High-intensity interval training vs. repeated-sprint training in tennis

The chronic effects of change of direction during repeated-sprint training on jumping, sprinting, and change-of-direction abilities in players: a systematic review and meta-analysis

Objectives

This systematic review and meta-analysis aimed to compare the effects of repeated sprint training with one change of direction (RS-OCOD) and multidirectional changes of direction (RS-MCOD) on players' jumping, sprinting, and change-of-direction (COD) ability.

Methods

Following PRISMA guidelines, 15 randomized controlled trials involving 223 players were analyzed. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using fixed- or random-effects models. Heterogeneity (I 2 statistic), publication bias (funnel plots and Egger's test), and sensitivity analyses were conducted. Subgroup analyses differentiated RS-OCOD and RS-MCOD outcomes.

Results

RS-COD training significantly improved countermovement jump (CMJ) (SMD = -0.68, 95% CI [-1.04 to -0.34]), 20-40 m sprinting ability (SMD = 0.70 [0.39, 1.01]), and COD ability (SMD = 0.77 [0.39, 1.16]). RS-MCOD demonstrated superior effects on 20-40 m sprinting ability (large effect: SMD = 0.97) and COD ability (large effect: SMD = 0.97), while RS-OCOD showed greater benefits for CMJ (large effect: SMD = -0.92). High heterogeneity (I 2 > 70%) was observed in 5 m/10 m sprint analyses, attributed to methodological diversity and age variability. Prediction intervals indicated potential overestimation of RS-MCOD effects.

Conclusion

RS-OCOD can significantly enhance a player's CMJ ability, while RS-MCOD can notably improve sprinting and COD abilities. These findings advocate for the incorporation of RS-COD into training programs to boost competitive performance. However, the effectiveness of RS-COD may vary based on the number and complexity of directional changes incorporated into the training regimen. Among them, RS-MCOD is prioritized for sports requiring frequent directional changes, whereas RS-OCOD enhances vertical jump performance in explosive sports.

Effects of high-intensity interval training on selected indicators of physical fitness among male team-sport athletes: A systematic review and meta-analysis

BACKGROUND

Superior physical fitness and performance are essential in male team sports. Among a myriad of training methodologies, high-intensity interval training (HIIT) has gained popularity owing to its unparalleled efficiency and effectiveness. Previous studies have established that HIIT is a proven and effective approach for enhancing various physiological performance outcomes, particularly oxygen consumption capacity, in individual sports. Despite potential differences in training practices between male and female athletes, HIIT is recognized as an anaerobic training approach for team-sport athletes. This systematic review aimed to comprehensively and innovatively analyze the existing literature to examine the effectiveness of HIIT on oxygen consumption performance among male team-sport athletes.

METHODS

A comprehensive literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines across the PubMed, SCOPUS, Web of Science, and SPORTDiscus databases until December 31, 2023. The inclusion criteria for this review encompassed research articles published in peer-reviewed journals that specifically focused on the impact of HIIT on the oxygen consumption performance of male players engaged in team sports. The study population exclusively consisted of male participants. The collected data included study characteristics, participant demographics, intervention details, and outcomes. Methodological quality assessment was performed using standardized criteria. The effect sizes (ESs) were calculated, and a meta-analysis was conducted using a random-effects model.

RESULTS

The literature search yielded 13 eligible studies encompassing 286 athletes aged 14-26 years. The meta-analysis showed statistically significant enhancements in maximal oxygen uptake (VO2max) in six studies (ES, 0.19-0.74; p < 0.005), Yo-Yo Intermittent Recovery Test (YYIRT) performance in six studies (ES, 0.20-2.07; p = 0.009), repeated-sprint ability total time (RSAtotal) in five studies (ES, 0.18-1.33; p < 0.001), and the best and average times for repeated-sprint ability (RSAbest and RSAmean, respectively) in four studies (ES, 0.47-1.50; p < 0.001). However, two studies did not report any significant differences in the outcomes of the Velocity in 30-15 Intermittent Fitness Test (VIFT) between the experimental and control groups (ES, -0.08 and -0.27; p = 0.87 and 0.443, respectively). Moreover, one study did not report any significant differences in the maximal aerobic speed (MAS) (ES, 0.41, p = 0.403).

CONCLUSIONS

HIIT significantly improved VO2max, YYIRT, and RSA; however, it did not appear to enhance VIFT and MAS performance, irrespective of age or competition level. These findings indicate that HIIT could serve as a valuable method for improving oxygen consumption performance (VO2max, YYIRT, and RSA) in male team-sport athletes, offering a time-efficient alternative to the traditional training methods. Further research is warranted to investigate its impact on performance outcomes in competitive settings and identify optimal HIIT protocols tailored to specific team sports.

Acute ingestion of acetaminophen improves cognitive and repeated high intensity short-term maximal performance in well-trained female athletes: a randomized placebo-controlled trial

This study examined the effect of acute acetaminophen (ACTP) ingestion on physical performance during the 5 m shuttle run test (5mSRT), attention, mood states, and the perception of perceived exertion (RPE), pain (PP), recovery (PRS), and delayed onset of muscle soreness (DOMS) in well-trained female athletes. In a randomized, placebo-controlled, double-blind, crossover trial, fifteen well-trained female athletes (age 21 ± 2 years, height 165 ± 6 cm, body mass 62 ± 5 kg) swallowed either 1.5 g of ACTP or 1.5 g of placebo. The profile of mood states (POMS) and digit cancellation (DCT) were assessed 45 min postingestion, and 5mSRT was performed 60 min postingestion. The RPE and PP were determined immediately after each 30-s repetition of the 5mSRT, and the PRS and DOMS were recorded at 5 min and 24 h post-5mSRT. For the 5mSRT, ACTP ingestion improved the greatest distance (+ 10.88%, p < 0.001), total distance (+ 11.33%, p = 0.0007) and fatigue index (+ 21.43%, p = 0.0003) compared to PLA. Likewise, the DCT score was better on the ACTP (p = 0.0007) than on the PLA. RPE, PP, PRS, and DOMS scores were improved after ACTP ingestion (p < 0.01 for all comparisons) compared to PLA. POMS scores were enhanced with ACTP ingestion compared to PLA (p < 0.01). In conclusion, this study indicates that acute acetaminophen ingestion can improve repeated high intensity short-term maximal performance, attention, mood states, and perceptions of exertion, pain, recovery, and muscle soreness in well-trained female athletes, suggesting potential benefits for their overall athletic performance and mood state.

The Effect of Ischemic Preconditioning on Tennis Exercise Performance and the Recovery Subsequent to a Simulated Tennis Match: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to investigate the effects of acute ischemic preconditioning (IPC) on tennis skill and physical exercise performance, as well as to explore whether 7-day repeated IPC (RIPC) accelerated fatigue recovery after a simulated tennis match.

METHODS

Twenty-nine male tennis-specific current students were randomly allocated into 1 of 2 groups: SHAM (n = 14, 3 × 5 min at 20 mm Hg) and IPC (n = 15, 3 × 5 min at 220 mm Hg). Participants in both groups engaged in acute IPC and RIPC interventions. After the first acute IPC intervention, assessments were conducted to evaluate tennis-specific skills and overall physical exercise capacity. Following completion of chronic RIPC interventions, all participants competed in a simulated tennis match specifically designed to induce fatigue. To evaluate recovery from this induced fatigue, physical exercise capacity tests were conducted at 24 and 48 hours postmatch, allowing for an assessment of the participants' recovery capabilities over time.

RESULTS

After the first acute intervention, notable differences were observed between the IPC and SHAM groups in their performance on the repeated-sprint ability test. Specifically, the total times recorded were significantly shorter in the IPC group compared with the SHAM group (IPC: 109.05 [2.70] vs SHAM: 114.57 [7.45] s, P = .012), and this trend was also reflected in their best times (IPC: 4.20 [0.18] s vs SHAM: 4.39 [0.30] s, P = .042), indicating an immediate benefit of the IPC intervention on sprint performance. After a 7-day RIPC intervention, significant changes were noted in the SHAM group's performance metrics postmatch. There was an increase (P < .001) in fatigue index from 22% (8%) to 30% (9%) during repeated-sprint ability test and a decrease in serve speed from 120.2 (17.5) to 106.7 (13.0) km/h (P = .002) and knee peek torque from 196.0 (49.0) to 162.7 (39) N (extension, 60°/s, P < .001) in the SHAM group 24 hours postmatch, relative to the IPC group. Moreover, compared with the SHAM group, the IPC group showed a lower rate of perceived exertion during the match (P < .001) and a decrease in visual analog scale score (P = .026) 24 hours postmatch, suggesting enhanced recovery and reduced perception of pain relative to the SHAM group.

