Performance In Team Sport Athletes Research Articles

Mental fatigue impairs repeated sprint and jump performance in team sport athletes

ObjectivesWe tested whether mental fatigue (MF), induced by a cognitively-demanding task, would impair repeated sprint ability (RSA) and repeated jump ability (RJA) performance, and whether physical fatigue and MF would impair psychomotor vigilance. DesignRandomized within-participant design. MethodsAfter establishing baseline peak countermovement jump (CMJ), 18 male participants performed 12 maximal 20-m (10-m linear + 10-m directional) repeated sprints (RSA random test) followed by 12 maximal repeated CMJs (RJA test) subsequent to 30-min Stroop task (MF) or a documentary (Control). Peak and mean running time and height, percent decrement score (Sdec), blood lactate, heart rate and RPE were measured for CMJ, RSA, and RJA tests. MF (M-VAS) and psychomotor vigilance [psychomotor vigilance test (PVT)] were measured at baseline, after each condition, and after the RSA/RJA tests. ResultsCompared to Control, the Stroop task elevated MF (p = .001), RPE ratings (all p < .031), and mean and Sdec performance in directional (but not linear) RSA (all p < .032) and RJA tests (all p < .034). PVT score worsened after Stroop task (p = .011) but not Control, declined after RSA/RJA tests in both conditions (all p < .023) and was lower in the MF condition (p = .029). No condition differences were noted for peak (CMJ, RSA and RJA tests) performance, blood lactate, and heart rate. ConclusionsMF impairs directional RSA, and RJA performance. This impairment was linked with increased RPE and without physiological changes. The progressive impairment in PVT score suggests a cumulatively negative effect of mental and physical fatigue on psychomotor vigilance.

The Effects of Strength and Conditioning Interventions on Sprinting Performance in Team Sport Athletes: A Systematic Review and Meta-Analysis.

Abstract Murphy, A, Burgess, K, Hall, AJ, Aspe, RR, and Swinton, PA. The effects of strength and conditioning interventions on sprinting performance in team sport athletes: a systematic review and meta-analysis. J Strength Cond Res 37(8): 1692–1702, 2023—Linear sprinting is a key determinant of athletic performance within team sports. The aims of the review were to quantify and compare the effectiveness of popular strength and conditioning (S&amp;C) training modes to improve sprint performance in team sport athletes, with additional focus on potential moderators and the relationships between improvements in physical factors (e.g., strength, power, and jump performance) and improvements in sprint performance. Inclusion was restricted to resistance, plyometric, sprint, and combined training interventions comprising team sport athletes. Multilevel, Bayesian’s meta-analysis and meta-regression models conducted with standardized mean difference effect sizes were used to investigate training modes and potential moderators. Weighted regression models conducted on shrunken estimates from initial Bayesian’s meta-analyses were used to quantify relationships between improvements in physical factors and sprint performance. Certainty of evidence was assessed using the grading of recommendations assessment development and evaluation (GRADE) approach. Similar improvements in sprint performance were obtained across training modes, with some evidence of the largest effects with resistance training ( = 0.55 [95% credible interval [CrI]: 0.36–0.78; very low certainty]). A strong moderating effect of training intensity was identified across all training modes with evidence of greater improvements in sprint performance with high-intensity training ( = 0.17 [95% CrI: 0.01–0.33; very low certainty]). Strong positive relationships were identified between improvements in all physical factors and sprint performance ( = 0.56 [95% CrI: 0.36–0.77; low certainty], = 0.80 [95% CrI: 0.50–1.0; low certainty], = 0.78 [95% CrI: 0.57–0.97; low certainty]). The findings indicate that focus on developing speed in team sport athletes should be placed on S&amp;C training with high intensities, including the use of resisted sprint training.

