Validity, Reliability and Sensitivity of Measures of Sporting Performance

Test-Retest Reliability of the One-Repetition Maximum (1RM) Strength Assessment: a Systematic Review

Background

The test–retest reliability of the one-repetition maximum (1RM) test varies across different studies. Given the inconsistent findings, it is unclear what the true reliability of the 1RM test is, and to what extent it is affected by measurement-related factors, such as exercise selection for the test, the number of familiarization trials and resistance training experience.

Objectives

The aim of this paper was to review studies that investigated the reliability of the 1RM test of muscular strength and summarize their findings.

Methods

The PRISMA guidelines were followed for this systematic review. Searches for studies were conducted through eight databases. Studies that investigated test–retest reliability of the 1RM test and presented intra-class correlation coefficient (ICC) and/or coefficient of variation (CV) were included. The COSMIN checklist was used for the assessment of the methodological quality of the included studies.

Results

After reviewing 1024 search records, 32 studies (pooled n = 1595) on test–retest reliability of 1RM assessment were found. All the studies were of moderate or excellent methodological quality. Test–retest ICCs ranged from 0.64 to 0.99 (median ICC = 0.97), where 92% of ICCs were ≥ 0.90, and 97% of ICCs were ≥ 0.80. The CVs ranged from 0.5 to 12.1% (median CV = 4.2%). ICCs were generally high (≥ 0.90), and most CVs were low (< 10%) for 1RM tests: (1) among those without and for those with some resistance training experience, (2) conducted with or without familiarization sessions, (3) with single-joint or multi-joint exercises, (4) for upper- and lower-body strength assessment, (5) among females and males, and (6) among young to middle-aged adults and among older adults. Most studies did not find systematic changes in test results between the trials.

Conclusions

Based on the results of this review, it can be concluded that the 1RM test generally has good to excellent test–retest reliability, regardless of resistance training experience, number of familiarization sessions, exercise selection, part of the body assessed (upper vs. lower body), and sex or age of participants. Researchers and practitioners, therefore, can use the 1RM test as a reliable test of muscular strength.

Reliability of the test of gross motor development: A systematic review

OBJECTIVE

To identify, synthesise and evaluate studies that investigated the reliability of the Test of Gross Motor Development (TGMD) variants.

METHODS

A systematic search was employed to identify studies that have investigated internal consistency, inter-rater, intra-rater and test-retest reliability of the TGMD variants through Scopus, Pubmed/MEDLINE, PsycINFO, Sport Discus and Web of Science databases.

RESULTS

Of the 265 studies identified, 23 were included. Internal consistency, evaluated in 14 studies, confirming good-to-excellent consistency for the overall score and general motor quotient (GMQ), and acceptable-to-excellent levels in both subscales (locomotor and ball skills). Inter-rater reliability, evaluated in 19 studies, showing good-to-excellent intra-class correlation coefficient (ICC) values in locomotor skills score, ball skills score, overall score, and GMQ. Intra-rater reliability, evaluated in 13 studies, displaying excellent ICC values in overall score and GMQ, and good-to-excellent ICC values in locomotor skills score and ball skills score. Test-retest reliability was evaluated in 15 studies with 100% of the statistics reported above the threshold of acceptable reliability when ICC was not used. Studies with ICC statistic showed good-to-excellent values in ball skills score, overall score, and GMQ; and moderate-to-excellent values in locomotor skills score.

CONCLUSIONS

Overall, the results of this systematic review indicate that, regardless of the variant of the test, the TMGD has moderate-to-excellent internal consistency, good-to-excellent inter-rater reliability, good-to-excellent intra-rater reliability, and moderate-to-excellent test-retest reliability. Considering the few high-quality studies in terms of internal consistency, it would be recommend to carry out further studies in this field to improve their quality. Since there is no gold standard for assessing FMS, TGMD variants could be appropriate when opting for a psychometrical robust test. However, standardized training protocols for coding TGMD variants seem to be necessary both for researchers and practitioners in order to ensure acceptable reliability.

The effect of astaxanthin supplementation on performance and fat oxidation during a 40 km cycling time trial

OBJECTIVES

This study aimed to investigate whether supplementation with 12 mg⋅day^-1 astaxanthin for 7 days can improve exercise performance and metabolism during a 40 km cycling time trial.

DESIGN

A randomised, double-blind, crossover design was employed.

METHODS

Twelve recreationally trained male cyclists (VO_2peak: 56.5 ± 5.5 mL⋅kg^-1⋅min^-1, W_max: 346.8  ± 38.4 W) were recruited. Prior to each experimental trial, participants were supplemented with either 12 mg⋅day^-1 astaxanthin or an appearance-matched placebo for 7 days (separated by 14 days of washout). On day 7 of supplementation, participants completed a 40 km cycling time trial on a cycle ergometer, with indices of exercise metabolism measured throughout.

RESULTS

Time to complete the 40 km cycling time trial was improved by 1.2 ± 1.7% following astaxanthin supplementation, from 70.76 ± 3.93 min in the placebo condition to 69.90 ± 3.78 min in the astaxanthin condition (mean improvement = 51 ± 71 s, p = 0.029, g = 0.21). Whole-body fat oxidation rates were also greater (+0.09 ± 0.13 g⋅min^-1, p = 0.044, g = 0.52), and the respiratory exchange ratio lower (-0.03 ± 0.04, p = 0.024, g = 0.60) between 39-40 km in the astaxanthin condition.

CONCLUSIONS

Supplementation with 12 mg⋅day^-1 astaxanthin for 7 days provided an ergogenic benefit to 40 km cycling time trial performance in recreationally trained male cyclists and enhanced whole-body fat oxidation rates in the final stages of this endurance-type performance event.

No Benefit of Ingestion of a Ketone Monoester Supplement on 10-km Running Performance

PURPOSE

Preexercise ingestion of exogenous ketones alters the metabolic response to exercise, but effects on exercise performance have been equivocal.

METHODS

On two occasions in a double-blind, randomized crossover design, eight endurance-trained runners performed 1 h of submaximal exercise at approximately 65% V˙O2max immediately followed by a 10-km self-paced time trial (TT) on a motorized treadmill. An 8% carbohydrate-electrolyte solution was consumed before and during exercise, either alone (CHO + PLA), or with 573 mg·kg of a ketone monoester supplement (CHO + KME). Expired air, HR, and RPE were monitored during submaximal exercise. Serial venous blood samples were assayed for plasma glucose, lactate, and β-hydroxybutyrate concentrations.

RESULTS

CHO + KME produced plasma β-hydroxybutyrate concentrations of approximately 1.0 to 1.3 mM during exercise (P < 0.001), but plasma glucose and lactate concentrations were similar during exercise in both trials. V˙O2, running economy, respiratory exchange ratio, HR, and RPE were also similar between trials. Performance in the 10-km TT was not different (P = 0.483) between CHO + KME (mean, 2402 s; 95% confidence interval, 2204-2600 s) and CHO + PLA (mean, 2422 s; 95% confidence interval, 2217-2628 s). Cognitive performance, measured by reaction time and a multitasking test, did not differ between trials.

CONCLUSIONS

Compared with carbohydrate alone, coingestion of KME by endurance-trained athletes elevated plasma β-hydroxybutyrate concentrations, but did not improve 10-km running TT or cognitive performance.

Test-Retest Reliability of the Yo-Yo Test: A Systematic Review

BACKGROUND

The Yo-Yo test is widely used both in the practical and research contexts; however, its true test-retest reliability remains unclear.

OBJECTIVE

The present systematic review aims to identify studies that have examined the test-retest reliability of the Yo-Yo test and summarize their results.

METHODS

A search of ten databases was performed to find studies that have investigated test-retest reliability of any variant of the Yo-Yo test. The COSMIN checklist was employed to assess the methodological quality of the included studies.

RESULTS

Nineteen studies of excellent or moderate methodological quality were included. When considering all variants of the Yo-Yo test, the included studies reported intra-class correlation coefficients for test-retest reliability ranging from 0.78 to 0.98 where 62% of all intra-class correlation coefficients were higher than 0.90, while 97% of intra-class correlation coefficients were higher than 0.80. The coefficients of variation ranged from 3.7 to 19.0%. Regardless of the variant of the test, the participants' familiarization with the test, and previous sport experience, the intra-class correlation coefficients generally seem high (≥ 0.90) and coefficients of variation low (< 10%).

CONCLUSIONS

The results of this review indicate that the Yo-Yo test (in all its variants) generally has good-to-excellent test-retest reliability. The evidence concerning reliability arises from 19 included studies that were of moderate or high methodological quality. Considering that most of the included studies examined the Yo-Yo intermittent recovery level 1 test while including Association Football players, more reliability studies examining Yo-Yo intermittent recovery level 2 test and Yo-Yo intermittent endurance level 1 and level 2 tests, and in the context of sports other than Association Football as well as in non-athletic populations, are required. Finally, future studies should explicitly state the type of intra-class correlation coefficient used for the reliability data analysis to allow for better between-study comparisons.