CONCLUSION

IPC could serve as a strategy to generate an ergogenic effect and recovery during training and competition.

Effects of a 6-week on-court training program on the International Tennis Number (ITN) and a range of physical fitness characteristics in young tennis players

The study aimed to (i) verify the effects of an on-court training program on the International Tennis Number (ITN) of young tennis players, as well as on a set of change of direction, linear sprint, and maximal oxygen uptake (VO2max) variables, and (ii) identify the main predictors of ITN. The sample consisted of 20 young male tennis players (mean age, 13.62 ± 0.23 years). Players underwent a 6-week on-court training program. The ITN and a number of change of direction variables (T-drill and repeated sprint ability), linear sprint (5 m, 10 m, and 20 m distances), and VO2max were measured. All variables improved significantly between the pre- and posttest (p < 0.001). The ITN (7.98 ± 6.06%, d = 0.82) and VO2max (6.77 ± 1.21%, d = 1.53) showed the greatest relative improvement with moderate to large effect sizes. The hierarchical linear model retained the time (estimate = 18.90, p < 0.001) and the T-drill (estimate = -64.77, p < 0.001) as significant predictors of the ITN. This indicates that the ITN improved significantly over the 6-week training program and that the T-drill test was the best and most significant predictor. Coaches and researchers are encouraged to monitor the ITN along with other physical fitness and technical variables. They can also use the T-drill test to understand the ITN of their players.

The Effects of Repeated-Sprint Training on Physical Fitness and Physiological Adaptation in Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

Repeated-sprint training (RST) is a common training method for enhancing physical fitness in athletes. To advance RST prescription, it is important to understand the effects of programming variables on physical fitness and physiological adaptation.

OBJECTIVES

This study (1) quantifies the pooled effects of running RST on changes in 10 and 20 m sprint time, maximal oxygen consumption (VO2max), Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) distance, repeated-sprint ability (RSA), countermovement jump (CMJ) height and change of direction (COD) ability in athletes, and (2) examines the moderating effects of program duration, training frequency, weekly volume, sprint modality, repetition distance, number of repetitions per set and number of sets per session on changes in these outcome measures.

METHODS

Pubmed, SPORTDiscus and Scopus databases were searched for original research articles up to 04 July 2023, investigating RST in healthy, able-bodied athletes, between 14 and 35 years of age, and a performance calibre of trained or above. RST interventions were limited to repeated, maximal running (land-based) sprints of ≤ 10 s duration, with ≤ 60 s recovery, performed for 2-12 weeks. A Downs and Black checklist was used to assess the methodological quality of the included studies. Eligible data were analysed using multi-level mixed-effects meta-analysis, with standardised mean changes determined for all outcomes. Standardised effects [Hedges G (G)] were evaluated based on coverage of their confidence (compatibility) intervals (CI) using a strength and conditioning specific reference value of G = 0.25 to declare an improvement (i.e. G > 0.25) or impairment (i.e. G < - 0.25) in outcome measures. Applying the same analysis, the effects of programming variables were then evaluated against a reference RST program, consisting of three sets of 6 × 30 m straight-line sprints performed twice per week for 6 weeks (1200 m weekly volume).

RESULTS

40 publications were included in our investigation, with data from 48 RST groups (541 athletes) and 19 active control groups (213 athletes). Across all studies, the effects of RST were compatible with improvements in VO2max (G 0.56, 90% CI 0.32-0.80), YYIR1 distance (G 0.61, 90% CI 0.43-0.79), RSA decrement (G - 0.61, 90% CI - 0.85 to - 0.37), linear sprint times (10 m: G - 0.35, 90% CI - 0.48 to - 0.22; 20 m: G - 0.48, 90% CI - 0.69 to - 0.27), RSA average time (G - 0.34, 90% CI - 0.49 to - 0.18), CMJ height (G 0.26, 90% CI 0.13-0.39) and COD ability (G - 0.32, 90% CI - 0.52 to - 0.12). Compared with the reference RST program, the effects of manipulating training frequency (+ 1 session per week), program duration (+ 1 extra training week), RST volume (+ 200 m per week), number of reps (+ 2 per set), number of sets per session (+ 1 set) or rep distance (+ 10 m per rep) were either non-substantial or comparable with an impairment in at least one outcome measure per programming variable.

CONCLUSIONS

Running-based RST improves speed, intermittent running performance, VO2max, RSA, COD ability and CMJ height in trained athletes. Performing three sets of 6 × 30 m sprints, twice per week for 6 weeks is effective for enhancing physical fitness and physiological adaptation. Additionally, since our findings do not provide conclusive support for the manipulation of RST variables, further work is needed to better understand how programming factors can be manipulated to augment training-induced adaptations.

STUDY REGISTRATION

Open Science Framework registration https://doi.org/10.17605/OSF.IO/RVNDW .

Effects of high-intensity interval training on strength, speed, and endurance performance among racket sports players: A systematic review

This study aims to present a critical review of the existing literature on the effects of High-Intensity Interval Training (HIIT) on strength, speed, and endurance performance among racket sports athletes. This study conducted a systematic literature review by PRISMA guidelines. Various well-known academic and scientific databases were used for research collection, including PubMed, EBSCOhost, Scopus, Web of Science, and Google Scholar. Out of 27 relevant studies, 10 were selected for inclusion in this systematic review, all meeting the required inclusion criteria. The quality of each study was assessed using the PEDro scale, with scores ranging from 3 to 5 for the selected studies. HIIT was found to improve racket players' VO2 max (maximum oxygen uptake), running and repetitive sprint performance, jumping performance, and hitting speed during play. Current findings indicate that HIIT can significantly benefit athletic performance. Long-term HIIT allows athletes to enhance their power while improving crucial variables related to both aerobic and anaerobic endurance. This anaerobic endurance and explosive power type is particularly vital for racket sports players. For example, athletes in table tennis and badminton must exert maximum effort during high-intensity middle and back-court play. Racket athletes also need to maintain a stable state while preserving ball speed and positioning, and must quickly recover to prepare for the next rally. This training mechanism can assist athletes in honing their skills and achieving more efficient hitting quality. Therefore, this paper recommends that racket sports athletes incorporate HIIT into their regular training routines. The suggested frequency is three times per week, with each training session lasting 30-40 minutes, and a total duration of six to eight weeks. Trial registration. Systematic Review Registration: [https://inplasy.com/], identififier[INPLASY20230080].

Effects of physical training programs on female tennis players' performance: a systematic review and meta-analysis

Background: Tennis is among the world's most popular and well-studied sports. Physical training has commonly been used as an intervention among athletes. However, a comprehensive review of the literature on the effects of physical training programs on female tennis players' performance is lacking. Therefore, this systematic review and meta-analysis aimed to determine the effects of physical training on performance outcomes in female tennis players. Methods: A comprehensive search was conducted on Web of Science, PubMed, SPORTDicus, Scopus, and CNKI from inception until July 2023 to select relevant articles from the accessible literature. Only controlled trials were included if they examined the effects of physical training on at least one measure of tennis-specific performance in female tennis players. The Cochrane RoB tool was employed to assess the risk of bias. The CERT scale was used to examine the quality of program information. The GRADE approach was adopted to evaluate the overall quality of the evidence. The Comprehensive Meta-Analysis software was used for the meta-analysis. Results: Nine studies were selected for the systematic review and seven for the meta-analysis, totaling 222 individuals. The study's exercise programs lasted 6-36 weeks, with training sessions ranging from 30 to 80 min, conducted one to five times per week. Muscle power (ES = 0.72; p = 0.003), muscle strength (ES = 0.65; p = 0.002), agility (ES = 0.69; p = 0.002), serve velocity (ES = 0.72; p = 0.013), and serve accuracy (ES = 1.14; p = 0.002) demonstrated significant improvement following physical training, while no notable changes in linear sprint speed (ES = 0.63; p = 0.07) were detected. Conclusion: Although research on physical training in sports is diversified, studies on training interventions among female tennis players are scarce. This review found that existing training programs yield some favorable outcomes for female tennis players. However, further research with high methodological quality is warranted on the tailoring of specific training programs for female tennis players. There should be more consistent measuring and reporting of data to facilitate meaningful data pooling for future meta-analyses.