Narrative Review on the Use of Sled Training to Improve Sprint Performance in Team Sport Athletes

ABSTRACT Sprinting is a key component for many individual and team sports. Therefore, to enhance sprint performance, various training methods are widely used by coaches and practitioners, including maximum sprint speed and resisted sprint training. Resisted sprinting with sled towing is a method that has recently received considerable attention from the sport science community. However, to date, no consensus exists regarding its acute and chronic effects in team sport athletes. This narrative review aimed to (a) review and analyze the mechanics of sprinting under unresisted and resisted conditions with a specific focus on team sport disciplines; (b) provide a thorough and applied discussion on the importance of considering acute and chronic effects of sled loading on technique, electromyographic activity, and force production, as well as on the role of muscle architecture and neural factors in sled training; (c) analyze the effects of increasing sled loads during acceleration and maximum velocity phases on contact and flight phases, while concomitantly examining kinetic, kinematic, and neuromuscular aspects, because all these factors affect each other and cannot be properly understood in isolation.

Does Acute Caffeine Supplementation Improve Physical Performance in Female Team-Sport Athletes? Evidence from a Systematic Review and Meta-Analysis.

Introduction: Recent original research and meta-analyses suggest that acute caffeine supplementation improves exercise performance in team-sport athletes (TSA). Nonetheless, most of the studies testing the effects of caffeine on TSA included samples of male athletes, and there is no meta-analysis of the performance-enhancing effects of caffeine on female TSA. The aim of the present study was to synthesize the existing literature regarding the effect of caffeine supplementation on physical performance in adult female TSA. Methods: A search was performed in Pubmed/Medline, SPORTDiscus and Scopus. The search was performed from the inception of indexing until 1 September 2021. Crossover randomized controlled trials (RCT) assessing the effects of oral caffeine intake on several aspects of performance in female TSA were selected. The methodological quality and risk of bias were assessed for individual studies using the Physiotherapy Evidence Database scale (PEDro) and the RoB 2 tool. A random-effects meta-analysis of standardized mean differences (SMD) was performed for several performance variables. Results: The search retrieved 18 articles that fulfilled the inclusion/exclusion criteria. Overall, most of the studies were of excellent quality with a low risk of bias. The meta-analysis results showed that caffeine increased performance in specific team-sport skills (SMD: 0.384, 95% confidence interval (CI): 0.077–0.691), countermovement jump (SMD: 0.208, CI: 0.079–0.337), total body impacts (SMD: 0.488; 95% CI: 0.050, 0.927) and handgrip strength (SMD: 0.395, CI: 0.126–0.665). No effects were found on the ratings of perceived exertion, squat jumps, agility, repeated sprint ability or agility tests performed after fatigue. Conclusions: The results of the meta-analysis revealed that acute caffeine intake was effective in increasing some aspects of team-sports performance in women athletes. Hence, caffeine could be considered as a supplementation strategy for female athletes competing in team sports.

Local and Remote Ischemic Preconditioning Improves Sprint Interval Exercise Performance in Team Sport Athletes.

The aim of this study was to investigate the effects of local (LIPC) and remote (RIPC) ischemic preconditioning on sprint interval exercise (SIE) performance. Fifteen male collegiate basketball players underwent a LIPC, RIPC, sham (SHAM), or control (CON) trial before conducting six sets of a 30-s Wingate-based SIE test. The oxygen uptake and heart rate were continuously measured during SIE test. The total work in the LIPC (+2.2%) and RIPC (+2.5%) conditions was significantly higher than that in the CON condition (p < 0.05). The mean power output (MPO) at the third and fourth sprint in the LIPC (+4.5%) and RIPC (+4.9%) conditions was significantly higher than that in the CON condition (p < 0.05). The percentage decrement score for MPO in the LIPC and RIPC condition was significantly lower than that in the CON condition (p < 0.05). No significant interaction effects were found in pH and blood lactate concentrations. There were no significant differences in the accumulated exercise time at ≥80%, 90%, and 100% of maximal oxygen uptake during SIE. Overall, both LIPC and RIPC could improve metabolic efficiency and performance during SIE in athletes.

Effects of Nutrition Education Interventions in Team Sport Players. A Systematic Review.

