo effect. The mean effect size was 0.60, suggesting a medium-to-large effect of nocebo intervention on motor performance. Based on this review, we conclude that nocebo effects do influence motor performance and can be evoked with negative verbal information. This effect may be more robust than the placebo effect but also depends on the type of motor performance, on the examined sample, and on the nocebo agent. Hence, nocebo effects should be recognized and controlled in empirical research on motor performance, and they should be prevented or extinguished in practical and therapeutic settings. More extensive examination of the nocebo effect on motor performance is warranted, especially using between-subjects research design and a "no agent" control condition.

The effects of a four weeks combined resistance training programme on cricket bowling velocity

Background

Despite the importance of resistance training for cricket pace bowlers, there is limited research displaying meaningful improvements in ball release velocity following resistance training.

Objectives

The study aimed at investigating the effects of a four weeks combined resistance training programme on ball release velocity in club cricket pace bowlers.

Methods

Eighteen adult male club level pace bowlers were allocated into a combined resistance training (CRT) group or a traditional cricket training (TR) group. The CRT group (n=9) performed two training sessions a week for four weeks, consisting of a combination of core and lower body strength exercises, plyometric exercises, and weighted implement training. The TR group (n=9) did no resistance training and only bowled with regular weighted cricket balls. Pre-testing/post-testing variables were ball release velocity, bowling accuracy, and upper and lower body neuromuscular performance.

Results

The CRT group significantly increased their ball release velocity by six percent (5.1 km·h^-1), effect size (ES) =0.65, p<0.001) after four weeks of training, while there was no significant difference in the TR group (0.00 km·h^-1, ES=0.0, p=0.674). There was no statistically significant difference in the bowling accuracy and lower body neuromuscular performance for both groups and the upper body neuromuscular performance for the CRT group.

Conclusion

This study provides evidence of a combined resistance training programme that can be used to improve bowling velocity in cricket pace bowlers. This increase in ball velocity was not related to any of the neuromuscular performance variables measured.

The Role of Trunk Training for Physical Fitness and Sport-Specific Performance. Protocol for a Meta-Analysis

The trunk (core) muscles are involved in daily functions (i. e., stabilizing the body in everyday tasks) and force generation of the limbs during athletic tasks such as kicking, throwing, or running. Even though trunk training is a popular means for improving physical fitness and athletic performance, the direct relationship of improved trunk function (i.e., stability, strength, or endurance), fitness and sport-specific performance is not conclusive. The aim of this proposed review is to evaluate the effects of trunk training on physical fitness and sport-specific performance, and to examine potential subject-related (e.g., age, sex) and trunk training-related moderator variables (e.g., training period, training frequency) for performance changes. We will conduct a systematic literature search in Web of Science, MEDLINE (via EBSCO) and SportDiscus. Relevant papers will be screened independently by two reviewers in two stages: (1) title and abstracts and (2) the full text of the remaining papers. A third reviewer will resolve possible disagreements. Data extraction and risk of bias of the included studies will be performed in addition to the PEDro scoring to judge the quality of the studies. A meta-analysis will be conducted to determine the efficacy of trunk training to increase physical fitness and sport-specific performance measures. In addition, subgroup univariate analyses were computed for subject-related (i.e., age, sex, performance level) and training-related moderator variables (i.e., training period, training frequency, training sessions, session duration). The results of this proposed systematic review and meta-analysis will assess the effects of trunk training on physical fitness and sport-specific and identify which subject-related and training-related moderate variables of trunk training modality might be beneficial for performance gains. This knowledge has potential importance for athletes and coaches in sports.

Troubleshooting a Nonresponder: Guidance for the Strength and Conditioning Coach

Ideally an athlete would continue to improve performance indefinitely over time, however improvement slows as the athlete approaches their genetic limits. Measuring performance is complex—performance may be temporarily depressed following aggressive training for multiple reasons, physiological and psychosocial. This reality may be vexing to the strength and conditioning coach, who, as a service provider, must answer to sport coaches about an athlete’s progress. Recently an evaluation mechanism for strength and conditioning coaches was proposed, in part to help coaches establish their effectiveness within the organization. Without formal guidance and realistic expectations, if an athlete is not bigger, leaner, stronger, etc. as a result of training within a specified timeframe, blame is often placed upon the strength and conditioning coach. The purpose of this article is to explore possible causes of what may be perceived as athlete non-responses to training and to provide guidance for the coach on how to handle those issues within their domain. A process of investigation is recommended, along with resources to assist coaches as they consider a broad range of issues, including enhancing existing testing methods, improving athlete behaviors, and adjusting processes designed to bring about performance improvement.