Impact of Post-Exercise Fructose-Maltodextrin Ingestion on Subsequent Endurance Performance

Background: Current sports nutrition guidelines recommend athletes ingest carbohydrates at 1.0–1.2 g·kg⁻¹·h⁻¹ to optimize repletion of muscle glycogen during short-term recovery from endurance exercise. However, they do not provide specific advice on monosaccharides (e.g., fructose or glucose) other than to ingest carbohydrates of moderate to high glycaemic index. Recent evidence suggests that combined ingestion of fructose and glucose in recovery leads to enhanced liver glycogen synthesis and that this translates into improvement of subsequent endurance capacity.

Purpose: The purpose of the present study was to investigate whether consuming a combination of fructose and glucose as opposed to glucose alone during short-term recovery (i.e., 4 h) from exhaustive exercise would also improve subsequent pre-loaded cycle time trial (TT) performance.

Methods: Eight participants (seven men, one woman; V∙O₂peak: 56.8 ± 5.0 mLO₂·min⁻¹·kg⁻¹; Wmax: 352 ± 41 W) participated in this randomized double-blind study. Each experimental session involved a glycogen reducing exercise bout in the morning, a 4-h recovery period and 1-h of steady state (SS) exercise at 50% Wmax followed by a ~40-min simulated TT. During recovery carbohydrates were ingested at a rate of 1.2 g·kg⁻¹·h⁻¹ in the form of fructose and maltodextrin (FRU + MD) or dextrose and maltodextrin (GLU + MD) (both in 1:1.5 ratio). Substrate oxidation rates, including ingested carbohydrate oxidation, were determined during the steady state (SS). Blood samples were collected during recovery, during the SS exercise and at the end of the TT for determination of glucose and lactate concentrations.

Results: There were no differences in TT performance [37.41 ± 3.45 (GLU + MD); 37.96 ± 5.20 min (FRU + MD), p = 0.547]. During the first 45-min of SS oxidation of ingested carbohydrates was greater in FRU + MD (1.86 ± 0.41 g⁻¹·min⁻¹ and 1.51 ± 0.37 g⁻¹·min⁻¹ for FRU + MD and GLU + MD, respectively; time x condition interaction p = 0.003) and there was a trend toward higher overall carbohydrate oxidation rates in FRU + MD (2.50 ± 0.36 g⁻¹·min⁻¹ and 2.31 ± 0.37 g⁻¹·min⁻¹ for FRU + MD and GLU + MD, respectively; p = 0.08). However, at 60-min of SS, differences in substrate oxidation disappeared.

Conclusion: Ingestion of combined fructose and glucose compared to glucose only during recovery from an exhaustive exercise bout increased the ingested carbohydrate oxidation rate during subsequent exercise. Under the conditions studied, subsequent TT performance was not improved with fructose-glucose.

No Differences Between Beetroot Juice and Placebo on Competitive 5-km Running Performance: A Double-Blind, Placebo-Controlled Trial

The authors examine the effect of an acute dose of beetroot juice on endurance running performance in "real-world" competitive settings. In total, 70 recreational runners (mean ± SD: age = 33.3 ± 12.3 years, training history = 11.9 ± 8.1 years, and hours per week training = 5.9 ± 3.5) completed a quasi-randomized, double-blind, placebo-controlled study of 5-km competitive time trials. Participants performed four trials separated by 1 week in the order of prebaseline, two experimental, and one postbaseline. Experimental trials consisted of the administration of 70-ml nitrate-rich beetroot juice (containing ∼4.1 mmol of nitrate, Beet It Sport®) or nitrate-depleted placebo (containing ∼0.04 mmol of nitrate, Beet It Sport®) 2.5 hr prior to time trials. Time to complete 5 km was recorded for each trial. No differences were shown between pre- and postbaseline (p = .128, coefficient variation = 2.66%). The average of these two trials is therefore used as baseline. Compared with baseline, participants ran faster with beetroot juice (mean differences = 22.2 ± 5.0 s, p < .001, d = 0.08) and placebo (22.9 ± 4.5 s, p < .001, d = 0.09). No differences in times were shown between beetroot juice and placebo (0.8 ± 5.7 s, p < .875, d = 0.00). These results indicate that an acute dose of beetroot juice does not improve competitive 5-km time-trial performance in recreational runners compared with placebo.

Running power meters and theoretical models based on laws of physics: Effects of environments and running conditions

Training prescription and load monitoring in running activities have benefited from power output (PW) data offered by new technologies. Nevertheless, to date, the sensitivity of PW data provided by these tools is still not completely clear. The aim of this study was to analyze the level of agreement between the P_W estimated by five commercial technologies and the two main internationally theoretical models based on laws of physics, in different environments and running conditions. Ten endurance-trained male athletes performed three submaximal running protocols on a treadmill (indoor) and an athletic track (outdoor), with changes in speed, body weight, and slope. P_W was simultaneously registered by the commercial technologies Stryd (Stryd_App and Stryd_Watch), RunScribe, Garmin_RP and Polar_V, whereas theoretical power output (TP_W) was calculated by the two mathematical models (TP_W1 and TP_W2). Statistics included, among others, the Pearson's correlation coefficient (r) and standard error of measurement (SEM). The Polar_V, and above all Stryd, showed the closest agreement with the TP_W1 (Stryd: r ≥ 0.947, SEM ≤ 11 W; PolarV: r ≥ 0.931, SEM ≤ 64 W) and TP_W2 (Stryd: r ≥ 0.933, SEM ≤ 60 W; Polar_V: r ≥ 0.932, SEM ≤ 24 W), both indoors and outdoors. On the other hand, the devices Garmin_RP (r ≤ 0.765, SEM ≥ 59 W) and RunScribe_. (r ≤ 0.508, SEM ≥ 125 W) showed the lowest agreement with the TP_W1 and TP_W2 models for all conditions and environments analyzed. The closest agreement of the Stryd and Polar_V technologies with the TP_W1 and TP_W2 models suggest these tools as the most sensitive, among those analyzed, for P_W measurement when changing environments and running conditions.

Analyzing the effects of combined small-sided games and strength and power training on the fitness status of under-19 elite football players

BACKGROUND

The purpose of this study was twofold: 1) to characterize a common microcycle considering both internal and external training loads; and 2) to identify the effects of small-sided games (SSGs) and of power and strength training on the fitness status of football players.

METHODS

Fifteen male football players (age: 18.55±0.39 years) participated in this study. Ninety-two consecutive training sessions were monitored and analyzed over a period of nineteen weeks. Rating of perceived exertion (RPE ) was used as an internal load marker, and the distances covered at different speed thresholds and accelerations/decelerations were used as external load markers to characterize the common microcycle. Participants' body composition, vertical jumping ability, maximal strength, speed, and agility were assessed twice before and after the training monitoring process.

RESULTS

The results revealed that match day -5 (MD-5) and MD-1 were associated with the lowest RPE scores (4.2 and 3.8 A.U., respectively). MD-4 and MD-3 were associated with the highest RPE values (9.2 and 8.8 A.U., respectively). Meaningful changes in RPE were found between training days. External load monitoring revealed that MD-4 had the highest values of accelerations and decelerations >2 m/s2/min (4.22 and 3.17, respectively) and MD-3 had the highest values of distance covered at high intensity (6.11 m/s2/min). Meaningful moderate improvements in jumping performance (d=0.90) and maximal strength parameters (d=0.83) were also found between assessments.

CONCLUSIONS

It was identified that the concurrent approach had meaningful impacts on the fitness development of players and should be considered by coaches for future training interventions.

A Simple Equation to Estimate Half-Marathon Race Time From the Cooper Test

BACKGROUND

Half-marathon races have become increasingly more popular with many recreational athletes all around the world. New and recreational runners are likely to have the greatest need for training advice to set running paces during long-distance races.

PURPOSE

To develop a simple equation to estimate half-marathon time from the Cooper test and verify its validity.

METHODS

One hundred ninety-eight recreational runners (177 men and 21 women, 40 [6.8] years and 33.7 [8] years, respectively) participated in this study. All runners completed the Cooper test 7 to 10 days prior to races. A stepwise multiple regression analysis was performed to select the main predictors of half-marathon time.

RESULTS

Simple correlation analysis showed that Cooper test performance (distance) was a good construct to estimate half-marathon time (r = -.906; 95% confidence interval, -0.927 to -0.877; P < .0001). The authors also derived an equation with a high predictive validity (R2 = .82; standard error of estimation = 5.19 min) and low systematic bias (mean differences between the predicted value and the criterion of 0.48 [5.2] min). Finally, the concordance coefficient of correlation (.9038) and proportional bias analysis (Kendall τ = -.0799; 95% confidence interval, -0.184 to 0.00453; P = .09) confirmed a good concurrent validity.

CONCLUSION

In this study, the authors derived an equation from the Cooper test data with a high predictive and concurrent validity and low bias.

Caffeine and Exercise: What Next?