Considering nutrition education interventions have been frequently implemented in team sport athletes and have shown promising results, this study aimed to summarize the effects of nutrition education interventions on eating habits, nutrition knowledge, body composition, and physical performance in team sport athletes. A systematic review was conducted using the following databases: PubMed/MEDLINE, Web of Science and SPORTDiscus. A total of 14 studies met the inclusion criteria for the review. The methodological quality of included studies was evaluated, and each study was assessed according to the analyzed variables (i.e., eating habits, nutrition knowledge, body composition, and physical performance). Most studies showed improvements in or maintenance of variables used to indicate eating habits, nutrition knowledge, and body composition. However, limited studies examined the effect of nutrition education interventions on physical performance, with existing studies demonstrating disparate results. These findings suggest implementation of nutrition education interventions in team sport athletes could be an effective strategy to improve their eating habits, nutrition knowledge, and body composition. Due to the heterogeneity across the included studies regarding sport modality, competition level, age, and sex of the athletes investigated, as well as the intervention type adopted (i.e., online or face-to-face), it is difficult to establish optimal nutrition education interventions for each analyzed variable.

Short-Term Repeated-Sprint Training in Hot and Cool Conditions Similarly Benefits Performance in Team-Sport Athletes.

This study compared the performance and physiological adaptations of short-term repeated-sprint training in HOT [40°C and 40% relative humidity (RH)] and COOL (20°C and 40% RH) conditions in team-sport athletes. Twenty-five trained males completed five training sessions of 60 min over 7 days in HOT (n = 13) or COOL (n = 12) conditions, consisting of a submaximal warm-up and four sets of maximal sprints. Before and after the intervention, intermittent shuttle running performance was assessed in cool and repeated-sprint ability in hot conditions; the latter preceded and followed by neuromuscular function testing. During the repeated-sprint training sessions, skin (~8.4°C) and core (~0.17°C) temperatures were higher in HOT than COOL (p < 0.05) conditions. Shuttle running distance increased after both interventions (p < 0.001), with a non-significant (p = 0.131) but larger effect in HOT (315 m, d = 1.18) than COOL (207 m, d = 0.51) conditions. Mean (~7%, p < 0.001) and peak (~5%, p < 0.05) power during repeated-sprinting increased following both interventions, whereas peak twitch force before the repeated-sprint assessment was ~10% lower after the interventions (p = 0.001). Heart rate during the repeated-sprint warm-up was reduced (~6 beats.min−1) following both interventions (p < 0.01). Rectal temperature was ~0.14°C lower throughout the repeated-sprint assessment after the interventions (p < 0.001), with larger effects in HOT than COOL during the warm-up (p = 0.082; d = −0.53 vs. d = −0.15) and repeated-sprints (p = 0.081; d = −0.54 vs. d = −0.02). Skin temperature (p = 0.004, d = −1.11) and thermal sensation (p = 0.015, d = −0.93) were lower during the repeated-sprints after training in HOT than COOL. Sweat rate increased (0.2 L.h−1) only after training in HOT (p = 0.027; d = 0.72). The intensive nature of brief repeated-sprint training induces similar improvements in repeated-sprint cycling ability in hot conditions and intermittent running performance in cool conditions, along with analogous physiological adaptations, irrespective of the environmental conditions in which training is undertaken.

Acute effect of inspiratory resistive loading on sprint interval exercise performance in team-sport athletes

This study examined acute effects of inspiratory resistive loading (IRL) during rest intervals on sprint interval exercise (SIE) performance. In a randomized crossover design, nine collegiate basketball players performed IRL (15 cmH2O) or passive recovery (CON) at 5-min rest intervals during and immediately after 6 sets of a 30-s SIE test. Performance, muscular oxygenation of vastus lateralis, blood lactate and pH were measured at each condition. Blood lactate at 5-min (−20.5 %) and 20-min (−21.3 %) after SIE were significantly lower in IRL than in CON. The pH at 5-min after SIE was significantly higher in IRL than in CON (+0.8 %, p < 0.05). However, the total work in IRL was significantly lower than in CON (−2.7 %, p < 0.05). Average changes in total hemoglobin at rest intervals in IRL were significantly lower than in CON (−34.5 %, p < 0.05). The IRL could attenuate exercise-induced metabolic acidosis; however, the decreased blood flow at rest intervals might increase the physical challenge in SIE.

Tapering strategies applied to plyometric jump training: a systematic review with meta-analysis of randomized-controlled trials.