A Review of Neurofeedback Training for Improving Sport Performance From the Perspective of User Experience

Neurofeedback training (NFT) is a non-invasive, safe, and effective method of regulating the nerve state of the brain. Presently, NFT is widely used to prevent and rehabilitate brain diseases and improve an individual's external performance. Among the various NFT methods, NFT to improve sport performance (SP-NFT) has become an important research and application focus worldwide. Several studies have shown that the method is effective in improving brain function and motor control performance. However, appropriate reviews and prospective directions for this technology are lacking. This paper proposes an SP-NFT classification method based on user experience, classifies and discusses various SP-NFT research schemes reported in the existing literature, and reviews the technical principles, application scenarios, and usage characteristics of different SP-NFT schemes. Several key issues in SP-NFT development, including the factors involved in neural mechanisms, scheme selection, learning basis, and experimental implementation, are discussed. Finally, directions for the future development of SP-NFT, including SP-NFT based on other electroencephalograph characteristics, SP-NFT integrated with other technologies, and SP-NFT commercialization, are suggested. These discussions are expected to provide some valuable ideas to researchers in related fields.

Frequency and type of adverse analytical findings in athletics: Differences among disciplines

Athletics is a highly diverse sport that contains a set of disciplines grouped into jumps, throws, races of varying distances, and combined events. From a physiological standpoint, the physical capabilities linked to success are quite different among disciplines, with varying involvements of muscle strength, muscle power, and endurance. Thus, the use of banned substances in athletics might be dictated by physical dimensions of each discipline. Thus, the aim of this investigation was to analyse the number and distribution of adverse analytical findings per drug class in athletic disciplines. The data included in this investigation were gathered from the Anti-Doping Testing Figure Report made available by the World Anti-Doping Agency (from 2016 to 2018). Interestingly, there were no differences in the frequency of adverse findings (overall,~0.95%, range from 0.77 to 1.70%) among disciplines despite long distance runners having the highest number of samples analysed per year (~9812 samples/year). Sprinters and throwers presented abnormally high proportions of adverse analytical findings within the group of anabolic agents (p < 0.01); middle- and long-distance runners presented atypically high proportions of findings related to peptide hormones and growth factors (p < 0.01); racewalkers presented atypically high proportions of banned diuretics and masking agents (p = 0.05). These results suggest that the proportion of athletes that are using banned substances is similar among the different disciplines of athletics. However, there are substantial differences in the class of drugs more commonly used in each discipline. This information can be used to effectively enhance anti-doping testing protocols in athletics.

Mood, Burnout, and Dispositional Optimism in Kayak Polo Players During Their Competitive Stage

The main objective of performance sport is to obtain achievements at the highest level through the adequate development of the athlete. The scientific literature demonstrates the fundamental role played by the inclusion of certain psychological variables in the training plan. This study examined the psychological profile of kayak polo players through the variables of burnout, optimism, and mood in the hours prior to the competition, relating these to each other and to some sociodemographic data. A sample of 86 canoeists, 60 men (69.8%) and 26 women (30.2%), with an age measurement of 24.4 ± 9.1 years belonging to the first male and female kayak polo division, completed the POMS-29, the LOT-R, and the IBD-R. Athletes' levels of optimism were found to be significantly correlated with mood. Optimism also influenced emotional exhaustion. In addition, seniority and internationality were decisive factors in the level of optimism and mood achieved.