Linear and Change of Direction Repeated Sprint Ability Tests: A Systematic Review

ABSTRACT

Kyles, A, Oliver, JL, Cahill, MJ, Lloyd, RS, and Pedley, J. Linear and change of direction repeated sprint ability tests: a systematic review. J Strength Cond Res 37(8): 1703-1717, 2023-The ability to repeatedly sprint is important in many sports, but there is no established protocol for measuring repeated sprint ability (RSA). The purpose of this review was to identify overground RSA protocols previously reported in the literature and to recommend standardized protocols. A systematic review of the literature was used to identify studies that have used an RSA test, with data describing protocol design extracted. One hundred eight studies were included in the review, across which 47 unique protocols were identified. Eighteen protocols included at least one change of direction (COD), and this increased mean sprint time compared with linear RSA tests (7.26 ± 1.84 vs. 4.48 ± 1.02 seconds). There was considerable variability across protocols regarding sprint distance (20-40 m), sprint repetitions (3-15), recovery duration (10-60 seconds), recovery type (active vs. passive), and work-to-rest ratio (≤1:1.4-19.2). Separate protocols are needed for linear and COD tests, and these should reflect the brief nature of intense periods of competition and stress the ability to recover. Based on data across studies for protocol design and to ensure a demanding work-to-rest ratio, it is suggested that a linear RSA should comprise 6 × 30 m sprints separated by 15 seconds of active recovery. To provide some parity to linear tests, to keep work duration brief and to maintain a demanding work-to-rest ratio, a COD RSA should comprise 6 × 30 m shuttle sprints (15 + 15 m), providing one change of direction (180° COD), and maintaining a 15-second active recovery.

The Acute Demands of Repeated-Sprint Training on Physiological, Neuromuscular, Perceptual and Performance Outcomes in Team Sport Athletes: A Systematic Review and Meta-analysis

BACKGROUND

Repeated-sprint training (RST) involves maximal-effort, short-duration sprints (≤ 10 s) interspersed with brief recovery periods (≤ 60 s). Knowledge about the acute demands of RST and the influence of programming variables has implications for training prescription.

OBJECTIVES

To investigate the physiological, neuromuscular, perceptual and performance demands of RST, while also examining the moderating effects of programming variables (sprint modality, number of repetitions per set, sprint repetition distance, inter-repetition rest modality and inter-repetition rest duration) on these outcomes.

METHODS

The databases Pubmed, SPORTDiscus, MEDLINE and Scopus were searched for original research articles investigating overground running RST in team sport athletes ≥ 16 years. Eligible data were analysed using multi-level mixed effects meta-analysis, with meta-regression performed on outcomes with ~ 50 samples (10 per moderator) to examine the influence of programming factors. Effects were evaluated based on coverage of their confidence (compatibility) limits (CL) against elected thresholds of practical importance.

RESULTS

From 908 data samples nested within 176 studies eligible for meta-analysis, the pooled effects (± 90% CL) of RST were as follows: average heart rate (HRavg) of 163 ± 9 bpm, peak heart rate (HRpeak) of 182 ± 3 bpm, average oxygen consumption of 42.4 ± 10.1 mL·kg-1·min-1, end-set blood lactate concentration (B[La]) of 10.7 ± 0.6 mmol·L-1, deciMax session ratings of perceived exertion (sRPE) of 6.5 ± 0.5 au, average sprint time (Savg) of 5.57 ± 0.26 s, best sprint time (Sbest) of 5.52 ± 0.27 s and percentage sprint decrement (Sdec) of 5.0 ± 0.3%. When compared with a reference protocol of 6 × 30 m straight-line sprints with 20 s passive inter-repetition rest, shuttle-based sprints were associated with a substantial increase in repetition time (Savg: 1.42 ± 0.11 s, Sbest: 1.55 ± 0.13 s), whereas the effect on sRPE was trivial (0.6 ± 0.9 au). Performing two more repetitions per set had a trivial effect on HRpeak (0.8 ± 1.0 bpm), B[La] (0.3 ± 0.2 mmol·L-1), sRPE (0.2 ± 0.2 au), Savg (0.01 ± 0.03) and Sdec (0.4; ± 0.2%). Sprinting 10 m further per repetition was associated with a substantial increase in B[La] (2.7; ± 0.7 mmol·L-1) and Sdec (1.7 ± 0.4%), whereas the effect on sRPE was trivial (0.7 ± 0.6). Resting for 10 s longer between repetitions was associated with a substantial reduction in B[La] (-1.1 ± 0.5 mmol·L-1), Savg (-0.09 ± 0.06 s) and Sdec (-1.4 ± 0.4%), while the effects on HRpeak (-0.7 ± 1.8 bpm) and sRPE (-0.5 ± 0.5 au) were trivial. All other moderating effects were compatible with both trivial and substantial effects [i.e. equal coverage of the confidence interval (CI) across a trivial and a substantial region in only one direction], or inconclusive (i.e. the CI spanned across substantial and trivial regions in both positive and negative directions).

CONCLUSIONS

The physiological, neuromuscular, perceptual and performance demands of RST are substantial, with some of these outcomes moderated by the manipulation of programming variables. To amplify physiological demands and performance decrement, longer sprint distances (> 30 m) and shorter, inter-repetition rest (≤ 20 s) are recommended. Alternatively, to mitigate fatigue and enhance acute sprint performance, shorter sprint distances (e.g. 15-25 m) with longer, passive inter-repetition rest (≥ 30 s) are recommended.

Training drills in high performance badminton-effects of interval duration on internal and external loads

Purpose: The aim of the present study was to analyze the impact of interval duration on training loads and technical skill performance in high performance badminton drills. Methods: On three experimental days, 19 internationally ranked players (13 male: 22.7 ± 3.8 years, 180 ± 6 cm, 71.5 ± 6.1 kg; 6 females: 20.4 ± 2.5 years, 168 ± 4 cm, 59.8 ± 6.0 kg) completed one of three protocols (T₁₀, T₃₀, and T₅₀) of a typical badminton specific drill, the so-called "Multifeeding" (the coach feeds shuttlecock without break in a random order) in a counterbalanced order. The protocols varied in interval duration (10, 30, and 50 s) but were matched for the rally-to-rest-ratio (1:1) and active playing time (600 s). Cardiorespiratory responses (portable spirometry, chest belt), energy metabolism (levels of blood lactate, La), rate of perceived exertion (RPE), player's kinematics (Local Positioning System), and technical skill performance (video analysis) were measured. Results: Average oxygen consumption (T₁₀ 45 ± 6; T₃₀ 46 ± 7; T₅₀ 44 ± 6 mL min^-1·kg^-1), Energy expenditure (886 ± 209; 919 ± 176; 870 ± 206 kcal h^-1), heart rate (164 ± 13; 165 ± 11; 165 ± 10 bpm) and RPE (16 ± 2; 17 ± 2; 17 ± 2) did not differ between the protocols. Respiratory exchange ratio (RER) and La significantly increased depending on interval duration (RER: 0.90 ± 0.05; 0.93 ± 0.03; 0.96 ± 0.04 and La: 3.6 ± 2.0; 5.6 ± 3.0; 7.3 ± 2.3 mmol l^-1). Stroke frequency (SF; 0.58 ± 0.05; 0.57 ± 0.05; 0.55 ± 0.06 strokes·s^-1) was similar while distance covered, and average running velocity were significantly lower for T₅₀ compared to T₁₀ (76 ± 17; 70 ± 13; 65 ± 11 m min^-1). Moreover, jump frequency in T₃₀ was higher than in T₁₀ (6.7 ± 3.1; 8.8 ± 3.8; 8.5 ± 4.2 jumps·min^-1), whereas differences in internal and external loads were not associated with changes in stroke precision (errors: 16 ± 6; 19 ± 4; 18 ± 4%; accuracy: 22 ± 6; 24 ± 8; 23 ± 8%). Conclusion: Anaerobic metabolic stimulus increases while running distance and velocity decrease, in case of longer interval durations. Even though there was no impact on stroke precision, extending the intervals beyond 30 s might impair external training load and skill performance. Consequently, interval duration should be defined carefully depending on the training goals.

VO2max (VO2peak) in elite athletes under high-intensity interval training: A meta-analysis

Consensus is lacking regarding whether high-intensity interval training (HIIT) effectively improves VO₂max (VO₂peak) in elite athletes (Athlete must be involved in regular competition at the national level). This meta-analysis compared the effects of HIIT and conventional training methods (continuous training, repeated-sprint training, high volume low-intensity training, high-intensity continuous running, sprint-interval training, moderate-intensity continuous training)on VO₂max in elite athletes. Nine studies were included, comprising 176 elite athletes (80 female). Compared to that with conventional training, VO₂max was significantly increased after HIIT (overall: 0.58 [0.30, 0.87], I² = 0.49, P = 0.03; males: 0.41 [0.06, 0.76], I² = 0%, P = 0.89). VO₂max had positive training effects when the HIIT recovery period had an interval time ≥2 min (0.44 [0.03, 0.84], I² = 0%, P = 0.99) and recovery phase intensity ≤40% (0.38 [0.05, 0.71], I² = 0%, P = 0.96). Thus, HIIT shows superiority over conventional training methods in improving VO₂max, promoting aerobic capacity, in elite athletes.