Caffeine is a widely utilized performance-enhancing supplement used by athletes and non-athletes alike. In recent years, a number of meta-analyses have demonstrated that caffeine's ergogenic effects on exercise performance are well-established and well-replicated, appearing consistent across a broad range of exercise modalities. As such, it is clear that caffeine is an ergogenic aid-but can we further explore the context of this ergogenic aid in order to better inform practice? We propose that future research should aim to better understand the nuances of caffeine use within sport and exercise. Here, we propose a number of areas for exploration within future caffeine research. These include an understanding of the effects of training status, habitual caffeine use, time of day, age, and sex on caffeine ergogenicity, as well as further insight into the modifying effects of genotype. We also propose that a better understanding of the wider, non-direct effects of caffeine on exercise, such as how it modifies sleep, anxiety, and post-exercise recovery, will ensure athletes can maximize the performance benefits of caffeine supplementation during both training and competition. Whilst not exhaustive, we hope that the questions provided within this manuscript will prompt researchers to explore areas with the potential to have a large impact on caffeine use in the future.

No effect of beetroot juice supplementation on exercise economy and performance in recreationally active females despite increased torque production

This study investigated the effects of acute and chronic beetroot juice (BRJ) supplementation on submaximal exercise oxygen uptake (VO₂), time trial (TT) performance, and contractile properties of the plantar flexors in females. Study 1: Using a double blind, randomized, crossover design, 12 recreationally active females using hormonal contraceptives supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d (~26 mmoles nitrate [NO3−]) or a NO3−‐free placebo (PLA). On days 1 and 8, participants cycled for 10 min at 50% and 70% VO_2peak and completed a 4 kJ/kg body mass TT. Plasma [NO3−] and nitrite ([NO₂⁻]) increased significantly following BRJ supplementation versus PLA. There was no effect of BRJ supplementation on VO₂ at 50% or 70% VO_2peak, or TT performance. Study 2: 12 recreationally active females (n = 7 from Study 1) using hormonal contraceptives participated in a baseline visit and were supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d. Maximum voluntary strength (MVC) of the plantar flexors was assessed and a torque‐frequency curve performed. BRJ had no effect on MVC, voluntary activation, peak twitch torque, time to peak torque, or half relaxation time. Following both acute (46.6 ± 4.9% of 100 Hz torque) and chronic (47.2 ± 4.4%) supplementation, 10 Hz torque was significantly greater compared to baseline (32.9 ± 2.6%). In summary, BRJ may not be an effective ergogenic aid in recreationally active females as it did not reduce submaximal exercise VO₂ or improve aerobic TT performance despite increasing low frequency torque production.

Measurement Characteristics of Athlete Monitoring Tools in Professional Australian Football

PURPOSE

To examine the measurement reliability and sensitivity of common athlete monitoring tools in professional Australian Football players.

METHODS

Test-retest reliability (noise) and weekly variation (signal) data were collected from 42 professional Australian footballers from 1 club during a competition season. Perceptual wellness was measured via questionnaires completed before main training sessions (48, 72, and 96 h postmatch), with players providing a rating (1-5 Likert scale) regarding their muscle soreness, sleep quality, fatigue level, stress, and motivation. Eccentric hamstring force and countermovement jumps were assessed via proprietary systems once per week. Heart rate recovery was assessed via a standard submaximal run test on a grass-covered field with players wearing a heart rate monitor. The heart rate recovery was calculated by subtracting average heart rate during final 10 seconds of rest from average heart rate during final 30 seconds of exercise. Typical test error was reported as coefficient of variation percentage (CV%) and intraclass coefficients. Sensitivity was calculated by dividing weekly CV% by test CV% to produce a signal to noise ratio.

RESULTS

All measures displayed acceptable sensitivity. Signal to noise ratio ranged from 1.3 to 11.1. Intraclass coefficients ranged from .30 to .97 for all measures.

CONCLUSIONS

The heart rate recovery test, countermovement jump test, eccentric hamstring force test, and perceptual wellness all possess acceptable measurement sensitivity. Signal to noise ratio analysis is a novel method of assessing measurement characteristics of monitoring tools. These data can be used by coaches and scientists to identify meaningful changes in common measures of fitness and fatigue in professional Australian football.

From Paper to Podium: Quantifying the Translational Potential of Performance Nutrition Research

Sport nutrition is one of the fastest growing and evolving disciplines of sport and exercise science, demonstrated by a 4-fold increase in the number of research papers between 2012 and 2018. Indeed, the scope of contemporary nutrition-related research could range from discovery of novel nutrient-sensitive cell-signalling pathways to the assessment of the effects of sports drinks on exercise performance. For the sport nutrition practitioner, the goal is to translate innovations in research to develop and administer practical interventions that contribute to the delivery of winning performances. Accordingly, step one in the translation of research to practice should always be a well-structured critique of the translational potential of the existing scientific evidence. To this end, we present an operational framework (the “Paper-2-Podium Matrix”) that provides a checklist of criteria for which to prompt the critical evaluation of performance nutrition-related research papers. In considering the (1) research context, (2) participant characteristics, (3) research design, (4) dietary and exercise controls, (5) validity and reliability of exercise performance tests, (6) data analytics, (7) feasibility of application, (8) risk/reward and (9) timing of the intervention, we aimed to provide a time-efficient framework to aid practitioners in their scientific appraisal of research. Ultimately, it is the combination of boldness of reform (i.e. innovations in research) and quality of execution (i.e. ease of administration of practical solutions) that is most likely to deliver the transition from paper to podium.

Development and Validation of a Checklist to Assess Proficient Performance of Basketball Straight Speed Dribbling Skill

The aim of this study was to develop and validate a checklist to assess proficient performance of basketball straight speed dribbling skill. The sample was composed of 100 children and adolescents between 7 and 15 years of age with and without structured practice in basketball. The validation process tested the validity domain, decision, tendencies, reliability, responsiveness, and objectivity. The results show that the checklist contains criteria that represent the speed dribbling skill and is sensible to distinguish between different proficiency levels of performance. The results also expressed high reliability and objectivity (intra and inter-rater). In light of the findings, we concluded that the checklist can be used to reliably analyze performance and evaluate the process of learning and development of the straight speed dribbling skill.

The Development of a Field-Based Kicking Assessment to Evaluate Australian Football Kicking Proficiency

Purpose: In Australian Football (AF), the ability to proficiently kick the ball is a critical skill and has been shown to be advantageous to a team's successful performance; however, a valid and reliable match referenced kicking assessment remains absent. Therefore, the aim of this study was to develop a valid and reliable AF kicking proficiency assessment comparative to match play kicking performance. Method: Youth male Australian Football players (n = 251) from different stages within the AF talent pathway were recruited. The developed AFFB-DKA (Australian Football Field-Based-Dynamic Kicking Assessment) considered particular constraints of match play kicking demands such as kick type, distance, delivery, and locomotion of the player receiving the ball. In total, 14 kicks were completed during the test. Validity (i.e., content, logical and construct) and reliability (i.e., test re-test) were assessed. Results: Findings indicate the kicking test can distinguish across and between age (i.e., U14; U16; U18) and skill groups (i.e., club; sub-elite; elite). The timeframe between U14 and U16 was identified as a potential key period where kicking skill acquisition may be most impressionable; however, further research is recommended to support this. Conclusion: The developed AFFB-DKA is the first Australian Football specific kicking assessment to consider and apply match play kicking constraints to make a more representative, valid and reliable assessment.

Effects of a commercially available branched-chain amino acid-alanine-carbohydrate-based sports supplement on perceived exertion and performance in high intensity endurance cycling tests

Background

Sports nutritional supplements containing branched-chain amino acids (BCAA) have been widely reported to improve psychological and biological aspects connected to central fatigue and performance in endurance exercise, although the topic is still open to debate. The aim of the present study was to determine whether the intake of a commercially available BCAA-based supplement, taken according to the manufacturer’s recommendations, could affect the rating of perceived exertion (RPE) and performance indexes at the beginning (1d) and end of a 9-week (9w) scheduled high intensity interval training program, with an experimental approach integrating the determination of psychometric, performance, metabolic and blood biochemical parameters.

Methods

This was a randomized double-blind placebo-controlled study. Thirty-two untrained, healthy young adults (20 males and 12 female) were enrolled. A high-intensity endurance cycling (HIEC) test was used to induce fatigue in the participants: HIEC consisted in ten 90 s sprints interspersed by ten 3 min recovery phases and followed by a final step time to exhaustion was used. In parallel with RPE, haematological values (creatine kinase, alanine, BCAA, tryptophan, ammonia and glucose levels), and performance indexes (maximal oxygen consumption - VO_2max, power associated with lactate thresholds - W_LT1, W_LT2 and time to exhaustion - TTE) were assessed. All subject took the supplement (13.2 g of carbohydrates; 3.2 g of BCAA and 1.6 g of L-alanine per dose) or placebo before each test and training session. Dietary habits and training load were monitored during the entire training period.

Results

The administration of the supplement (SU) at 1d reduced RPE by 9% during the recovery phase, as compared to the placebo (PL); at 9w the RPE scores were reduced by 13 and 21% during the sprint and recovery phase, respectively; at 9w, prolonged supplement intake also improved TTE and TRIMP. SU intake invariably promoted a rapid increase (within 1 h) of BCAA serum blood levels and prevented the post-HIEC tryptophan: BCAA ratio increase found in the PL group, at both 1d and 9w. There was no difference in dietary habits between groups and those habits did not change over time; no difference in glycemia was found between SU and PL. VO_2max, W_LT1 and W_LT2 values improved over time, but were unaffected by supplement intake.