Putting Attention on the Spot in Coaching: Shifting to an External Focus of Attention With Imagery Techniques to Improve Basketball Free-Throw Shooting Performance

Attentional focus is an area that has garnered considerable attention in the sport psychology and motor performance literature. This is unsurprising given that attentional focus has been directly linked to performance outcomes and is susceptible to coaching input. While research has amassed supporting benefits of an external focus of attention (EFA) on motor performance using verbal instruction, other studies have challenged the notion that an EFA is more beneficial than an internal focus of attention (IFA) for sport-related performance. Further, it is unclear what type of instructions may serve to direct an athlete to an EFA and, in particular, if coaching can utilize imagery to orient an athlete toward an EFA. In the present exploratory study, we evaluate the effectiveness of instruction to improve free-throw shooting performance with an emphasis on an EFA brought about by implementing techniques borrowed from the imagery literature. This was tested relative to an alternate approach with an IFA induced through an emphasis on technique, devised to more closely resemble input typical of coach-to-athlete instruction. Twenty-five male and female university basketball players completed both conditions in a fully counterbalanced within-subject design. Results confirmed that participants in the EFA imagery condition had greater shooting accuracy than in the IFA technique condition. The study provides initial evidence that EFA coaching can borrow from imagery techniques, though future research should elucidate the underlying mechanisms of the effect.

Transcranial Alternating Current Stimulation (tACS) Does Not Affect Sports People's Explosive Power: A Pilot Study

Purpose: This study is aimed to preliminary investigate whether transcranial alternating current stimulation (tACS) could affect explosive power considering genetic background in sport subjects. Methods: Seventeen healthy sports volunteers with at least 3 years of sports activities participated in the experiment. After 2 weeks of familiarization performed without any stimulation, each participant received either 50 Hz-tACS or sham-tACS. Before and after stimulation, subjects performed the following tests: (1) the squat jump with the hands on the hips (SJ); (2) countermovement jump with the hands on the hips (CMJ); (3) countermovement jump with arm swing (CMJ-AS); (4) 15-s Bosco's test; (5) seated backward overhead medicine ball throw (SBOMBT); (6) seated chest pass throw (SCPT) with a 3-kg rubber medicine ball; and (7) hand-grip test. Additionally, saliva samples were collected from each participant. Genotyping analysis was carried out by polymerase chain reaction (PCR). Results: No significant differences were found in sport performance of subjects after 50 Hz-tACS. Additionally, we did not find any influence of genetic background on tACS-related effect on physical performance. These results suggest that tACS at gamma frequency is not able to induce an after-effect modulating sport performance. Further investigations with larger sample size are needed in order to understand the potential role of non-invasive brain stimulation techniques (NIBS) in motor performances. Conclusions: Gamma-tACS applied before the physical performance fails to improve explosive power in sport subjects.

Running Patterns in LaLiga Before and After Suspension of the Competition Due to COVID-19

In the first wave of the COVID-19 outbreak (spring 2020), the first division of professional soccer in Spain (LaLiga) was suspended for 12 weeks as part of the lockdown imposed by the Spanish health authorities. Professional soccer players were confined to home for 8 weeks and then a retraining period of 4 weeks was set before the first competitive match. When competition was resumed, professional soccer teams competed in a congested calendar (11 matchdays in 39 days) while some in-game regulations were altered (up to 5 substitutions, refreshment pauses). The current research presents an analysis of running patterns before suspension and after resumption of LaLiga to determine how the lockdown affected players’ physical performance. To aid in this purpose, a pairwise comparison was performed of running patterns of the 2019–2020 vs. 2018–2019 season (i.e., control season). Using a two-way ANOVA (season x matchday), it was found that there was no main effect of the season on total running distance per match (P = 0.288) nor in the distances covered < 14.0 km/h (P = 0.294), at 21.0–23.9 km/h (P = 0.266), and at ≥ 24.0 km/h (P = 0.112). Only the distance at 14.0–20.9 km/h was affected by the season (P = 0.019) with a lower running distance on matchday 34 in the 2019–2020 vs. 2018–2019 season. The number of substitutions (from 2.9 to 4.5 substitutions per game; P < 0.001) and match duration (96 vs. 100 min; P < 0.001) significantly increased after resumption respect to the previous season. These data suggest that high-intensity running performance of professional soccer teams was maintained after the resumption of the competition while the alterations likely aided in the in-game regulations facilitated the maintenance of soccer physical performance.

Psychological and Physiological Features Associated with Swimming Performance

BACKGROUND

The aim of the present research was to study the psychological and physiological features associated with aerobic and anaerobic performance in trained swimmers.