Effects of athletic training on physical fitness and stroke velocity in healthy youth and adult tennis players: A systematic review and meta-analysis

Better physical fitness and stroke velocity in healthy elite compared to sub-elite tennis players have been shown in previous studies. However, evidence-based knowledge regarding the effectiveness of athletic training on physical fitness and stroke velocity is currently lacking. Thus, the objective of this systematic review with meta-analysis was to characterize, aggregate, and quantify athletic training effects on measures of physical fitness and stroke velocity in healthy youth and adult tennis players. A computerized systematic literature search was performed in the databases PubMed, Web of Science, and SportDiscus from their inception date to August 2022. Studies were included, among others, if the intervention period lasted a minimum of four weeks and if at least one parameter of physical fitness (i.e., speed, agility, lower-extremity muscle power, upper-extremity muscle power/strength, endurance, balance, flexibility) or stroke performance (i.e., stroke velocity) was tested. Initially, 11,511 articles were identified, after removing duplicates and assessing abstracts and full texts, 24 articles were used to calculate weighted standardized mean differences (SMD). For measures of physical fitness, athletic training resulted in small (speed: SMD = 0.44), moderate (endurance: SMD = 0.61, upper-extremity muscle power: SMD = 0.72; flexibility: SMD = 0.63), and large (agility: SMD = 0.93, lower-extremity muscle power: SMD = 0.88; upper-extremity muscle strength: SMD = 0.90; balance: SMD = 0.88) effects. Further, a large effect (SMD = 0.90) on stroke velocity was detected. The additionally performed sub-analyses showed differences in the effectiveness of athletic training on variables of physical fitness and stroke speed when considering players' age (i.e., youth players: <18 years; adult players: ≥18 years). Precisely, there was a high potential for training-related adaptations in adult players with respect to lower-extremity muscle power, upper-extremity muscle strength, and stroke velocity and in youth players with respect to endurance. Interventions to promote physical fitness and stroke velocity in healthy tennis players revealed varying levels of effectiveness ranging from small to large and these were additionally affected by players' age. Therefore, future studies should investigate modalities to increase training efficacy in youth and adult tennis players, especially for fitness components that showed small- to moderate-sized changes.

Effects of Functional Phenolics Dietary Supplementation on Athletes' Performance and Recovery: A Review

In recent years, many efforts have been made to identify micronutrients or nutritional strategies capable of preventing, or at least, attenuating, exercise-induced muscle damage and oxidative stress, and improving athlete performance. The reason is that most exercises induce various changes in mitochondria and cellular cytosol that lead to the generation of reactive species and free radicals whose accumulation can be harmful to human health. Among them, supplementation with phenolic compounds seems to be a promising approach since their chemical structure, composed of catechol, pyrogallol, and methoxy groups, gives them remarkable health-promoting properties, such as the ability to suppress inflammatory processes, counteract oxidative damage, boost the immune system, and thus, reduce muscle soreness and accelerate recovery. Phenolic compounds have also already been shown to be effective in improving temporal performance and reducing psychological stress and fatigue. Therefore, the aim of this review is to summarize and discuss the current knowledge on the effects of dietary phenolics on physical performance and recovery in athletes and sports practitioners. Overall, the reports show that phenolics exert important benefits on exercise-induced muscle damage as well as play a biological/physiological role in improving physical performance.

Impact of HIIT Sessions with and without Cognitive Load on Cortical Arousal, Accuracy and Perceived Exertion in Amateur Tennis Players

The aim of the present study was to investigate the effects of high-intensity interval training (HIIT) exercises, with and without cognitive load, on the accuracy, critical flicker fusion threshold (CFFT), and rating of perceived exertion (RPE) on recreational tennis players. A total of 32 players of tennis at recreational level (25 men and 7 women) were enrolled in this cross-sectional the study. Participants had to perform, randomly, two HIIT sessions. In one of them, cognitive load was induced by conducting an incongruent Stroop during rests. After training accuracy of tennis serve, CFFT, and RPE were measured. Results showed that accuracy after baseline and HIIT without cognitive load were significantly higher than after HIIT with cognitive load. RPE significantly increased (p-value < 0.001) after HIIT sessions in both, with and without cognitive load. However, significant differences were not observed between the two sessions in the RPE (p-value = 0.405). Furthermore, differences were not obtained in the CFFT neither within nor between sessions (p-value > 0.05). Therefore, HIIT with and without cognitive load increased the RPE in recreational tennis players. Furthermore, HIIT sessions with cognitive load significant altered tennis serve accuracy.

Effects of short sprint interval training on aerobic and anaerobic indices: A systematic review and meta-analysis

The effects of short sprint interval training (sSIT) with efforts of ≤10 seconds on maximal oxygen consumption (V̇O₂ max), aerobic and anaerobic performances remain unknown. To verify the effectiveness of sSIT in physically active adults and athletes, a systematic literature search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases PubMed/MEDLINE, ISI Web of Science, SPORTDiscus were systematically searched on the 9^th of May 2020 and updated on the 14^th of September 2021. Inclusion criteria were based on PICO and included healthy athletes and active adults of any sex (≤40 years), performing supervised sSIT (≤10 s of "all out" and non "all out" efforts) of at least 2 weeks, with a minimum of 6 sessions. As a comparator, a non-sSIT control group, another high-intensity interval training (HIIT) group, or a continuous training (CT) group were required. A total of 18 studies was deemed eligible. The estimated SMDs based on the random-effects model were -0.56 (95% CI: -0.79, -0.33, p < 0.001) for V̇O₂ max, -0.43 (95% CI: -0.67, -0.20, p < 0.001) for aerobic performance, and -0.44 (95% CI: -0.70, -0.18, p < 0.001) for anaerobic performance after sSIT vs. no exercise/usual training. However, there were no significant differences (p > 0.05) for all outcomes when comparing sSIT vs. HIIT/CT. Our findings indicate a very high effectiveness of sSIT protocols in different exercise modes (e.g. cycling, running, paddling, punching) to improve V̇O₂ max, aerobic and anaerobic performances in physically active young healthy adults and athletes.

Evidence-Based Effects of High-Intensity Interval Training on Exercise Capacity and Health: A Review with Historical Perspective

Engaging in regular exercise results in a range of physiological adaptations offering benefits for exercise capacity and health, independent of age, gender or the presence of chronic diseases. Accumulating evidence shows that lack of time is a major impediment to exercise, causing physical inactivity worldwide. This issue has resulted in momentum for interval training models known to elicit higher enjoyment and induce adaptations similar to or greater than moderate-intensity continuous training, despite a lower total exercise volume. Although there is no universal definition, high-intensity interval exercise is characterized by repeated short bursts of intense activity, performed with a "near maximal" or "all-out" effort corresponding to ≥90% of maximal oxygen uptake or >75% of maximal power, with periods of rest or low-intensity exercise. Research has indicated that high-intensity interval training induces numerous physiological adaptations that improve exercise capacity (maximal oxygen uptake, aerobic endurance, anaerobic capacity etc.) and metabolic health in both clinical and healthy (athletes, active and inactive individuals without any apparent disease or disorder) populations. In this paper, a brief history of high-intensity interval training is presented, based on the novel findings of some selected studies on exercise capacity and health, starting from the early 1920s to date. Further, an overview of the mechanisms underlying the physiological adaptations in response to high-intensity interval training is provided.

On the Use of the Repeated-Sprint Training in Hypoxia in Tennis

PURPOSE

To examine physiological and technical responses to repeated-sprint training in normobaric hypoxia at ∼3,000 m (RSH, n = 11) or in normoxia (RSN, n = 11) compared to a control group (CON, n = 8) in well-trained tennis players. Participants were 28.8 ± 5.9 years old without any previous experience of training in hypoxia.

METHODS

In addition to maintaining their usual training (CON), both RSH and RSN groups completed five tennis specific repeated-shuttle sprint sessions (4 × 5 × ∼8 s maximal sprints with ∼22 s passive recovery and ∼5 min rest between sets) over 12 days. Before (Pre), the week after (Post-1) and 3 weeks after Post-1 (Post-2), physical/technical performance during Test to Exhaustion Specific to Tennis (TEST), repeated-sprint ability (RSA) (8 × ∼20 m shuttle runs-departing every 20 s) and heart rate variability (HRV) were assessed.