The purpose of this systematic review was to analyze the effect of plyometric jump training (PJT) applied in conjunction with tapering strategies on the jump performance of team-sport athletes. The meta-analysis included: 1) randomized-controlled studies that incorporated a PJT program; 2) cohorts of team-sport athletes; 3) jump performance assessments; and 4) studies that incorporated a programmed taper. A systematic search was conducted in distinct electronic databases for relevant studies. Aside from jump performance, the extracted data included characteristics of the participants, PJT, and tapering. Means and standard deviations were used to calculate the effect sizes (ES). To assess the effects of moderator variables, subgroup analyses were performed. The statistical significance level was set as P<0.05. From 7020 records initially identified, 14 studies were eligible for meta-analysis. Across all included studies, there was a moderate, significant improvement in jump performance (ES=0.73; P<0.001). Additionally, the subgroup analysis demonstrated that the duration and intensity of the taper and the volume of the PJT induced similar improvements in jump performance (P<0.01). In summary, PJT interventions that included a programmed taper induced significant improvements in jump performance in team-sport athletes. These effects were observed after different tapering strategies in terms of volume, taper duration, and the type of PJT prescribed.

Transferable Benefits of Cycle Hypoventilation Training for Run-Based Performance in Team-Sport Athletes.

To determine whether high-intensity training with voluntary hypoventilation at low lung volume (VHL) in cycling could improve running performance in team-sport athletes. Twenty well-fit subjects competing in different team sports completed, over a 3-week period, 6 high-intensity training sessions in cycling (repeated 8-s exercise bouts at 150% of maximal aerobic power) either with VHL or with normal breathing conditions. Before (Pre) and after (Post) training, the subjects performed a repeated-sprint-ability test (RSA) in running (12 × 20-m all-out sprints), a 200-m maximal run, and the Yo-Yo Intermittent Recovery Level 1 test (YYIR1). There was no difference between Pre and Post in the mean and best velocities reached in the RSA test, as well as in performance and maximal blood lactate concentration in the 200-m-run trial in both groups. On the other hand, performance was greater in the second part of the RSA test, and the fatigue index of this test was lower (5.18% [1.3%] vs 7.72% [1.6%]; P < .01) after the VHL intervention only. Performance was also greater in the YYIR1 in the VHL group (1468 [313] vs 1111 [248]m; P < .01), whereas no change occurred in the normal-breathing-condition group. This study showed that performing high-intensity cycle training with VHL could improve RSA and possibly endurance performance in running. On the other hand, this kind of approach does not seem to induce transferable benefits for anaerobic performance.

Two Sets of Dynamic Stretching of the Lower Body Musculature Improves Linear Repeated-Sprint Performance in Team-Sports.

Background: Warm-up including dynamic stretching is a popular and widely accepted practice as a pre-exercise routine for athletes. However, a shortage of studies investigating the impact of dynamic stretching on linear repeated-sprint performance exists. Objectives: The present study aims to look at the effect of different volumes of dynamic stretching on 30 m linear repeated sprint performance in team sport athletes. Methods: Fifteen male university team-sport players [age (mean ± SD) 22.1 ± 0.6 years, stature 166.9 ± 6.6cm and body mass 67.5 ± 8.0kg] underwent 3 sessions in this within-subjects counterbalanced study. All sessions included a general warm-up (5-minutes self-paced), followed by a dynamic stretching protocol (one set-DSS1; two sets-DSS2; three sets-DSS3) comprised of five active dynamic exercises for lower body musculature (gastrocnemius, gluteals, hamstrings, quadriceps and hip extensor). A standardized specific warm-up was then undertaken followed by a repeated-sprint test (6 × 30-m sprint with 30 seconds active recovery). Results: Values for average sprint time (AST) and total sprint times (TST) were significantly faster (P = 0.005) following DSS2 compared to DSS1 and DSS3. Fatigue index (FI) was significantly lower in DSS2 compared to DSS1 and DSS3 (P 0.05) for best sprint time (BST), mean sprint time (MST) or rating of perceived exertion (RPE). Conclusions: In conclusion, a dynamic warm-up consisting of two sets resulted in improved performance in repeated-sprint. The exact mechanisms associated with this established ergogenic benefit is still unclear and requires more research.