Conclusions

On the whole, these results suggest that i) the intake of the BCAA-based commercially available supplement used in this study reduces RPE as a likely consequence of an improvement in the serum tryptophan: BCAA ratio; ii) over time, reduced RPE allows subjects to sustain higher workloads, leading to increased TRIMP and TTE.

The availability of task-specific feedback does not affect 20 km time trial cycling performance or test-retest reliability in trained cyclists

OBJECTIVES

This study examined the influence of the availability of task-specific feedback on 20 km time trial (20TT) cycling performance and test-retest reliability.

DESIGN

Thirty trained, club-level cyclists completed two 20TT's on different days, with (feedback, FB) or without (no-feedback, NFB) task-specific feedback (i.e., power output, cadence, gear and heart rate [HR]). Elapsed distance was provided in both conditions.

METHODS

During trials, ergometer variables and HR were continuously recorded, and a rating of perceived exertion (RPE) was collected every 2 km. Data were analysed using linear mixed-effects models in a Bayesian framework, and Cohen's d was calculated for standardised differences. The reliability of finish time and mean power output (PO) was determined via multiple indices, including intraclass correlations (ICC).

RESULTS

Performance, pacing behaviour, and RPE were not statistically different between conditions. The posterior mean difference [95% credible interval] between TT1 and TT2 for FB and NFB was 10s [-5, 25] and -2s [-17, 14], respectively. In TT2, HR was statistically higher (∼8bmin^-1) in FB compared to NFB after 13 km (d = 2.08-2.25). However, this result was explained by differences in maximal HR. Finish time (FB: ICC= 0.99; NFB: ICC=0.99) and mean power output (FB: ICC=0.99; NFB: ICC=0.99) in each condition were substantially reliable.

CONCLUSIONS

The availability of task-specific information did not affect 20TT performance or reliability. Except for elapsed distance, task-specific feedback should be withheld from trained cyclists when evaluating interventions that may affect performance, to prevent participants from recalling previous performance settings.

Improving biologic predictors of cycling endurance performance with near-infrared spectroscopy derived measures of skeletal muscle respiration: E pluribus unum

The study aim was to compare the predictive validity of the often referenced traditional model of human endurance performance (i.e. oxygen consumption, VO2 , or power at maximal effort, fatigue threshold values, and indices of exercise efficiency) versus measures of skeletal muscle oxidative potential in relation to endurance cycling performance. We hypothesized that skeletal muscle oxidative potential would more completely explain endurance performance than the traditional model, which has never been collectively verified with cycling. Accordingly, we obtained nine measures of VO2 or power at maximal efforts, 20 measures reflective of various fatigue threshold values, 14 indices of cycling efficiency, and near-infrared spectroscopy-derived measures reflecting in vivo skeletal muscle oxidative potential. Forward regression modeling identified variable combinations that best explained 25-km time trial time-to-completion (TTC) across a group of trained male participants (n = 24). The time constant for skeletal muscle oxygen consumption recovery, a validated measure of maximal skeletal muscle respiration, explained 92.7% of TTC variance by itself (Adj R2  = .927, F = 294.2, SEE = 71.2, p < .001). Alternatively, the best complete traditional model of performance, including VO2max (L·min-1 ), %VO2max determined by the ventilatory equivalents method, and cycling economy at 50 W, only explained 76.2% of TTC variance (Adj R2  = .762, F = 25.6, SEE = 128.7, p < .001). These results confirm our hypothesis by demonstrating that maximal rates of skeletal muscle respiration more completely explain cycling endurance performance than even the best combination of traditional variables long postulated to predict human endurance performance.

Validity and reliability of an Australian football small-sided game to assess kicking proficiency

In Australian Football (AF), small sided games have been used extensively as an alternative training method for technical and physical adaptations. Considering their application to AF, it is surprising a valid and reliable small-sided game kicking assessment remains absent. Therefore, the aim of this study was to develop a valid and reliable 5v6 Australian football small-sided game kicking proficiency assessment. Youth male AF players (n = 145) from different stages within the AF talent pathway were recruited. Validity (i.e., logical and construct) and reliability (i.e., test re-test) were assessed. The largest kicking proficiency difference was between U13 and U16 players and between novice and sub-elite players. Between the ages of U16 and U18 kicking proficiency appears to stabilise. The Australian football small-sided kicking assessment was 97% successful in identifying players as either novice or sub-elite. Larger physical performance (i.e., odometer, m/min-1 and %HIR) outputs were noted between U14 and U18 players and novice and sub-elite players. Collectively, these findings suggest the Australian football small-sided kicking assessment is a valid and reliable AF kicking proficiency assessment tool and may provide worthwhile information to coaches regarding kicking performance along the AFL pathway, to profile player strengths whilst identifying specific areas of improvement.

Postexercise Glucose–Fructose Coingestion Augments Cycling Capacity During Short-Term and Overnight Recovery From Exhaustive Exercise, Compared With Isocaloric Glucose

During short-term recovery, postexercise glucose–fructose coingestion can accelerate total glycogen repletion and augment recovery of running capacity. It is unknown if this advantage translates to cycling, or to a longer (e.g., overnight) recovery. Using two experiments, the present research investigated if postexercise glucose–fructose coingestion augments exercise capacity following 4-hr (short experiment; n = 8) and 15-hr (overnight experiment; n = 8) recoveries from exhaustive exercise in trained cyclists, compared with isocaloric glucose alone. In each experiment, a glycogen depleting exercise protocol was followed by a 4-hr recovery, with ingestion of 1.5 or 1.2 g·kg−1·hr−1 carbohydrate in the short experiment (double blind) and the overnight experiment (single blind), respectively. Treatments were provided in a randomized order using a crossover design. Four or fifteen hours after the glycogen depletion protocol, participants cycled to exhaustion at 70% Wmax or 65% Wmax in the short experiment and the overnight experiment, respectively. In both experiments there was no difference in substrate oxidation or blood glucose and lactate concentrations between treatments during the exercise capacity test (trial effect, p > .05). Nevertheless, cycling capacity was greater in glucose + fructose versus glucose only in the short experiment (28.0 ± 8.4 vs. 22.8 ± 7.3 min, d = 0.65, p = .039) and the overnight experiment (35.9 ± 10.7 vs. 30.6 ± 9.2 min, d = 0.53, p = .026). This is the first study to demonstrate that postexercise glucose–fructose coingestion enhances cycling capacity following short-term (4 hr) and overnight (15 hr) recovery durations. Therefore, if multistage endurance athletes are ingesting glucose for rapid postexercise recovery then fructose containing carbohydrates may be advisable.

Wearables for Integrative Performance and Tactic Analyses: Opportunities, Challenges, and Future Directions

Micro-electromechanical systems (MEMS) have reduced drastically in size, cost, and power consumption, while improving accuracy. The combination of different sensor technologies is considered a promising step in the monitoring of athletes. Those "wearables" enable the capturing of relevant physiological and tactical information in individual and team sports and thus replacing subjective, time-consuming and qualitative methods with objective, quantitative ones. Prior studies mainly comprised sports categories such as: targeting sports, batting and fielding games as well as net and wall games, focusing on the detection of individual, non-locomotive movements. The increasing capabilities of wearables allow for more complex and integrative analysis expanding research into the last category: invasion sports. Such holistic approaches allow the derivation of metrics, estimation of physical conditions and the analysis of team strategic behavior, accompanied by integrative knowledge gains in technical, tactical, physical, and mental aspects of a sport. However, prior and current researchers find the precise measurement of the actual movement within highly dynamic and non-linear movement difficult. Thus, the present article showcases an overview of the environments in which the wearables are employed. It elaborates their use in individual as well as team-related performance analyses with a special focus on reliability and validity, challenges, and future directions.

The Effect of Adaptive Sports on Individuals with Acquired Neurological Disabilities and Its Role in Rehabilitation: A Systematic Review

The aims of this systematic review were to report on the feasibility of adaptive sports for individuals with acquired central neurological lesion; to analyze the effects of this approach according to the domains of the International Classification of Functioning, Health and Disability (ICF); and to emit guiding points for future research. Two authors searched PubMed, Scopus, Cochrane, Pedro, and SPORTdiscus for eligible trials. Data concerning demographics, outcome measures, results, and conclusions were extracted, and a qualitative synthesis was performed. Adaptive sports seem to be a feasible, efficient, and cost-effective complement to conventional rehabilitation. Significant effects were found on all domains of the ICF, except "environmental factors." Key factors, such as intervention volume, intensity, and type, play a determining role. This review is the first to expose the beneficial effects of adaptive sports practice among individuals with neurological lesions by relying on prospective evidence.