METHODS

A correlation and stepwise regression analyses were conducted with the data obtained in a RESTQ-76 sport questionnaire, a heart rate variability test, and an anaerobic and aerobic swimming performance efforts of 20 swimmers.

RESULTS

Aerobic performance correlated, principally, with parameters related to parasympathetic modulation measured in the frequency and time domains of the heart rate variability (LF/HF r: -0.806, p < 0.001; NN50 r: 0.937, p < 0.001). Swimmers' anaerobic performance correlated to psychological features (low stress r: 0.526, p: 0.025, and high fatigue r: -0.506, p: 0.032).

CONCLUSION

Swimming performance presented different psychological and physiological features depending on the probe characteristic. Specifically, swimmers' anaerobic performance was associated with psychological features (low stress and high fatigue perception) and aerobic performance with physiological features (high parasympathetic modulation). This information could help coaches to know the variables to control in their swimmers, depending on the probe in which they compete (anaerobic or aerobic).

Losing the Home Field Advantage When Playing Behind Closed Doors During COVID-19: Change or Chance?

Due to restrictions against the COVID-19 pandemic, spectators were not allowed to attend soccer matches at the end of the 2019/2020 season. Previous studies suggest that the absence of a home crowd changes the home field advantage in terms of match outcomes, offensive performance, and referee decisions. However, because of the small sample sizes, these changes may be random rather than meaningful. To test this, we created 1,000,000 randomized samples from the previous four seasons with the exact same number of matches played behind closed doors in Europe's four most elite soccer leagues at the end of the 2019/2020 season. We found that across countries (Germany, Spain, Italy, and England), performance indices and referee decisions (except red cards) indeed changed to the detriment of the home team beyond the level of chance. However, this overall pattern could be ascribed to specific countries. Most importantly, the proportion of points won by the home teams declined significantly only in Germany, which was accompanied by a meaningful increase in (1) the proportion of goals scored by the away teams and (2) the proportion of yellow cards given to the home teams. We conclude that the home field advantage may indeed be lost when spectators are absent. However, in future studies, more detailed behavioral analyses are needed to determine the robustness and the behavioral determinants of this phenomenon across leagues and countries.

Melatonin supplementation improves psychomotor and physical performance in collegiate student-athletes following a sleep deprivation night

Several studies report sleep deprivation negatively impacts post-cognitive and physical performance, and other functions. Recent findings indicate ingestion of melatonin prior to exercise enhances tolerance to training and improves competition. We investigated the effects of melatonin supplementation on psychomotor performance and selected physical fitness measures of collegiate student-athletes following 4 h and 24 h of sleep deprivation. The study employed a repeated-measures, double-blind, randomized controlled protocol with posttest control group design with six conditions [3 sleep conditions (without sleep deprivation, 4 h sleep deprivation (4SD) and 24 h sleep deprivation (24SD)) × 2 supplementation conditions (melatonin and placebo)]. Ten trained male collegiate student-athletes (mean ± SD; age: 20 ± 2 y) attended the laboratory on six occasions with 72 h between successive visits. Placebo or 6 mg of melatonin were administered orally in capsules 30 min before the tests of: static and dynamic balance, reaction time, and anaerobic power. Also, blood lactate was measured before and 3 min after the anaerobic power exercise. During the placebo session, the results indicated that 4SD and 24SD had negative effect on the measured parameters, with higher impacts of the 24SD condition. Compared to placebo and during both 4SD and 24SD conditions, melatonin had a positive effect on static and dynamic balance, anaerobic power, blood lactic acid, and reaction time (p < .05). However, 6 mg melatonin ingestion had no significant effect on all dependent variables in collegiate student-athletes after the night without a sleep deprivation (p > .05). In conclusion, 6 mg of melatonin may be used by student-athletes to improve balance and psychomotor and physical performances after 4 h or 24 h of sleep deprivation.