RESULTS

From Pre to Post-1 and Post-2, RSH improved TEST time to exhaustion (+18.2 and +17.3%; both P < 0.001), while the "onset of blood lactate accumulation" at 4 mmol L-1 occurred at later stages (+24.4 and +19.8%, both P < 0.01). At the same time points, ball accuracy at 100% V̇O2m ax increased in RSH only (+38.2%, P = 0.003 and +40.9%, P = 0.007). Markers of TEST performance did not change for both RSN and CON. Compared to Pre, RSA total time increased significantly at Post-1 and Post-2 (-1.9 and -2.5%, P < 0.05) in RSH only and this was accompanied by larger absolute Δ total hemoglobin (+82.5 and +137%, both P < 0.001). HRV did not change either supine or standing positions.

CONCLUSION

Five repeated sprint training sessions in hypoxia using tennis specific shuttle runs improve physiological and technical responses to TEST, RSA, and accompanying muscle perfusion responses in well-trained tennis players.

The Impact of a Motor Imagery-Based Training Program on Agility, Speed, and Reaction Time in a Sample of Young Tennis Athletes during Ramadan Fasting: Insights and Implications from a Randomized, Controlled Experimental Trial

The objective of this study was to explore whether a training program incorporating motor imagery could have an effect on physical performance outcomes in terms of agility, speed, and reaction time in a sample of tennis athletes who fasted during the month of Ramadan. Recruited subjects were 27 young male tennis players, randomly allocated to two groups: the imaging training group (n = 13) and a control group (n = 14). The study was designed as a randomized, controlled experimental study. The control group was engaged in watching videos concerning the history of the Olympic Games, whereas the motor imagery group followed a motor imagery-based training program. Physical performance outcomes were assessed during four sessions (one before Ramadan and three during Ramadan) by means of field tests. Our results revealed a drop in all performance outcomes measured in the middle and at the end of Ramadan for both groups (p < 0.01). The effect of the group × time interaction (p < 0.01) was reported for all physical performance outcomes measured for the two groups. This drop in performance was greater for the control group compared to the motor imagery group in the middle and at the end of Ramadan. This study showed that fasting during Ramadan reduced agility, speed, and reaction time performance for tennis players. A motor imagery-based training program could be an effective approach to reduce the effect of fasting during Ramadan and stabilize physical performance outcomes in terms of agility, speed, and reaction time for male tennis players.

Comparison of sprint training and high intensity interval training on oxidative stress and aerobic capacity in male soccer players

The study compared the two popular modes of training: repeated sprint and interval, in terms of oxidative load and aerobic capacity. 20 male collegiate soccer players were assigned into either a repeated sprint training (RST) or high intensity interval training (HIIT) group. Training protocols were for a period of 4 weeks (3 times/week). Serum levels of superoxide dismutase, catalase and glutathione, in addition to maximal oxygen uptake and maximum voluntary isometric contraction for quadriceps and hamstrings were measured before training and within 24 h after the completion of training. Significant improvement (P≤0.05) in antioxidant defence response and leg strength was seen in both groups. However, improvement in aerobic capacity was non-significant in RST as compared to HIIT. These findings indicate that both RST and HIIT can be used as a conditioning exercise to alleviate exercise-induced oxidative stress in the competition phase in addition to improvement in aerobic capacity.

Effects of Resisted Vs. Conventional Sprint Training on Physical Fitness in Young Elite Tennis Players

This study aimed to compare the effects of 6-week resisted sprint (RST) versus conventional (unresisted) sprint training (CG) on sprint time, change of direction (COD) speed, repeated sprint ability (RSA) and jump performance (countermovement jump (CMJ) and standing long jump (SLJ)) in male young tennis players. Twenty players (age: 16.5 ± 0.3 years; body mass: 72.2 ± 5.5 kg; body height: 180.6 ± 4.6 cm) were randomly assigned to one of the two groups: RST (n = 10) and CG (n = 10). The training program was similar for both groups consisting of acceleration and deceleration exercises at short distances (3-4 m), and speed and agility drills. The RST group used weighted vests or elastic cords during the exercises. After 6 weeks of intervention, both training regimes resulted in small-to-moderate improvements in acceleration and sprint ability (5, 10, 20 m), SLJ and CMJ performances, COD pivoting on both, the non-dominant (moderate effect) and the dominant (small effect) foot, and the percentage of decrement (small effects) during a RSA test. Between-group comparisons showed that the SLJ (Δ = 2.0%) and 5 m sprint time (Δ = 1.1%) improved more in the RST group compared with the CG group. This study showed that 6 weeks of RST or unresisted training are time-efficient training regimes for physical improvements in young male tennis players.

Sodium citrate supplementation enhances tennis skill performance: a crossover, placebo-controlled, double blind study

Background

The efficacy of sodium citrate supplementation (SC) in exercise performance is unclear. Therefore, the aim of this study was to investigate the effect of SC on skilled tennis performance.

Methods

Ten Brazilian nationally-ranked young male tennis players (age: 17 ± 1 yrs.; stature: 176.7 ± 5.2 cm; body mass: 68.4 ± 7.9 kg) participated in this crossover, placebo-controlled, double-blind study. Upon arrival, at baseline, in both experimental sessions blood was collected, then subjects ingested either sodium citrate (SC - 0.5 g^.kg⁻¹BM in capsules of 500 mg) or a placebo (PLA). Two hours later, pre-match blood was collected then skills tests (skill tennis performance test - STPT, repeated-sprint ability shuttle test - RSA) were performed followed by a 1-h simulated match. Immediately following the match, blood was again collected, and STPT, and RSA were administered.

Results

All metabolic parameters (i.e. base excess, pH, bicarbonate, and blood lactate) increased (p < 0.001) from baseline to pre-match and post-match in SC condition. Each metabolic parameter was greater (p < 0.001) in SC compared to PLA condition at both pre- and post-match. The SC condition elicited a greater (p < 0.01) shot consistency at post-match in the STPT vs. PLA condition (SC: 58.5 ± 14.8% vs. PLA: 40.4 ± 10.4%). A greater (p < 0.001) amount of games won was observed in the simulated match for SC condition vs. PLA condition (SC: 8.0 ± 1.6 vs. PLA: 6.0 ± 1.7). Additionally, the games won during the simulated match in SC condition was positively correlated with percentage shot consistency (r = 0.67, p < 0.001).

Conclusions

The current findings suggest that SC supplementation is an effective ergogenic aid to enhance skilled tennis performance.

Effects of different repeated sprint-training frequencies in youth soccer players

The aim of this study was to determine the effects of 2 different repeated-sprint ability (RSA) training frequencies (2 RSA sessions per week [RSA2D] or 1 RSA session [RSA1D]) under volume-equated conditions on sprint and RSA performance in under-15 (U15) soccer players. Twenty-seven youth male soccer players (age: 12.29±0.47 years; height: 158.35±10.86 cm; weight: 45.08±8.05 kg) were randomly assigned to RSA2D (n=14) or RSA1D (n=13) groups. The players performed the same RSA training for 6 weeks, and only the training frequency differed between the groups. Before and after the training period, 5 m sprint, 10 m sprint, 20 m sprint and the RSA test were assessed. No significant time × group interactions were observed (p>0.05). Within-group analysis showed significant improvements in 20 m sprint (p=0.046, partial eta squared [η _p ² ] = 0.150, large) and RSA average time (p=0.001, η _p ² =0.438, large), fastest time (p=0.012, η _p ² =0.229, large), and total time (p=0.001, η _p ² =0.438, large) from pre-test to post-test in RSA1D and RSA2D groups. However, no significant pre-post changes (p>0.05) were found in 5 m and 10 m sprint tests. In the between-group analysis, there were no significant differences between RSA1D and RSA2D groups in any variable. In conclusion, the current findings suggest that 6 weeks of RSA training 1 or 2 times per week in addition to typical soccer training produced significant and similar improvements in sprint and RSA performances. This information could be useful for coaches when planning training sessions during congested fixtures of soccer competitions or in periods when the emphasis should be placed on other physical qualities.

Effects of High-Intensity Interval Training vs. On-Court Tennis Training in Young Tennis Players

Kilit, B and Arslan, E. Effects of high-intensity interval training vs. on-court tennis training in young tennis players. J Strength Cond Res 33(1): 188-196, 2019-This study aimed to examine the effects of 6 weeks of high-intensity interval training (HIIT) vs. 6 weeks of on-court tennis training (OTT) on the psychophysiological responses, performance responses, and technical scores of young tennis players. Twenty-nine young male tennis players (aged 13.8 ± 0.4 years) were divided into HIIT (n = 14) and OTT groups (n = 15). Both groups trained for the same total training duration with passive rest in each session. Pre-test and post-test included maximum oxygen consumption ((Equation is included in full-text article.)max), sprinting, jumping, 400-m running time, a tennis-specific technical test, and the t-drill agility test. The training interventions resulted in similar improvements in (Equation is included in full-text article.)max responses (HIIT: +5.2%, d = 1.36 [large effect]; OTT: +5.5%, d = 1.50 [large effect]). Both training protocols increased jumping and sprinting performances significantly from pre-testing to post-testing (p < 0.05, d values ranging from 0.40 to 1.10). The OTT group showed significantly higher performance responses in terms of the agility test performance and technical scores (p < 0.05, d = ranging from 0.77 to 0.88 [moderate effect]) compared with the HIIT group. By contrast, the HIIT group exhibited significantly higher performance responses in terms of the 400-m running time (p < 0.05, d = 1.32 [large effect]). Our results showed that tennis-specific on-court drills might be a more effective training strategy to improve agility and technical ability with greater physical enjoyment, whereas HIIT may be more appropriate for speed-based conditioning in young tennis players.