The Negative Influence of Air Travel on Health and Performance in the National Basketball Association: A Narrative Review.

Air travel requirements are a concern for National Basketball Association (NBA) coaches, players, and owners, as sport-based research has demonstrated short-haul flights (≤6 h) increase injury risk and impede performance. However, examination of the impact of air travel on player health and performance specifically in the NBA is scarce. Therefore, we conducted a narrative review of literature examining the influence of air travel on health and performance in team sport athletes with suggestions for future research directions in the NBA. Prominent empirical findings and practical recommendations are highlighted pertaining to sleep, nutrition, recovery, and scheduling strategies to alleviate the negative effects of air travel on health and performance in NBA players.

Correction to: The Effect of Natural or Simulated Altitude Training on High-Intensity Intermittent Running Performance in Team-Sport Athletes: A Meta-Analysis.

Page 10, Fig.2: The filled circle labelled "3" was plotted inaccurately and should have been in the "harmful" section of the graph, as shown in the corrected version below.

The Effect of Natural or Simulated Altitude Training on High-Intensity Intermittent Running Performance in Team-Sport Athletes: A Meta-Analysis.

While adaptation to hypoxia at natural or simulated altitude has long been used with endurance athletes, it has only recently gained popularity for team-sport athletes. To analyse the effect of hypoxic interventions on high-intensity intermittent running performance in team-sport athletes. A systematic literature search of five journal databases was performed. Percent change in performance (distance covered) in the Yo-Yo intermittent recovery test (level 1 and level 2 were used without differentiation) in hypoxic (natural or simulated altitude) and control (sea level or normoxic placebo) groups was meta-analyzed with a mixed model. The modifying effects of study characteristics (type and dose of hypoxic exposure, training duration, post-altitude duration) were estimated with fixed effects, random effects allowed for repeated measurement within studies and residual real differences between studies, and the standard-error weighting factors were derived or imputed via standard deviations of change scores. Effects and their uncertainty were assessed with magnitude-based inference, with a smallest important improvement of 4% estimated via between-athlete standard deviations of performance at baseline. Ten studies qualified for inclusion, but two were excluded owing to small sample size and risk of publication bias. Hypoxic interventions occurred over a period of 7-28days, and the range of total hypoxic exposure (in effective altitude-hours) was 4.5-33kmh in the intermittent-hypoxia studies and 180-710kmh in the live-high studies. There were 11 control and 15 experimental study-estimates in the final meta-analysis. Training effects were moderate and very likely beneficial in the control groups at 1week (20±14%, percent estimate,±90% confidence limits) and 4-week post-intervention (25±23%). The intermittent and live-high hypoxic groups experienced additional likely beneficial gains at 1week (13±16%; 13±15%) and 4-week post-intervention (19±20%; 18±19%). The difference in performance between intermittent and live-high interventions was unclear, as were the dose of hypoxia and inclusion of training in hypoxia. Hypoxic intervention appears to be a worthwhile training strategy for improvement in high-intensity running performance in team-sport athletes, with enhanced performance over control groups persisting for at least 4weeks post-intervention. Pending further research on the type of hypoxia, dose of hypoxia and training in hypoxia, coaches have considerable scope for customising hypoxic training methods to best suit their team's training schedule.

Acute Ingestion of Caffeinated Chewing Gum Improves Repeated Sprint Performance of Team Sport Athletes With Low Habitual Caffeine Consumption.