Serum Levels of Brain-Derived Neurotrophic Factor and Other Neurotrophins in Elite Athletes: Potential Markers of the Use of Transcranial Direct Current Stimulation in Sport

Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation that may enhance mental and physical performance in sports, representing a potential new form of doping (“brain doping” or “electromagnetic doping”). This study aims to identify diagnostic biomarkers for detecting the possible abuse of tDCS in sport. Brain-Derived Neurotrophic Factor (BDNF) and other neurotrophins (NT, such as beta nerve growth factor, NGF) were pre-selected as potential candidates since their serum values have been observed to change following tDCS. Neurotrophins were measured using ELISA assays in 92 serum samples collected from elite athletes, classified by sex (males = 74; females = 18), age (range 17–25 n = 27, 26–35 n = 36, and over 35 n = 14; age not known n = 15), type of sports practiced (endurance n = 74; power n = 18), and type of sample collection (“in competition” n = 24; “out of competition” n = 68). Single nucleotide polymorphisms (rs6265, rs11030099, and rs11030100) were genotyped on 88 samples to determine their influence on the analytes' basal levels. Athletes older than 35 presented higher BDNF values than younger individuals (p < 0.05). Samples collected “in competition” showed higher BDNF concentrations than those collected “out of competition” (p < 0.05). The studied polymorphisms appeared to affect only on proBDNF, not altering BDNF serum concentrations. NT-3 and NT-4 were poorly detectable in serum. Our results suggest that BDNF can be considered as a first biomarker to detect the abuse of tDCS in sport doping. Further studies are necessary to assess whether proBDNF and beta NGF can also be considered suitable biomarkers to detect the recourse to electromagnetic brain stimulation in sports, especially in the case their serum levels can be monitored longitudinally. To the best of our knowledge, this is the first study aimed to pre-select serum biomarkers to identify the use of tDCS, and represents the first step toward the development of an indirect strategy, preferably based on the longitudinal monitoring of individual data, for the future detection of “brain doping” in sports.

Career Outlook and Performance of Professional Athletes After Achilles Tendon Rupture: A Systematic Review

BACKGROUND

The purpose of this systematic review is to examine the literature on Achilles tendon (AT) injuries in professional athletes to determine their rate of return to play (RTP), performance, and career outcome after AT rupture.

METHODS

A literature search of MEDLINE, Google Scholar, CINAHL, and Cochrane Library databases was performed. Included studies reported outcomes related to RTP (time and rate), durability and player participation, and player performance following AT rupture in professional athletes of the National Football League (NFL), National Basketball Association (NBA), Major League Baseball (MLB), and professional soccer leagues.

RESULTS

Fifteen studies met inclusion criteria for analysis. Athletes were able to return to professional sport participation 76% of the time, with mean time to RTP of 11 months following AT injury. Athletes experienced a decline in player efficiency ratings, power ratings, and sport- and position-specific statistics in the NFL, NBA, and professional soccer leagues compared to noninjured controls. RTP rate was significantly lower following AT rupture in comparison to athletes sustaining other common orthopedic injuries such as anterior cruciate ligament injuries, meniscal tears, and ankle fractures in both NFL and NBA athletes.

CONCLUSION

AT rupture prohibits nearly 25% of professional athletes from returning to their respective sport. Of those able to return to compete at a professional level, the mean time to RTP is 11 months-nearly double the estimated 6-month recovery for RTP in the general population. Furthermore, player performance and durability were curtailed following AT rupture. This review of the literature should be used to set evidence-based goals and establish realistic expectations for RTP for elite athletes following AT injuries.

LEVEL OF EVIDENCE

Level III, systematic review.

Blood flow restriction training and the high-performance athlete: science to application

The manipulation of blood flow in conjunction with skeletal muscle contraction has greatly informed the physiological understanding of muscle fatigue, blood pressure reflexes, and metabolism in humans. Recent interest in using intentional blood flow restriction (BFR) has focused on elucidating how exercise during periods of reduced blood flow affects typical training adaptations. A large initial appeal for BFR training was driven by studies demonstrating rapid increases in muscle size, strength, and endurance capacity, even when notably low intensities and resistances, which would typically be incapable of stimulating change in healthy populations, were used. The incorporation of BFR exercise into the training of strength- and endurance-trained athletes has recently been shown to provide additive training effects that augment skeletal muscle and cardiovascular adaptations. Recent observations suggest BFR exercise alters acute physiological stressors such as local muscle oxygen availability and vascular shear stress, which may lead to adaptations that are not easily attained with conventional training. This review explores these concepts and summarizes both the evidence base and knowledge gaps regarding the application of BFR training for athletes.