The effects of same-session combined exercise training on cardiorespiratory and functional fitness in older adults: a systematic review and meta-analysis

Endurance and strength training are effective strategies for counteracting age-associated reductions in physical performance in older adults, with a combination of both exercise modes recommended to maximise potential fitness benefits. This meta-analysis sought to quantify the effects of same-session combined endurance and strength training on fitness in adults aged over 50 years. Five electronic databases were searched with studies required to include one of the following outcome measures: VO_2peak, 6-min walk test (6MWT), 8-ft timed up-and-go (TUG), and 30-s chair stand. Separate random-effects meta-analyses compared combined training with (1) no-exercise control, (2) endurance training, and (3) strength training with probabilistic magnitude-based inferences subsequently applied. Twenty-seven studies involving 1346 subjects with a mean age of 68.8 years (range 54–85 years) were included in the analysis. The meta-analysed effect on VO_2peak was a moderately beneficial effect for the combined training compared to no-exercise controls (3.6 mL kg⁻¹ min⁻¹; ± 95% confidence limits 0.8 mL kg⁻¹ min⁻¹) with additional increases for studies with greater proportions of female participants and shorter training interventions. Combined training also had small-to-moderately beneficial effects on VO_2peak when compared to endurance training (0.8 mL kg⁻¹ min⁻¹; ± 1.0 mL kg⁻¹ min⁻¹), 30-s chair stand when compared with strength training (1.1 repetitions; ± 0.5 repetitions) and on TUG (0.8 s; ± 0.7 s), 30-s chair stand (2.8 repetitions; ± 1.7 repetitions), and 6MWT (31.5 m; ± 22.4 m) when compared to no-exercise controls. All other comparisons were unclear. Same-session combined training can induce clinically relevant fitness improvements in older adults.

Reliability of a Novel Badminton Intermittent Exercise Protocol

Purpose: Badminton is a sport characterized by high-intensity activity interspersed with short rests requiring specific physiological fitness, skills and game tactics. This study aimed to develop, describe and establish the reliability of a novel badminton intermittent exercise protocol, to simulate singles match-play (Part A) and assess match-fitness (Part B). Method: Twelve well-trained male badminton players performed a two-part protocol, mimicking the demands and activity of match-play, on two occasions with at least 72-h recovery. Part A imitated match-play and consisted of 40 stages alternating between 20 s work - receiving shuttlecocks from a launcher and ghosting (simulated) actions - and 40 s rest. Part B was an open-ended period, challenging match-fitness, designed to exhaust participants within 10 min. Physiological responses (heart rate, blood lactate and ratings of perceived exertion) (Part A and B) and time to exhaustion (Part B) were determined both times. Results: There were no differences in performance and physiological responses between trials (p > .05). The protocol demonstrated excellent reliability (intraclass correlation coefficient > 0.89) for all variables. Time to exhaustion (Part B) was 198 ± 98 s and 194 ± 82 s, respectively. Mean (Part A) and peak (Part B) heart rates were 166 ± 9; 191 ± 8 b∙min^-1 and 166 ± 9; 191 ± 7 b∙min^-1 and blood lactate concentrations (Part B) 11.8 ± 2.3 and 11.5 ± 2.1 mmol∙l^-1 for trials 1 and 2, respectively. Conclusion: The protocol reliably induces match-like responses and can be used to assess match-fitness for training/research purposes.

Validity and Reliability of a New Specific Parkour Test: Physiological and Performance Responses

Main aim of this study was examining validity and reliability of using a new specific Parkour repeated sprint ability test (SPRSA) for assessing repeated sprint ability while facing obstacles and establishing between-day reliability and sensitivity of SPRSA related to its physiological and performance responses. Thirteen high-level traceurs (three females) performed in random order and twice eight tests for assessing a total of 23 variables: SPRSA (a typical maximal-speed shuttle run interspersed with four Parkour competition-common fundamentals) and seven established fitness tests, core stability, hand-grip, vertical-jump, long-jump, pull-up, 300-m shuttle run (as a field test for anaerobic capacity), and Leger test. Except for muscular elasticity index of vertical jump test (intra-class Correlation Coefficient model 3,1 [ICC₃,₁] = 0.54 [fair]), fitness tests’ ICC₃,₁s resulted excellent (ICC₃,₁: 0.93–1.00). SPRSA total time and time of its fastest sprint (SPRSA peak time) were significantly correlated with the majority of core stability (r: −0.79 to 0.59; P < 0.01–0.05), jumping (r: −0.78 to 0.67; P < 0.01–0.05), pull-up tests (r: −0.86; P < 0.01), 300-m shuttle run test total time (r: 0.77–0.82; P < 0.01), and Leger test-estimated VO₂ max (r: −0.78; P < 0.01). Principal component analysis (PCA) of the 23 variables led to extraction of four significant components (each due to different variables’ combinations), which explained 90.2% of 23 variables’ total variance. SPRSA (i.e., total and peak time) showed high reliability (ICC₃,₁: 0.991–0.998 and standard-error-of-measurement %: 0.07–0.32). Finally, SPRSA showed high sensitivity (smallest-worthwhile-change %: 0.29–0.68). Considering its excellent logical and strong ecological validity, SPRSA may serve as a valid specific field test for Parkour sport. In addition, thanks to its high reliability and sensitivity, this test is suitable for monitoring, evaluating, and programming training processes for Parkour practitioners in repeated sprint ability involving crossing obstacles.

Is the Functional Threshold Power Interchangeable With the Maximal Lactate Steady State in Trained Cyclists?

PURPOSE

Functional threshold power (FTP), determined as 95% of the average power during a 20-min time trial, is suggested as a practical test for the determination of the maximal lactate steady state (MLSS) in cycling. Therefore, the objective of the present study was to determine the validity of FTP in predicting MLSS.

METHODS

A total of 15 cyclists, 7 classified as trained and 8 as well trained (mean [SD] maximal oxygen uptake 62.3 [6.4] mL·kg-1·min-1, maximal aerobic power 329 [30] W), performed an incremental test to exhaustion, an FTP test, and several constant-load tests to determine the MLSS. The bias ± 95% limits of agreement (LoA), typical error of the estimate (TEE), and Pearson coefficient of correlation (r) were calculated to assess validity.

RESULTS

For the power-output measures, FTP presented a bias ± 95% LoA of 1.4% ± 9.2%, a moderate TEE (4.7%), and nearly perfect correlation (r = .91) with MLSS in all cyclists together. When divided by training level, the bias ± 95% LoA and TEE were higher in the trained group (1.4% ± 11.8% and 6.4%, respectively) than in the well-trained group (1.3% ± 7.4% and 3.0%, respectively). For the heart-rate measurement, FTP presented a bias ± 95% LoA of -1.4% ± 8.2%, TEE of 4.0%, and very large correlation (r = .80) with MLSS.

CONCLUSION

Therefore, trained and well-trained cyclists can use FTP as a noninvasive and practical alternative to estimate MLSS.

Validity and reliability of speed tests used in soccer: A systematic review

Introduction

Speed is an important prerequisite in soccer. Therefore, a large number of tests have been developed aiming to investigate several speed skills relevant to soccer. This systematic review aimed to examine the validity and reliability of speed tests used in adult soccer players.

Methods

A systematic search was performed according to the PRISMA guidelines. Studies were included if they investigated speed tests in adult soccer players and reported validity (construct and criterion) or reliability (intraday and interday) data. The tests were categorized into linear-sprint, repeated-sprint, change-of-direction sprint, agility, and tests incorporating combinations of these skills.

Results

In total, 90 studies covering 167 tests were included. Linear-sprint (n = 67) and change-of-direction sprint (n = 60) were studied most often, followed by combinations of the aforementioned (n = 21) and repeated-sprint tests (n = 15). Agility tests were examined fewest (n = 4). Mainly based on construct validity studies, acceptable validity was reported for the majority of the tests in all categories, except for agility tests, where no validity study was identified. Regarding intraday and interday reliability, ICCs>0.75 and CVs<3.0% were evident for most of the tests in all categories. These results applied for total and average times. In contrast, measures representing fatigue such as percent decrement scores indicated inconsistent validity findings. Regarding reliability, ICCs were 0.11–0.49 and CVs were 16.8–51.0%.

Conclusion

Except for agility tests, several tests for all categories with acceptable levels of validity and high levels of reliability for adult soccer players are available. Caution should be given when interpreting fatigue measures, e.g., percent decrement scores. Given the lack of accepted gold-standard tests for each category, researchers and practitioners may base their test selection on the broad database provided in this systematic review. Future research should pay attention to the criterion validity examining the relationship between test results and match parameters as well as to the development and evaluation of soccer-specific agility tests.