The effects of acute ingestion of caffeine on short-duration high-intensity performance are equivocal, while studies of novel modes of delivery and the efficacy of low doses of caffeine are warranted. The aims of the present study were to investigate the effect of acute ingestion of caffeinated chewing gum on repeated sprint performance (RSP) in team sport athletes, and whether habitual caffeine consumption alters the ergogenic effect, if any, on RSP. A total of 18 male team sport athletes undertook four RSP trials using a 40-m maximum shuttle run test, which incorporates 10 × 40-m sprints with 30s between the start of each sprint. Each participant completed two familiarization sessions, followed by caffeine (CAF; caffeinated chewing gum; 200mg caffeine) and placebo (PLA; noncaffeinated chewing gum) trials in a randomized, double-blind manner. RSP, assessed by sprint performance decrement (%), did not differ (p = .209; effect size = 0.16; N = 18) between CAF (5.00 ± 2.84%) and PLA (5.43 ± 2.68%). Secondary analysis revealed that low habitual caffeine consumers (<40mg/day, n = 10) experienced an attenuation of sprint performance decrement during CAF relative to PLA (5.53 ± 3.12% vs. 6.53 ± 2.91%, respectively; p = .049; effect size =0.33); an effect not observed in moderate/high habitual caffeine consumers (>130mg/day, n = 6; 3.98 ± 2.57% vs. 3.80 ± 1.79%, respectively; p = .684; effect size = 0.08). The data suggest that a low dose of caffeine in the form of caffeinated chewing gum attenuates the sprint performance decrement during RSP by team sport athletes with low, but not moderate-to-high, habitual consumption of caffeine.

The Relationship between Unilateral Dynamic Stability and Multidirectional Jump Performance in Team Sport Athletes

AbstractThis study investigated relationships between dynamic stability and multidirectional jumping. A modified Star Excursion Balance Test (mSEBT), incorporating unilateral lower-body reaching in posteromedial, medial, and anteromedial directions, assessed dynamic stability. Unilateral vertical (VJ), standing broad (SBJ) and lateral jumps (LJ) assessed leg power. VJ power and relative SBJ and LJ distances were calculated. Thirty-two team sport athletes completed the mSEBT when each leg was used for stance, and left- and right-leg VJ, SBJ, and LJ. Correlations were drawn between data recorded from each leg when used for mSEBT stance and for each jump. Participants were dichotomized into better and lesser dynamic stability groups according to the sum of excursions for each leg. A one-way ANOVA determined mSEBT and jump differences (p&lt; 0.05). The left-leg posteromedial and medial excursions correlated with VJ power; the medial excursion correlated with the LJ. The right-leg posteromedial excursion correlated with the SBJ; the anteromedial excursion correlated with the SBJ, and relative SBJ and LJ (r = 0.35-0.45). There were no differences in unilateral jumping between the better and lesser groups. Although there is some relationship with dynamic stability, this study further highlighted the complex interaction between the physical and technical characteristics of multidirectional jumping.

Application of 'live low-train high' for enhancing normoxic exercise performance in team sport athletes.

Hypoxic training techniques are increasingly used by athletes in an attempt to improve performance in normoxic environments. The 'live low-train high (LLTH)' model of hypoxic training may be of particular interest to athletes because LLTH protocols generally involve shorter hypoxic exposures (approximately two to five sessions per week of <3 h) than other traditional hypoxic training techniques (e.g., live high-train high or live high-train low). However, the methods employed in LLTH studies to date vary greatly with respect to exposure times, training intensities, training modalities, degrees of hypoxia and performance outcomes assessed. Whilst recent reviews provide some insight into how LLTH may be applied to enhance performance, little attention has been given to how training intensity/modality may specifically influence subsequent performance in normoxia. Therefore, this systematic review aims to evaluate the normoxic performance outcomes of the available LLTH literature, with a particular focus on training intensity and modality. A systematic search was conducted to capture all LLTH studies with a matched normoxic (control) training group and the assessment of performance under normoxic conditions. Studies were excluded if no training was completed during the hypoxic exposures, or if these exposures exceeded 3 h per day. Four electronic databases were searched (PubMed, SPORTDiscus, EMBASE and Web of Science) during August 2013, and these searches were supplemented by additional manual searches until December 2013. After the electronic and manual searches, 40 papers were deemed to meet the inclusion criteria, representing 31 separate studies. Within these 31 studies, four types of LLTH were identified: (1) continuous low-intensity training in hypoxia (CHT, n = 16), (2) interval hypoxic training (IHT, n = 4), (3) repeated sprint training in hypoxia (RSH, n = 3) and (4) resistance training in hypoxia (RTH, n = 4). Four studies also used a combination of CHT and IHT. The majority of studies reported no difference in normoxic performance between the hypoxic and normoxic training groups (n = 19), while nine reported greater improvements in the hypoxic group and three reported poorer outcomes compared with the control group. Selection of training intensity (including matching relative or absolute intensity between normoxic and hypoxic groups) was identified as a key factor in mediating the subsequent normoxic performance outcomes. Five studies included some form of normoxic training for the hypoxic group and 14 studies assessed performance outcomes not specific to the training intensity/modality completed during the training intervention. Four modes of LLTH are identified in the current literature (CHT, IHT, RSH and RTH), with training mode and intensity appearing to be key factors in mediating subsequent performance responses in normoxia. Improvements in normoxic performance appear most likely following high-intensity, short-term and intermittent training (e.g., IHT, RSH). LLTH programmes should carefully apply the principles of training and testing specificity and include some high-intensity training in normoxia. For RTH, it is unclear whether the associated adaptations are greater than those of traditional (maximal) resistance training programmes.