Effects of Repeated-Sprint Training in Hypoxia on Tennis-Specific Performance in Well-Trained Players

This study examined the physiological, physical and technical responses to repeated-sprint training in normobaric hypoxia [RSH, inspired fraction of oxygen (FiO ₂ ) 14.5%] vs. normoxia (RSN, FiO ₂ 20.9%). Within 12 days, eighteen well-trained tennis players (RSH, n=9 vs. RSN, n=9) completed five specific repeated-sprint sessions that consisted of four sets of 5 maximal shuttle-run sprints. Testing sessions included repeated-sprint ability and Test to Exhaustion Specific to Tennis (TEST). TEST’s maximal duration to exhaustion and time to attain the ‘onset of blood lactate accumulation’ at 4 mMol.L ⁻¹ (OBLA) improvements were significantly higher in RSH compared to RSN. Change in time to attain OBLA was concomitant with observations similar in time to the second ventilatory threshold. Significant interaction (P=0.003) was found for ball accuracy with greater increase in RSH (+13.8%, P=0.013) vs. RSN (–4.6%, P=0.15). A correlation (r=0.59, P<0.001) was observed between change in ball accuracy and TEST’s time to exhaustion. Greater improvement in some tennis-specific physical and technical parameters was observed after only 5 sessions of RSH vs. RSN in well-trained tennis players.

Active Recovery After High-Intensity Interval-Training Does Not Attenuate Training Adaptation

Objective: High-intensity interval training (HIIT) can be extremely demanding and can consequently produce high blood lactate levels. Previous studies have shown that lactate is a potent metabolic stimulus, which is important for adaptation. Active recovery (ACT) after intensive exercise, however, enhances blood lactate removal in comparison with passive recovery (PAS) and, consequently, may attenuate endurance performance improvements. Therefore, the aim of this study was to examine the influence of regular ACT on training adaptations during a HIIT mesocycle.

Methods: Twenty-six well-trained male intermittent sport athletes (age: 23.5 ± 2.5 years; O₂max: 55.36 ± 3.69 ml min kg^-1) participated in a randomized controlled trial consisting of 4 weeks of a running-based HIIT mesocycle with a total of 12 HIIT sessions. After each training session, participants completed 15 min of either moderate jogging (ACT) or PAS. Subjects were matched to the ACT or PAS groups according to age and performance. Before the HIIT program and 1 week after the last training session, the athletes performed a progressive incremental exercise test on a motor-driven treadmill to determine O₂max, maximum running velocity (vmax), the running velocity at which O₂max occurs (vO₂max), and anaerobic lactate threshold (AT). Furthermore, repeated sprint ability (RSA) were determined.

Results: In the whole group the HIIT mesocycle induced significant or small to moderate changes in vmax (p < 0.001, effect size [ES] = 0.65,), vO₂max (p < 0.001, ES = 0.62), and AT (p < 0.001, ES = 0.56) compared with the values before the intervention. O₂max and RSA remained unchanged throughout the study. In addition, no significant differences in the changes were noted in any of the parameters between ACT and PAS except for AT (p < 0.05, ES = 0.57).

Conclusion: Regular use of individualized ACT did not attenuate training adaptations during a HIIT mesocycle compared to PAS. Interestingly, we found that the ACT group obtained a significantly higher AT following the training program compared to the PAS group. This could be because ACT allows a continuation of the training at a low intensity and may activate specific adaptive mechanisms that are not triggered during PAS.

High-Intensity Small-Sided Games versus Repeated Sprint Training in Junior Soccer Players

The aim of this study was to compare the effects of high-intensity small-sided games training (SSGT) versus repeated-sprint training (RST) on repeated-sprint ability (RSA), soccer specific endurance performance and short passing ability among junior soccer players. The junior soccer players were recruited from of a professional team (age 16.9 ± 1.1 years). The tests included the repeated-shuttle-sprint ability test (RSSAT), Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) and Loughborough Soccer Passing Test (LSPT). Nineteen participants were randomly assigned to either the small-sided games training (SSGTG) (n = 10) or repeated-sprint training group (RSTG) (n = 9). Small-sided games or repeated-sprint training were added to the regular training sessions for two days of the regular practice week. The Wilcoxon signed-rank and Mann-Whitney U tests were used to examine differences in groups and training effects. A time x training group effect was found in the improvement of short-passing ability for the smallsided games training group which showed significantly better scores than the repeated-sprint training group (p ≤ 0.05). Both groups showed similar improvements in RSAdecrement (p < 0.05). Only the repeated-sprint training group improved in the Yo-Yo IR1 (p < 0.05). This study clearly shows that high-intensity small-sided games training can be used as an effective training mode to enhance both repeated sprint ability and short-passing ability.

Evaluating Injury Risk and Gender Performance on Health- and Skill-Related Fitness Assessments

Grier, TL, Canham-Chervak, M, Bushman, TT, Anderson, MK, North, WJ, and Jones, BH. Evaluating injury risk and gender performance on health- and skill-related fitness assessments. J Strength Cond Res 31(4): 971-980, 2017-The purpose of this analysis was to investigate the association of injury risk and gender performance on health- and skill-related fitness assessments. A survey was used to collect personal characteristics and Army Physical Fitness Test scores (2-mile run, push-ups, and sit-ups). Within the same day, 9 physical fitness assessments were performed. Percent body fat was estimated using height, weight, age, and sex. All fitness assessment data were categorized into tertiles of high, moderate and low performance. To investigate potential injury risk predicted by fitness assessment performance, injury risk ratios, odds ratios (ORs), and 95% confidence intervals (CIs) were calculated using medical record data. A total of 3,264 soldiers completed surveys and physical fitness assessments. Tertiles of fitness performance with men and women combined showed that on an average, 14% of women and 70% of men were in the moderate- and high-performance groups. Among men, higher injury risk was independently associated with low performance on a 2-mile run (ORslow/fast = 1.51, 95% CI 1.18-1.94) and low performance on a weighted 300-yard shuttle run (ORslow/fast = 1.36, 95% CI 1.06-1.74). For women, a higher risk of injury was associated with low performance on the 2-mile run (ORslow/fast = 2.38, 95% CI 1.04-5.74). Therefore, out of the 13 fitness assessments, the 2-mile run and weighted 300-yard shuttle run can also (in addition to measuring performance) be utilized to identify soldiers or athletes who are at a higher risk of experiencing an injury.

The effects of 20-m repeated sprint training on aerobic capacity in college volleyball players

Study aim: The purpose of this study was to examine the effects of a repeated sprint training program in addition to volleyball training on the aerobic capacity of college volleyball players.

Materials and methods: Eighteen male volleyball players were randomly assigned to either an experimental group (n = 9, age: 21.2 ± 1.3 years) or a control (n = 9, age: 21.2 ± 1.6 years) group. Both groups followed a traditional volleyball training program three times per week for 6 weeks. The experimental group additionally performed a repeated sprint training protocol immediately before each volleyball training session. The repeated sprint training consisted of 1-3 sets of 5 × 20 m maximal sprints with 20 seconds of active recovery between sprints and 4 min of passive recovery between sets. Before and after the 6-week training period, all participants performed an incremental treadmill test to determine maximal oxygen uptake (VO2max) and time to exhaustion, and the repeated sprint test (10 × 20 m with a 20‑second recovery between each sprint).

Results: The experimental group showed significant improvements in VO2max (+7.1 ± 4.8%; p = 0.001) and running time to exhaustion (+15.8 ± 6.8%; p = 0.004) after training. The best 20-m sprint time (−2.3 ± 2.5%; p = 0.029), mean sprint time (−5.3 ± 3.1%; p = 0.001) and fatigue index (−34.1 ± 28.2%; p = 0.012) also improved significantly in the experimental group. None of these variables changed significantly in the control group (p > 0.05).

Conclusions: The current findings indicate that the addition of a repeated sprint training program can improve both the aerobic capacity and anaerobic performance of college volleyball players.

Short- or long-rest intervals during repeated-sprint training in soccer?