Performance in male and female elite tennis across season of birth

In the field of sports, there is an overrepresentation of athletes born in the initial months of the selection year, and an underrepresentation of athletes born in the latter months of the selection year. This season of birth effect appears to lead to a disadvantage in performance, even though with a considerable variability regarding age, sex, and skill. This study addressed season of birth effects on performance with the best one hundred male and female tennis players in the world. Specifically, we examined whether season of birth moderates the association of body height and ranking position with tennis performance. The main findings indicated that body height and rank associated in the expected direction with first service wins, break points saved, and a success rate describing the ratio of match wins to match defeats. For females born later in the selection year, however, height was unrelated to the percentage of first service wins or break points saved, and occupying higher positions in the ranking did not contribute to improve the ratio of wins to defeats. These findings suggest that season of birth effects on performance might operate for women but not for men when comparing highly selected populations such as the best tennis players in the world.

Effects of Acute Caffeine Intake on Power Output and Movement Velocity During a Multiple-Set Bench Press Exercise Among Mild Caffeine Users

The main goal of this study was to evaluate the effectiveness of an acute dose of caffeine (6 mg/kg body mass (b.m.)) on power output and bar velocity during a bench press multiple-set resistance training session in participants with mild daily caffeine consumption (in the range of 1 to 3 mg/kg/b.m). Thirteen recreationally active male participants (age: 21.9 ± 1.2 years, body mass: 74.4 ± 5.3 kg, body mass index: 23.1 ± 1.6 kg/m2, bench press onerepetition maximum (1RM): 79.2 ± 14.9 kg), with daily caffeine ingestion of 1.56 ± 0.56 mg/kg/b.m., participated in the study with a randomized double-blind experimental design. Each participant performed two identical experimental sessions, 60 min after the intake of a placebo (PLAC) or 6 mg/kg/b.m. of caffeine (CAF-6). In each experimental session, participants performed 5 sets of 5 repetitions of the bench press exercise with a load equivalent to 70% 1RM. The eccentric and concentric phases of the bench press exercise were performed at maximal possible velocity in each repetition. Bar velocity was recorded with a linear position transducer and power output was calculated using velocity and load data. A two-way repeated measures ANOVA indicated no significant substance x set interaction for mean power output (MP), mean bar velocity (MV), peak power output (PP) and peak bar velocity (PV). However, there was a significant main effect of substance on MP (p < 0.01; η2 = 0.47) and MV (p < 0.01; η2 =0.45). Post hoc analysis for main effect revealed that MP and MV values in the CAF-6 group were higher than in the PLAC group in all 5 sets of the exercise (p < 0.05). In conclusion, this study demonstrated that an acute dose of caffeine before resistance exercise increased mean power output and mean bar velocity during a multiple-set bench press exercise protocol among mild caffeine users.

Impact of Ischemic Intra-Conditioning on Power Output and Bar Velocity of the Upper Limbs

This study evaluated the effects of ischemic conditioning on power output and bar velocity in the bench press exercise. Ten healthy males (age: 25 ± 2 years; body mass: 92 ± 8 kg; bench press one repetition maximum -1RM: 145 ± 13 kg), took part in two experimental sessions (with and without ischemia), 1 week apart in random and counterbalanced order. In the ischemic condition, cuffs placed around the upper part of the arms were inflated to 80% of arterial occlusion pressure before each set, while in the control condition there was no blood flow restriction. The exercise protocol included 5 sets of three repetitions each, against a resistance equal to 60% 1RM, with 5 min recovery intervals between sets. There was a main effect of condition for mean power output (MP) and mean bar velocity (MV) (p = 0.01), with overall MP being higher in ischemia than in control by 5.6 ± 4.1% (mean ± 90% compatibility limits), a standardized effect size (ES) of 0.51. Overall MV was also higher by 5.5 ± 4.0%, ES = 0.63. Peak power output (PP) and peak bar velocity (PV) were similar in set 1 of the control and ischemia condition (1039 ± 105 vs. 1054 ± 82 W; 684 ± 74 vs. 696 ± 53 W; 1.09 ± 0.07 vs. 1.12 ± 0.09 m/s; 0.81 ± 0.05 vs. 0.82 ± 0.05 m/s, p = 0.67 to 0.99, mean ± standard deviation). However, from set 3 onward (p = 0.03 to 0.001), PP and PV were higher in ischemia compared with control, with the highest difference observed in set 5 (10.9 ± 5.9%, ES = 0.73 for PP and 8.6 ± 4.6%; ES = 0.89 for PV). These results indicate that ischemia used before each set of the bench press exercise increases power output and bar velocity and this may be used as performance-enhancing stimulus during explosive resistance training.