Effect of Different Simulated Altitudes on Repeat-Sprint Performance in Team-Sport Athletes

This study aimed to assess the impact of 3 heights of simulated altitude exposure on repeat-sprint performance in team-sport athletes. Ten trained male team-sport athletes completed 3 sets of repeated sprints (9 × 4 s) on a nonmotorized treadmill at sea level and at simulated altitudes of 2000, 3000, and 4000 m. Participants completed 4 trials in a random order over 4 wk, with mean power output (MPO), peak power output (PPO), blood lactate concentration (Bla), and oxygen saturation (SaO2) recorded after each set. Each increase in simulated altitude corresponded with a significant decrease in SaO2. Total work across all sets was highest at sea level and correspondingly lower at each successive altitude (P < .05; sea level < 2000 m < 3000 m < 4000 m). In the first set, MPO was reduced only at 4000 m, but for subsequent sets, decreases in MPO were observed at all altitudes (P < .05; 2000 m < 3000 m < 4000 m). PPO was maintained in all sets except for set 3 at 4000 m (P < .05; vs sea level and 2000 m). BLa levels were highest at 4000 m and significantly greater (P < .05) than at sea level after all sets. These results suggest that "higher may not be better," as a simulated altitude of 4000 m may potentially blunt absolute training quality. Therefore, it is recommended that a moderate simulated altitude (2000-3000 m) be employed when implementing intermittent hypoxic repeat-sprint training for team-sport athletes.

Effect of Beta Alanine and Sodium Bicarbonate Supplementation on Repeated-Sprint Performance

This study aimed to investigate if combining beta alanine (BA) and sodium bicarbonate (NaHCO3) supplementation could lead to enhanced repeated-sprint performance in team-sport athletes, beyond what is possible with either supplement alone. Participants (n = 24) completed duplicate trials of a repeated-sprint test (3 sets; 6 × 20 m departing every 25 seconds, 4 minutes active recovery between sets) and were then allocated into 4 groups as follows: BA only (n = 6; 28 days BA, acute sodium chloride placebo); NaHCO3 only (n = 6; 28 days glucose placebo, acute NaHCO3); BA/NaHCO3 (n = 6; 28 days BA, acute NaHCO3); placebo only (n = 6; 28 days glucose placebo, acute sodium chloride placebo), then completed duplicate trials postsupplementation. Sodium bicarbonate alone resulted in moderate effect size (d = 0.40-0.71) and "likely" and "very likely" benefit for overall total sprint times (TST) and for each individual set and for first sprint (sets 2 and 3) and best sprint time (sets 2 and 3). Combining BA and NaHCO3 resulted in "possible" to "likely" benefits for overall TST and for sets 2 and 3. First sprint (set 3) and best sprint time (sets 2 and 3) also showed "likely" benefit after this trial. The BA and placebo groups showed no differences in performance after supplementation. In conclusion, these results indicate that supplementation with acute NaHCO3 improved repeated-sprint performance more than either a combination of NaHCO3 and BA or BA alone.

Update in the understanding of altitude-induced limitations to performance in team-sport athletes

The internationalism of field-based team sports (TS) such as football and rugby requires teams to compete in tournaments held at low to moderate altitude (∼1200–2500 m). In TS, acceleration, speed...