The Ottawa Paramedic Physical Ability Test: test-retest reliability and analysis of sex-based performance differences

The Ottawa Paramedic Physical Ability Test (OPPAT) is a physical employment standard (PES) that candidates must pass as a pre-hire requirement and that incumbents may have to pass prior to returning to work after absence, to demonstrate their physical capabilities as required to safely meet the demands of paramedic work. Consistent with best practice guidelines for PES development, it is important to establish reliability and to investigate sex-based performance differences. Active duty paramedics completed the OPPAT twice while candidates completed the OPPAT six times. Across all participants, a median improvement of 76.0 s was observed in OPPAT performance (922.0-846.0 s) between trial 1 and trial 2. Among candidates, OPPAT performance stabilised by the fourth trial confirming reliability. Sex-based analyses revealed median differences in OPPAT performance time of 39.0 and 63.0 s between males and females during the first and second trials respectively. Practitioner summary: Active duty paramedics and candidates performed the Ottawa Paramedic Physical Ability Test (OPPAT) faster following familiarisation. Among candidates, performance time stabilised by the fourth trial. Performance time was slower among females, but this had less impact on females' ability to meet the OPPAT standard.

The Impact of Preconditioning Strategies Designed to Improve 2000-m Rowing Ergometer Performance in Trained Rowers: A Systematic Review and Meta-Analysis

PURPOSE

The 2000-m rowing-ergometer test is the most common measure of rowing performance. Because athletes use different intervention strategies for enhancing performance, investigating the effect of preconditioning strategies on the 2000-m test is of great relevance. This study evaluated the effects of different preconditioning strategies on 2000-m rowing-ergometer performance in trained rowers.

METHODS

A search of electronic databases (PubMed, Google Scholar, and Web of Science) identified 27 effects of different preconditioning strategies from 17 studies. Outcomes were calculated as percentage differences between control and experimental interventions, and data were presented as mean ± 90% confidence interval. Performance data were converted to the same metrics, that is, mean power. Meta-regression analyses were conducted to assess whether performance level or caffeine dose could affect the percentage change.

RESULTS

The overall beneficial effect on 2000-m mean power was 2.1% (90% confidence limit [CL] ±0.6%). Training status affected the percentage change with interventions, with a -1.1% (90% CL ±1.2%) possible small decrease for 1.0-W·kg-1 increment in performance baseline. Caffeine consumption most likely improves performance, with superior effect in higher doses (≥6 mg·kg-1). Sodium bicarbonate and beta-alanine consumption resulted in likely (2.6% [90% CL ±1.5%]) and very likely (1.4% [90% CL ±1.2%]) performance improvements, respectively. However, some preconditioning strategies such as heat acclimation, rehydration, and creatine resulted in small to moderate enhancements in 2000-m performance.

CONCLUSIONS

Supplementation of caffeine and beta-alanine is a popular and effective strategy to improve 2000-m ergometer performance in trained rowers. Additional research is warranted to confirm the benefit of other strategies to 2000-m rowing-ergometer performance.

Nitrate supplementation improves physical performance specifically in non-athletes during prolonged open-ended tests: a systematic review and meta-analysis

Nitrate (NO3 -) is an ergogenic nutritional supplement that is widely used to improve physical performance. However, the effectiveness of NO3 - supplementation has not been systematically investigated in individuals with different physical fitness levels. The present study analysed whether different fitness levels (non-athletes v. athletes or classification of performance levels), duration of the test used to measure performance (short v. long duration) and the test protocol (time trials v. open-ended tests v. graded-exercise tests) influence the effects of NO3 - supplementation on performance. This systematic review and meta-analysis was conducted and reported according to the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A systematic search of electronic databases, including PubMed, Web of Science, SPORTDiscus and ProQuest, was performed in August 2017. On the basis of the search and inclusion criteria, fifty-four and fifty-three placebo-controlled studies evaluating the effects of NO3 - supplementation on performance in humans were included in the systematic review and meta-analysis, respectively. NO3 - supplementation was ergogenic in non-athletes (mean effect size (ES) 0·25; 95 % CI 0·11, 0·38), particularly in evaluations of performance using long-duration open-ended tests (ES 0·47; 95 % CI 0·23, 0·71). In contrast, NO3 - supplementation did not enhance the performance of athletes (ES 0·04; 95 % CI -0·05, 0·15). After objectively classifying the participants into different performance levels, the frequency of trials showing ergogenic effects in individuals classified at lower levels was higher than that in individuals classified at higher levels. Thus, the present study indicates that dietary NO3 - supplementation improves physical performance in non-athletes, particularly during long-duration open-ended tests.

Nicotine Supplementation Does Not Influence Performance of a 1h Cycling Time-Trial in Trained Males

The use of nicotine amongst professional and elite athletes is high, with anecdotal evidence indicating increased prevalence amongst cycling sports. However, previous investigations into its effects on performance have not used high-validity or -reliability protocols nor trained cyclists. Therefore, the present study determined whether nicotine administration proved ergogenic during a ∼1 h self-paced cycling time-trial (TT). Ten well-trained male cyclists (34 ± 9 years; 71 ± 8 kg; O₂max: 71 ± 6 ml ⋅ kg⁻¹ ⋅ min⁻¹) completed three work-dependent TT following ∼30 min administration of 2 mg nicotine gum (GUM), ∼10 h administration of 7 mg ⋅ 24 h⁻¹ nicotine patch (PAT) or color- and flavor-matched placebos (PLA) in a randomized, crossover, and double blind design. Measures of nicotine’s primary metabolite (cotinine), core body temperature, heart rate, blood biochemistry (pH, HCO₃⁻, La⁻) and Borg’s rating of perceived exertion (RPE) accompanied performance measures of time and power output. Plasma concentrations of cotinine were highest for PAT, followed by GUM, then PLA, respectively (p < 0.01). GUM and PAT resulted in no significant improvement in performance time compared to PLA (62.9 ± 4.1 min, 62.6 ± 4.5 min, and 63.3 ± 4.1 min, respectively; p = 0.73), with mean power outputs of 264 ± 31, 265 ± 32, and 263 ± 33 W, respectively (p = 0.74). Core body temperature was similar between trials (p = 0.33) whilst HR averaged 170 ± 10, 170 ± 11, and 171 ± 11 beats ⋅ min⁻¹ (p = 0.60) for GUM, PAT, and PLA, respectively. There were no differences between trials for any blood biochemistry (all p > 0.46) or RPE with mean values of 16.7 ± 0.9, 16.8 ± 0.7, and 16.8 ± 0.8 (p = 0.89) for GUM, PAT, and PLA, respectively. In conclusion: (i) nicotine administration, whether via gum or transdermal patch, did not exert an ergogenic or ergolytic effect on self-paced cycling performance of ∼1 h; (ii) systemic delivery of nicotine was greatest when using a transdermal patch; and (iii) nicotine administration did not alter any of the psycho-physiological measures observed.

Postexercise Fructose-Maltodextrin Ingestion Enhances Subsequent Endurance Capacity

PURPOSE

Restoring skeletal muscle and hepatic glycogen content during short-term (<6 h) recovery from prolonged exercise is pertinent for athletes seeking to maximize performance in repeated exercise bouts. Previous research suggests that coingestion of fructose-glucose carbohydrate sources augments hepatic and has equivalent effects on skeletal muscle glycogen storage during short-term recovery from prolonged exercise compared with isocaloric glucose ingestion. The aim of the present investigation was to determine whether this has a discernible effect on subsequent exercise capacity.

METHODS

Eight trained endurance runners and triathletes performed two experimental trials in a single-blind, randomized, and counterbalanced crossover design. Trials involved treadmill running to exhaustion at 70% V˙O2max, a 4-h recovery with 90 g·h of glucose-maltodextrin (GLU + MAL) or fructose-maltodextrin (FRU + MAL) ingestion (1:1.5 ratio), and a second bout of treadmill running to exhaustion at 70% V˙O2max.

RESULTS

Exercise capacity in bout 2 was significantly greater with FRU + MAL (81.4 ± 22.3 vs 61.4 ± 9.6 min, P = 0.02), a large magnitude effect (effect size = 1.84 ± 1.12, 32.4% ± 19.9%). Total carbohydrate oxidation rates were not significantly different during bout 1 or 2 between trials, although total carbohydrate oxidized in bout 2 was significantly greater with FRU + MAL (223 ± 66 vs 157 ± 26 g, P = 0.02). Ingested carbohydrate oxidation rates were greater during bout 2 with FRU + MAL (P = 0.001). Plasma glucose and nonesterified fatty acid concentrations were not significantly different between trials. Plasma lactate concentrations were significantly greater during recovery before bout 2 with FRU + MAL (P = 0.001). Self-reported nausea and stomach fullness during bout 2 were marginally in favor of FRU + MAL.

CONCLUSION

Short-term recovery of endurance capacity was significantly enhanced with FRU + MAL versus GLU + MAL ingestion during recovery.

Considerations When Assessing Endurance in Combat Sport Athletes

Combat sports encompass a range of sports, each involving physical combat between participants. Such sports are unique, with competitive success influenced by a diverse range of physical characteristics. Effectively identifying and evaluating each characteristic is essential for athletes and support staff alike. Previous research investigating the relationship between combat sports performance and measures of strength and power is robust. However, research investigating the relationship between combat sports performance and assessments of endurance is less conclusive. As a physical characteristic, endurance is complex and influenced by multiple factors including mechanical efficiency, maximal aerobic capacity, metabolic thresholds, and anaerobic capacities. To assess endurance of combat sports athletes, previous research has employed methods ranging from incremental exercise tests to circuits involving sports-specific techniques. These tests range in their ability to discern various physiological attributes or performance characteristics, with varying levels of accuracy and ecological validity. In fact, it is unclear how various physiological attributes influence combat sport endurance performance. Further, the sensitivity of sports specific skills in performance based tests is also unclear. When developing or utilizing tests to better understand an athletes' combat sports-specific endurance characteristic, it is important to consider what information the test will and will not provide. Additionally, it is important to determine which combination of performance and physiological assessments will provide the most comprehensive picture. Strengthening the understanding of assessing combat sport-specific endurance as a physiological process and as a performance metric will improve the quality of future research and help support staff effectively monitor their athlete's characteristics.