The present study compared the effects of two repeated-sprint training (RST) programs, differing in duration of the between-sprint rest intervals, on various soccer-related exercise performances. For 5 weeks during the competitive season, twenty-nine young trained male soccer players either replaced two of their habitual fitness conditioning sessions with RST characterized by short (5–15; n = 9) or long (5–30; n = 10) rest intervals, or served as control (n = 10). The 5–15 and 5–30 protocols consisted of 6 repetitions of 30-m (~5 s) straight-line sprints interspersed with 15 s or 30 s of passive recovery, respectively. 5–15 improved 200-m sprint time (2.0±1.5%; p<0.05) and had a likely positive impact on 20-m sprint performance, whereas 5–30 lowered the 20-m sprint time (2.7±1.6%; p<0.05) but was only possibly effective for enhancing the 200-m sprint performance. The distance covered during the Yo-Yo Intermittent Recovery Test Level 2 increased following 5–15 (11.4±5.0%; p<0.05), which was possibly better than the non-significant 6.5% enhancement observed in 5–30. Improvements in the total time of a repeated-sprint ability test were possibly greater following 5–30 (3.6±0.9%; p<0.05) compared to 5–15 (2.6±1.1%; p<0.05). Both RST interventions led to similar beneficial (p<0.05) reductions in the percentage decrement score (~30%) of the repeated-sprint ability test as well as in blood lactate concentration during submaximal exercise (17–18%). No changes occurred in the control group. In soccer players, RST over a 5-week in-season period is an efficient means to simultaneously develop different components of fitness relevant to match performance, with different benefits induced by shorter compared to longer rest intervals.

Specific physical trainability in elite young soccer players: efficiency over 6 weeks' in-season training

The aim of the present study was to compare the effects of 3 training protocols (plyometric [PLYO], agility [AG], or repeated shuttle sprints [RS]) on physical performance in the same population of young soccer players. Forty-two youth-level male players (13.6±0.3-years; 1.65±0.07 m; 54.1±6.5 kg; body fat: 12.8±2.6%) participated in a short-term (6-week) randomized parallel fully controlled training study (pre-to-post measurements): PLYO group, n=10; AG group, n=10; RS group, n=12; and control group [CON] n=10. PLYO training = 9 lower limb exercises (2-3 sets of 8-12 repetitions). The AG group performed planned AG drills and direction changes. RS training consisted of 2-4 sets of 5-6x 20 to 30 m shuttle sprints (20 seconds recovery in between). Progressive overload principles were incorporated into the programme by increasing the number of foot contacts and varying the complexity of the exercises. Pre/post-training tests were: bilateral standing horizontal jump, and unilateral horizontal jumps, sprint (30 m with 10 m lap time), agility (20 m zigzag), and repeated sprint ability (RSA) (i.e. 6x30 m shuttle sprints: 2x15 m with 180° turns). Significant main effects for time (i.e. training application) and group (training type) were detected. Improvements in horizontal jumping were higher (p<0.01: ES=large) in PLYO. The RS group improved significantly more (p<0.01; ES=large) than other groups: 30 m sprint, RSA_best and RSA_mean performances. Significantly greater increases in 20 m zigzag performance were observed following AG and RS training (4.0 and 3.8%, respectively) compared with PLYO (2.0%) and CON training (0.8%). No significant differences were reported in the RSA_dec between groups. Elite young male soccer players’ physical performances can be significantly and specifically improved either using PLYO or AG or RSA training over short-term in-season training.

Physiological responses and match characteristics in professional tennis players during a one-hour simulated tennis match

The purpose of this study was to investigate the effects of serve and return game situations on physiological responses and match characteristics in professional male tennis players during one hour-long simulated singles tennis matches. Ten internationally ranked tennis players (age 22.2 ± 2.8 years; body height 180.7 ± 4.4 cm; body mass 75.9 ± 8.9 kg) participated in this study. Their physiological responses were measured using two portable analyzers during indoor hard court matches. Ratings of perceived exertion were also determined at the end of the game. The variables describing the characteristics of the matches determined from video recordings were: (a) duration of rallies; (b) rest time; (c) work-to-rest ratio; (d) effective playing time; and (d) strokes per rally. Significant differences (p<0.05) were found between serving and returning conditions in an hour-long simulated singles tennis match in terms of oxygen uptake, a heart rate, ratings of perceived exertion, pulmonary ventilation, respiration frequency and a respiratory gas exchange ratio. In addition, both the heart rate and ratings of perceived exertion responses were moderately correlated with the duration of rallies and strokes per rally (r = 0.60 to 0.26; p<0.05). Taken together, these results indicate that the serve game situation has a significant effect on the physiological response in an hour-long simulated tennis match between professional male tennis players. These findings might be used for the physiological adaptations required for tennis-specific aerobic endurance.

On the Use of a Test to Exhaustion Specific to Tennis (TEST) with Ball Hitting by Elite Players

Purpose

We aimed to a) introduce a new Test to Exhaustion Specific to Tennis (TEST) and compare performance (test duration) and physiological responses to those obtained during the 20-m multistage shuttle test (MSST), and b) determine to which extent those variables correlate with performance level (tennis competitive ranking) for both test procedures.

Methods

Twenty-seven junior players (8 males, 19 females) members of the national teams of the French Tennis Federation completed MSST and TEST, including elements of the game (ball hitting, intermittent activity, lateral displacement), in a randomized order. Cardiorespiratory responses were compared at submaximal (respiratory compensation point) and maximal loads between the two tests.

Results

At the respiratory compensation point oxygen uptake (50.1 ± 4.7 vs. 47.5 ± 4.3 mL.min^-1.kg^-1, p = 0.02), but not minute ventilation and heart rate, was higher for TEST compared to MSST. However, load increment and physiological responses at exhaustion did not differ between the two tests. Players’ ranking correlated negatively with oxygen uptake measured at submaximal and maximal loads for both TEST (r = -0.41; p = 0.01 and -0.55; p = 0.004) and MSST (r = -0.38; P = 0.05 and -0.51; p = 0.1).

Conclusion

Using TEST provides a tennis-specific assessment of aerobic fitness and may be used to prescribe aerobic exercise in a context more appropriate to the game than MSST. Results also indicate that VO₂ values both at submaximal and maximal load reached during TEST and MSST are moderate predictors of players competitive ranking.

The effects of repeated-sprint training on field-based fitness measures: a meta-analysis of controlled and non-controlled trials

BACKGROUND

Repeated-sprint training appears to be an efficient and practical means for the simultaneous development of different components of fitness relevant to team sports.

OBJECTIVE

Our objective was to systematically review the literature and meta-analyse the effect of repeated-sprint training on a selection of field-based measures of athletic performance, i.e. counter-movement jump, 10 m sprint, 20 m sprint, 30 m sprint, repeated-sprint ability and high-intensity intermittent running performance.

DATA SOURCES

The SPORTDiscus, PubMed, MEDLINE and Web of Science databases were searched for original research articles. Search terms included 'repeated-sprint training', 'sprint training', 'aerobic endurance', 'repeated-sprint ability', 'counter-movement jump' and 'sprint performance'.

STUDY SELECTION

Inclusion criteria included intervention consisting of a series of ≤10 s sprints with ≤60 s recovery; trained participants; intervention duration of 2-12 weeks; field-based fitness measures; running- or cycling-based intervention; published up to, and including, February 2014.

DATA EXTRACTION

Our final dataset included six trials for counter-movement jump (two controlled trials), eight trials for 10 m sprint, four trials for 20 m sprint (three controlled trials), two trials for 30 m sprint, eight trials for repeated-sprint ability and three trials for high-intensity intermittent running performance. Analyses were conducted using comprehensive meta-analysis software. Uncertainty in the meta-analysed effect of repeated-sprint training was expressed as 95% confidence limits (CL), along with the probability that the true value of the effect was trivial, beneficial or harmful. Magnitude-based inferences were based on standardised thresholds for small, moderate and large changes of 0.2, 0.6 and 1.2 standard deviations, respectively.

RESULTS

Repeated-sprint training had a likely small beneficial effect in non-controlled counter-movement jump trials (effect size 0.33; 95% CL ±0.30), with a possibly moderate beneficial effect in controlled trials (0.63; 95% CL ±0.44). There was a very likely small beneficial effect on 10 m sprint time in non-controlled trials (-0.42; 95% CL ±0.24), with a possibly moderate beneficial effect on 20 m sprint time in non-controlled (-0.49; 95% CL ±0.46) and controlled (-0.65; 95% CL ±0.61) trials. Repeated-sprint training had a possibly large beneficial effect on 30 m sprint performance in non-controlled trials (-1.01; 95% CL ±0.93), with possibly moderate beneficial effects on repeated-sprint ability (-0.62; 95% CL ±0.25) and high-intensity intermittent running performance (-0.61; 95% CL ±0.54).