Comparison of instability resistance training, traditional resistance training and plyometric training on athletic performance parameters

OBJECTIVES

The objective of the study was to compare traditional resistance, instability resistance, and plyometric training methods on measures of athletic performance in healthy subjects.

METHODS

Sixty five healthy, physically active male students were randomly assigned to the following groups: traditional resistance training (RT, n=22), instability training (IT, n=22), and plyometric training (PLY, n=21).Athletic performance parameters were assessed pre- and post-training using chair squat test, standing stork test, shuttle run test, t-test, and vertical jump test.

RESULTS

General linear univariate model with baseline as covariate (ANCOVA) was used for analyzing the change in outcome from baseline to post-treatment. Statistically significant improvement was observed in all the athletic performance parameters in all three groups after seven weeks of training (p-value<0.05). The highest change in chair squat test was reported for RT compared to IT (p-value<0.001) and PLY (p-value<0.001). The change in standing stork test among the IT group was substantially higher than that among RT (p-value=0.007) but did not significantly differ from that among the PLY (p-value=0.27). No statistically significant difference was observed in post-test values of vertical jump test among three groups. The highest change in t-test and shuttle run test was reported for PLY compared to IT (p-value<0.001) and RT (p-value<0.001).

CONCLUSIONS

Based on the findings of this study, it is suggested that IT and PLY can be included with traditional RT to improve various aspects of athletic performance in healthy physically active individuals. The current study will give an insight to athletes, coaches, and trainers regarding utilization of appropriate training methods in enhancing athletic performance. However, further research is required to establish the effectiveness.

Blood-flow-restricted exercise: Strategies for enhancing muscle adaptation and performance in the endurance-trained athlete

NEW FINDINGS

What is the topic of this review? Blood-flow-restricted (BFR) exercise represents a potential approach to augment the adaptive response to training and improve performance in endurance-trained individuals. What advances does it highlight? When combined with low-load resistance exercise, low- and moderate-intensity endurance exercise and sprint interval exercise, BFR can provide an augmented acute stimulus for angiogenesis and mitochondrial biogenesis. These augmented acute responses can translate into enhanced capillary supply and mitochondrial function, and subsequent endurance-type performance, although this might depend on the nature of the exercise stimulus. There is a requirement to clarify whether BFR training interventions can be used by high-performance endurance athletes within their structured training programme.

ABSTRACT

A key objective of the training programme for an endurance athlete is to optimize the underlying physiological determinants of performance. Training-induced adaptations are governed by physiological and metabolic stressors, which initiate transcriptional and translational signalling cascades to increase the abundance and/or function of proteins to improve physiological function. One important consideration is that training adaptations are reduced as training status increases, which is reflected at the molecular level as a blunting of the acute signalling response to exercise. This review examines blood-flow-restricted (BFR) exercise as a strategy for augmenting exercise-induced stressors and subsequent molecular signalling responses to enhance the physiological characteristics of the endurance athlete. Focus is placed on the processes of capillary growth and mitochondrial biogenesis. Recent evidence supports that BFR exercise presents an intensified training stimulus beyond that of performing the same exercise alone. We suggest that this has the potential to induce enhanced physiological adaptations, including increases in capillary supply and mitochondrial function, which can contribute to an improvement in performance of endurance exercise. There is, however, a lack of consensus regarding the potency of BFR training, which is invariably attributable to the different modes, intensities and durations of exercise and BFR methods. Further studies are needed to confirm its potential in the endurance-trained athlete.