Short-Term Mediterranean Diet Improves Endurance Exercise Performance: A Randomized-Sequence Crossover Trial

Objective: Healthful dietary patterns have constituents that are known to improve exercise performance, such as antioxidants, nitrates, and alkalizing effects. However, ergogenic effects of such diets have not been evaluated. We hypothesized that a short-term Mediterranean diet results in better exercise performance, as compared to a typical Western diet. Methods: Eleven recreationally active women (n = 7) and men (n = 4) (body mass index, 24.6 ± 3.2 kg/m²; age 28 ± 3 years) were studied in a randomized-sequence crossover study, in which they underwent exercise performance testing on one occasion after 4 days of a Mediterranean diet and on another occasion after 4 days of a Western diet. A 9- to 16-day washout period separated the two trials. Endurance exercise performance was evaluated with a 5-km treadmill time trial. Anaerobic exercise performance tests included a Wingate cycle test, a vertical jump test, and hand grip dynamometry. Results: Five-kilometer run time was 6% ± 3% shorter (faster) in the Mediterranean diet trial than in the Western diet trial (27.09 ± 3.55 vs 28.59 ± 3.21 minutes; p = 0.030) despite similar heart rates (160 ± 5 vs 160 ± 4 beats/min; p = 0.941) and ratings of perceived exertion (14.6 ± 0.5 vs 15.0 ± 0.5; p = 0.356). No differences between the diet conditions were observed for anaerobic exercise tests, including peak and mean power from the Wingate test (both p ≥ 0.05), the vertical jump test (p = 0.19), and the hand grip strength test (p = 0.69). Conclusions: Our findings extend existing evidence of the health benefits of the Mediterranean diet by showing that this diet is also effective for improving endurance exercise performance in as little as 4 days. Further studies are warranted to determine whether a longer-term Mediterranean diet provides greater benefits and whether it might also be beneficial for anaerobic exercise performance and muscle strength and power.

The performance and aerobic endurance effects of high-intensity versus moderate-intensity continuous running

The aim of the present study was to investigate the performance and aerobic endurance effects of high-intensity (HICR) versus moderate-intensity continuous running (MICR), which were nonmatched for total work. Twenty healthy recreational athletes (aged 28 ± 5 years) were randomly assigned to an HICR, MICR, or no-intervention control (C) group. The HICR group (n = 7) performed a 20-min strenuous, almost exhausting, run above lactate threshold (LT) at ∼88% of maximal heart rate (HR_max), whereas the MICR group (n = 7) performed a 40-min run at ∼80% HR_max. Both the HICR and MICR groups performed 3 intervention sessions a week, in addition to ∼60% of their regular aerobic exercise, for 10 weeks. The C group (n = 6) performed regular physical exercise throughout the study. Time to exhaustion, during a ∼4-8-min ramp test procedure, was significantly increased by 23% and 24% (P < 0.01) following HICR or MICR, respectively, with no significant difference in the change in time to exhaustion (P = 1.00) at pre- to post-training between the 2 training modalities (HICR and MICR). In the HICR group, maximal oxygen consumption and velocity at LT increased significantly by 5.0% and 6.8% (P < 0.01), respectively. The MICR group increased relative maximal oxygen consumption (mL·kg^-1·min^-1) significantly by 4.7% (P < 0.05), whereas the pulmonary respiratory gas-exchange ratio was significantly decreased at a submaximal workload by 4.2% (P < 0.01), indicating enhanced fat oxidation. No performance or physiological effects were observed in the C group. The present study indicates that even with a substantially lower total energy turnover, HICR can be as performance enhancing as MICR. Moreover, HICR can increase maximal aerobic power, whereas MICR may enhance fat oxidation.

Histamine-Receptor Antagonists Slow 10-km Cycling Performance in Competitive Cyclists

Histamine is released within skeletal muscle during exercise. In humans, antihistamines have no effect on speed, power output, or time-to-completion of short-duration high-intensity exercise. In mice, blocking histamine's actions decreases speed and duration of endurance tasks. It is unknown if these opposing outcomes are the result of differences in histamine's actions between species or are related to duration and/or intensity of exercise, as blocking histamine during endurance exercise has not been examined in humans.

PURPOSE

Determine the effects of histamine-receptor antagonism on cycling time trial performance in humans, with and without a preceding bout of sustained steady-state exercise.

METHODS

Eleven (3F) competitive cyclists performed six 10-km time trials on separate days. The first two time trials served as familiarization. The next four time trials were performed in randomized-block order, where two were preceded by 120 min of seated rest (rest) and two by 120 min of cycling exercise (Exercise) at 50% V˙O2peak. Within each block, subjects consumed either combined histamine H1 and H2 receptor antagonists (Blockade) or Placebo, before the start of the 120-min Rest/Exercise.

RESULTS

Blockade had no discernible effects on hemodynamic or metabolic variables during Rest or Exercise. However, Blockade increased time-to-completion of the 10-km time trial compared with Placebo (+10.5 ± 3.7 s, P < 0.05). Slowing from placebo to blockade was not different between rest (+8.7 ± 5.2 s) and Exercise (+12.3 ± 5.8 s, P = 0.716).

CONCLUSIONS

Exercise-related histaminergic signaling appears inherent to endurance exercise and may play a role in facilitating optimal function during high-intensity endurance exercise.

Frequency Speed of Kick Test Performance Comparison Between Female Taekwondo Athletes of Different Competitive Levels

Santos, JFS and Franchini, E. Frequency speed of kick test performance comparison between female taekwondo athletes of different competitive levels. J Strength Cond Res 32(10): 2934-2938, 2018-Construct validity is a desirable characteristic in any performance test to differentiate athletes. However, no taekwondo-specific test was investigated with this purpose. The purpose of this study was to compare female taekwondo athletes grouped in different competitive levels. Forty-two female taekwondo athletes divided into International/National (median [interquartile range]; n = 21, age: 20 [18-25] years; body mass: 60 [53-72] kg; height: 164 [161-170] cm; and practice time: 8 [5-13] years) and State/Regional group (median [interquartile range]; n = 21; age: 18 [17-25] years; body mass: 57 [52-63] kg; height: 165 [160-172] cm; and practice time: 5 [2-8] years) volunteered to participate in this study. The female taekwondo athletes performed frequency speed of kick test (FSKT) with 10 seconds (FSKT10s) and intermittent 90 seconds (FSKTmult) during the competitive period. Differences between international/national and state/regional group were observed, with superiority to international/national group, for FSKT10s (U = 114.5, p = 0.007, ESr (effect size) = -0.42 [small]), FSKT1 (U = 127.0, p = 0.016, ESr = -0.37 [small]), FSKT2 (U = 108.5, p = 0.004, ESr = -0.45 [small]), FSKT3 (U = 127.0, p = 0.015, ESr = -0.37 [small]), and FSKTtotal (U = 124.0, p = 0.015, ESr = -0.38 [small]). Based on the results of this study, the FSKT seems to be a good tool to discriminate performance of female taekwondo athletes and could be used by coaches and athletes in their evaluation routines.

The Reliability of 4-Minute and 20-Minute Time Trials and Their Relationships to Functional Threshold Power in Trained Cyclists

PURPOSE

The mean power output (MPO) from a 60-min time trial (TT)-also known as functional threshold power, or FTP-is a standard measure of cycling performance; however, shorter performance tests are desirable to reduce the burden of performance testing. The authors sought to determine the reliability of 4- and 20-min TTs and the extent to which these short TTs were associated with 60-min MPO.

METHODS

Trained male cyclists (n = 8; age = 25 [5] y; VO2max = 71 [5] mL/kg/min) performed two 4-min TTs, two 20-min TTs, and one 60-min TT. Critical power (CP) was estimated from 4- and 20-min TTs. The typical error of the mean (TEM) and intraclass correlation coefficient (ICC) were calculated to assess reliability, and R2 values were calculated to assess relationships with 60-min MPO.

RESULTS

Pairs of 4-min TTs (mean: 417 [SD: 45] W vs 412 [49] W, P = .25; TEM = 8.1 W; ICC = .98), 20-min TTs (342 [36] W vs 344 [33] W, P = .41; TEM = 4.6 W; ICC = .99), and CP estimates (323 [35] W vs 328 [32] W, P = .25; TEM = 6.5; ICC = .98) were reliable. The 4-min MPO (R2 = .95), 20-min MPO (R2 = .92), estimated CP (R2 = .82), and combination of the 4- and 20-min MPO (adjusted R2 = .98) were strongly associated with the 60-min MPO (309 [26] W).