CONCLUSIONS

Repeated-sprint training can induce small to large improvements in power, speed, repeated-sprint ability and endurance, and may have relevance for training in team sports.

Five Weeks of Sprint and High-Intensity Interval Training Improves Paddling Performance in Adolescent Surfers

Farley, ORL, Secomb, JL, Parsonage, JR, Lundgren, LE, Abbiss, CR, and Sheppard, JM. Five weeks of sprint and high-intensity interval training improves paddling performance in adolescent surfers. J Strength Cond Res 30(9): 2446-2452, 2016-The purpose of our study was to examine the effects of sprint interval training (SIT; 10 seconds) and high-intensity interval training (HIT; 30 seconds) on surfing athletes paddling performance (400-m time trial and repeat-sprint paddle performance). Twenty-four competitive adolescent surfers (19 male, 5 female; age = 14.4 ± 1.3 years, mass: 50.1 ± 10.7 kg, and stature: 159.9 ± 10.3 cm) were assigned to perform either 5 weeks of SIT and HIT. Participants completed a repeated-sprint paddle ability test (RSPT, 15-m surfboard sprint paddle initiated every 40 seconds × 10 bouts) and 400-m endurance surfboard paddle time trial before and after training. High-intensity interval training decreased the total time to complete the 400 m by 15.8 ± 16.1 seconds (p = 0.03), and SIT decreased the total time to complete the RSPT by 6.5 ± 4.3 seconds (p = 0.02). Fatigue index during the RSPT (first-slowest effort) was lower after HIT and SIT (p ≤ 0.001 and p = 0.02, respectively). There were no significant differences in performance changes in the 400 m (total time) and RSPT (total time, fastest 15 m time, and peak velocity) between HIT and SIT. Our study indicates that HIT and SIT may be implemented to the training program of surfers to improve aerobic and repeat-sprint paddle ability, both of which are identified as key aspects of the sport. In addition, these findings indicate that 400-m paddle and RSPT can discriminate between aerobic and anaerobic training adaptations, with aerobic gains likely from HIT and anaerobic gains from SIT.

Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players

The aim of this study was to investigate the effects of implementing motor imagery (MI) during specific tennis high intensity intermittent training (HIIT) sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included verbal encouragements for physical efforts and served as control condition. Results revealed that similar cardiac demand was observed during both sessions, while implementing MI maintained groundstroke accuracy. Embedding MI during HIIT enabled the development of physical fitness and the preservation of stroke performance. These findings bring new insight to tennis and conditioning coaches in order to fulfil the benefits of specific playing HIIT sessions, and therefore to optimise the training time.

Physiological Responses of Young Tennis Players to Training Drills and Simulated Match Play

The aim of this study was to investigate the responses of young tennis players during 5 different training drills and to compare the responses between drills. Ten (17.0 ± 1.2 years) male tennis players participated in this study. Each athlete completed 5 total training drills. Drills 1-4 consisted of each player returning balls from a ball-serving machine and were stroke/time-controlled over 6 points. The fifth drill was a simulated match (SM) play, between 2 opposing players, and also lasted 6 points. The 4 stroke/time-controlled drills had the following strokes/time for each point: drill 1: 2 strokes/∼4 seconds, drill 2: 4 strokes/∼8 seconds, drill 3: 7 strokes/∼14 seconds, drill 4: 10 strokes/∼20 seconds. Peak heart rate (HR), blood lactate concentration (LA), and rating of perceived exertion (RPE) were measured after the first, third, and sixth point of each drill. Drills were performed in a randomized crossover design; a 2-way repeated-measures analysis of variance was used with significance set at p ≤ 0.05. All dependent variables (HR, LA, and RPE) significantly increased (p ≤ 0.05) as strokes, and time per rally increased in each drill. Furthermore, all variables were elevated to a greater magnitude (p ≤ 0.05) during the 7 and 10 stroke drills after the first, third, and sixth points when compared with the SM and the 2 and 4 stroke drills at the corresponding time points. These results suggest that the physiological responses to tennis training drills were stroke/time-dependent. Therefore, because of the intense intermittent nature of tennis, stroke/time-controlled drills, which require significant physiological demands, should be incorporated along with technically focused shorter drills to fully mimic the conditions of competitive match play.

Tennis Play Intensity Distribution and Relation with Aerobic Fitness in Competitive Players

The aims of this study were (i) to describe the relative intensity of simulated tennis play based on the cumulative time spent in three metabolic intensity zones, and (ii) to determine the relationships between this play intensity distribution and the aerobic fitness of a group of competitive players. 20 male players of advanced to elite level (ITN) performed an incremental on-court specific endurance tennis test to exhaustion to determine maximal oxygen uptake (VO2max) and the first and second ventilatory thresholds (VT1, VT2). Ventilatory and gas exchange parameters were monitored using a telemetric portable gas analyser (K4 b2, Cosmed, Rome, Italy). Two weeks later the participants played a simulated tennis set against an opponent of similar level. Intensity zones (1: low, 2: moderate, and 3: high) were delimited by the individual VO2 values corresponding to VT1 and VT2, and expressed as percentage of maximum VO2 and heart rate. When expressed relative to VO2max, percentage of playing time in zone 1 (77 ± 25%) was significantly higher (p < 0.001) than in zone 2 (20 ± 21%) and zone 3 (3 ± 5%). Moderate to high positive correlations were found between VT1, VT2 and VO2max, and the percentage of playing time spent in zone 1 (r = 0.68-0.75), as well as low to high inverse correlations between the metabolic variables and the percentage of time spent in zone 2 and 3 (r = -0.49-0.75). Players with better aerobic fitness play at relatively lower intensities. We conclude that players spent more than 75% of the time in their low-intensity zone, with less than 25% of the time spent at moderate to high intensities. Aerobic fitness appears to determine the metabolic intensity that players can sustain throughout the game.

Playing vs. nonplaying aerobic training in tennis: physiological and performance outcomes

This study compared the effects of playing and nonplaying high intensity intermittent training (HIIT) on physiological demands and tennis stroke performance in young tennis players. Eleven competitive male players (13.4 ± 1.3 years) completed both a playing and nonplaying HIIT session of equal distance, in random order. During each HIIT session, heart rate (HR), blood lactate, and ratings of perceived exertion (RPE) were monitored. Before and after each HIIT session, the velocity and accuracy of the serve, and forehand and backhand strokes were evaluated. The results demonstrated that both HIIT sessions achieved an average HR greater than 90% HRmax. The physiological demands (average HR) were greater during the playing session compared to the nonplaying session, despite similar lactate concentrations and a lower RPE. The results also indicate a reduction in shot velocity after both HIIT sessions; however, the playing HIIT session had a more deleterious effect on stroke accuracy. These findings suggest that 1) both HIIT sessions may be sufficient to develop maximal aerobic power, 2) playing HIIT sessions provide a greater physiological demand with a lower RPE, and 3) playing HIIT has a greater deleterious effect on stroke performance, and in particular on the accuracy component of the ground stroke performance, and should be incorporated appropriately into a periodization program in young male tennis players.

Effects of Glycolytic-Based Interval Training on Anaerobic Capacity in Soccer Players

Purpose. The aim of this study was to determine the magnitude of changes in anaerobic endurance in response to a training protocol targeting glycolytic capacity. Methods. The study involved 24 soccer players from two U-18 teams. One team served as an experimental (E) group the other a control (C). Besides standard soccer practice performed by both groups, an interval training protocol was administered to the experimental group twice a week (15 sessions). One training repetition involved running a soccerspecific course. Repetition time was equal to 15 s interspersed with 45 s passive recovery. Total number of repetitions was determined by the ability to maintain target time (power) in subsequent repetitions. A 5% reduction in the distance covered (m) compared with the first repetition ended a set. The number of sets was based on the ability of player to maintain target time per repetition. Rest interval between sets was 15 min. Anaerobic performance was assessed before and after the 8-week protocol by the Wingate test in which arterial blood gases, blood lactate concentration, and respiratory variables on a breath-by-breath basis were measured. Results. Distance covered in group E in the first training session was 470.38 ± 77.82 m and 1182.31 ± 164.44 m in the last session. Post-intervention total work (273.63 ± 18.32 to 284.98 ± 15.76 J/kg) and maximum power (13.28 ± 1.43 to 14.14 ± 1.25 W/kg) significantly increased in the Wingate test. Statistically significant increases in lactate concentration (10.64 ± 1.54 and 12.72 ± 1.59 mmol/l) and lower blood pH (7.21 ± 0.03 and 7.19 ± 0.02) were also observed. No significant changes in any of the above variables were observed in group C. Conclusions. Interval training develops glycolytic capacity but with large inter-individual variability.