CONCLUSION

The 4- and 20-min TTs appear useful for assessing performance in trained, if not elite, cyclists.

The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial

Background

β-alanine (βA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting < 4 minutes (min), which may be dependent on total, as opposed to daily, dose. The ergogenic effect of βA has also been demonstrated for 2000-m rowing performance prompting interest in whether βA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two βA dosing strategies on 30-min rowing and subsequent sprint performance.

Methods

Following University Ethics approval, twenty-seven healthy, male rowers (age: 24 ± 2 years; body-height: 1.81 ± 0.02 m; body-mass: 82.3 ± 2.5 kg; body-fat: 14.2 ± 1.0%) were randomised in a double-blind manner to 4 weeks of: i) βA (2.4 g·d^− 1, βA1); ii) matched total βA (4.8 g on alternate days, βA2); or iii) cornflour placebo (2.4 g·d^− 1, PL). Participants completed a laboratory 30-min rowing time-trial, followed by 3x30-seconds (s) maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg^− 1), cardio-respiratory measures and perceived exertion were assessed for each 10-min split. Blood lactate ([La-]_b mmol·L^− 1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (P ≤ 0.05).

Results

Total 30-min time-trial distance significantly increased from T1-T3 within βA1 only (7397 ± 195 m to 7580 ± 171 m, P = 0.002, ƞp² = 0.196), including absolute average power (194.8 ± 18.3 W to 204.2 ± 15.5 W, P = 0.04, ƞp² = 0.115) and relative average power output (2.28 ± 0.15 W·kg^− 1 to 2.41 ± 0.12 W·kg^− 1, P = 0.031, ƞp² = 0.122). These findings were potentially explained by within-group significance for the same variables for the first 10 min split (P ≤ 0.01), and for distance covered (P = 0.01) in the second 10-min split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P > 0.05) with comparable values at T3 for mean distance (βA1: 163.9 ± 3.8 m; βA2: 161.2 ± 3.5 m; PL: 162.7 ± 3.6 m), average power (βA1: 352.7 ± 14.5 W; βA2: 342.2 ± 13.5 W; PL: 348.2 ± 13.9 W) and lactate (βA1: 10.0 ± 0.9 mmol·L^− 1; βA2: 9.2 ± 1.1 mmol·L^− 1; PL: 8.7 ± 0.9 mmol·L^− 1).

Conclusions

Whilst daily βA may confer individual benefits, these results demonstrate limited impact of βA (irrespective of dosing strategy) on 30-min rowing or subsequent sprint performance. Further investigation of βA dosage > 2.4 g·d^− 1 and/or chronic intervention periods (> 4–8 weeks) may be warranted based on within-group observations.

Protein intake in the early recovery period after exhaustive exercise improves performance the following day

The aim of the present study was to investigate the effect of protein and carbohydrate ingestion during early recovery from exhaustive exercise on performance after 18-h recovery. Eight elite cyclists (V̇o2max: 74.0 ± 1.6 ml·kg−1·min−1) completed two exercise and diet interventions in a double-blinded, randomized, crossover design. Participants cycled first at 73% of V̇o2max (W73%) followed by 1-min intervals at 90% of V̇o2max until exhaustion. During the first 2 h of recovery, participants ingested either 1.2 g carbohydrate·kg−1·h−1 (CHO) or 0.8 g carbohydrate + 0.4 g protein·kg−1·h−1 (CHO + PROT). The diet during the remaining recovery period was similar for both interventions and adjusted to body weight. After an 18-h recovery, cycling performance was assessed with a 10-s sprint test, 30 min of cycling at W73%, and a cycling time trial (TT). The TT was 8.5% faster (41:53 ± 1:51 vs. 45:26 ± 1:32 min; P < 0.03) after CHO + PROT compared with CHO. Mean power output during the sprints was 3.7% higher in CHO + PROT compared with CHO (1,063 ± 54 vs. 1,026 ± 53 W; P = 0.01). Nitrogen balance in the recovery period was negative in CHO and neutral in CHO + PROT (−82.4 ± 11.5 vs. 7.0 ± 15.4 mg/kg; P < 0.01). In conclusion, TT and sprint performances were improved 18 h after exhaustive cycling by CHO + PROT supplementation during the first 2 h of recovery compared with isoenergetic CHO supplementation. Our results indicate that intake of carbohydrate plus protein after exhaustive endurance exercise more rapidly converts the body from a catabolic to an anabolic state than carbohydrate alone, thus speeding recovery and improving subsequent cycling performance.

NEW & NOTEWORTHY Prolonged high intensity endurance exercise depends on glycogen utilization and high oxidative capacity. Still, exhaustion develops and effective recovery strategies are required to compete in multiday stage races. We show that coingestion of protein and carbohydrate during the first 2 h of recovery is superior to isoenergetic intake of carbohydrate to stimulate recovery, and improves both endurance time-trial and 10-s sprint performance the following day in elite cyclists.

Reliability, usefulness and construct validity of the Combined Basketball Skill Test (CBST)

This study aimed to assess the reliability, usefulness and construct validity of the newly developed Combined Basketball Skill Test (CBST). Fifteen recreational (age = 22.8 ± 4.2 y, stature = 184.8 ± 6.5 cm, body mass = 81.6 ± 9.6 kg, training experience = 9.8 ± 5.3 y) and fifteen semiprofessional (age = 18.9 ± 3.3 y, stature = 190.5 ± 8.1 cm, body mass = 84.2 ± 11.2 kg, training experience = 11.1 ± 3.5 y) players volunteered to participate in this study. Test-retest reliability and usefulness were examined for recreational players, while construct validity was evaluated comparing the two player groups. The CBST is composed of 12 trials and its outcome measures include: completion time (sum of the 12 trial times); penalty time (sum of the times from the 12 trials); performance time (completion time + penalty time) and total number of errors. Relative reliability analysis showed acceptable ICC values (i.e. ≥0.70) in all the studied variables. Absolute reliability analysis showed a CV < 5% for completion (1.6%) and performance (2.0%) time, while a CV >5% is reported for the remaining variables. The usefulness of the test was considered "Marginal" and "Good" when comparing TE values with SWC₀₂ and SWC₀₅, respectively for all the studied variables. Likely and very likely differences were shown between recreational and semiprofessional players in all investigated variables. Results showed that the CBST is reliable, useful to detect moderate changes and valid to assess basketball skills.

Using Portable Force Plates to Assess Vertical Jump Performance: A Metrological Appraisal

The purpose of this study was to verify the metrological properties of portable force plates that are used to assess countermovement jump performance. While 88 participants (38 males, 50 females) were included in the agreement analyses, 84 participants (37 males and 47 females) completed the reliability part of the study. This randomized crossover design suggests that portable force plates could be used interchangeably with a reference system. Indeed, the differences between both devices were all considered trivial (effect size (ES) < 0.20), and the mean bias was never greater than 3.41% in comparison to the reference system. In addition, the absolute and relative reliability parameters were found to be acceptable for clinical use, even when used on different floor surfaces. However, it was found that the ratio between flight time and contraction time (FTCT) showed questionable reliability when tests were conducted on different surfaces (intraclass correlation coefficient = 0.49; coefficient of variation = 26.72%). Therefore, practitioners should be careful when installing the portable device on different floor surfaces in order to optimize the reliability and the ability to detect real change in the context of a countermovement jump monitoring process.

Time-trial performance is not impaired in either competitive athletes or untrained individuals following a prolonged cognitive task

It has been reported that mental fatigue decreases exercise performance during high-intensity constant-work-rate exercise (CWR) and self-paced time trials (TT) in recreationally-trained individuals. The purpose of this study was to determine whether performance is impaired following a prolonged cognitive task in individuals trained for competitive sport. Ten trained competitive athletes (ATH) and ten untrained healthy men (UNT) completed a 6-min severe-intensity CWR followed by a 6-min cycling TT immediately following cognitive tasks designed to either perturb (Stroop colour-word task and N-back task; PCT) or maintain a neutral (documentary watching; CON) mental state. UNT had a higher heart rate (75 ± 9 v. 69 ± 7 bpm; P = 0.002) and a lower positive affect PANAS score (19.9 ± 7.5 v. 24.3 ± 4.6; P = 0.036) for PCT compared to CON. ATH showed no difference in heart rate, but had a higher negative affect score for PCT compared to CON (15.1 ± 3.7 v. 12.2 ± 2.7; P = 0.029). Pulmonary O₂ uptake during CWR was not different between PCT and CON for ATH or UNT. Work completed during TT was not different between PCT and CON for ATH (PCT 103 ± 12 kJ; CON 102 ± 12 kJ; P > 0.05) or UNT (PCT 75 ± 11 kJ; CON 74 ± 12 kJ; P > 0.05). Compared to CON, during PCT, UNT showed unchanged psychological stress responses, whereas ATH demonstrated increased psychological stress responses. However, regardless of this distinction, exercise performance was not affected by PCT in either competitive athletes or untrained individuals.